tor/ReleaseNotes

This document summarizes new features and bugfixes in each stable release
of Tor. If you want to see more detailed descriptions of the changes in
each development snapshot, see the ChangeLog file.

Changes in version 0.2.4.29 - 2017-06-08
  Tor 0.2.4.29 backports a fix for a bug that would allow an attacker to
  remotely crash a hidden service with an assertion failure. Anyone
  running a hidden service should upgrade to this version, or to some
  other version with fixes for TROVE-2017-005.  (Versions before 0.3.0
  are not affected by TROVE-2017-004.)

  o Major bugfixes (hidden service, relay, security):
    - Fix a remotely triggerable assertion failure caused by receiving a
      BEGIN_DIR cell on a hidden service rendezvous circuit. Fixes bug
      22494, tracked as TROVE-2017-005 and CVE-2017-0376; bugfix
      on 0.2.2.1-alpha.

  o Minor features (geoip):
    - Update geoip and geoip6 to the May 2 2017 Maxmind GeoLite2
      Country database.

  o Minor bugfixes (correctness):
    - Avoid undefined behavior when parsing IPv6 entries from the geoip6
      file. Fixes bug 22490; bugfix on 0.2.4.6-alpha.


Changes in version 0.2.4.28 - 2017-03-03
  Tor 0.2.4.28 backports a number of security fixes from later Tor
  releases.  Anybody running Tor 0.2.4.27 or earlier should upgrade to
  this release, if for some reason they cannot upgrade to a later
  release series.

  Note that support for Tor 0.2.4.x is ending soon: we will not issue
  any fixes for the Tor 0.2.4.x series after 1 August 2017.  If you need
  a Tor release series with long-term support, we recommend Tor 0.2.9.x.

  o Directory authority changes (backport from 0.2.8.5-rc):
    - Urras is no longer a directory authority. Closes ticket 19271.

  o Directory authority changes (backport from 0.2.9.2-alpha):
    - The "Tonga" bridge authority has been retired; the new bridge
      authority is "Bifroest". Closes tickets 19728 and 19690.

  o Directory authority key updates (backport from 0.2.8.1-alpha):
    - Update the V3 identity key for the dannenberg directory authority:
      it was changed on 18 November 2015. Closes task 17906. Patch
      by "teor".

  o Major features (security fixes, backport from 0.2.9.4-alpha):
    - Prevent a class of security bugs caused by treating the contents
      of a buffer chunk as if they were a NUL-terminated string. At
      least one such bug seems to be present in all currently used
      versions of Tor, and would allow an attacker to remotely crash
      most Tor instances, especially those compiled with extra compiler
      hardening. With this defense in place, such bugs can't crash Tor,
      though we should still fix them as they occur. Closes ticket
      20384 (TROVE-2016-10-001).

  o Major bugfixes (parsing, security, backport from 0.2.9.8):
    - Fix a bug in parsing that could cause clients to read a single
      byte past the end of an allocated region. This bug could be used
      to cause hardened clients (built with --enable-expensive-hardening)
      to crash if they tried to visit a hostile hidden service. Non-
      hardened clients are only affected depending on the details of
      their platform's memory allocator. Fixes bug 21018; bugfix on
      0.2.0.8-alpha. Found by using libFuzzer. Also tracked as TROVE-
      2016-12-002 and as CVE-2016-1254.

  o Major bugfixes (security, correctness, backport from 0.2.7.4-rc):
    - Fix an error that could cause us to read 4 bytes before the
      beginning of an openssl string. This bug could be used to cause
      Tor to crash on systems with unusual malloc implementations, or
      systems with unusual hardening installed. Fixes bug 17404; bugfix
      on 0.2.3.6-alpha.

  o Major bugfixes (security, pointers, backport from 0.2.8.2-alpha):
    - Avoid a difficult-to-trigger heap corruption attack when extending
      a smartlist to contain over 16GB of pointers. Fixes bug 18162;
      bugfix on 0.1.1.11-alpha, which fixed a related bug incompletely.
      Reported by Guido Vranken.

  o Major bugfixes (dns proxy mode, crash, backport from 0.2.8.2-alpha):
    - Avoid crashing when running as a DNS proxy. Fixes bug 16248;
      bugfix on 0.2.0.1-alpha. Patch from "cypherpunks".

  o Major bugfixes (guard selection, backport from 0.2.7.6):
    - Actually look at the Guard flag when selecting a new directory
      guard. When we implemented the directory guard design, we
      accidentally started treating all relays as if they have the Guard
      flag during guard selection, leading to weaker anonymity and worse
      performance. Fixes bug 17772; bugfix on 0.2.4.8-alpha. Discovered
      by Mohsen Imani.

  o Major bugfixes (key management, backport from 0.2.8.3-alpha):
    - If OpenSSL fails to generate an RSA key, do not retain a dangling
      pointer to the previous (uninitialized) key value. The impact here
      should be limited to a difficult-to-trigger crash, if OpenSSL is
      running an engine that makes key generation failures possible, or
      if OpenSSL runs out of memory. Fixes bug 19152; bugfix on
      0.2.1.10-alpha. Found by Yuan Jochen Kang, Suman Jana, and
      Baishakhi Ray.

  o Major bugfixes (parsing, backported from 0.3.0.4-rc):
    - Fix an integer underflow bug when comparing malformed Tor
      versions. This bug could crash Tor when built with
      --enable-expensive-hardening, or on Tor 0.2.9.1-alpha through Tor
      0.2.9.8, which were built with -ftrapv by default. In other cases
      it was harmless. Part of TROVE-2017-001. Fixes bug 21278; bugfix
      on 0.0.8pre1. Found by OSS-Fuzz.

  o Minor features (security, memory erasure, backport from 0.2.8.1-alpha):
    - Make memwipe() do nothing when passed a NULL pointer or buffer of
      zero size. Check size argument to memwipe() for underflow. Fixes
      bug 18089; bugfix on 0.2.3.25 and 0.2.4.6-alpha. Reported by "gk",
      patch by "teor".

  o Minor features (bug-resistance, backport from 0.2.8.2-alpha):
    - Make Tor survive errors involving connections without a
      corresponding event object. Previously we'd fail with an
      assertion; now we produce a log message. Related to bug 16248.

  o Minor features (DoS-resistance, backport from 0.2.7.1-alpha):
    - Make it harder for attackers to overload hidden services with
      introductions, by blocking multiple introduction requests on the
      same circuit. Resolves ticket 15515.

  o Minor features (geoip):
    - Update geoip and geoip6 to the February 8 2017 Maxmind GeoLite2
      Country database.

  o Minor bugfixes (compilation, backport from 0.2.7.6):
    - Fix a compilation warning with Clang 3.6: Do not check the
      presence of an address which can never be NULL. Fixes bug 17781.

  o Minor bugfixes (hidden service, backport from 0.2.7.1-alpha):
    - Fix an out-of-bounds read when parsing invalid INTRODUCE2 cells on
      a client authorized hidden service. Fixes bug 15823; bugfix
      on 0.2.1.6-alpha.


Changes in version 0.2.4.27 - 2015-04-06
  Tor 0.2.4.27 backports two fixes from 0.2.6.7 for security issues that
  could be used by an attacker to crash hidden services, or crash clients
  visiting hidden services. Hidden services should upgrade as soon as
  possible; clients should upgrade whenever packages become available.

  This release also backports a simple improvement to make hidden
  services a bit less vulnerable to denial-of-service attacks.

  o Major bugfixes (security, hidden service):
    - Fix an issue that would allow a malicious client to trigger an
      assertion failure and halt a hidden service. Fixes bug 15600;
      bugfix on 0.2.1.6-alpha. Reported by "disgleirio".
    - Fix a bug that could cause a client to crash with an assertion
      failure when parsing a malformed hidden service descriptor. Fixes
      bug 15601; bugfix on 0.2.1.5-alpha. Found by "DonnchaC".

  o Minor features (DoS-resistance, hidden service):
    - Introduction points no longer allow multiple INTRODUCE1 cells to
      arrive on the same circuit. This should make it more expensive for
      attackers to overwhelm hidden services with introductions.
      Resolves ticket 15515.


Changes in version 0.2.4.26 - 2015-03-17
  Tor 0.2.4.26 includes an updated list of directory authorities.  It
  also backports a couple of stability and security bugfixes from 0.2.5
  and beyond.

  o Directory authority changes:
    - Remove turtles as a directory authority.
    - Add longclaw as a new (v3) directory authority. This implements
      ticket 13296. This keeps the directory authority count at 9.
    - The directory authority Faravahar has a new IP address. This
      closes ticket 14487.

  o Major bugfixes (exit node stability, also in 0.2.6.3-alpha):
    - Fix an assertion failure that could occur under high DNS load.
      Fixes bug 14129; bugfix on Tor 0.0.7rc1. Found by "jowr";
      diagnosed and fixed by "cypherpunks".

  o Major bugfixes (relay, stability, possible security, also in 0.2.6.4-rc):
    - Fix a bug that could lead to a relay crashing with an assertion
      failure if a buffer of exactly the wrong layout was passed to
      buf_pullup() at exactly the wrong time. Fixes bug 15083; bugfix on
      0.2.0.10-alpha. Patch from 'cypherpunks'.
    - Do not assert if the 'data' pointer on a buffer is advanced to the
      very end of the buffer; log a BUG message instead. Only assert if
      it is past that point. Fixes bug 15083; bugfix on 0.2.0.10-alpha.

  o Minor features (geoip):
    - Update geoip to the March 3 2015 Maxmind GeoLite2 Country database.
    - Update geoip6 to the March 3 2015 Maxmind GeoLite2
      Country database.


Changes in version 0.2.4.25 - 2014-10-20
  Tor 0.2.4.25 disables SSL3 in response to the recent "POODLE" attack
  (even though POODLE does not affect Tor). It also works around a crash
  bug caused by some operating systems' response to the "POODLE" attack
  (which does affect Tor).

  o Major security fixes (also in 0.2.5.9-rc):
    - Disable support for SSLv3. All versions of OpenSSL in use with Tor
      today support TLS 1.0 or later, so we can safely turn off support
      for this old (and insecure) protocol. Fixes bug 13426.

  o Major bugfixes (openssl bug workaround, also in 0.2.5.9-rc):
    - Avoid crashing when using OpenSSL version 0.9.8zc, 1.0.0o, or
      1.0.1j, built with the 'no-ssl3' configuration option. Fixes bug
      13471. This is a workaround for an OpenSSL bug.


Changes in version 0.2.4.24 - 2014-09-22
  Tor 0.2.4.24 fixes a bug that affects consistency and speed when
  connecting to hidden services, and it updates the location of one of
  the directory authorities.

  o Major bugfixes:
    - Clients now send the correct address for their chosen rendezvous
      point when trying to access a hidden service. They used to send
      the wrong address, which would still work some of the time because
      they also sent the identity digest of the rendezvous point, and if
      the hidden service happened to try connecting to the rendezvous
      point from a relay that already had a connection open to it,
      the relay would reuse that connection. Now connections to hidden
      services should be more robust and faster. Also, this bug meant
      that clients were leaking to the hidden service whether they were
      on a little-endian (common) or big-endian (rare) system, which for
      some users might have reduced their anonymity. Fixes bug 13151;
      bugfix on 0.2.1.5-alpha.

  o Directory authority changes:
    - Change IP address for gabelmoo (v3 directory authority).

  o Minor features (geoip):
    - Update geoip and geoip6 to the August 7 2014 Maxmind GeoLite2
      Country database.


Changes in version 0.2.4.23 - 2014-07-28
  Tor 0.2.4.23 brings us a big step closer to slowing down the risk from
  guard rotation, and also backports several important fixes from the
  Tor 0.2.5 alpha release series.

  o Major features:
    - Clients now look at the "usecreatefast" consensus parameter to
      decide whether to use CREATE_FAST or CREATE cells for the first hop
      of their circuit. This approach can improve security on connections
      where Tor's circuit handshake is stronger than the available TLS
      connection security levels, but the tradeoff is more computational
      load on guard relays. Implements proposal 221. Resolves ticket 9386.
    - Make the number of entry guards configurable via a new
      NumEntryGuards consensus parameter, and the number of directory
      guards configurable via a new NumDirectoryGuards consensus
      parameter. Implements ticket 12688.

  o Major bugfixes:
    - Fix a bug in the bounds-checking in the 32-bit curve25519-donna
      implementation that caused incorrect results on 32-bit
      implementations when certain malformed inputs were used along with
      a small class of private ntor keys. This bug does not currently
      appear to allow an attacker to learn private keys or impersonate a
      Tor server, but it could provide a means to distinguish 32-bit Tor
      implementations from 64-bit Tor implementations. Fixes bug 12694;
      bugfix on 0.2.4.8-alpha. Bug found by Robert Ransom; fix from
      Adam Langley.

  o Minor bugfixes:
    - Warn and drop the circuit if we receive an inbound 'relay early'
      cell. Those used to be normal to receive on hidden service circuits
      due to bug 1038, but the buggy Tor versions are long gone from
      the network so we can afford to resume watching for them. Resolves
      the rest of bug 1038; bugfix on 0.2.1.19.
    - Correct a confusing error message when trying to extend a circuit
      via the control protocol but we don't know a descriptor or
      microdescriptor for one of the specified relays. Fixes bug 12718;
      bugfix on 0.2.3.1-alpha.
    - Avoid an illegal read from stack when initializing the TLS
      module using a version of OpenSSL without all of the ciphers
      used by the v2 link handshake. Fixes bug 12227; bugfix on
      0.2.4.8-alpha.  Found by "starlight".

  o Minor features:
    - Update geoip and geoip6 to the July 10 2014 Maxmind GeoLite2
      Country database.


Changes in version 0.2.4.22 - 2014-05-16
  Tor 0.2.4.22 backports numerous high-priority fixes from the Tor 0.2.5
  alpha release series. These include blocking all authority signing
  keys that may have been affected by the OpenSSL "heartbleed" bug,
  choosing a far more secure set of TLS ciphersuites by default, closing
  a couple of memory leaks that could be used to run a target relay out
  of RAM, and several others.

  o Major features (security, backport from 0.2.5.4-alpha):
    - Block authority signing keys that were used on authorities
      vulnerable to the "heartbleed" bug in OpenSSL (CVE-2014-0160). (We
      don't have any evidence that these keys _were_ compromised; we're
      doing this to be prudent.) Resolves ticket 11464.

  o Major bugfixes (security, OOM):
    - Fix a memory leak that could occur if a microdescriptor parse
      fails during the tokenizing step. This bug could enable a memory
      exhaustion attack by directory servers. Fixes bug 11649; bugfix
      on 0.2.2.6-alpha.

  o Major bugfixes (TLS cipher selection, backport from 0.2.5.4-alpha):
    - The relay ciphersuite list is now generated automatically based on
      uniform criteria, and includes all OpenSSL ciphersuites with
      acceptable strength and forward secrecy. Previously, we had left
      some perfectly fine ciphersuites unsupported due to omission or
      typo. Resolves bugs 11513, 11492, 11498, 11499. Bugs reported by
      'cypherpunks'. Bugfix on 0.2.4.8-alpha.
    - Relays now trust themselves to have a better view than clients of
      which TLS ciphersuites are better than others. (Thanks to bug
      11513, the relay list is now well-considered, whereas the client
      list has been chosen mainly for anti-fingerprinting purposes.)
      Relays prefer: AES over 3DES; then ECDHE over DHE; then GCM over
      CBC; then SHA384 over SHA256 over SHA1; and last, AES256 over
      AES128. Resolves ticket 11528.
    - Clients now try to advertise the same list of ciphersuites as
      Firefox 28. This change enables selection of (fast) GCM
      ciphersuites, disables some strange old ciphers, and stops
      advertising the ECDH (not to be confused with ECDHE) ciphersuites.
      Resolves ticket 11438.

  o Minor bugfixes (configuration, security):
    - When running a hidden service, do not allow TunneledDirConns 0:
      trying to set that option together with a hidden service would
      otherwise prevent the hidden service from running, and also make
      it publish its descriptors directly over HTTP. Fixes bug 10849;
      bugfix on 0.2.1.1-alpha.

  o Minor bugfixes (controller, backport from 0.2.5.4-alpha):
    - Avoid sending a garbage value to the controller when a circuit is
      cannibalized. Fixes bug 11519; bugfix on 0.2.3.11-alpha.

  o Minor bugfixes (exit relay, backport from 0.2.5.4-alpha):
    - Stop leaking memory when we successfully resolve a PTR record.
      Fixes bug 11437; bugfix on 0.2.4.7-alpha.

  o Minor bugfixes (bridge client, backport from 0.2.5.4-alpha):
    - Avoid 60-second delays in the bootstrapping process when Tor is
      launching for a second time while using bridges. Fixes bug 9229;
      bugfix on 0.2.0.3-alpha.

  o Minor bugfixes (relays and bridges, backport from 0.2.5.4-alpha):
    - Give the correct URL in the warning message when trying to run a
      relay on an ancient version of Windows. Fixes bug 9393.

  o Minor bugfixes (compilation):
    - Fix a compilation error when compiling with --disable-curve25519.
      Fixes bug 9700; bugfix on 0.2.4.17-rc.

  o Minor bugfixes:
    - Downgrade the warning severity for the the "md was still
      referenced 1 node(s)" warning. Tor 0.2.5.4-alpha has better code
      for trying to diagnose this bug, and the current warning in
      earlier versions of tor achieves nothing useful. Addresses warning
      from bug 7164.

  o Minor features (log verbosity, backport from 0.2.5.4-alpha):
    - When we run out of usable circuit IDs on a channel, log only one
      warning for the whole channel, and describe how many circuits
      there were on the channel. Fixes part of ticket 11553.

  o Minor features (security, backport from 0.2.5.4-alpha):
    - Decrease the lower limit of MaxMemInCellQueues to 256 MBytes (but
      leave the default at 8GBytes), to better support Raspberry Pi
      users. Fixes bug 9686; bugfix on 0.2.4.14-alpha.

  o Documentation (backport from 0.2.5.4-alpha):
    - Correctly document that we search for a system torrc file before
      looking in ~/.torrc. Fixes documentation side of 9213; bugfix on
      0.2.3.18-rc.


Changes in version 0.2.4.21 - 2014-02-28
  Tor 0.2.4.21 further improves security against potential adversaries who
  find breaking 1024-bit crypto doable, and backports several stability
  and robustness patches from the 0.2.5 branch.

  o Major features (client security):
    - When we choose a path for a 3-hop circuit, make sure it contains
      at least one relay that supports the NTor circuit extension
      handshake. Otherwise, there is a chance that we're building
      a circuit that's worth attacking by an adversary who finds
      breaking 1024-bit crypto doable, and that chance changes the game
      theory. Implements ticket 9777.

  o Major bugfixes:
    - Do not treat streams that fail with reason
      END_STREAM_REASON_INTERNAL as indicating a definite circuit failure,
      since it could also indicate an ENETUNREACH connection error. Fixes
      part of bug 10777; bugfix on 0.2.4.8-alpha.

  o Code simplification and refactoring:
    - Remove data structures which were introduced to implement the
      CellStatistics option: they are now redundant with the new timestamp
      field in the regular packed_cell_t data structure, which we did
      in 0.2.4.18-rc in order to resolve bug 9093. Resolves ticket 10870.

  o Minor features:
    - Always clear OpenSSL bignums before freeing them -- even bignums
      that don't contain secrets. Resolves ticket 10793. Patch by
      Florent Daigniere.
    - Build without warnings under clang 3.4. (We have some macros that
      define static functions only some of which will get used later in
      the module. Starting with clang 3.4, these give a warning unless the
      unused attribute is set on them.) Resolves ticket 10904.
    - Update geoip and geoip6 files to the February 7 2014 Maxmind
      GeoLite2 Country database.

  o Minor bugfixes:
    - Set the listen() backlog limit to the largest actually supported
      on the system, not to the value in a header file. Fixes bug 9716;
      bugfix on every released Tor.
    - Treat ENETUNREACH, EACCES, and EPERM connection failures at an
      exit node as a NOROUTE error, not an INTERNAL error, since they
      can apparently happen when trying to connect to the wrong sort
      of netblocks. Fixes part of bug 10777; bugfix on 0.1.0.1-rc.
    - Fix build warnings about missing "a2x" comment when building the
      manpages from scratch on OpenBSD; OpenBSD calls it "a2x.py".
      Fixes bug 10929; bugfix on 0.2.2.9-alpha. Patch from Dana Koch.
    - Avoid a segfault on SIGUSR1, where we had freed a connection but did
      not entirely remove it from the connection lists. Fixes bug 9602;
      bugfix on 0.2.4.4-alpha.
    - Fix a segmentation fault in our benchmark code when running with
      Fedora's OpenSSL package, or any other OpenSSL that provides
      ECDH but not P224. Fixes bug 10835; bugfix on 0.2.4.8-alpha.
    - Turn "circuit handshake stats since last time" log messages into a
      heartbeat message. Fixes bug 10485; bugfix on 0.2.4.17-rc.

  o Documentation fixes:
    - Document that all but one DirPort entry must have the NoAdvertise
      flag set. Fixes bug 10470; bugfix on 0.2.3.3-alpha / 0.2.3.16-alpha.


Changes in version 0.2.4.20 - 2013-12-22
  Tor 0.2.4.20 fixes potentially poor random number generation for users
  who 1) use OpenSSL 1.0.0 or later, 2) set "HardwareAccel 1" in their
  torrc file, 3) have "Sandy Bridge" or "Ivy Bridge" Intel processors,
  and 4) have no state file in their DataDirectory (as would happen on
  first start). Users who generated relay or hidden service identity
  keys in such a situation should discard them and generate new ones.

  This release also fixes a logic error that caused Tor clients to build
  many more preemptive circuits than they actually need.

  o Major bugfixes:
    - Do not allow OpenSSL engines to replace the PRNG, even when
      HardwareAccel is set. The only default builtin PRNG engine uses
      the Intel RDRAND instruction to replace the entire PRNG, and
      ignores all attempts to seed it with more entropy. That's
      cryptographically stupid: the right response to a new alleged
      entropy source is never to discard all previously used entropy
      sources. Fixes bug 10402; works around behavior introduced in
      OpenSSL 1.0.0. Diagnosis and investigation thanks to "coderman"
      and "rl1987".
    - Fix assertion failure when AutomapHostsOnResolve yields an IPv6
      address. Fixes bug 10465; bugfix on 0.2.4.7-alpha.
    - Avoid launching spurious extra circuits when a stream is pending.
      This fixes a bug where any circuit that _wasn't_ unusable for new
      streams would be treated as if it were, causing extra circuits to
      be launched. Fixes bug 10456; bugfix on 0.2.4.12-alpha.

  o Minor bugfixes:
    - Avoid a crash bug when starting with a corrupted microdescriptor
      cache file. Fixes bug 10406; bugfix on 0.2.2.6-alpha.
    - If we fail to dump a previously cached microdescriptor to disk, avoid
      freeing duplicate data later on. Fixes bug 10423; bugfix on
      0.2.4.13-alpha. Spotted by "bobnomnom".


Changes in version 0.2.4.19 - 2013-12-11
  The Tor 0.2.4 release series is dedicated to the memory of Aaron Swartz
  (1986-2013). Aaron worked on diverse projects including helping to guide
  Creative Commons, playing a key role in stopping SOPA/PIPA, bringing
  transparency to the U.S government's PACER documents, and contributing
  design and development for Tor and Tor2Web. Aaron was one of the latest
  martyrs in our collective fight for civil liberties and human rights,
  and his death is all the more painful because he was one of us.

  Tor 0.2.4.19, the first stable release in the 0.2.4 branch, features
  a new circuit handshake and link encryption that use ECC to provide
  better security and efficiency; makes relays better manage circuit
  creation requests; uses "directory guards" to reduce client enumeration
  risks; makes bridges collect and report statistics about the pluggable
  transports they support; cleans up and improves our geoip database;
  gets much closer to IPv6 support for clients, bridges, and relays; makes
  directory authorities use measured bandwidths rather than advertised
  ones when computing flags and thresholds; disables client-side DNS
  caching to reduce tracking risks; and fixes a big bug in bridge
  reachability testing. This release introduces two new design
  abstractions in the code: a new "channel" abstraction between circuits
  and or_connections to allow for implementing alternate relay-to-relay
  transports, and a new "circuitmux" abstraction storing the queue of
  circuits for a channel. The release also includes many stability,
  security, and privacy fixes.

  o Major features (new circuit handshake):
    - Tor now supports a new circuit extension handshake designed by Ian
      Goldberg, Douglas Stebila, and Berkant Ustaoglu. Our original
      circuit extension handshake, later called "TAP", was a bit slow
      (especially on the relay side), had a fragile security proof, and
      used weaker keys than we'd now prefer. The new circuit handshake
      uses Dan Bernstein's "curve25519" elliptic-curve Diffie-Hellman
      function, making it significantly more secure than the older
      handshake, and significantly faster. Tor can use one of two built-in
      pure-C curve25519-donna implementations by Adam Langley, or it
      can link against the "nacl" library for a tuned version if present.

      The built-in version is very fast for 64-bit systems when building
      with GCC. The built-in 32-bit version is still faster than the
      old TAP protocol, but using libnacl is better on most such hosts.

      Implements proposal 216; closes ticket 7202.

  o Major features (better link encryption):
    - Relays can now enable the ECDHE TLS ciphersuites when available
      and appropriate. These ciphersuites let us negotiate forward-secure
      TLS secret keys more safely and more efficiently than with our
      previous use of Diffie-Hellman modulo a 1024-bit prime. By default,
      public relays prefer the (faster) P224 group, and bridges prefer
      the (more common) P256 group; you can override this with the
      TLSECGroup option.

      This feature requires clients running 0.2.3.17-beta or later,
      and requires both sides to be running OpenSSL 1.0.0 or later
      with ECC support. OpenSSL 1.0.1, with the compile-time option
      "enable-ec_nistp_64_gcc_128", is highly recommended.

      Implements the relay side of proposal 198; closes ticket 7200.

    - Re-enable TLS 1.1 and 1.2 when built with OpenSSL 1.0.1e or later.
      Resolves ticket 6055. (OpenSSL before 1.0.1 didn't have TLS 1.1 or
      1.2, and OpenSSL from 1.0.1 through 1.0.1d had bugs that prevented
      renegotiation from working with TLS 1.1 or 1.2, so we had disabled
      them to solve bug 6033.)

  o Major features (relay performance):
    - Instead of limiting the number of queued onionskins (aka circuit
      create requests) to a fixed, hard-to-configure number, we limit
      the size of the queue based on how many we expect to be able to
      process in a given amount of time. We estimate the time it will
      take to process an onionskin based on average processing time
      of previous onionskins. Closes ticket 7291. You'll never have to
      configure MaxOnionsPending again.
    - Relays process the new "NTor" circuit-level handshake requests
      with higher priority than the old "TAP" circuit-level handshake
      requests. We still process some TAP requests to not totally starve
      0.2.3 clients when NTor becomes popular. A new consensus parameter
      "NumNTorsPerTAP" lets us tune the balance later if we need to.
      Implements ticket 9574.

  o Major features (client bootstrapping resilience):
    - Add a new "FallbackDir" torrc option to use when we can't use
      a directory mirror from the consensus (either because we lack a
      consensus, or because they're all down). Currently, all authorities
      are fallbacks by default, and there are no other default fallbacks,
      but that will change. This option will allow us to give clients a
      longer list of servers to try to get a consensus from when first
      connecting to the Tor network, and thereby reduce load on the
      directory authorities. Implements proposal 206, "Preconfigured
      directory sources for bootstrapping". We also removed the old
      "FallbackNetworkstatus" option, since we never got it working well
      enough to use it. Closes bug 572.
    - If we have no circuits open, use a relaxed timeout (the
      95th-percentile cutoff) until a circuit succeeds. This heuristic
      should allow Tor to succeed at building circuits even when the
      network connection drastically changes. Should help with bug 3443.

  o Major features (use of guards):
    - Support directory guards (proposal 207): when possible, clients now
      use their entry guards for non-anonymous directory requests. This
      can help prevent client enumeration. Note that this behavior only
      works when we have a usable consensus directory, and when options
      about what to download are more or less standard. In the future we
      should re-bootstrap from our guards, rather than re-bootstrapping
      from the preconfigured list of directory sources that ships with
      Tor. Resolves ticket 6526.
    - Raise the default time that a client keeps an entry guard from
      "1-2 months" to "2-3 months", as suggested by Tariq Elahi's WPES
      2012 paper. (We would make it even longer, but we need better client
      load balancing first.) Also, make the guard lifetime controllable
      via a new GuardLifetime torrc option and a GuardLifetime consensus
      parameter. Start of a fix for bug 8240; bugfix on 0.1.1.11-alpha.

  o Major features (bridges with pluggable transports):
    - Bridges now report the pluggable transports they support to the
      bridge authority, so it can pass the supported transports on to
      bridgedb and/or eventually do reachability testing. Implements
      ticket 3589.
    - Automatically forward the TCP ports of pluggable transport
      proxies using tor-fw-helper if PortForwarding is enabled. Implements
      ticket 4567.

  o Major features (geoip database):
    - Maxmind began labelling Tor relays as being in country "A1",
      which breaks by-country node selection inside Tor. Now we use a
      script to replace "A1" ("Anonymous Proxy") entries in our geoip
      file with real country codes. This script fixes about 90% of "A1"
      entries automatically and uses manual country code assignments to
      fix the remaining 10%. See src/config/README.geoip for details.
      Fixes bug 6266.
    - Add GeoIP database for IPv6 addresses. The new config option
      is GeoIPv6File.
    - Update to the October 2 2013 Maxmind GeoLite Country database.

  o Major features (IPv6):
    - Clients who set "ClientUseIPv6 1" may connect to entry nodes over
      IPv6. Set "ClientPreferIPv6ORPort 1" to make this even more likely
      to happen. Implements ticket 5535.
    - All kind of relays, not just bridges, can now advertise an IPv6
      OR port. Implements ticket 6362.
    - Relays can now exit to IPv6 addresses: make sure that you have IPv6
      connectivity, then set the IPv6Exit flag to 1. Also make sure your
      exit policy reads as you would like: the address * applies to all
      address families, whereas *4 is IPv4 address only, and *6 is IPv6
      addresses only. On the client side, you'll need to wait for enough
      exits to support IPv6, apply the "IPv6Traffic" flag to a SocksPort,
      and use Socks5. Closes ticket 5547, implements proposal 117 as
      revised in proposal 208.
    - Bridge authorities now accept IPv6 bridge addresses and include
      them in network status documents. Implements ticket 5534.
    - Directory authorities vote on IPv6 OR ports. Implements ticket 6363.

  o Major features (directory authorities):
    - Directory authorities now prefer using measured bandwidths to
      advertised ones when computing flags and thresholds. Resolves
      ticket 8273.
    - Directory authorities that vote measured bandwidths about more
      than a threshold number of relays now treat relays with
      unmeasured bandwidths as having bandwidth 0 when computing their
      flags. Resolves ticket 8435.
    - Directory authorities now support a new consensus method (17)
      where they cap the published bandwidth of relays for which
      insufficient bandwidth measurements exist. Fixes part of bug 2286.
    - Directory authorities that set "DisableV2DirectoryInfo_ 1" no longer
      serve any v2 directory information. Now we can test disabling the
      old deprecated v2 directory format, and see whether doing so has
      any effect on network load. Begins to fix bug 6783.

  o Major features (build and portability):
    - Switch to a nonrecursive Makefile structure. Now instead of each
      Makefile.am invoking other Makefile.am's, there is a master
      Makefile.am that includes the others. This change makes our build
      process slightly more maintainable, and improves parallelism for
      building with make -j. Original patch by Stewart Smith; various
      fixes by Jim Meyering.
    - Where available, we now use automake's "silent" make rules by
      default, so that warnings are easier to spot. You can get the old
      behavior with "make V=1". Patch by Stewart Smith for ticket 6522.
    - Resume building correctly with MSVC and Makefile.nmake. This patch
      resolves numerous bugs and fixes reported by ultramage, including
      7305, 7308, 7309, 7310, 7312, 7313, 7315, 7316, and 7669.

  o Security features:
    - Switch to a completely time-invariant approach for picking nodes
      weighted by bandwidth. Our old approach would run through the
      part of the loop after it had made its choice slightly slower
      than it ran through the part of the loop before it had made its
      choice. Addresses ticket 6538.
    - Disable the use of Guard nodes when in Tor2WebMode. Guard usage
      by tor2web clients allows hidden services to identify tor2web
      clients through their repeated selection of the same rendezvous
      and introduction point circuit endpoints (their guards). Resolves
      ticket 6888.

  o Major bugfixes (relay denial of service):
    - When we have too much memory queued in circuits (according to a new
      MaxMemInCellQueues option), close the circuits that have the oldest
      queued cells, on the theory that those are most responsible for
      us running low on memory. This prevents us from running out of
      memory as a relay if circuits fill up faster than they can be
      drained. Fixes bugs 9063 and 9093; bugfix on the 54th commit of
      Tor. This bug is a further fix beyond bug 6252, whose fix was
      merged into 0.2.3.21-rc.
    - Reject bogus create and relay cells with 0 circuit ID or 0 stream
      ID: these could be used to create unexpected streams and circuits
      which would count as "present" to some parts of Tor but "absent"
      to others, leading to zombie circuits and streams or to a bandwidth
      denial-of-service. Fixes bug 7889; bugfix on every released version
      of Tor. Reported by "oftc_must_be_destroyed".
    - Avoid a bug where our response to TLS renegotiation under certain
      network conditions could lead to a busy-loop, with 100% CPU
      consumption. Fixes bug 5650; bugfix on 0.2.0.16-alpha.

  o Major bugfixes (asserts, crashes, leaks):
    - Prevent the get_freelists() function from running off the end of
      the list of freelists if it somehow gets an unrecognized
      allocation. Fixes bug 8844; bugfix on 0.2.0.16-alpha. Reported by
      eugenis.
    - Avoid a memory leak where we would leak a consensus body when we
      find that a consensus which we couldn't previously verify due to
      missing certificates is now verifiable. Fixes bug 8719; bugfix
      on 0.2.0.10-alpha.
    - If we are unable to save a microdescriptor to the journal, do not
      drop it from memory and then reattempt downloading it. Fixes bug
      9645; bugfix on 0.2.2.6-alpha.
    - Fix an assertion failure that would occur when disabling the
      ORPort setting on a running Tor process while accounting was
      enabled. Fixes bug 6979; bugfix on 0.2.2.18-alpha.
    - Avoid an assertion failure on OpenBSD (and perhaps other BSDs)
      when an exit connection with optimistic data succeeds immediately
      rather than returning EINPROGRESS. Fixes bug 9017; bugfix on
      0.2.3.1-alpha.
    - Fix a memory leak that would occur whenever a configuration
      option changed. Fixes bug 8718; bugfix on 0.2.3.3-alpha.

  o Major bugfixes (relay rate limiting):
    - When a TLS write is partially successful but incomplete, remember
      that the flushed part has been flushed, and notice that bytes were
      actually written. Reported and fixed pseudonymously. Fixes bug 7708;
      bugfix on Tor 0.1.0.5-rc.
    - Raise the default BandwidthRate/BandwidthBurst values from 5MB/10MB
      to 1GB/1GB. The previous defaults were intended to be "basically
      infinite", but it turns out they're now limiting our 100mbit+
      relays and bridges. Fixes bug 6605; bugfix on 0.2.0.10-alpha (the
      last time we raised it).
    - No longer stop reading or writing on cpuworker connections when
      our rate limiting buckets go empty. Now we should handle circuit
      handshake requests more promptly. Resolves bug 9731.

  o Major bugfixes (client-side privacy):
    - When we mark a circuit as unusable for new circuits, have it
      continue to be unusable for new circuits even if MaxCircuitDirtiness
      is increased too much at the wrong time, or the system clock jumps
      backwards. Fixes bug 6174; bugfix on 0.0.2pre26.
    - If ClientDNSRejectInternalAddresses ("do not believe DNS queries
      which have resolved to internal addresses") is set, apply that
      rule to IPv6 as well. Fixes bug 8475; bugfix on 0.2.0.7-alpha.
    - When an exit relay rejects a stream with reason "exit policy", but
      we only know an exit policy summary (e.g. from the microdesc
      consensus) for it, do not mark the relay as useless for all exiting.
      Instead, mark just the circuit as unsuitable for that particular
      address. Fixes part of bug 7582; bugfix on 0.2.3.2-alpha.

  o Major bugfixes (stream isolation):
    - Allow applications to get proper stream isolation with
      IsolateSOCKSAuth. Many SOCKS5 clients that want to offer
      username/password authentication also offer "no authentication". Tor
      had previously preferred "no authentication", so the applications
      never actually sent Tor their auth details. Now Tor selects
      username/password authentication if it's offered. You can disable
      this behavior on a per-SOCKSPort basis via PreferSOCKSNoAuth. Fixes
      bug 8117; bugfix on 0.2.3.3-alpha.
    - Follow the socks5 protocol when offering username/password
      authentication. The fix for bug 8117 exposed this bug, and it
      turns out real-world applications like Pidgin do care. Bugfix on
      0.2.3.2-alpha; fixes bug 8879.

  o Major bugfixes (client circuit building):
    - Alter circuit build timeout measurement to start at the point
      where we begin the CREATE/CREATE_FAST step (as opposed to circuit
      initialization). This should make our timeout measurements more
      uniform. Previously, we were sometimes including ORconn setup time
      in our circuit build time measurements. Should resolve bug 3443.
    - If the circuit build timeout logic is disabled (via the consensus,
      or because we are an authority), then don't build testing circuits.
      Fixes bug 9657; bugfix on 0.2.2.14-alpha.

  o Major bugfixes (client-side DNS):
    - Turn off the client-side DNS cache by default. Updating and using
      the DNS cache is now configurable on a per-client-port
      level. SOCKSPort, DNSPort, etc lines may now contain
      {No,}Cache{IPv4,IPv6,}DNS lines to indicate that we shouldn't
      cache these types of DNS answers when we receive them from an
      exit node in response to an application request on this port, and
      {No,}UseCached{IPv4,IPv6,DNS} lines to indicate that if we have
      cached DNS answers of these types, we shouldn't use them. It's
      potentially risky to use cached DNS answers at the client, since
      doing so can indicate to one exit what answers we've gotten
      for DNS lookups in the past. With IPv6, this becomes especially
      problematic. Using cached DNS answers for requests on the same
      circuit would present less linkability risk, since all traffic
      on a circuit is already linkable, but it would also provide
      little performance benefit: the exit node caches DNS replies
      too. Implements a simplified version of Proposal 205. Implements
      ticket 7570.

  o Major bugfixes (hidden service privacy):
    - Limit hidden service descriptors to at most ten introduction
      points, to slow one kind of guard enumeration. Fixes bug 9002;
      bugfix on 0.1.1.11-alpha.

  o Major bugfixes (directory fetching):
    - If the time to download the next old-style networkstatus is in
      the future, do not decline to consider whether to download the
      next microdescriptor networkstatus. Fixes bug 9564; bugfix on
      0.2.3.14-alpha.
    - We used to always request authority certificates by identity digest,
      meaning we'd get the newest one even when we wanted one with a
      different signing key. Then we would complain about being given
      a certificate we already had, and never get the one we really
      wanted. Now we use the "fp-sk/" resource as well as the "fp/"
      resource to request the one we want. Fixes bug 5595; bugfix on
      0.2.0.8-alpha.

  o Major bugfixes (bridge reachability):
    - Bridges now send AUTH_CHALLENGE cells during their v3 handshakes;
      previously they did not, which prevented them from receiving
      successful connections from relays for self-test or bandwidth
      testing. Also, when a relay is extending a circuit to a bridge,
      it needs to send a NETINFO cell, even when the bridge hasn't sent
      an AUTH_CHALLENGE cell. Fixes bug 9546; bugfix on 0.2.3.6-alpha.

  o Major bugfixes (control interface):
    - When receiving a new configuration file via the control port's
      LOADCONF command, do not treat the defaults file as absent.
      Fixes bug 9122; bugfix on 0.2.3.9-alpha.

  o Major bugfixes (directory authorities):
    - Stop marking every relay as having been down for one hour every
      time we restart a directory authority. These artificial downtimes
      were messing with our Stable and Guard flag calculations. Fixes
      bug 8218 (introduced by the fix for 1035). Bugfix on 0.2.2.23-alpha.
    - When computing directory thresholds, ignore any rejected-as-sybil
      nodes during the computation so that they can't influence Fast,
      Guard, etc. (We should have done this for proposal 109.) Fixes
      bug 8146.
    - When marking a node as a likely sybil, reset its uptime metrics
      to zero, so that it cannot time towards getting marked as Guard,
      Stable, or HSDir. (We should have done this for proposal 109.) Fixes
      bug 8147.
    - Fix a bug in the voting algorithm that could yield incorrect results
      when a non-naming authority declared too many flags. Fixes bug 9200;
      bugfix on 0.2.0.3-alpha.

  o Internal abstraction features:
    - Introduce new channel_t abstraction between circuits and
      or_connection_t to allow for implementing alternate OR-to-OR
      transports. A channel_t is an abstract object which can either be a
      cell-bearing channel, which is responsible for authenticating and
      handshaking with the remote OR and transmitting cells to and from
      it, or a listening channel, which spawns new cell-bearing channels
      at the request of remote ORs. Implements part of ticket 6465.
    - Make a channel_tls_t subclass of channel_t, adapting it to the
      existing or_connection_t code. The V2/V3 protocol handshaking
      code which formerly resided in command.c has been moved below the
      channel_t abstraction layer and may be found in channeltls.c now.
      Implements the rest of ticket 6465.
    - Introduce new circuitmux_t storing the queue of circuits for
      a channel; this encapsulates and abstracts the queue logic and
      circuit selection policy, and allows the latter to be overridden
      easily by switching out a policy object. The existing EWMA behavior
      is now implemented as a circuitmux_policy_t. Resolves ticket 6816.

  o New build requirements:
    - Tor now requires OpenSSL 0.9.8 or later. OpenSSL 1.0.0 or later is
      strongly recommended.
    - Tor maintainers now require Automake version 1.9 or later to build
      Tor from the Git repository. (Automake is not required when building
      from a source distribution.)

  o Minor features (protocol):
    - No longer include the "opt" prefix when generating routerinfos
      or v2 directories: it has been needless since Tor 0.1.2. Closes
      ticket 5124.
    - Reject EXTEND cells sent to nonexistent streams. According to the
      spec, an EXTEND cell sent to _any_ nonzero stream ID is invalid, but
      we were only checking for stream IDs that were currently in use.
      Found while hunting for more instances of bug 6271. Bugfix on
      0.0.2pre8, which introduced incremental circuit construction.
    - Tor relays and clients now support a better CREATE/EXTEND cell
      format, allowing the sender to specify multiple address, identity,
      and handshake types. Implements Robert Ransom's proposal 200;
      closes ticket 7199.
    - Reject as invalid most directory objects containing a NUL.
      Belt-and-suspender fix for bug 8037.

  o Minor features (security):
    - Clear keys and key-derived material left on the stack in
      rendservice.c and rendclient.c. Check return value of
      crypto_pk_write_private_key_to_string() in rend_service_load_keys().
      These fixes should make us more forward-secure against cold-boot
      attacks and the like. Fixes bug 2385.
    - Use our own weak RNG when we need a weak RNG. Windows's rand() and
      Irix's random() only return 15 bits; Solaris's random() returns more
      bits but its RAND_MAX says it only returns 15, and so on. Motivated
      by the fix for bug 7801; bugfix on 0.2.2.20-alpha.

  o Minor features (control protocol):
    - Add a "GETINFO signal/names" control port command. Implements
      ticket 3842.
    - Provide default values for all options via "GETINFO config/defaults".
      Implements ticket 4971.
    - Allow an optional $ before the node identity digest in the
      controller command GETINFO ns/id/<identity>, for consistency with
      md/id/<identity> and desc/id/<identity>. Resolves ticket 7059.
    - Add CACHED keyword to ADDRMAP events in the control protocol
      to indicate whether a DNS result will be cached or not. Resolves
      ticket 8596.
    - Generate bootstrapping status update events correctly when fetching
      microdescriptors. Fixes bug 9927.

  o Minor features (path selection):
    - When deciding whether we have enough descriptors to build circuits,
      instead of looking at raw relay counts, look at which fraction
      of (bandwidth-weighted) paths we're able to build. This approach
      keeps clients from building circuits if their paths are likely to
      stand out statistically. The default fraction of paths needed is
      taken from the consensus directory; you can override it with the
      new PathsNeededToBuildCircuits option. Fixes ticket 5956.
    - When any country code is listed in ExcludeNodes or ExcludeExitNodes,
      and we have GeoIP information, also exclude all nodes with unknown
      countries "??" and "A1". This behavior is controlled by the
      new GeoIPExcludeUnknown option: you can make such nodes always
      excluded with "GeoIPExcludeUnknown 1", and disable the feature
      with "GeoIPExcludeUnknown 0". Setting "GeoIPExcludeUnknown auto"
      gets you the default behavior. Implements feature 7706.

  o Minor features (hidden services):
    - Improve circuit build timeout handling for hidden services.
      In particular: adjust build timeouts more accurately depending
      upon the number of hop-RTTs that a particular circuit type
      undergoes. Additionally, launch intro circuits in parallel
      if they timeout, and take the first one to reply as valid.
    - The Tor client now ignores sub-domain components of a .onion
      address. This change makes HTTP "virtual" hosting
      possible: http://foo.aaaaaaaaaaaaaaaa.onion/ and
      http://bar.aaaaaaaaaaaaaaaa.onion/ can be two different websites
      hosted on the same hidden service. Implements proposal 204.
    - Enable Tor to read configuration, state, and key information from
      a FIFO. Previously Tor would only read from files with a positive
      stat.st_size. Code from meejah; fixes bug 6044.

  o Minor features (clients):
    - Teach bridge-using clients to avoid 0.2.2.x bridges when making
      microdescriptor-related dir requests, and only fall back to normal
      descriptors if none of their bridges can handle microdescriptors
      (as opposed to the fix in ticket 4013, which caused them to fall
      back to normal descriptors if *any* of their bridges preferred
      them). Resolves ticket 4994.
    - Tweak tor-fw-helper to accept an arbitrary amount of arbitrary
      TCP ports to forward. In the past it only accepted two ports:
      the ORPort and the DirPort.

  o Minor features (protecting client timestamps):
    - Clients no longer send timestamps in their NETINFO cells. These were
      not used for anything, and they provided one small way for clients
      to be distinguished from each other as they moved from network to
      network or behind NAT. Implements part of proposal 222.
    - Clients now round timestamps in INTRODUCE cells down to the nearest
      10 minutes. If a new Support022HiddenServices option is set to 0, or
      if it's set to "auto" and the feature is disabled in the consensus,
      the timestamp is sent as 0 instead. Implements part of proposal 222.
    - Stop sending timestamps in AUTHENTICATE cells. This is not such
      a big deal from a security point of view, but it achieves no actual
      good purpose, and isn't needed. Implements part of proposal 222.
    - Reduce down accuracy of timestamps in hidden service descriptors.
      Implements part of proposal 222.

  o Minor features (bridges):
    - Make bridge relays check once a minute for whether their IP
      address has changed, rather than only every 15 minutes. Resolves
      bugs 1913 and 1992.
    - Bridge statistics now count bridge clients connecting over IPv6:
      bridge statistics files now list "bridge-ip-versions" and
      extra-info documents list "geoip6-db-digest". The control protocol
      "CLIENTS_SEEN" and "ip-to-country" queries now support IPv6. Initial
      implementation by "shkoo", addressing ticket 5055.
    - Add a new torrc option "ServerTransportListenAddr" to let bridge
      operators select the address where their pluggable transports will
      listen for connections. Resolves ticket 7013.
    - Randomize the lifetime of our SSL link certificate, so censors can't
      use the static value for filtering Tor flows. Resolves ticket 8443;
      related to ticket 4014 which was included in 0.2.2.33.

  o Minor features (relays):
    - Option OutboundBindAddress can be specified multiple times and
      accepts IPv6 addresses. Resolves ticket 6876.

  o Minor features (IPv6, client side):
    - AutomapHostsOnResolve now supports IPv6 addresses. By default, we
      prefer to hand out virtual IPv6 addresses, since there are more of
      them and we can't run out. To override this behavior and make IPv4
      addresses preferred, set NoPreferIPv6Automap on whatever SOCKSPort
      or DNSPort you're using for resolving. Implements ticket 7571.
    - AutomapHostsOnResolve responses are now randomized, to avoid
      annoying situations where Tor is restarted and applications
      connect to the wrong addresses.
    - Never try more than 1000 times to pick a new virtual address when
      AutomapHostsOnResolve is set. That's good enough so long as we
      aren't close to handing out our entire virtual address space;
      if you're getting there, it's best to switch to IPv6 virtual
      addresses anyway.

  o Minor features (IPv6, relay/authority side):
    - New config option "AuthDirHasIPv6Connectivity 1" that directory
      authorities should set if they have IPv6 connectivity and want to
      do reachability tests for IPv6 relays. Implements feature 5974.
    - A relay with an IPv6 OR port now sends that address in NETINFO
      cells (in addition to its other address). Implements ticket 6364.

  o Minor features (directory authorities):
    - Directory authorities no long accept descriptors for any version of
      Tor before 0.2.2.35, or for any 0.2.3 release before 0.2.3.10-alpha.
      These versions are insecure, unsupported, or both. Implements
      ticket 6789.
    - When directory authorities are computing thresholds for flags,
      never let the threshold for the Fast flag fall below 4096
      bytes. Also, do not consider nodes with extremely low bandwidths
      when deciding thresholds for various directory flags. This change
      should raise our threshold for Fast relays, possibly in turn
      improving overall network performance; see ticket 1854. Resolves
      ticket 8145.
    - Directory authorities now include inside each vote a statement of
      the performance thresholds they used when assigning flags.
      Implements ticket 8151.
    - Add an "ignoring-advertised-bws" boolean to the flag-threshold lines
      in directory authority votes to describe whether they have enough
      measured bandwidths to ignore advertised (relay descriptor)
      bandwidth claims. Resolves ticket 8711.

  o Minor features (path bias detection):
    - Path Use Bias: Perform separate accounting for successful circuit
      use. Keep separate statistics on stream attempt rates versus stream
      success rates for each guard. Provide configurable thresholds to
      determine when to emit log messages or disable use of guards that
      fail too many stream attempts. Resolves ticket 7802.
    - Create three levels of Path Bias log messages, as opposed to just
      two. These are configurable via consensus as well as via the torrc
      options PathBiasNoticeRate, PathBiasWarnRate, PathBiasExtremeRate.
      The default values are 0.70, 0.50, and 0.30 respectively.
    - Separate the log message levels from the decision to drop guards,
      which also is available via torrc option PathBiasDropGuards.
      PathBiasDropGuards still defaults to 0 (off).
    - Deprecate PathBiasDisableRate in favor of PathBiasDropGuards
      in combination with PathBiasExtremeRate.
    - Increase the default values for PathBiasScaleThreshold and
      PathBiasCircThreshold from (200, 20) to (300, 150).
    - Add in circuit usage accounting to path bias. If we try to use a
      built circuit but fail for any reason, it counts as path bias.
      Certain classes of circuits where the adversary gets to pick your
      destination node are exempt from this accounting. Usage accounting
      can be specifically disabled via consensus parameter or torrc.
    - Convert all internal path bias state to double-precision floating
      point, to avoid roundoff error and other issues.
    - Only record path bias information for circuits that have completed
      *two* hops. Assuming end-to-end tagging is the attack vector, this
      makes us more resilient to ambient circuit failure without any
      detection capability loss.

  o Minor features (build):
    - Tor now builds correctly on Bitrig, an OpenBSD fork. Patch from
      dhill. Resolves ticket 6982.
    - Compile on win64 using mingw64. Fixes bug 7260; patches from
      "yayooo".
    - Work correctly on Unix systems where EAGAIN and EWOULDBLOCK are
      separate error codes; or at least, don't break for that reason.
      Fixes bug 7935. Reported by "oftc_must_be_destroyed".

  o Build improvements (autotools):
    - Warn if building on a platform with an unsigned time_t: there
      are too many places where Tor currently assumes that time_t can
      hold negative values. We'd like to fix them all, but probably
      some will remain.
    - Do not report status verbosely from autogen.sh unless the -v flag
      is specified. Fixes issue 4664. Patch from Onizuka.
    - Detect and reject attempts to build Tor with threading support
      when OpenSSL has been compiled without threading support.
      Fixes bug 6673.
    - Try to detect if we are ever building on a platform where
      memset(...,0,...) does not set the value of a double to 0.0. Such
      platforms are permitted by the C standard, though in practice
      they're pretty rare (since IEEE 754 is nigh-ubiquitous). We don't
      currently support them, but it's better to detect them and fail
      than to perform erroneously.
    - We no longer warn so much when generating manpages from their
      asciidoc source.
    - Use Ville Laurikari's implementation of AX_CHECK_SIGN() to determine
      the signs of types during autoconf. This is better than our old
      approach, which didn't work when cross-compiling.

  o Minor features (log messages, warnings):
    - Detect when we're running with a version of OpenSSL other than the
      one we compiled with. This conflict has occasionally given people
      hard-to-track-down errors.
    - Warn users who run hidden services on a Tor client with
      UseEntryGuards disabled that their hidden services will be
      vulnerable to http://freehaven.net/anonbib/#hs-attack06 (the
      attack which motivated Tor to support entry guards in the first
      place). Resolves ticket 6889.
    - Warn when we are binding low ports when hibernation is enabled;
      previously we had warned when we were _advertising_ low ports with
      hibernation enabled. Fixes bug 7285; bugfix on 0.2.3.9-alpha.
    - Issue a warning when running with the bufferevents backend enabled.
      It's still not stable, and people should know that they're likely
      to hit unexpected problems. Closes ticket 9147.

  o Minor features (log messages, notices):
    - Refactor resolve_my_address() so it returns the method by which we
      decided our public IP address (explicitly configured, resolved from
      explicit hostname, guessed from interfaces, learned by gethostname).
      Now we can provide more helpful log messages when a relay guesses
      its IP address incorrectly (e.g. due to unexpected lines in
      /etc/hosts). Resolves ticket 2267.
    - Track how many "TAP" and "NTor" circuit handshake requests we get,
      and how many we complete, and log it every hour to help relay
      operators follow trends in network load. Addresses ticket 9658.

  o Minor features (log messages, diagnostics):
    - If we fail to free a microdescriptor because of bug 7164, log
      the filename and line number from which we tried to free it.
    - We compute the overhead from passing onionskins back and forth to
      cpuworkers, and report it when dumping statistics in response to
      SIGUSR1. Supports ticket 7291.
    - Add another diagnostic to the heartbeat message: track and log
      overhead that TLS is adding to the data we write. If this is
      high, we are sending too little data to SSL_write at a time.
      Diagnostic for bug 7707.
    - Log packaged cell fullness as part of the heartbeat message.
      Diagnosis to try to determine the extent of bug 7743.
    - Add more detail to a log message about relaxed timeouts, to help
      track bug 7799.
    - When learning a fingerprint for a bridge, log its corresponding
      transport type. Implements ticket 7896.
    - Warn more aggressively when flushing microdescriptors to a
      microdescriptor cache fails, in an attempt to mitigate bug 8031,
      or at least make it more diagnosable.
    - Improve the log message when "Bug/attack: unexpected sendme cell
      from client" occurs, to help us track bug 8093.
    - Improve debugging output to help track down bug 8185 ("Bug:
      outgoing relay cell has n_chan==NULL. Dropping.")

  o Minor features (log messages, quieter bootstrapping):
    - Log fewer lines at level "notice" about our OpenSSL and Libevent
      versions and capabilities when everything is going right. Resolves
      part of ticket 6736.
    - Omit the first heartbeat log message, because it never has anything
      useful to say, and it clutters up the bootstrapping messages.
      Resolves ticket 6758.
    - Don't log about reloading the microdescriptor cache at startup. Our
      bootstrap warnings are supposed to tell the user when there's a
      problem, and our bootstrap notices say when there isn't. Resolves
      ticket 6759; bugfix on 0.2.2.6-alpha.
    - Don't log "I learned some more directory information" when we're
      reading cached directory information. Reserve it for when new
      directory information arrives in response to a fetch. Resolves
      ticket 6760.
    - Don't complain about bootstrapping problems while hibernating.
      These complaints reflect a general code problem, but not one
      with any problematic effects (no connections are actually
      opened). Fixes part of bug 7302; bugfix on 0.2.3.2-alpha.

  o Minor features (testing):
    - In our testsuite, create temporary directories with a bit more
      entropy in their name to make name collisions less likely. Fixes
      bug 8638.
    - Add benchmarks for DH (1024-bit multiplicative group) and ECDH
      (P-256) Diffie-Hellman handshakes to src/or/bench.
    - Add benchmark functions to test onion handshake performance.

  o Renamed options:
    - The DirServer option is now DirAuthority, for consistency with
      current naming patterns. You can still use the old DirServer form.

  o Minor bugfixes (protocol):
    - Fix the handling of a TRUNCATE cell when it arrives while the
      circuit extension is in progress. Fixes bug 7947; bugfix on 0.0.7.1.
    - When a Tor client gets a "truncated" relay cell, the first byte of
      its payload specifies why the circuit was truncated. We were
      ignoring this 'reason' byte when tearing down the circuit, resulting
      in the controller not being told why the circuit closed. Now we
      pass the reason from the truncated cell to the controller. Bugfix
      on 0.1.2.3-alpha; fixes bug 7039.
    - Fix a misframing issue when reading the version numbers in a
      VERSIONS cell. Previously we would recognize [00 01 00 02] as
      'version 1, version 2, and version 0x100', when it should have
      only included versions 1 and 2. Fixes bug 8059; bugfix on
      0.2.0.10-alpha. Reported pseudonymously.
    - Make the format and order of STREAM events for DNS lookups
      consistent among the various ways to launch DNS lookups. Fixes
      bug 8203; bugfix on 0.2.0.24-rc. Patch by "Desoxy".

  o Minor bugfixes (syscalls and disk interaction):
    - Always check the return values of functions fcntl() and
      setsockopt(). We don't believe these are ever actually failing in
      practice, but better safe than sorry. Also, checking these return
      values should please analysis tools like Coverity. Patch from
      'flupzor'. Fixes bug 8206; bugfix on all versions of Tor.
    - Avoid double-closing the listener socket in our socketpair()
      replacement (used on Windows) in the case where the addresses on
      our opened sockets don't match what we expected. Fixes bug 9400;
      bugfix on 0.0.2pre7. Found by Coverity.
    - Correctly store microdescriptors and extrainfo descriptors that
      include an internal NUL byte. Fixes bug 8037; bugfix on
      0.2.0.1-alpha. Bug reported by "cypherpunks".
    - If for some reason we fail to write a microdescriptor while
      rebuilding the cache, do not let the annotations from that
      microdescriptor linger in the cache file, and do not let the
      microdescriptor stay recorded as present in its old location.
      Fixes bug 9047; bugfix on 0.2.2.6-alpha.
    - Use direct writes rather than stdio when building microdescriptor
      caches, in an attempt to mitigate bug 8031, or at least make it
      less common.

  o Minor fixes (config options):
    - Warn and fail if a server is configured not to advertise any
      ORPorts at all. (We need *something* to put in our descriptor,
      or we just won't work.)
    - Behave correctly when the user disables LearnCircuitBuildTimeout
      but doesn't tell us what they would like the timeout to be. Fixes
      bug 6304; bugfix on 0.2.2.14-alpha.
    - Rename the (internal-use-only) UsingTestingNetworkDefaults option
      to start with a triple-underscore so the controller won't touch it.
      Patch by Meejah. Fixes bug 3155. Bugfix on 0.2.2.23-alpha.
    - Rename the (testing-use-only) _UseFilteringSSLBufferevents option
      so it doesn't start with _. Fixes bug 3155. Bugfix on 0.2.3.1-alpha.
    - When autodetecting the number of CPUs, use the number of available
      CPUs in preference to the number of configured CPUs. Inform the
      user if this reduces the number of available CPUs. Fixes bug 8002;
      bugfix on 0.2.3.1-alpha.
    - Command-line option "--version" implies "--quiet". Fixes bug 6997.
    - Make it an error when you set EntryNodes but disable UseGuardNodes,
      since it will (surprisingly to some users) ignore EntryNodes. Fixes
      bug 8180; bugfix on 0.2.3.11-alpha.
    - Avoid overflows when the user sets MaxCircuitDirtiness to a
      ridiculously high value, by imposing a (ridiculously high) 30-day
      maximum on MaxCircuitDirtiness.

  o Minor bugfixes (control protocol):
    - Stop sending a stray "(null)" in some cases for the server status
      "EXTERNAL_ADDRESS" controller event. Resolves bug 8200; bugfix
      on 0.1.2.6-alpha.
    - The ADDRMAP command can no longer generate an ill-formed error
      code on a failed MAPADDRESS. It now says "internal" rather than
      an English sentence fragment with spaces in the middle. Bugfix on
      Tor 0.2.0.19-alpha.

  o Minor bugfixes (clients / edges):
    - When we receive a RELAY_END cell with the reason DONE, or with no
      reason, before receiving a RELAY_CONNECTED cell, report the SOCKS
      status as "connection refused". Previously we reported these cases
      as success but then immediately closed the connection. Fixes bug
      7902; bugfix on 0.1.0.1-rc. Reported by "oftc_must_be_destroyed".
    - If the guard we choose first doesn't answer, we would try the
      second guard, but once we connected to the second guard we would
      abandon it and retry the first one, slowing down bootstrapping.
      The fix is to treat all our initially chosen guards as acceptable
      to use. Fixes bug 9946; bugfix on 0.1.1.11-alpha.
    - When choosing which stream on a formerly stalled circuit to wake
      first, make better use of the platform's weak RNG. Previously,
      we had been using the % ("modulo") operator to try to generate a
      1/N chance of picking each stream, but this behaves badly with
      many platforms' choice of weak RNG. Fixes bug 7801; bugfix on
      0.2.2.20-alpha.

  o Minor bugfixes (path bias detection):
    - If the state file's path bias counts are invalid (presumably from a
      buggy Tor prior to 0.2.4.10-alpha), make them correct. Also add
      additional checks and log messages to the scaling of Path Bias
      counts, in case there still are remaining issues with scaling.
      Should help resolve bug 8235.
    - Prevent rounding error in path bias counts when scaling
      them down, and use the correct scale factor default. Also demote
      some path bias related log messages down a level and make others
      less scary sounding. Fixes bug 6647. Bugfix on 0.2.3.17-beta.
    - Remove a source of rounding error during path bias count scaling;
      don't count cannibalized circuits as used for path bias until we
      actually try to use them; and fix a circuit_package_relay_cell()
      warning message about n_chan==NULL. Fixes bug 7802.
    - Paste the description for PathBias parameters from the man
      page into or.h, so the code documents them too. Fixes bug 7982;
      bugfix on 0.2.3.17-beta.

  o Minor bugfixes (relays):
    - Stop trying to resolve our hostname so often (e.g. every time we
      think about doing a directory fetch). Now we reuse the cached
      answer in some cases. Fixes bugs 1992 (bugfix on 0.2.0.20-rc)
      and 2410 (bugfix on 0.1.2.2-alpha).
    - When examining the list of network interfaces to find our address,
      do not consider non-running or disabled network interfaces. Fixes
      bug 9904; bugfix on 0.2.3.11-alpha. Patch from "hantwister".

  o Minor bugfixes (blocking resistance):
    - Only disable TLS session ticket support when running as a TLS
      server. Now clients will blend better with regular Firefox
      connections. Fixes bug 7189; bugfix on Tor 0.2.3.23-rc.

  o Minor bugfixes (IPv6):
    - Use square brackets around IPv6 addresses in numerous places
      that needed them, including log messages, HTTPS CONNECT proxy
      requests, TransportProxy statefile entries, and pluggable transport
      extra-info lines. Fixes bug 7011; patch by David Fifield.

  o Minor bugfixes (directory authorities):
    - Reject consensus votes with more than 64 known-flags. We aren't even
      close to that limit yet, and our code doesn't handle it correctly.
      Fixes bug 6833; bugfix on 0.2.0.1-alpha.
    - Correctly handle votes with more than 31 flags. Fixes bug 6853;
      bugfix on 0.2.0.3-alpha.

  o Minor bugfixes (memory leaks):
    - Avoid leaking memory if we fail to compute a consensus signature
      or we generate a consensus we can't parse. Bugfix on 0.2.0.5-alpha.
    - Fix a memory leak when receiving headers from an HTTPS proxy. Bugfix
      on 0.2.1.1-alpha; fixes bug 7816.
    - Fix a memory leak during safe-cookie controller authentication.
      Bugfix on 0.2.3.13-alpha; fixes bug 7816.
    - Free some more still-in-use memory at exit, to make hunting for
      memory leaks easier. Resolves bug 7029.

  o Minor bugfixes (code correctness):
    - Increase the width of the field used to remember a connection's
      link protocol version to two bytes. Harmless for now, since the
      only currently recognized versions are one byte long. Reported
      pseudonymously. Fixes bug 8062; bugfix on 0.2.0.10-alpha.
    - Fix a crash when debugging unit tests on Windows: deallocate a
      shared library with FreeLibrary, not CloseHandle. Fixes bug 7306;
      bugfix on 0.2.2.17-alpha. Reported by "ultramage".
    - When detecting the largest possible file descriptor (in order to
      close all file descriptors when launching a new program), actually
      use _SC_OPEN_MAX. The old code for doing this was very, very broken.
      Fixes bug 8209; bugfix on 0.2.3.1-alpha. Found by Coverity; this
      is CID 743383.
    - Avoid a crash if we fail to generate an extrainfo descriptor.
      Fixes bug 8208; bugfix on 0.2.3.16-alpha. Found by Coverity;
      this is CID 718634.
    - Avoid an off-by-one error when checking buffer boundaries when
      formatting the exit status of a pluggable transport helper.
      This is probably not an exploitable bug, but better safe than
      sorry. Fixes bug 9928; bugfix on 0.2.3.18-rc. Bug found by
      Pedro Ribeiro.
    - Get rid of a couple of harmless clang warnings, where we compared
      enums to ints. These warnings are newly introduced in clang 3.2.

  o Minor bugfixes (code cleanliness):
    - Avoid use of reserved identifiers in our C code. The C standard
      doesn't like us declaring anything that starts with an
      underscore, so let's knock it off before we get in trouble. Fix
      for bug 1031; bugfix on the first Tor commit.
    - Fix round_to_power_of_2() so it doesn't invoke undefined behavior
      with large values. This situation was untriggered, but nevertheless
      incorrect. Fixes bug 6831; bugfix on 0.2.0.1-alpha.
    - Fix an impossible buffer overrun in the AES unit tests. Fixes
      bug 8845; bugfix on 0.2.0.7-alpha. Found by eugenis.
    - Fix handling of rendezvous client authorization types over 8.
      Fixes bug 6861; bugfix on 0.2.1.5-alpha.
    - Remove a couple of extraneous semicolons that were upsetting the
      cparser library. Patch by Christian Grothoff. Fixes bug 7115;
      bugfix on 0.2.2.1-alpha.
    - When complaining about a client port on a public address, log
      which address we're complaining about. Fixes bug 4020; bugfix on
      0.2.3.3-alpha. Patch by Tom Fitzhenry.

  o Minor bugfixes (log messages, warnings):
    - If we encounter a write failure on a SOCKS connection before we
      finish our SOCKS handshake, don't warn that we closed the
      connection before we could send a SOCKS reply. Fixes bug 8427;
      bugfix on 0.1.0.1-rc.
    - Fix a directory authority warn caused when we have a large amount
      of badexit bandwidth. Fixes bug 8419; bugfix on 0.2.2.10-alpha.
    - Downgrade "Failed to hand off onionskin" messages to "debug"
      severity, since they're typically redundant with the "Your computer
      is too slow" messages. Fixes bug 7038; bugfix on 0.2.2.16-alpha.
    - Avoid spurious warnings when configuring multiple client ports of
      which only some are nonlocal. Previously, we had claimed that some
      were nonlocal when in fact they weren't. Fixes bug 7836; bugfix on
      0.2.3.3-alpha.

  o Minor bugfixes (log messages, other):
    - Fix log messages and comments to avoid saying "GMT" when we mean
      "UTC". Fixes bug 6113.
    - When rejecting a configuration because we were unable to parse a
      quoted string, log an actual error message. Fixes bug 7950; bugfix
      on 0.2.0.16-alpha.
    - Correctly recognize that [::1] is a loopback address. Fixes
      bug 8377; bugfix on 0.2.1.3-alpha.
    - Don't log inappropriate heartbeat messages when hibernating: a
      hibernating node is _expected_ to drop out of the consensus,
      decide it isn't bootstrapped, and so forth. Fixes bug 7302;
      bugfix on 0.2.3.1-alpha.
    - Eliminate several instances where we use "Nickname=ID" to refer to
      nodes in logs. Use "Nickname (ID)" instead. (Elsewhere, we still use
      "$ID=Nickname", which is also acceptable.) Fixes bug 7065. Bugfix
      on 0.2.3.21-rc.

  o Minor bugfixes (build):
    - Fix some bugs in tor-fw-helper-natpmp when trying to build and
      run it on Windows. More bugs likely remain. Patch from Gisle Vanem.
      Fixes bug 7280; bugfix on 0.2.3.1-alpha.

  o Documentation fixes:
    - Make the torify manpage no longer refer to tsocks; torify hasn't
      supported tsocks since 0.2.3.14-alpha.
    - Make the tor manpage no longer reference tsocks.
    - Fix the GeoIPExcludeUnknown documentation to refer to
      ExcludeExitNodes rather than the currently nonexistent
      ExcludeEntryNodes. Spotted by "hamahangi" on tor-talk.
    - Resolve a typo in torrc.sample.in. Fixes bug 6819; bugfix on
      0.2.3.14-alpha.
    - Say "KBytes" rather than "KB" in the man page (for various values
      of K), to further reduce confusion about whether Tor counts in
      units of memory or fractions of units of memory. Resolves ticket 7054.
    - Update tor-fw-helper.1.txt and tor-fw-helper.c to make option
      names match. Fixes bug 7768.
    - Fix the documentation of HeartbeatPeriod to say that the heartbeat
      message is logged at notice, not at info.
    - Clarify the usage and risks of setting the ContactInfo torrc line
      for your relay or bridge. Resolves ticket 9854.
    - Add anchors to the manpage so we can link to the html version of
      the documentation for specific options. Resolves ticket 9866.
    - Replace remaining references to DirServer in man page and
      log entries. Resolves ticket 10124.

  o Removed features:
    - Stop exporting estimates of v2 and v3 directory traffic shares
      in extrainfo documents. They were unneeded and sometimes inaccurate.
      Also stop exporting any v2 directory request statistics. Resolves
      ticket 5823.
    - Drop support for detecting and warning about versions of Libevent
      before 1.3e. Nothing reasonable ships with them any longer; warning
      the user about them shouldn't be needed. Resolves ticket 6826.
    - Now that all versions before 0.2.2.x are disallowed, we no longer
      need to work around their missing features. Remove a bunch of
      compatibility code.

  o Removed files:
    - The tor-tsocks.conf is no longer distributed or installed. We
      recommend that tsocks users use torsocks instead. Resolves
      ticket 8290.
    - Remove some of the older contents of doc/ as obsolete; move others
      to torspec.git. Fixes bug 8965.

  o Code simplification:
    - Avoid using character buffers when constructing most directory
      objects: this approach was unwieldy and error-prone. Instead,
      build smartlists of strings, and concatenate them when done.
    - Rename "isin" functions to "contains", for grammar. Resolves
      ticket 5285.
    - Rename Tor's logging function log() to tor_log(), to avoid conflicts
      with the natural logarithm function from the system libm. Resolves
      ticket 7599.
    - Start using OpenBSD's implementation of queue.h, so that we don't
      need to hand-roll our own pointer and list structures whenever we
      need them. (We can't rely on a sys/queue.h, since some operating
      systems don't have them, and the ones that do have them don't all
      present the same extensions.)
    - Start using OpenBSD's implementation of queue.h (originally by
      Niels Provos).
    - Enhance our internal sscanf replacement so that we can eliminate
      the last remaining uses of the system sscanf. (Though those uses
      of sscanf were safe, sscanf itself is generally error prone, so
      we want to eliminate when we can.) Fixes ticket 4195 and Coverity
      CID 448.
    - Replace all calls to snprintf() outside of src/ext with
      tor_snprintf(). Also remove the #define to replace snprintf with
      _snprintf on Windows; they have different semantics, and all of
      our callers should be using tor_snprintf() anyway. Fixes bug 7304.

  o Refactoring:
    - Add a wrapper function for the common "log a message with a
      rate-limit" case.
    - Split the onion.c file into separate modules for the onion queue
      and the different handshakes it supports.
    - Move the client-side address-map/virtual-address/DNS-cache code
      out of connection_edge.c into a new addressmap.c module.
    - Move the entry node code from circuitbuild.c to its own file.
    - Move the circuit build timeout tracking code from circuitbuild.c
      to its own file.
    - Source files taken from other packages now reside in src/ext;
      previously they were scattered around the rest of Tor.
    - Move the generic "config" code into a new file, and have "config.c"
      hold only torrc- and state-related code. Resolves ticket 6823.
    - Move the core of our "choose a weighted element at random" logic
      into its own function, and give it unit tests. Now the logic is
      testable, and a little less fragile too.
    - Move ipv6_preferred from routerinfo_t to node_t. Addresses bug 4620.
    - Move last_reachable and testing_since from routerinfo_t to node_t.
      Implements ticket 5529.
    - Add replaycache_t structure, functions and unit tests, then refactor
      rend_service_introduce() to be more clear to read, improve, debug,
      and test. Resolves bug 6177.

  o Removed code:
    - Remove some now-needless code that tried to aggressively flush
      OR connections as data was added to them. Since 0.2.0.1-alpha, our
      cell queue logic has saved us from the failure mode that this code
      was supposed to prevent. Removing this code will limit the number
      of baroque control flow paths through Tor's network logic. Reported
      pseudonymously on IRC. Fixes bug 6468; bugfix on 0.2.0.1-alpha.
    - Remove unused code for parsing v1 directories and "running routers"
      documents. Fixes bug 6887.
    - Remove the marshalling/unmarshalling code for sending requests to
      cpuworkers over a socket, and instead just send structs. The
      recipient will always be the same Tor binary as the sender, so
      any encoding is overkill.
    - Remove the testing_since field of node_t, which hasn't been used
      for anything since 0.2.0.9-alpha.
    - Finally remove support for malloc_good_size and malloc_usable_size.
      We had hoped that these functions would let us eke a little more
      memory out of our malloc implementation. Unfortunately, the only
      implementations that provided these functions are also ones that
      are already efficient about not overallocation: they never got us
      more than 7 or so bytes per allocation. Removing them saves us a
      little code complexity and a nontrivial amount of build complexity.


Changes in version 0.2.3.25 - 2012-11-19
  The Tor 0.2.3 release series is dedicated to the memory of Len "rabbi"
  Sassaman (1980-2011), a long-time cypherpunk, anonymity researcher,
  Mixmaster maintainer, Pynchon Gate co-designer, CodeCon organizer,
  programmer, and friend. Unstinting in his dedication to the cause of
  freedom, he inspired and helped many of us as we began our work on
  anonymity, and inspires us still. Please honor his memory by writing
  software to protect people's freedoms, and by helping others to do so.

  Tor 0.2.3.25, the first stable release in the 0.2.3 branch, features
  significantly reduced directory overhead (via microdescriptors),
  enormous crypto performance improvements for fast relays on new
  enough hardware, a new v3 TLS handshake protocol that can better
  resist fingerprinting, support for protocol obfuscation plugins (aka
  pluggable transports), better scalability for hidden services, IPv6
  support for bridges, performance improvements like allowing clients
  to skip the first round-trip on the circuit ("optimistic data") and
  refilling token buckets more often, a new "stream isolation" design
  to isolate different applications on different circuits, and many
  stability, security, and privacy fixes.

  Major features (v3 directory protocol):
    - Clients now use microdescriptors instead of regular descriptors
      to build circuits. Microdescriptors are authority-generated
      summaries of regular descriptors' contents, designed to change very
      rarely (see proposal 158 for details). This feature is designed
      to save bandwidth, especially for clients on slow internet
      connections. Use "UseMicrodescriptors 0" to disable it.
    - Caches now download, cache, and serve microdescriptors, as well
      as multiple "flavors" of the consensus, including a flavor that
      describes microdescriptors.

  o Major features (build hardening):
    - Enable gcc and ld hardening by default. Resolves ticket 5210.

  o Major features (relay scaling):
    - When built to use OpenSSL 1.0.1, and built for an x86 or x86_64
      instruction set, take advantage of OpenSSL's AESNI, bitsliced, or
      vectorized AES implementations as appropriate. These can be much,
      much faster than other AES implementations.
    - When using OpenSSL 1.0.0 or later, use OpenSSL's counter mode
      implementation. It makes AES_CTR about 7% faster than our old one
      (which was about 10% faster than the one OpenSSL used to provide).
      Resolves ticket 4526.
    - Use OpenSSL's EVP interface for AES encryption, so that all AES
      operations can use hardware acceleration (if present). Resolves
      ticket 4442.
    - Unconditionally use OpenSSL's AES implementation instead of our
      old built-in one. OpenSSL's AES has been better for a while, and
      relatively few servers should still be on any version of OpenSSL
      that doesn't have good optimized assembly AES.

  o Major features (blocking resistance):
    - Update TLS cipher list to match Firefox 8 and later. Resolves
      ticket 4744.
    - Remove support for clients falsely claiming to support standard
      ciphersuites that they can actually provide. As of modern OpenSSL
      versions, it's not necessary to fake any standard ciphersuite,
      and doing so prevents us from using better ciphersuites in the
      future, since servers can't know whether an advertised ciphersuite
      is really supported or not. Some hosts -- notably, ones with very
      old versions of OpenSSL or where OpenSSL has been built with ECC
      disabled -- will stand out because of this change; TBB users should
      not be affected. Implements the client side of proposal 198.
    - Implement a new handshake protocol (v3) for authenticating Tors to
      each other over TLS. It should be more resistant to fingerprinting
      than previous protocols, and should require less TLS hacking for
      future Tor implementations. Implements proposal 176.
    - Allow variable-length padding cells, to disguise the length of
      Tor's TLS records. Implements part of proposal 184.
    - While we're trying to bootstrap, record how many TLS connections
      fail in each state, and report which states saw the most failures
      in response to any bootstrap failures. This feature may speed up
      diagnosis of censorship events. Implements ticket 3116.

  o Major features (pluggable transports):
    - Clients and bridges can now be configured to use a separate
      "transport" proxy. This approach makes the censorship arms race
      easier by allowing bridges to use protocol obfuscation plugins.
      Implements proposal 180 (tickets 2841 and 3472).

  o Major features (DoS resistance):
    - Now that Tor 0.2.0.x is completely deprecated, enable the final
      part of "Proposal 110: Avoiding infinite length circuits" by
      refusing all circuit-extend requests that do not use a relay_early
      cell. This change helps Tor resist a class of denial-of-service
      attacks by limiting the maximum circuit length.
    - Tear down the circuit if we get an unexpected SENDME cell. Clients
      could use this trick to make their circuits receive cells faster
      than our flow control would have allowed, or to gum up the network,
      or possibly to do targeted memory denial-of-service attacks on
      entry nodes. Fixes bug 6252. Bugfix on the 54th commit on Tor --
      from July 2002, before the release of Tor 0.0.0.

  o Major features (hidden services):
    - Adjust the number of introduction points that a hidden service
      will try to maintain based on how long its introduction points
      remain in use and how many introductions they handle. Fixes
      part of bug 3825.
    - Add a "tor2web mode" for clients that want to connect to hidden
      services non-anonymously (and possibly more quickly). As a safety
      measure to try to keep users from turning this on without knowing
      what they are doing, tor2web mode must be explicitly enabled at
      compile time, and a copy of Tor compiled to run in tor2web mode
      cannot be used as a normal Tor client. Implements feature 2553.

  o Major features (IPv6):
    - Clients can now connect to private bridges over IPv6. Bridges
      still need at least one IPv4 address in order to connect to
      other relays. Note that we don't yet handle the case where the
      user has two bridge lines for the same bridge (one IPv4, one
      IPv6). Implements parts of proposal 186.

  o Major features (directory authorities):
    - Use a more secure consensus parameter voting algorithm. Now at
      least three directory authorities or a majority of them must
      vote on a given parameter before it will be included in the
      consensus. Implements proposal 178.
    - Remove the artificially low cutoff of 20KB to guarantee the Fast
      flag. In the past few years the average relay speed has picked
      up, and while the "top 7/8 of the network get the Fast flag" and
      "all relays with 20KB or more of capacity get the Fast flag" rules
      used to have the same result, now the top 7/8 of the network has
      a capacity more like 32KB. Bugfix on 0.2.1.14-rc. Fixes bug 4489.

  o Major features (performance):
    - Exit nodes now accept and queue data on not-yet-connected streams.
      Previously, the client wasn't allowed to send data until the
      stream was connected, which slowed down all connections. This
      change will enable clients to perform a "fast-start" on streams
      and send data without having to wait for a confirmation that the
      stream has opened. Patch from Ian Goldberg; implements the server
      side of Proposal 174.
    - When using an exit relay running 0.2.3.x, clients can now
      "optimistically" send data before the exit relay reports that
      the stream has opened. This saves a round trip when starting
      connections where the client speaks first (such as web browsing).
      This behavior is controlled by a consensus parameter (currently
      disabled). To turn it on or off manually, use the "OptimisticData"
      torrc option. Implements proposal 181; code by Ian Goldberg.
    - Add a new TokenBucketRefillInterval option to refill token buckets
      more frequently than once per second. This should improve network
      performance, alleviate queueing problems, and make traffic less
      bursty. Implements proposal 183; closes ticket 3630. Design by
      Florian Tschorsch and Björn Scheuermann; implementation by
      Florian Tschorsch.
    - Raise the threshold of server descriptors needed (75%) and exit
      server descriptors needed (50%) before we will declare ourselves
      bootstrapped. This will make clients start building circuits a
      little later, but makes the initially constructed circuits less
      skewed and less in conflict with further directory fetches. Fixes
      ticket 3196.

  o Major features (relays):
    - Relays now try regenerating and uploading their descriptor more
      frequently if they are not listed in the consensus, or if the
      version of their descriptor listed in the consensus is too
      old. This fix should prevent situations where a server declines
      to re-publish itself because it has done so too recently, even
      though the authorities decided not to list its recent-enough
      descriptor. Fix for bug 3327.

  o Major features (stream isolation):
    - You can now configure Tor so that streams from different
      applications are isolated on different circuits, to prevent an
      attacker who sees your streams as they leave an exit node from
      linking your sessions to one another. To do this, choose some way
      to distinguish the applications: have them connect to different
      SocksPorts, or have one of them use SOCKS4 while the other uses
      SOCKS5, or have them pass different authentication strings to the
      SOCKS proxy. Then, use the new SocksPort syntax to configure the
      degree of isolation you need. This implements Proposal 171.
    - There's a new syntax for specifying multiple client ports (such as
      SOCKSPort, TransPort, DNSPort, NATDPort): you can now just declare
      multiple *Port entries with full addr:port syntax on each.
      The old *ListenAddress format is still supported, but you can't
      mix it with the new *Port syntax.

  o Major features (bufferevents):
    - Tor can now optionally build with the "bufferevents" buffered IO
      backend provided by Libevent 2. To use this feature, make sure you
      have the latest possible version of Libevent, and pass the
      --enable-bufferevents flag to configure when building Tor from
      source. This feature will make our networking code more flexible,
      let us stack layers on each other, and let us use more efficient
      zero-copy transports where available.
    - Add experimental support for running on Windows with IOCP and no
      kernel-space socket buffers. This feature is controlled by a new
      "UserspaceIOCPBuffers" config option (off by default), which has
      no effect unless Tor has been built with bufferevents enabled,
      you're running on Windows, and you've set "DisableIOCP 0". In the
      long run, this may help solve or mitigate bug 98.

  o Major features (path selection):
    - The EntryNodes option can now include country codes like {de} or IP
      addresses or network masks. Previously we had disallowed these
      options because we didn't have an efficient way to keep the list up
      to date. Addresses ticket 1982, but see bug 2798 for an unresolved
      issue here.

  o Major features (port forwarding):
    - Add support for automatic port mapping on the many home routers
      that support NAT-PMP or UPnP. To build the support code, you'll
      need to have the libnatpnp library and/or the libminiupnpc library,
      and you'll need to enable the feature specifically by passing
      "--enable-upnp" and/or "--enable-natpnp" to ./configure. To turn
      it on, use the new PortForwarding option.

  o Major features (logging):
    - Add a new 'Heartbeat' log message type to periodically log a message
      describing Tor's status at level Notice. This feature is meant for
      operators who log at notice, and want to make sure that their Tor
      server is still working. Implementation by George Kadianakis.
    - Make logging resolution configurable with a new LogTimeGranularity
      option, and change the default from 1 millisecond to 1 second.
      Implements enhancement 1668.

  o Major features (other):
    - New "DisableNetwork" config option to prevent Tor from launching any
      connections or accepting any connections except on a control port.
      Bundles and controllers can set this option before letting Tor talk
      to the rest of the network, for example to prevent any connections
      to a non-bridge address. Packages like Orbot can also use this
      option to instruct Tor to save power when the network is off.
    - Try to use system facilities for enumerating local interface
      addresses, before falling back to our old approach (which was
      binding a UDP socket, and calling getsockname() on it). That
      approach was scaring OS X users whose draconian firewall
      software warned about binding to UDP sockets regardless of
      whether packets were sent. Now we try to use getifaddrs(),
      SIOCGIFCONF, or GetAdaptersAddresses(), depending on what the
      system supports. Resolves ticket 1827.
    - Add experimental support for a "defaults" torrc file to be parsed
      before the regular torrc. Torrc options override the defaults file's
      options in the same way that the command line overrides the torrc.
      The SAVECONF controller command saves only those options which
      differ between the current configuration and the defaults file. HUP
      reloads both files. Implements task 4552.

  o New directory authorities:
    - Add Faravahar (run by Sina Rabbani) as the ninth v3 directory
      authority. Closes ticket 5749.

  o Security/privacy fixes:
    - Avoid read-from-freed-memory and double-free bugs that could occur
      when a DNS request fails while launching it. Fixes bug 6480;
      bugfix on 0.2.0.1-alpha.
    - Reject any attempt to extend to an internal address. Without
      this fix, a router could be used to probe addresses on an internal
      network to see whether they were accepting connections. Fixes bug
      6710; bugfix on 0.0.8pre1.
    - Close any connection that sends unrecognized junk before the TLS
      handshake. Solves an issue noted in bug 4369.
    - The advertised platform of a relay now includes only its operating
      system's name (e.g., "Linux", "Darwin", "Windows 7"), and not
      its service pack level (for Windows) or its CPU architecture
      (for Unix). Also drop the "git-XYZ" tag in the version. Packagers
      can insert an extra string in the platform line by setting the
      preprocessor variable TOR_BUILD_TAG. Resolves bug 2988.
    - Disable TLS session tickets. OpenSSL's implementation was giving
      our TLS session keys the lifetime of our TLS context objects, when
      perfect forward secrecy would want us to discard anything that
      could decrypt a link connection as soon as the link connection
      was closed. Fixes bug 7139; bugfix on all versions of Tor linked
      against OpenSSL 1.0.0 or later. Found by Florent Daignière.
    - Tor tries to wipe potentially sensitive data after using it, so
      that if some subsequent security failure exposes Tor's memory,
      the damage will be limited. But we had a bug where the compiler
      was eliminating these wipe operations when it decided that the
      memory was no longer visible to a (correctly running) program,
      hence defeating our attempt at defense in depth. We fix that
      by using OpenSSL's OPENSSL_cleanse() operation, which a compiler
      is unlikely to optimize away. Future versions of Tor may use
      a less ridiculously heavy approach for this. Fixes bug 7352.
      Reported in an article by Andrey Karpov.

  o Major bugfixes (crashes and asserts):
    - Avoid a pair of double-free and use-after-mark bugs that can
      occur with certain timings in canceled and re-received DNS
      requests. Fixes bug 6472; bugfix on 0.0.7rc1.
    - Fix a denial of service attack by which any directory authority
      could crash all the others, or by which a single v2 directory
      authority could crash everybody downloading v2 directory
      information. Fixes bug 7191; bugfix on 0.2.0.10-alpha.
    - Fix an assert that directory authorities could trigger on sighup
      during some configuration state transitions. We now don't treat
      it as a fatal error when the new descriptor we just generated in
      init_keys() isn't accepted. Fixes bug 4438; bugfix on 0.2.1.9-alpha.
    - Avoid segfault when starting up having run with an extremely old
      version of Tor and parsing its state file. Fixes bug 6801; bugfix
      on 0.2.2.23-alpha.

  o Major bugfixes (clients):
    - If we are unable to find any exit that supports our predicted ports,
      stop calling them predicted, so that we don't loop and build
      hopeless circuits indefinitely. Fixes bug 3296; bugfix on 0.0.9pre6,
      which introduced predicted ports.
    - Check at each new consensus whether our entry guards were picked
      long enough ago that we should rotate them. Previously, we only
      did this check at startup, which could lead to us holding a guard
      indefinitely. Fixes bug 5380; bugfix on 0.2.1.14-rc.
    - When fetching a bridge descriptor from a bridge authority,
      always do so anonymously, whether we have been able to open
      circuits or not. Partial fix for bug 1938; bugfix on 0.2.0.7-alpha.
      This behavior makes it *safer* to use UpdateBridgesFromAuthority,
      but we'll need to wait for bug 6010 before it's actually usable.

  o Major bugfixes (directory voting):
    - Check more thoroughly to prevent a rogue authority from
      double-voting on any consensus directory parameter. Previously,
      authorities would crash in this case if the total number of
      votes for any parameter exceeded the number of active voters,
      but would let it pass otherwise. Partially fixes bug 5786; bugfix
      on 0.2.2.2-alpha.
    - When computing weight parameters, behave more robustly in the
      presence of a bad bwweightscale value. Previously, the authorities
      would crash if they agreed on a sufficiently broken weight_scale
      value; now, they use a reasonable default and carry on. Fixes the
      rest of bug 5786; bugfix on 0.2.2.17-alpha.
    - If authorities are unable to get a v2 consensus document from other
      directory authorities, they no longer fall back to fetching
      them from regular directory caches. Fixes bug 5635; bugfix on
      0.2.2.26-beta, where routers stopped downloading v2 consensus
      documents entirely.

  o Major bugfixes (relays):
    - Fix a bug handling SENDME cells on nonexistent streams that could
      result in bizarre window values. Report and patch contributed
      pseudonymously. Fixes part of bug 6271. This bug was introduced
      before the first Tor release, in svn commit r152.
    - Don't update the AccountingSoftLimitHitAt state file entry whenever
      tor gets started. This prevents a wrong average bandwidth
      estimate, which would cause relays to always start a new accounting
      interval at the earliest possible moment. Fixes bug 2003; bugfix
      on 0.2.2.7-alpha. Reported by Bryon Eldridge, who also helped
      immensely in tracking this bug down.
    - Fix a possible crash bug when checking for deactivated circuits
      in connection_or_flush_from_first_active_circuit(). Fixes bug 6341;
      bugfix on 0.2.2.7-alpha. Bug report and fix received pseudonymously.
    - Set the SO_REUSEADDR socket option before we call bind() on outgoing
      connections. This change should allow busy exit relays to stop
      running out of available sockets as quickly. Fixes bug 4950;
      bugfix on 0.2.2.26-beta.

  o Major bugfixes (blocking resistance):
    - Bridges no longer include their address in NETINFO cells on outgoing
      OR connections, to allow them to blend in better with clients.
      Removes another avenue for enumerating bridges. Reported by
      "troll_un". Fixes bug 4348; bugfix on 0.2.0.10-alpha, when NETINFO
      cells were introduced.
    - Warn the user when HTTPProxy, but no other proxy type, is
      configured. This can cause surprising behavior: it doesn't send
      all of Tor's traffic over the HTTPProxy -- it sends unencrypted
      directory traffic only. Resolves ticket 4663.

  o Major bugfixes (hidden services):
    - Improve hidden service robustness: when an attempt to connect to
      a hidden service ends, be willing to refetch its hidden service
      descriptors from each of the HSDir relays responsible for them
      immediately. Previously, we would not consider refetching the
      service's descriptors from each HSDir for 15 minutes after the last
      fetch, which was inconvenient if the hidden service was not running
      during the first attempt. Bugfix on 0.2.0.18-alpha; fixes bug 3335.
    - Hidden services now ignore the timestamps on INTRODUCE2 cells.
      They used to check that the timestamp was within 30 minutes
      of their system clock, so they could cap the size of their
      replay-detection cache, but that approach unnecessarily refused
      service to clients with wrong clocks. Bugfix on 0.2.1.6-alpha, when
      the v3 intro-point protocol (the first one which sent a timestamp
      field in the INTRODUCE2 cell) was introduced; fixes bug 3460.
    - When one of a hidden service's introduction points appears to be
      unreachable, stop trying it. Previously, we would keep trying
      to build circuits to the introduction point until we lost the
      descriptor, usually because the user gave up and restarted Tor.
      Fixes part of bug 3825.

  o Changes to default torrc file:
    - Stop listing "socksport 9050" in torrc.sample. We open a socks
      port on 9050 by default anyway, so this should not change anything
      in practice.
    - Stop mentioning the deprecated *ListenAddress options in
      torrc.sample. Fixes bug 5438.
    - Document unit of bandwidth-related options in sample torrc.
      Fixes bug 5621.
    - Fix broken URLs in the sample torrc file, and tell readers about
      the OutboundBindAddress, ExitPolicyRejectPrivate, and
      PublishServerDescriptor options. Addresses bug 4652.

  o Minor features (directory authorities):
    - Consider new, removed or changed IPv6 OR ports a non-cosmetic
      change when the authority is deciding whether to accept a newly
      uploaded descriptor. Implements ticket 6423.
    - Directory authorities are now a little more lenient at accepting
      older router descriptors, or newer router descriptors that don't
      make big changes. This should help ameliorate past and future
      issues where routers think they have uploaded valid descriptors,
      but the authorities don't think so. Fix for ticket 2479.
    - Authority operators can now vote for all relays in a given
      set of countries to be BadDir/BadExit/Invalid/Rejected.
    - Provide two consensus parameters (FastFlagMinThreshold and
      FastFlagMaxThreshold) to control the range of allowable bandwidths
      for the Fast directory flag. These allow authorities to run
      experiments on appropriate requirements for being a "Fast" node.
      The AuthDirFastGuarantee config value still applies. Implements
      ticket 3946.

  o Minor features (bridges / bridge authorities):
    - Make bridge SSL certificates a bit more stealthy by using random
      serial numbers, in the same fashion as OpenSSL when generating
      self-signed certificates. Implements ticket 4584.
    - Tag a bridge's descriptor as "never to be sent unencrypted".
      This shouldn't matter, since bridges don't open non-anonymous
      connections to the bridge authority and don't allow unencrypted
      directory connections from clients, but we might as well make
      sure. Closes bug 5139.
    - The Bridge Authority now writes statistics on how many bridge
      descriptors it gave out in total, and how many unique descriptors
      it gave out. It also lists how often the most and least commonly
      fetched descriptors were given out, as well as the median and
      25th/75th percentile. Implements tickets 4200 and 4294.

  o Minor features (IPv6):
    - Make the code that clients use to detect an address change be
      IPv6-aware, so that it won't fill clients' logs with error
      messages when trying to get the IPv4 address of an IPv6
      connection. Implements ticket 5537.
    - Relays now understand an IPv6 address when they get one from a
      directory server. Resolves ticket 4875.

  o Minor features (hidden services):
    - Expire old or over-used hidden service introduction points.
      Required by fix for bug 3460.
    - Reduce the lifetime of elements of hidden services' Diffie-Hellman
      public key replay-detection cache from 60 minutes to 5 minutes. This
      replay-detection cache is now used only to detect multiple
      INTRODUCE2 cells specifying the same rendezvous point, so we can
      avoid launching multiple simultaneous attempts to connect to it.
    - When a hidden service's introduction point times out, consider
      trying it again during the next attempt to connect to the
      HS. Previously, we would not try it again unless a newly fetched
      descriptor contained it. Required by fixes for bugs 1297 and 3825.

  o Minor features (relays):
    - Relays now include a reason for regenerating their descriptors
      in an HTTP header when uploading to the authorities. This will
      make it easier to debug descriptor-upload issues in the future.
    - Turn on directory request statistics by default and include them in
      extra-info descriptors. Don't break if we have no GeoIP database.
    - Replace files in stats/ rather than appending to them. Now that we
      include statistics in extra-info descriptors, it makes no sense to
      keep old statistics forever. Implements ticket 2930.
    - Relays that set "ConnDirectionStatistics 1" write statistics on the
      bidirectional use of connections to disk every 24 hours.
    - Add a GeoIP file digest to the extra-info descriptor. Implements
      ticket 1883.

  o Minor features (new config options):
    - New config option "DynamicDHGroups" (disabled by default) provides
      each bridge with a unique prime DH modulus to be used during
      SSL handshakes. This option attempts to help against censors
      who might use the Apache DH modulus as a static identifier for
      bridges. Addresses ticket 4548.
    - New config option "DisableDebuggerAttachment" (on by default)
      to prevent basic debugging attachment attempts by other processes.
      Supports Mac OS X and Gnu/Linux. Resolves ticket 3313.
    - Ordinarily, Tor does not count traffic from private addresses (like
      127.0.0.1 or 10.0.0.1) when calculating rate limits or accounting.
      There is now a new option, CountPrivateBandwidth, to disable this
      behavior. Patch from Daniel Cagara.

  o Minor features (different behavior for old config options):
    - Allow MapAddress directives to specify matches against super-domains,
      as in "MapAddress *.torproject.org *.torproject.org.torserver.exit".
      Implements issue 933.
    - Don't disable the DirPort when we cannot exceed our AccountingMax
      limit during this interval because the effective bandwidthrate is
      low enough. This is useful in a situation where AccountMax is only
      used as an additional safeguard or to provide statistics.
    - Add port 6523 (Gobby) to LongLivedPorts. Patch by intrigeri;
      implements ticket 3439.
    - When configuring a large set of nodes in EntryNodes, and there are
      enough of them listed as Guard so that we don't need to consider
      the non-guard entries, prefer the ones listed with the Guard flag.
    - If you set the NumCPUs option to 0, Tor will now try to detect how
      many CPUs you have. This is the new default behavior.
    - The NodeFamily option -- which let you declare that you want to
      consider nodes to be part of a family whether they list themselves
      that way or not -- now allows IP address ranges and country codes.

  o Minor features (new command-line config behavior):
    - Slightly change behavior of "list" options (that is, config
      options that can appear more than once) when they appear both in
      torrc and on the command line. Previously, the command-line options
      would be appended to the ones from torrc. Now, the command-line
      options override the torrc options entirely. This new behavior
      allows the user to override list options (like exit policies and
      ports to listen on) from the command line, rather than simply
      appending to the list.
    - You can get the old (appending) command-line behavior for "list"
      options by prefixing the option name with a "+".
    - You can remove all the values for a "list" option from the command
      line without adding any new ones by prefixing the option name
      with a "/".

  o Minor features (controller, new events):
    - Extend the control protocol to report flags that control a circuit's
      path selection in CIRC events and in replies to 'GETINFO
      circuit-status'. Implements part of ticket 2411.
    - Extend the control protocol to report the hidden service address
      and current state of a hidden-service-related circuit in CIRC
      events and in replies to 'GETINFO circuit-status'. Implements part
      of ticket 2411.
    - Include the creation time of a circuit in CIRC and CIRC2
      control-port events and the list produced by the 'GETINFO
      circuit-status' control-port command.
    - Add a new CONF_CHANGED event so that controllers can be notified
      of any configuration changes made by other controllers, or by the
      user. Implements ticket 1692.
    - Add a new SIGNAL event to the controller interface so that
      controllers can be notified when Tor handles a signal. Resolves
      issue 1955. Patch by John Brooks.

  o Minor features (controller, new getinfo options):
    - Expose our view of whether we have gone dormant to the controller,
      via a new "GETINFO dormant" value. Torbutton and other controllers
      can use this to avoid doing periodic requests through Tor while
      it's dormant (bug 4718). Resolves ticket 5954.
    - Add a new GETINFO option to get total bytes read and written. Patch
      from pipe, revised by atagar. Resolves ticket 2345.
    - Implement new GETINFO controller fields to provide information about
      the Tor process's pid, euid, username, and resource limits.

  o Minor features (controller, other):
    - Allow controllers to request an event notification whenever a
      circuit is cannibalized or its purpose is changed. Implements
      part of ticket 3457.
    - Use absolute path names when reporting the torrc filename in the
      control protocol, so a controller can more easily find the torrc
      file. Resolves bug 1101.
    - When reporting the path to the cookie file to the controller,
      give an absolute path. Resolves ticket 4881.

  o Minor features (log messages):
    - Add more information to a log statement that might help track down
      bug 4091. If you're seeing "Bug: tor_addr_is_internal() called with a
      non-IP address" messages (or any Bug messages, for that matter!),
      please let us know about it.
    - If EntryNodes are given, but UseEntryGuards is set to 0, warn that
      EntryNodes will have no effect. Resolves issue 2571.
    - Try to make the introductory warning message that Tor prints on
      startup more useful for actually finding help and information.
      Resolves ticket 2474.
    - When the system call to create a listener socket fails, log the
      error message explaining why. This may help diagnose bug 4027.

  o Minor features (other):
    - When we fail to initialize Libevent, retry with IOCP disabled so we
      don't need to turn on multi-threading support in Libevent, which in
      turn requires a working socketpair(). This is a workaround for bug
      4457, which affects Libevent versions from 2.0.1-alpha through
      2.0.15-stable.
    - When starting as root and then changing our UID via the User
      control option, and we have a ControlSocket configured, make sure
      that the ControlSocket is owned by the same account that Tor will
      run under. Implements ticket 3421; fix by Jérémy Bobbio.
    - Accept attempts to include a password authenticator in the
      handshake, as supported by SOCKS5. This handles SOCKS clients that
      don't know how to omit a password when authenticating. Resolves
      bug 1666.
    - Check for and recover from inconsistency in the microdescriptor
      cache. This will make it harder for us to accidentally free a
      microdescriptor without removing it from the appropriate data
      structures. Fixes issue 3135; issue noted by "wanoskarnet".
    - Shorten links in the tor-exit-notice file. Patch by Christian Kujau.

  o Minor bugfixes (code security):
    - Prevent a null-pointer dereference when receiving a data cell
      for a nonexistent stream when the circuit in question has an
      empty deliver window. We don't believe this is triggerable,
      since we don't currently allow deliver windows to become empty,
      but the logic is tricky enough that it's better to make the code
      robust. Fixes bug 5541; bugfix on 0.0.2pre14.
    - Fix a (harmless) integer overflow in cell statistics reported by
      some fast relays. Fixes bug 5849; bugfix on 0.2.2.1-alpha.
    - Fix our implementation of crypto_random_hostname() so it can't
      overflow on ridiculously large inputs. (No Tor version has ever
      provided this kind of bad inputs, but let's be correct in depth.)
      Fixes bug 4413; bugfix on 0.2.2.9-alpha. Fix by Stephen Palmateer.
    - Add a (probably redundant) memory clear between iterations of
      the router status voting loop, to prevent future coding errors
      where data might leak between iterations of the loop. Resolves
      ticket 6514.

  o Minor bugfixes (wrapper functions):
    - Abort if tor_vasprintf() fails in connection_printf_to_buf() (a
      utility function used in the control-port code). This shouldn't
      ever happen unless Tor is completely out of memory, but if it did
      happen and Tor somehow recovered from it, Tor could have sent a log
      message to a control port in the middle of a reply to a controller
      command. Fixes part of bug 3428; bugfix on 0.1.2.3-alpha.
    - Fix some (not actually triggerable) buffer size checks in usage of
      tor_inet_ntop(). Fixes bug 4434; bugfix on Tor 0.2.0.1-alpha. Patch
      by Anders Sundman.
    - Fix parsing of some corner-cases with tor_inet_pton(). Fixes
      bug 4515; bugfix on 0.2.0.1-alpha; fix by Anders Sundman.
    - Enforce correct return behavior of tor_vsscanf() when the '%%'
      pattern is used. Fixes bug 5558. Bugfix on 0.2.1.13.
    - Make our replacement implementation of strtok_r() compatible with
      the standard behavior of strtok_r(). Patch by nils. Fixes bug 5091;
      bugfix on 0.2.2.1-alpha.
    - Find more places in the code that should have been testing for
      invalid sockets using the SOCKET_OK macro. Required for a fix
      for bug 4533. Bugfix on 0.2.2.28-beta.

  o Minor bugfixes (code correctness):
    - Check return value of fputs() when writing authority certificate
      file. Fixes Coverity issue 709056; bugfix on 0.2.0.1-alpha.
    - When building Tor on Windows with -DUNICODE (not default), ensure
      that error messages, filenames, and DNS server names are always
      NUL-terminated when we convert them to a single-byte encoding.
      Fixes bug 5909; bugfix on 0.2.2.16-alpha.
    - Fix a memory leak when trying to launch a DNS request when the
      nameservers are unconfigurable. Fixes bug 5916; bugfix on Tor
      0.1.2.1-alpha.
    - Correct file sizes when reading binary files on Cygwin, to avoid
      a bug where Tor would fail to read its state file. Fixes bug 6844;
      bugfix on 0.1.2.7-alpha.
    - Make sure to set *socket_error in all error cases in
      connection_connect(), so it can't produce a warning about
      errno being zero from errno_to_orconn_end_reason(). Bugfix on
      0.2.1.1-alpha; resolves ticket 6028.
    - Initialize conn->addr to a valid state in spawn_cpuworker(). Fixes
      bug 4532; found by "troll_un".

  o Minor bugfixes (clients):
    - Allow one-hop directory-fetching circuits the full "circuit build
      timeout" period, rather than just half of it, before failing them
      and marking the relay down. This fix should help reduce cases where
      clients declare relays (or worse, bridges) unreachable because
      the TLS handshake takes a few seconds to complete. Fixes bug 6743;
      bugfix on 0.2.2.2-alpha, where we changed the timeout from a static
      30 seconds.
    - Ensure we don't cannibalize circuits that are longer than three hops
      already, so we don't end up making circuits with 5 or more
      hops. Patch contributed by wanoskarnet. Fixes bug 5231; bugfix on
      0.1.0.1-rc which introduced cannibalization.

  o Minor bugfixes (relays):
    - Don't publish a new relay descriptor when we reload our onion key,
      unless the onion key has actually changed. Fixes bug 3263 and
      resolves another cause of bug 1810. Bugfix on 0.1.1.11-alpha.
    - When relays refuse a "create" cell because their queue of pending
      create cells is too big (typically because their cpu can't keep up
      with the arrival rate), send back reason "resource limit" rather
      than reason "internal", so network measurement scripts can get a
      more accurate picture. Bugfix on 0.1.1.11-alpha; fixes bug 7037.
    - Exit nodes don't need to fetch certificates for authorities that
      they don't recognize; only directory authorities, bridges,
      and caches need to do that. Fixes part of bug 2297; bugfix on
      0.2.2.11-alpha.

  o Minor bugfixes (directory authority / mirrors):
    - Avoid O(n^2) performance characteristics when parsing a large
      extrainfo cache. Fixes bug 5828; bugfix on 0.2.0.1-alpha.
    - Authorities no longer include any router in their microdescriptor
      consensuses for which they couldn't generate or agree on a
      microdescriptor. Fixes the second piece of bug 6404; fix on
      0.2.2.6-alpha.
    - When checking for requested signatures on the latest consensus
      before serving it to a client, make sure to check the right
      consensus flavor. Bugfix on 0.2.2.6-alpha.
    - Fix an edge case where TestingTorNetwork is set but the authorities
      and relays all have an uptime of zero, so the private Tor network
      could briefly lack support for hidden services. Fixes bug 3886;
      bugfix on 0.2.2.18-alpha.
    - Directory caches no longer refuse to clean out descriptors because
      of missing v2 networkstatus documents, unless they're configured
      to retrieve v2 networkstatus documents. Fixes bug 4838; bugfix on
      0.2.2.26-beta. Patch by Daniel Bryg.
    - Don't serve or accept v2 hidden service descriptors over a relay's
      DirPort. It's never correct to do so, and disabling it might
      make it more annoying to exploit any bugs that turn up in the
      descriptor-parsing code. Fixes bug 7149.

  o Minor bugfixes (hidden services, client-side):
    - Assert that hidden-service-related operations are not performed
      using single-hop circuits. Previously, Tor would assert that
      client-side streams are not attached to single-hop circuits,
      but not that other sensitive operations on the client and service
      side are not performed using single-hop circuits. Fixes bug 3332;
      bugfix on 0.0.6.
    - Avoid undefined behaviour when parsing the list of supported
      rendezvous/introduction protocols in a hidden service descriptor.
      Previously, Tor would have confused (as-yet-unused) protocol version
      numbers greater than 32 with lower ones on many platforms. Fixes
      bug 6827; bugfix on 0.2.0.10-alpha. Found by George Kadianakis.
    - Don't close hidden service client circuits which have almost
      finished connecting to their destination when they reach
      the normal circuit-build timeout. Previously, we would close
      introduction circuits which are waiting for an acknowledgement
      from the introduction point, and rendezvous circuits which have
      been specified in an INTRODUCE1 cell sent to a hidden service,
      after the normal CBT. Now, we mark them as 'timed out', and launch
      another rendezvous attempt in parallel. This behavior change can
      be disabled using the new CloseHSClientCircuitsImmediatelyOnTimeout
      option. Fixes part of bug 1297; bugfix on 0.2.2.2-alpha.

  o Minor bugfixes (hidden services, service-side):
    - Don't close hidden-service-side rendezvous circuits when they
      reach the normal circuit-build timeout. This behaviour change can
      be disabled using the new
      CloseHSServiceRendCircuitsImmediatelyOnTimeout option. Fixes the
      remaining part of bug 1297; bugfix on 0.2.2.2-alpha.
    - Don't launch more than 10 service-side introduction-point circuits
      for a hidden service in five minutes. Previously, we would consider
      launching more introduction-point circuits if at least one second
      had passed without any introduction-point circuits failing. Fixes
      bug 4607; bugfix on 0.0.7pre1.

  o Minor bugfixes (config option behavior):
    - If the user tries to set MyFamily on a bridge, refuse to
      do so, and warn about the security implications. Fixes bug 4657;
      bugfix on 0.2.0.3-alpha.
    - The "--quiet" and "--hush" options now apply not only to Tor's
      behavior before logs are configured, but also to Tor's behavior in
      the absense of configured logs. Fixes bug 3550; bugfix on
      0.2.0.10-alpha.
    - Change the AllowDotExit rules so they should actually work.
      We now enforce AllowDotExit only immediately after receiving an
      address via SOCKS or DNSPort: other sources are free to provide
      .exit addresses after the resolution occurs. Fixes bug 3940;
      bugfix on 0.2.2.1-alpha.
    - Make "LearnCircuitBuildTimeout 0" work more reliably. Specifically,
      don't depend on the consensus parameters or compute adaptive
      timeouts when it is disabled. Fixes bug 5049; bugfix on
      0.2.2.14-alpha.
    - After we pick a directory mirror, we would refuse to use it if
      it's in our ExcludeExitNodes list, resulting in mysterious failures
      to bootstrap for people who just wanted to avoid exiting from
      certain locations. Fixes bug 5623; bugfix on 0.2.2.25-alpha.
    - When told to add a bridge with the same digest as a preexisting
      bridge but a different addr:port, change the addr:port as
      requested. Previously we would not notice the change. Fixes half
      of bug 5603; fix on 0.2.2.26-beta.

  o Minor bugfixes (controller):
    - Allow manual 'authenticate' commands to the controller interface
      from netcat (nc) as well as telnet. We were rejecting them because
      they didn't come with the expected whitespace at the end of the
      command. Bugfix on 0.1.1.1-alpha; fixes bug 2893.
    - Report a real bootstrap problem to the controller on router
      identity mismatch. Previously we just said "foo", which probably
      made a lot of sense at the time. Fixes bug 4169; bugfix on
      0.2.1.1-alpha.
    - When we receive a SIGHUP and the controller __ReloadTorrcOnSIGHUP
      option is set to 0 (which Vidalia version 0.2.16 now does when
      a SAVECONF attempt fails), perform other actions that SIGHUP
      usually causes (like reopening the logs). Fixes bug 5095; bugfix
      on 0.2.1.9-alpha.
    - Correctly handle checking the permissions on the parent
      directory of a control socket in the root directory. Bug found
      by Esteban Manchado Velázquez. Fixes bug 5089; bugfix on Tor
      0.2.2.26-beta.
    - End AUTHCHALLENGE error messages (in the control protocol) with
      a CRLF. Fixes bug 5760; bugfix on 0.2.2.36.

  o Minor bugfixes (network reading/writing):
    - Disable writing on marked-for-close connections when they are
      blocked on bandwidth, to prevent busy-looping in Libevent. Fixes
      bug 5263; bugfix on 0.0.2pre13, where we first added a special
      case for flushing marked connections.
    - Make sure that there are no unhandled pending TLS errors before
      reading from a TLS stream. We had checks in 0.1.0.3-rc, but
      lost them in 0.1.0.5-rc when we refactored read_to_buf_tls().
      Bugfix on 0.1.0.5-rc; fixes bug 4528.
    - Detect SSL handshake even when the initial attempt to write the
      server hello fails. Fixes bug 4592; bugfix on 0.2.0.13-alpha.
    - If the client fails to set a reasonable set of ciphersuites
      during its v2 handshake renegotiation, allow the renegotiation to
      continue nevertheless (i.e. send all the required certificates).
      Fixes bug 4591; bugfix on 0.2.0.20-rc.

  o Minor bugfixes (other):
    - Exit nodes now correctly report EADDRINUSE and EADDRNOTAVAIL as
      resource exhaustion, so that clients can adjust their load to
      try other exits. Fixes bug 4710; bugfix on 0.1.0.1-rc, which
      started using END_STREAM_REASON_RESOURCELIMIT.
    - Don't check for whether the address we're using for outbound
      connections has changed until after the outbound connection has
      completed. On Windows, getsockname() doesn't succeed until the
      connection is finished. Fixes bug 5374; bugfix on 0.1.1.14-alpha.
    - Don't hold a Windows file handle open for every file mapping;
      the file mapping handle is sufficient. Fixes bug 5951; bugfix on
      0.1.2.1-alpha.
    - Fix wrong TCP port range in parse_port_range(). Fixes bug 6218;
      bugfix on 0.2.1.10-alpha.
    - If we fail to write a microdescriptor to the disk cache, do not
      continue replacing the old microdescriptor file. Fixes bug 2954;
      bugfix on 0.2.2.6-alpha.

  o Minor bugfixes (log messages, path selection):
    - Downgrade "set buildtimeout to low value" messages to "info"
      severity; they were never an actual problem, there was never
      anything reasonable to do about them, and they tended to spam logs
      from time to time. Fixes bug 6251; bugfix on 0.2.2.2-alpha.
    - Rate-limit the "Weighted bandwidth is 0.000000" message, and add
      more information to it, so that we can track it down in case it
      returns again. Mitigates bug 5235.
    - Check CircuitBuildTimeout and LearnCircuitBuildTimeout in
      options_validate(); warn if LearnCircuitBuildTimeout is disabled and
      CircuitBuildTimeout is set unreasonably low. Resolves ticket 5452.
    - Issue a log message if a guard completes less than 40% of your
      circuits. Threshold is configurable by torrc option
      PathBiasNoticeRate and consensus parameter pb_noticepct. There is
      additional, off-by-default code to disable guards which fail too
      many circuits. Addresses ticket 5458.

  o Minor bugfixes (log messages, client):
    - Downgrade "Got a certificate, but we already have it" log messages
      from warning to info, except when we're a dirauth. Fixes bug 5238;
      bugfix on 0.2.1.7-alpha.
    - Fix the log message describing how we work around discovering
      that our version is the ill-fated OpenSSL 0.9.8l. Fixes bug
      4837; bugfix on 0.2.2.9-alpha.
    - When logging about a disallowed .exit name, do not also call it
      an "invalid onion address". Fixes bug 3325; bugfix on 0.2.2.9-alpha.
    - Fix a log message suggesting that people contact a non-existent
      email address. Fixes bug 3448.
    - Rephrase the log message emitted if the TestSocks check is
      successful. Patch from Fabian Keil; fixes bug 4094.
    - Log (at debug level) whenever a circuit's purpose is changed.
    - Log SSL state transitions at log level DEBUG, log domain
      HANDSHAKE. This can be useful for debugging censorship events.
      Implements ticket 3264.
    - We now log which torrc file we're using on startup. Implements
      ticket 2444.
    - Rate-limit log messages when asked to connect anonymously to
      a private address. When these hit, they tended to hit fast and
      often. Also, don't bother trying to connect to addresses that we
      are sure will resolve to 127.0.0.1: getting 127.0.0.1 in a directory
      reply makes us think we have been lied to, even when the address the
      client tried to connect to was "localhost." Resolves ticket 2822.

  o Minor bugfixes (log messages, non-client):
    - Downgrade "eventdns rejected address" message to LOG_PROTOCOL_WARN.
      Fixes bug 5932; bugfix on 0.2.2.7-alpha.
    - Don't log that we have "decided to publish new relay descriptor"
      unless we are actually publishing a descriptor. Fixes bug 3942;
      bugfix on 0.2.2.28-beta.
    - Log which authority we're missing votes from when we go to fetch
      them from the other auths.
    - Replace "Sending publish request" log messages with "Launching
      upload", so that they no longer confusingly imply that we're
      sending something to a directory we might not even be connected
      to yet. Fixes bug 3311; bugfix on 0.2.0.10-alpha.
    - Warn when Tor is configured to use accounting in a way that can
      link a hidden service to some other hidden service or public
      address. Resolves ticket 6490.
    - Fix a minor formatting issue in one of tor-gencert's error messages.
      Fixes bug 4574.

  o Testing:
    - Update to the latest version of the tinytest unit testing framework.
      This includes a couple of bugfixes that can be relevant for
      running forked unit tests on Windows, and removes all reserved
      identifiers.
    - Avoid a false positive in the util/threads unit test by increasing
      the maximum timeout time. Fixes bug 6227; bugfix on 0.2.0.4-alpha.
    - Make it possible to set the TestingTorNetwork configuration
      option using AlternateDirAuthority and AlternateBridgeAuthority
      as an alternative to setting DirServer. Addresses ticket 6377.
    - Add a unit test for the environment_variable_names_equal() function.
    - A wide variety of new unit tests by Esteban Manchado Velázquez.
    - Numerous new unit tests for functions in util.c and address.c by
      Anders Sundman.
    - The long-disabled benchmark tests are now split into their own
      ./src/test/bench binary.
    - The benchmark tests can now use more accurate timers than
      gettimeofday() when such timers are available.
    - Use tt_assert(), not tor_assert(), for checking for test failures.
      This makes the unit tests more able to go on in the event that
      one of them fails.

  o Build improvements:
    - Use the dead_strip option when building Tor on OS X. This reduces
      binary size by almost 19% when linking openssl and libevent
      statically, which we do for Tor Browser Bundle.
    - Provide a better error message about possible OSX Asciidoc failure
      reasons. Fixes bug 6436.
    - Detect attempts to build Tor on (as yet hypothetical) versions
      of Windows where sizeof(intptr_t) != sizeof(SOCKET). Partial
      fix for bug 4533. Bugfix on 0.2.2.28-beta.
    - On Windows, we now define the _WIN32_WINNT macros only if they
      are not already defined. This lets the person building Tor decide,
      if they want, to require a later version of Windows.
    - Our autogen.sh script now uses autoreconf to launch autoconf,
      automake, and so on. This is more robust against some of the failure
      modes associated with running the autotools pieces on their own.
    - Running "make version" now displays the version of Tor that
      we're about to build. Idea from katmagic; resolves issue 4400.
    - Make 'tor --digests' list hashes of all Tor source files. Bugfix
      on 0.2.2.4-alpha; fixes bug 3427.
    - New --enable-static-tor configure option for building Tor as
      statically as possible. Idea, general hackery and thoughts from
      Alexei Czeskis, John Gilmore, Jacob Appelbaum. Implements ticket
      2702.
    - Limited, experimental support for building with nmake and MSVC.

  o Build requirements:
    - Building Tor with bufferevent support now requires Libevent
      2.0.13-stable or later. Previous versions of Libevent had bugs in
      SSL-related bufferevents and related issues that would make Tor
      work badly with bufferevents. Requiring 2.0.13-stable also allows
      Tor with bufferevents to take advantage of Libevent APIs
      introduced after 2.0.8-rc.
    - Our build system requires automake 1.6 or later to create the
      Makefile.in files. Previously, you could have used 1.4.
      This only affects developers and people building Tor from git;
      people who build Tor from the source distribution without changing
      the Makefile.am files should be fine.
    - Detect when we try to build on a platform that doesn't define
      AF_UNSPEC to 0. We don't work there, so refuse to compile.

  o Build fixes (compile/link):
    - Format more doubles with %f, not %lf. Patch from grarpamp to make
      Tor build correctly on older BSDs again. Fixes bug 3894; bugfix on
      Tor 0.2.0.8-alpha.
    - When building with --enable-static-tor on OpenBSD, do not
      erroneously attempt to link -lrt. Fixes bug 5103.
    - Set _WIN32_WINNT to 0x0501 consistently throughout the code, so
      that IPv6 stuff will compile on MSVC, and compilation issues
      will be easier to track down. Fixes bug 5861.
    - Fix build and 64-bit compile warnings from --enable-openbsd-malloc.
      Fixes bug 6379. Bugfix on 0.2.0.20-rc.
    - Make Tor build correctly again with -DUNICODE -D_UNICODE defined.
      Fixes bug 6097; bugfix on 0.2.2.16-alpha.

  o Build fixes (other):
    - Use the _WIN32 macro throughout our code to detect Windows.
      (Previously we had used the obsolete 'WIN32' and the idiosyncratic
      'MS_WINDOWS'.)
    - Properly handle the case where the build-tree is not the same
      as the source tree when generating src/common/common_sha1.i,
      src/or/micro-revision.i, and src/or/or_sha1.i. Fixes bug 3953;
      bugfix on 0.2.0.1-alpha.
    - During configure, search for library containing cos function as
      libm lives in libcore on some platforms (BeOS/Haiku). Linking
      against libm was hard-coded before. Fixes the first part of bug
      4727; bugfix on 0.2.2.2-alpha. Patch and analysis by Martin Hebnes
      Pedersen.
    - Prevent a false positive from the check-spaces script, by disabling
      the "whitespace between function name and (" check for functions
      named 'op()'.

  o Packaging (RPM) changes:
    - Update our default RPM spec files to work with mock and rpmbuild
      on RHEL/Fedora. They have an updated set of dependencies and
      conflicts, a fix for an ancient typo when creating the "_tor"
      user, and better instructions. Thanks to Ondrej Mikle for the
      patch series. Fixes bug 6043.
    - On OpenSUSE, create the /var/run/tor directory on startup if it
      is not already created. Patch from Andreas Stieger. Fixes bug 2573.

  o Code refactoring (safety):
    - Do not use SMARTLIST_FOREACH for any loop whose body exceeds
      10 lines. Also, don't nest them. Doing so in the past has
      led to hard-to-debug code. The new style is to use the
      SMARTLIST_FOREACH_{BEGIN,END} pair. Addresses issue 6400.
    - Use macros to indicate OpenSSL versions, so we don't need to worry
      about accidental hexadecimal bit shifts.
    - Use tor_sscanf() in place of scanf() in more places through the
      code. This makes us a little more locale-independent, and
      should help shut up code-analysis tools that can't tell
      a safe sscanf string from a dangerous one.
    - Convert more instances of tor_snprintf+tor_strdup into tor_asprintf.
    - Use the smartlist_add_asprintf() alias more consistently.

  o Code refactoring (consolidate):
    - A major revision to our internal node-selecting and listing logic.
      Tor already had at least two major ways to look at the question of
      "which Tor servers do we know about": a list of router descriptors,
      and a list of entries in the current consensus. With
      microdescriptors, we're adding a third. Having so many systems
      without an abstraction layer over them was hurting the codebase.
      Now, we have a new "node_t" abstraction that presents a consistent
      interface to a client's view of a Tor node, and holds (nearly) all
      of the mutable state formerly in routerinfo_t and routerstatus_t.
    - Move tor_gettimeofday_cached() into compat_libevent.c, and use
      Libevent's notion of cached time when possible.
    - Remove duplicate code for invoking getrlimit() from control.c.
    - Use OpenSSL's built-in SSL_state_string_long() instead of our
      own homebrewed ssl_state_to_string() replacement. Patch from
      Emile Snyder. Fixes bug 4653.
    - Change the symmetric cipher interface so that creating and
      initializing a stream cipher are no longer separate functions.

  o Code refactoring (separate):
    - Make a new "entry connection" struct as an internal subtype of "edge
      connection", to simplify the code and make exit connections smaller.
    - Split connection_about_to_close() into separate functions for each
      connection type.
    - Rewrite the listener-selection logic so that parsing which ports
      we want to listen on is now separate from binding to the ports
      we want.

  o Code refactoring (name changes):
    - Rename a handful of old identifiers, mostly related to crypto
      structures and crypto functions. By convention, our "create an
      object" functions are called "type_new()", our "free an object"
      functions are called "type_free()", and our types indicate that
      they are types only with a final "_t". But a handful of older
      types and functions broke these rules, with function names like
      "type_create" or "subsystem_op_type", or with type names like
      type_env_t.
    - Rename Tor functions that turn strings into addresses, so that
      "parse" indicates that no hostname resolution occurs, and
      "lookup" indicates that hostname resolution may occur. This
      should help prevent mistakes in the future. Fixes bug 3512.
    - Use the name "CERTS" consistently to refer to the new cell type;
      we were calling it CERT in some places and CERTS in others.
    - Use a TOR_INVALID_SOCKET macro when initializing a socket to an
      invalid value, rather than just -1.
    - Rename the bench_{aes,dmap} functions to test_*, so that tinytest
      can pick them up when the tests aren't disabled. Bugfix on
      0.2.2.4-alpha which introduced tinytest.

  o Code refactoring (other):
    - Defensively refactor rend_mid_rendezvous() so that protocol
      violations and length checks happen in the beginning. Fixes
      bug 5645.
    - Remove the pure attribute from all functions that used it
      previously. In many cases we assigned it incorrectly, because the
      functions might assert or call impure functions, and we don't have
      evidence that keeping the pure attribute is worthwhile. Implements
      changes suggested in ticket 4421.
    - Move the replay-detection cache for the RSA-encrypted parts of
      INTRODUCE2 cells to the introduction point data structures.
      Previously, we would use one replay-detection cache per hidden
      service. Required by fix for bug 3460.
    - The helper programs tor-gencert, tor-resolve, and tor-checkkey
      no longer link against Libevent: they never used it, but
      our library structure used to force them to link it.

  o Removed features and files:
    - Remove all internal support for unpadded RSA. We never used it, and
      it would be a bad idea to start.
    - Remove some workaround code for OpenSSL 0.9.6 (which is no longer
      supported).
    - Remove some redundant #include directives throughout the code.
      Patch from Andrea Gelmini.
    - Remove some old code to remember statistics about which descriptors
      we've served as a directory mirror. The feature wasn't used and
      is outdated now that microdescriptors are around.
    - Remove some old code to work around even older versions of Tor that
      used forked processes to handle DNS requests. Such versions of Tor
      are no longer in use as relays.
    - The "torify" script no longer supports the "tsocks" socksifier
      tool, since tsocks doesn't support DNS and UDP right for Tor.
      Everyone should be using torsocks instead. Fixes bugs 3530 and
      5180. Based on a patch by "ugh".
    - Remove the torrc.bridge file: we don't use it for anything, and
      it had become badly desynchronized from torrc.sample. Resolves
      bug 5622.

  o Documentation:
    - Begin a doc/state-contents.txt file to explain the contents of
      the Tor state file. Fixes bug 2987.
    - Clarify the documentation for the Alternate*Authority options.
      Fixes bug 6387.
    - Document the --defaults-torrc option, and the new semantics for
      overriding, extending, and clearing lists of options. Closes
      bug 4748.
    - Add missing man page documentation for consensus and microdesc
      files. Resolves ticket 6732.
    - Fix some typos in the manpages. Patch from A. Costa. Fixes bug 6500.

  o Documentation fixes:
    - Improve the manual's documentation for the NT Service command-line
      options. Addresses ticket 3964.
    - Clarify SessionGroup documentation slightly; resolves ticket 5437.
    - Document the changes to the ORPort and DirPort options, and the
      fact that {OR/Dir}ListenAddress is now unnecessary (and
      therefore deprecated). Resolves ticket 5597.
    - Correct a broken faq link in the INSTALL file. Fixes bug 2307.
    - Clarify that hidden services are TCP only. Fixes bug 6024.


Changes in version 0.2.2.39 - 2012-09-11
  Tor 0.2.2.39 fixes two more opportunities for remotely triggerable
  assertions.

  o Security fixes:
    - Fix an assertion failure in tor_timegm() that could be triggered
      by a badly formatted directory object. Bug found by fuzzing with
      Radamsa. Fixes bug 6811; bugfix on 0.2.0.20-rc.
    - Do not crash when comparing an address with port value 0 to an
      address policy. This bug could have been used to cause a remote
      assertion failure by or against directory authorities, or to
      allow some applications to crash clients. Fixes bug 6690; bugfix
      on 0.2.1.10-alpha.


Changes in version 0.2.2.38 - 2012-08-12
  Tor 0.2.2.38 fixes a remotely triggerable crash bug, and fixes a timing
  attack that could in theory leak path information.

  o Security fixes:
    - Avoid an uninitialized memory read when reading a vote or consensus
      document that has an unrecognized flavor name. This read could
      lead to a remote crash bug. Fixes bug 6530; bugfix on 0.2.2.6-alpha.
    - Try to leak less information about what relays a client is
      choosing to a side-channel attacker. Previously, a Tor client would
      stop iterating through the list of available relays as soon as it
      had chosen one, thus finishing a little earlier when it picked
      a router earlier in the list. If an attacker can recover this
      timing information (nontrivial but not proven to be impossible),
      they could learn some coarse-grained information about which relays
      a client was picking (middle nodes in particular are likelier to
      be affected than exits). The timing attack might be mitigated by
      other factors (see bug 6537 for some discussion), but it's best
      not to take chances. Fixes bug 6537; bugfix on 0.0.8rc1.


Changes in version 0.2.2.37 - 2012-06-06
  Tor 0.2.2.37 introduces a workaround for a critical renegotiation
  bug in OpenSSL 1.0.1 (where 20% of the Tor network can't talk to itself
  currently).

  o Major bugfixes:
    - Work around a bug in OpenSSL that broke renegotiation with TLS
      1.1 and TLS 1.2. Without this workaround, all attempts to speak
      the v2 Tor connection protocol when both sides were using OpenSSL
      1.0.1 would fail. Resolves ticket 6033.
    - When waiting for a client to renegotiate, don't allow it to add
      any bytes to the input buffer. This fixes a potential DoS issue.
      Fixes bugs 5934 and 6007; bugfix on 0.2.0.20-rc.
    - Fix an edge case where if we fetch or publish a hidden service
      descriptor, we might build a 4-hop circuit and then use that circuit
      for exiting afterwards -- even if the new last hop doesn't obey our
      ExitNodes config option. Fixes bug 5283; bugfix on 0.2.0.10-alpha.

  o Minor bugfixes:
    - Fix a build warning with Clang 3.1 related to our use of vasprintf.
      Fixes bug 5969. Bugfix on 0.2.2.11-alpha.

  o Minor features:
    - Tell GCC and Clang to check for any errors in format strings passed
      to the tor_v*(print|scan)f functions.


Changes in version 0.2.2.36 - 2012-05-24
  Tor 0.2.2.36 updates the addresses for two of the eight directory
  authorities, fixes some potential anonymity and security issues,
  and fixes several crash bugs.

  Tor 0.2.1.x has reached its end-of-life. Those Tor versions have many
  known flaws, and nobody should be using them. You should upgrade. If
  you're using a Linux or BSD and its packages are obsolete, stop using
  those packages and upgrade anyway.

  o Directory authority changes:
    - Change IP address for maatuska (v3 directory authority).
    - Change IP address for ides (v3 directory authority), and rename
      it to turtles.

  o Security fixes:
    - When building or running with any version of OpenSSL earlier
      than 0.9.8s or 1.0.0f, disable SSLv3 support. These OpenSSL
      versions have a bug (CVE-2011-4576) in which their block cipher
      padding includes uninitialized data, potentially leaking sensitive
      information to any peer with whom they make a SSLv3 connection. Tor
      does not use SSL v3 by default, but a hostile client or server
      could force an SSLv3 connection in order to gain information that
      they shouldn't have been able to get. The best solution here is to
      upgrade to OpenSSL 0.9.8s or 1.0.0f (or later). But when building
      or running with a non-upgraded OpenSSL, we disable SSLv3 entirely
      to make sure that the bug can't happen.
    - Never use a bridge or a controller-supplied node as an exit, even
      if its exit policy allows it. Found by wanoskarnet. Fixes bug
      5342. Bugfix on 0.1.1.15-rc (for controller-purpose descriptors)
      and 0.2.0.3-alpha (for bridge-purpose descriptors).
    - Only build circuits if we have a sufficient threshold of the total
      descriptors that are marked in the consensus with the "Exit"
      flag. This mitigates an attack proposed by wanoskarnet, in which
      all of a client's bridges collude to restrict the exit nodes that
      the client knows about. Fixes bug 5343.
    - Provide controllers with a safer way to implement the cookie
      authentication mechanism. With the old method, if another locally
      running program could convince a controller that it was the Tor
      process, then that program could trick the controller into telling
      it the contents of an arbitrary 32-byte file. The new "SAFECOOKIE"
      authentication method uses a challenge-response approach to prevent
      this attack. Fixes bug 5185; implements proposal 193.

  o Major bugfixes:
    - Avoid logging uninitialized data when unable to decode a hidden
      service descriptor cookie. Fixes bug 5647; bugfix on 0.2.1.5-alpha.
    - Avoid a client-side assertion failure when receiving an INTRODUCE2
      cell on a general purpose circuit. Fixes bug 5644; bugfix on
      0.2.1.6-alpha.
    - Fix builds when the path to sed, openssl, or sha1sum contains
      spaces, which is pretty common on Windows. Fixes bug 5065; bugfix
      on 0.2.2.1-alpha.
    - Correct our replacements for the timeradd() and timersub() functions
      on platforms that lack them (for example, Windows). The timersub()
      function is used when expiring circuits, while timeradd() is
      currently unused. Bug report and patch by Vektor. Fixes bug 4778;
      bugfix on 0.2.2.24-alpha.
    - Fix the SOCKET_OK test that we use to tell when socket
      creation fails so that it works on Win64. Fixes part of bug 4533;
      bugfix on 0.2.2.29-beta. Bug found by wanoskarnet.

  o Minor bugfixes:
    - Reject out-of-range times like 23:59:61 in parse_rfc1123_time().
      Fixes bug 5346; bugfix on 0.0.8pre3.
    - Make our number-parsing functions always treat too-large values
      as an error, even when those values exceed the width of the
      underlying type. Previously, if the caller provided these
      functions with minima or maxima set to the extreme values of the
      underlying integer type, these functions would return those
      values on overflow rather than treating overflow as an error.
      Fixes part of bug 5786; bugfix on 0.0.9.
    - Older Linux kernels erroneously respond to strange nmap behavior
      by having accept() return successfully with a zero-length
      socket. When this happens, just close the connection. Previously,
      we would try harder to learn the remote address: but there was
      no such remote address to learn, and our method for trying to
      learn it was incorrect. Fixes bugs 1240, 4745, and 4747. Bugfix
      on 0.1.0.3-rc. Reported and diagnosed by "r1eo".
    - Correct parsing of certain date types in parse_http_time().
      Without this patch, If-Modified-Since would behave
      incorrectly. Fixes bug 5346; bugfix on 0.2.0.2-alpha. Patch from
      Esteban Manchado Velázques.
    - Change the BridgePassword feature (part of the "bridge community"
      design, which is not yet implemented) to use a time-independent
      comparison. The old behavior might have allowed an adversary
      to use timing to guess the BridgePassword value. Fixes bug 5543;
      bugfix on 0.2.0.14-alpha.
    - Detect and reject certain misformed escape sequences in
      configuration values. Previously, these values would cause us
      to crash if received in a torrc file or over an authenticated
      control port. Bug found by Esteban Manchado Velázquez, and
      independently by Robert Connolly from Matta Consulting who further
      noted that it allows a post-authentication heap overflow. Patch
      by Alexander Schrijver. Fixes bugs 5090 and 5402 (CVE 2012-1668);
      bugfix on 0.2.0.16-alpha.
    - Fix a compile warning when using the --enable-openbsd-malloc
      configure option. Fixes bug 5340; bugfix on 0.2.0.20-rc.
    - During configure, detect when we're building with clang version
      3.0 or lower and disable the -Wnormalized=id and -Woverride-init
      CFLAGS. clang doesn't support them yet.
    - When sending an HTTP/1.1 proxy request, include a Host header.
      Fixes bug 5593; bugfix on 0.2.2.1-alpha.
    - Fix a NULL-pointer dereference on a badly formed SETCIRCUITPURPOSE
      command. Found by mikeyc. Fixes bug 5796; bugfix on 0.2.2.9-alpha.
    - If we hit the error case where routerlist_insert() replaces an
      existing (old) server descriptor, make sure to remove that
      server descriptor from the old_routers list. Fix related to bug
      1776. Bugfix on 0.2.2.18-alpha.

  o Minor bugfixes (documentation and log messages):
    - Fix a typo in a log message in rend_service_rendezvous_has_opened().
      Fixes bug 4856; bugfix on Tor 0.0.6.
    - Update "ClientOnly" man page entry to explain that there isn't
      really any point to messing with it. Resolves ticket 5005.
    - Document the GiveGuardFlagTo_CVE_2011_2768_VulnerableRelays
      directory authority option (introduced in Tor 0.2.2.34).
    - Downgrade the "We're missing a certificate" message from notice
      to info: people kept mistaking it for a real problem, whereas it
      is seldom the problem even when we are failing to bootstrap. Fixes
      bug 5067; bugfix on 0.2.0.10-alpha.
    - Correctly spell "connect" in a log message on failure to create a
      controlsocket. Fixes bug 4803; bugfix on 0.2.2.26-beta.
    - Clarify the behavior of MaxCircuitDirtiness with hidden service
      circuits. Fixes issue 5259.

  o Minor features:
    - Directory authorities now reject versions of Tor older than
      0.2.1.30, and Tor versions between 0.2.2.1-alpha and 0.2.2.20-alpha
      inclusive. These versions accounted for only a small fraction of
      the Tor network, and have numerous known security issues. Resolves
      issue 4788.
    - Update to the May 1 2012 Maxmind GeoLite Country database.

  - Feature removal:
    - When sending or relaying a RELAY_EARLY cell, we used to convert
      it to a RELAY cell if the connection was using the v1 link
      protocol. This was a workaround for older versions of Tor, which
      didn't handle RELAY_EARLY cells properly. Now that all supported
      versions can handle RELAY_EARLY cells, and now that we're enforcing
      the "no RELAY_EXTEND commands except in RELAY_EARLY cells" rule,
      remove this workaround. Addresses bug 4786.


Changes in version 0.2.2.35 - 2011-12-16
  Tor 0.2.2.35 fixes a critical heap-overflow security issue in Tor's
  buffers code. Absolutely everybody should upgrade.

  The bug relied on an incorrect calculation when making data continuous
  in one of our IO buffers, if the first chunk of the buffer was
  misaligned by just the wrong amount. The miscalculation would allow an
  attacker to overflow a piece of heap-allocated memory. To mount this
  attack, the attacker would need to either open a SOCKS connection to
  Tor's SocksPort (usually restricted to localhost), or target a Tor
  instance configured to make its connections through a SOCKS proxy
  (which Tor does not do by default).

  Good security practice requires that all heap-overflow bugs should be
  presumed to be exploitable until proven otherwise, so we are treating
  this as a potential code execution attack. Please upgrade immediately!
  This bug does not affect bufferevents-based builds of Tor. Special
  thanks to "Vektor" for reporting this issue to us!

  Tor 0.2.2.35 also fixes several bugs in previous versions, including
  crash bugs for unusual configurations, and a long-term bug that
  would prevent Tor from starting on Windows machines with draconian
  AV software.

  With this release, we remind everyone that 0.2.0.x has reached its
  formal end-of-life. Those Tor versions have many known flaws, and
  nobody should be using them. You should upgrade -- ideally to the
  0.2.2.x series. If you're using a Linux or BSD and its packages are
  obsolete, stop using those packages and upgrade anyway.

  The Tor 0.2.1.x series is also approaching its end-of-life: it will no
  longer receive support after some time in early 2012.

  o Major bugfixes:
    - Fix a heap overflow bug that could occur when trying to pull
      data into the first chunk of a buffer, when that chunk had
      already had some data drained from it. Fixes CVE-2011-2778;
      bugfix on 0.2.0.16-alpha. Reported by "Vektor".
    - Initialize Libevent with the EVENT_BASE_FLAG_NOLOCK flag enabled, so
      that it doesn't attempt to allocate a socketpair. This could cause
      some problems on Windows systems with overzealous firewalls. Fix for
      bug 4457; workaround for Libevent versions 2.0.1-alpha through
      2.0.15-stable.
    - If we mark an OR connection for close based on a cell we process,
      don't process any further cells on it. We already avoid further
      reads on marked-for-close connections, but now we also discard the
      cells we'd already read. Fixes bug 4299; bugfix on 0.2.0.10-alpha,
      which was the first version where we might mark a connection for
      close based on processing a cell on it.
    - Correctly sanity-check that we don't underflow on a memory
      allocation (and then assert) for hidden service introduction
      point decryption. Bug discovered by Dan Rosenberg. Fixes bug 4410;
      bugfix on 0.2.1.5-alpha.
    - Fix a memory leak when we check whether a hidden service
      descriptor has any usable introduction points left. Fixes bug
      4424. Bugfix on 0.2.2.25-alpha.
    - Don't crash when we're running as a relay and don't have a GeoIP
      file. Bugfix on 0.2.2.34; fixes bug 4340. This backports a fix
      we've had in the 0.2.3.x branch already.
    - When running as a client, do not print a misleading (and plain
      wrong) log message that we're collecting "directory request"
      statistics: clients don't collect statistics. Also don't create a
      useless (because empty) stats file in the stats/ directory. Fixes
      bug 4353; bugfix on 0.2.2.34.

  o Minor bugfixes:
    - Detect failure to initialize Libevent. This fix provides better
      detection for future instances of bug 4457.
    - Avoid frequent calls to the fairly expensive cull_wedged_cpuworkers
      function. This was eating up hideously large amounts of time on some
      busy servers. Fixes bug 4518; bugfix on 0.0.9.8.
    - Resolve an integer overflow bug in smartlist_ensure_capacity().
      Fixes bug 4230; bugfix on Tor 0.1.0.1-rc. Based on a patch by
      Mansour Moufid.
    - Don't warn about unused log_mutex in log.c when building with
      --disable-threads using a recent GCC. Fixes bug 4437; bugfix on
      0.1.0.6-rc which introduced --disable-threads.
    - When configuring, starting, or stopping an NT service, stop
      immediately after the service configuration attempt has succeeded
      or failed. Fixes bug 3963; bugfix on 0.2.0.7-alpha.
    - When sending a NETINFO cell, include the original address
      received for the other side, not its canonical address. Found
      by "troll_un"; fixes bug 4349; bugfix on 0.2.0.10-alpha.
    - Fix a typo in a hibernation-related log message. Fixes bug 4331;
      bugfix on 0.2.2.23-alpha; found by "tmpname0901".
    - Fix a memory leak in launch_direct_bridge_descriptor_fetch() that
      occurred when a client tried to fetch a descriptor for a bridge
      in ExcludeNodes. Fixes bug 4383; bugfix on 0.2.2.25-alpha.
    - Backport fixes for a pair of compilation warnings on Windows.
      Fixes bug 4521; bugfix on 0.2.2.28-beta and on 0.2.2.29-beta.
    - If we had ever tried to call tor_addr_to_str on an address of
      unknown type, we would have done a strdup on an uninitialized
      buffer. Now we won't. Fixes bug 4529; bugfix on 0.2.1.3-alpha.
      Reported by "troll_un".
    - Correctly detect and handle transient lookup failures from
      tor_addr_lookup. Fixes bug 4530; bugfix on 0.2.1.5-alpha.
      Reported by "troll_un".
    - Fix null-pointer access that could occur if TLS allocation failed.
      Fixes bug 4531; bugfix on 0.2.0.20-rc. Found by "troll_un".
    - Use tor_socket_t type for listener argument to accept(). Fixes bug
      4535; bugfix on 0.2.2.28-beta. Found by "troll_un".

  o Minor features:
    - Add two new config options for directory authorities:
      AuthDirFastGuarantee sets a bandwidth threshold for guaranteeing the
      Fast flag, and AuthDirGuardBWGuarantee sets a bandwidth threshold
      that is always sufficient to satisfy the bandwidth requirement for
      the Guard flag. Now it will be easier for researchers to simulate
      Tor networks with different values. Resolves ticket 4484.
    - When Tor ignores a hidden service specified in its configuration,
      include the hidden service's directory in the warning message.
      Previously, we would only tell the user that some hidden service
      was ignored. Bugfix on 0.0.6; fixes bug 4426.
    - Update to the December 6 2011 Maxmind GeoLite Country database.

  o Packaging changes:
    - Make it easier to automate expert package builds on Windows,
      by removing an absolute path from makensis.exe command.


Changes in version 0.2.1.32 - 2011-12-16
  Tor 0.2.1.32 backports important security and privacy fixes for
  oldstable. This release is intended only for package maintainers and
  others who cannot use the 0.2.2 stable series. All others should be
  using Tor 0.2.2.x or newer.

  The Tor 0.2.1.x series will reach formal end-of-life some time in
  early 2012; we will stop releasing patches for it then.

  o Major bugfixes (also included in 0.2.2.x):
    - Correctly sanity-check that we don't underflow on a memory
      allocation (and then assert) for hidden service introduction
      point decryption. Bug discovered by Dan Rosenberg. Fixes bug 4410;
      bugfix on 0.2.1.5-alpha.
    - Fix a heap overflow bug that could occur when trying to pull
      data into the first chunk of a buffer, when that chunk had
      already had some data drained from it. Fixes CVE-2011-2778;
      bugfix on 0.2.0.16-alpha. Reported by "Vektor".

  o Minor features:
    - Update to the December 6 2011 Maxmind GeoLite Country database.


Changes in version 0.2.2.34 - 2011-10-26
  Tor 0.2.2.34 fixes a critical anonymity vulnerability where an attacker
  can deanonymize Tor users. Everybody should upgrade.

  The attack relies on four components: 1) Clients reuse their TLS cert
  when talking to different relays, so relays can recognize a user by
  the identity key in her cert. 2) An attacker who knows the client's
  identity key can probe each guard relay to see if that identity key
  is connected to that guard relay right now. 3) A variety of active
  attacks in the literature (starting from "Low-Cost Traffic Analysis
  of Tor" by Murdoch and Danezis in 2005) allow a malicious website to
  discover the guard relays that a Tor user visiting the website is using.
  4) Clients typically pick three guards at random, so the set of guards
  for a given user could well be a unique fingerprint for her. This
  release fixes components #1 and #2, which is enough to block the attack;
  the other two remain as open research problems. Special thanks to
  "frosty_un" for reporting the issue to us!

  Clients should upgrade so they are no longer recognizable by the TLS
  certs they present. Relays should upgrade so they no longer allow a
  remote attacker to probe them to test whether unpatched clients are
  currently connected to them.

  This release also fixes several vulnerabilities that allow an attacker
  to enumerate bridge relays. Some bridge enumeration attacks still
  remain; see for example proposal 188.

  o Privacy/anonymity fixes (clients):
    - Clients and bridges no longer send TLS certificate chains on
      outgoing OR connections. Previously, each client or bridge would
      use the same cert chain for all outgoing OR connections until
      its IP address changes, which allowed any relay that the client
      or bridge contacted to determine which entry guards it is using.
      Fixes CVE-2011-2768. Bugfix on 0.0.9pre5; found by "frosty_un".
    - If a relay receives a CREATE_FAST cell on a TLS connection, it
      no longer considers that connection as suitable for satisfying a
      circuit EXTEND request. Now relays can protect clients from the
      CVE-2011-2768 issue even if the clients haven't upgraded yet.
    - Directory authorities no longer assign the Guard flag to relays
      that haven't upgraded to the above "refuse EXTEND requests
      to client connections" fix. Now directory authorities can
      protect clients from the CVE-2011-2768 issue even if neither
      the clients nor the relays have upgraded yet. There's a new
      "GiveGuardFlagTo_CVE_2011_2768_VulnerableRelays" config option
      to let us transition smoothly, else tomorrow there would be no
      guard relays.

  o Privacy/anonymity fixes (bridge enumeration):
    - Bridge relays now do their directory fetches inside Tor TLS
      connections, like all the other clients do, rather than connecting
      directly to the DirPort like public relays do. Removes another
      avenue for enumerating bridges. Fixes bug 4115; bugfix on 0.2.0.35.
    - Bridges relays now build circuits for themselves in a more similar
      way to how clients build them. Removes another avenue for
      enumerating bridges. Fixes bug 4124; bugfix on 0.2.0.3-alpha,
      when bridges were introduced.
    - Bridges now refuse CREATE or CREATE_FAST cells on OR connections
      that they initiated. Relays could distinguish incoming bridge
      connections from client connections, creating another avenue for
      enumerating bridges. Fixes CVE-2011-2769. Bugfix on 0.2.0.3-alpha.
      Found by "frosty_un".

  o Major bugfixes:
    - Fix a crash bug when changing node restrictions while a DNS lookup
      is in-progress. Fixes bug 4259; bugfix on 0.2.2.25-alpha. Bugfix
      by "Tey'".
    - Don't launch a useless circuit after failing to use one of a
      hidden service's introduction points. Previously, we would
      launch a new introduction circuit, but not set the hidden service
      which that circuit was intended to connect to, so it would never
      actually be used. A different piece of code would then create a
      new introduction circuit correctly. Bug reported by katmagic and
      found by Sebastian Hahn. Bugfix on 0.2.1.13-alpha; fixes bug 4212.

  o Minor bugfixes:
    - Change an integer overflow check in the OpenBSD_Malloc code so
      that GCC is less likely to eliminate it as impossible. Patch
      from Mansour Moufid. Fixes bug 4059.
    - When a hidden service turns an extra service-side introduction
      circuit into a general-purpose circuit, free the rend_data and
      intro_key fields first, so we won't leak memory if the circuit
      is cannibalized for use as another service-side introduction
      circuit. Bugfix on 0.2.1.7-alpha; fixes bug 4251.
    - Bridges now skip DNS self-tests, to act a little more stealthily.
      Fixes bug 4201; bugfix on 0.2.0.3-alpha, which first introduced
      bridges. Patch by "warms0x".
    - Fix internal bug-checking logic that was supposed to catch
      failures in digest generation so that it will fail more robustly
      if we ask for a nonexistent algorithm. Found by Coverity Scan.
      Bugfix on 0.2.2.1-alpha; fixes Coverity CID 479.
    - Report any failure in init_keys() calls launched because our
      IP address has changed. Spotted by Coverity Scan. Bugfix on
      0.1.1.4-alpha; fixes CID 484.

  o Minor bugfixes (log messages and documentation):
    - Remove a confusing dollar sign from the example fingerprint in the
      man page, and also make the example fingerprint a valid one. Fixes
      bug 4309; bugfix on 0.2.1.3-alpha.
    - The next version of Windows will be called Windows 8, and it has
      a major version of 6, minor version of 2. Correctly identify that
      version instead of calling it "Very recent version". Resolves
      ticket 4153; reported by funkstar.
    - Downgrade log messages about circuit timeout calibration from
      "notice" to "info": they don't require or suggest any human
      intervention. Patch from Tom Lowenthal. Fixes bug 4063;
      bugfix on 0.2.2.14-alpha.

  o Minor features:
    - Turn on directory request statistics by default and include them in
      extra-info descriptors. Don't break if we have no GeoIP database.
      Backported from 0.2.3.1-alpha; implements ticket 3951.
    - Update to the October 4 2011 Maxmind GeoLite Country database.


Changes in version 0.2.1.31 - 2011-10-26
  Tor 0.2.1.31 backports important security and privacy fixes for
  oldstable. This release is intended only for package maintainers and
  others who cannot use the 0.2.2 stable series. All others should be
  using Tor 0.2.2.x or newer.

  o Security fixes (also included in 0.2.2.x):
    - Replace all potentially sensitive memory comparison operations
      with versions whose runtime does not depend on the data being
      compared. This will help resist a class of attacks where an
      adversary can use variations in timing information to learn
      sensitive data. Fix for one case of bug 3122. (Safe memcmp
      implementation by Robert Ransom based partially on code by DJB.)
    - Fix an assert in parsing router descriptors containing IPv6
      addresses. This one took down the directory authorities when
      somebody tried some experimental code. Bugfix on 0.2.1.3-alpha.

  o Privacy/anonymity fixes (also included in 0.2.2.x):
    - Clients and bridges no longer send TLS certificate chains on
      outgoing OR connections. Previously, each client or bridge would
      use the same cert chain for all outgoing OR connections until
      its IP address changes, which allowed any relay that the client
      or bridge contacted to determine which entry guards it is using.
      Fixes CVE-2011-2768. Bugfix on 0.0.9pre5; found by "frosty_un".
    - If a relay receives a CREATE_FAST cell on a TLS connection, it
      no longer considers that connection as suitable for satisfying a
      circuit EXTEND request. Now relays can protect clients from the
      CVE-2011-2768 issue even if the clients haven't upgraded yet.
    - Bridges now refuse CREATE or CREATE_FAST cells on OR connections
      that they initiated. Relays could distinguish incoming bridge 
      connections from client connections, creating another avenue for
      enumerating bridges. Fixes CVE-2011-2769. Bugfix on 0.2.0.3-alpha.
      Found by "frosty_un".
    - When receiving a hidden service descriptor, check that it is for
      the hidden service we wanted. Previously, Tor would store any
      hidden service descriptors that a directory gave it, whether it
      wanted them or not. This wouldn't have let an attacker impersonate
      a hidden service, but it did let directories pre-seed a client
      with descriptors that it didn't want. Bugfix on 0.0.6.
    - Avoid linkability based on cached hidden service descriptors: forget
      all hidden service descriptors cached as a client when processing a
      SIGNAL NEWNYM command. Fixes bug 3000; bugfix on 0.0.6.
    - Make the bridge directory authority refuse to answer directory
      requests for "all" descriptors. It used to include bridge
      descriptors in its answer, which was a major information leak.
      Found by "piebeer". Bugfix on 0.2.0.3-alpha.
    - Don't attach new streams to old rendezvous circuits after SIGNAL
      NEWNYM. Previously, we would keep using an existing rendezvous
      circuit if it remained open (i.e. if it were kept open by a
      long-lived stream, or if a new stream were attached to it before
      Tor could notice that it was old and no longer in use). Bugfix on
      0.1.1.15-rc; fixes bug 3375.

  o Minor bugfixes (also included in 0.2.2.x):
    - When we restart our relay, we might get a successful connection
      from the outside before we've started our reachability tests,
      triggering a warning: "ORPort found reachable, but I have no
      routerinfo yet. Failing to inform controller of success." This
      bug was harmless unless Tor is running under a controller
      like Vidalia, in which case the controller would never get a
      REACHABILITY_SUCCEEDED status event. Bugfix on 0.1.2.6-alpha;
      fixes bug 1172.
    - Build correctly on OSX with zlib 1.2.4 and higher with all warnings
      enabled. Fixes bug 1526.
    - Remove undocumented option "-F" from tor-resolve: it hasn't done
      anything since 0.2.1.16-rc.
    - Avoid signed/unsigned comparisons by making SIZE_T_CEILING unsigned.
      None of the cases where we did this before were wrong, but by making
      this change we avoid warnings. Fixes bug 2475; bugfix on 0.2.1.28.
    - Fix a rare crash bug that could occur when a client was configured
      with a large number of bridges. Fixes bug 2629; bugfix on
      0.2.1.2-alpha. Bugfix by trac user "shitlei".
    - Correct the warning displayed when a rendezvous descriptor exceeds
      the maximum size. Fixes bug 2750; bugfix on 0.2.1.5-alpha. Found by
      John Brooks.
    - Fix an uncommon assertion failure when running with DNSPort under
      heavy load. Fixes bug 2933; bugfix on 0.2.0.1-alpha.
    - When warning about missing zlib development packages during compile,
      give the correct package names. Bugfix on 0.2.0.1-alpha.
    - Require that introduction point keys and onion keys have public
      exponent 65537. Bugfix on 0.2.0.10-alpha.
    - Do not crash when our configuration file becomes unreadable, for
      example due to a permissions change, between when we start up
      and when a controller calls SAVECONF. Fixes bug 3135; bugfix
      on 0.0.9pre6.
    - Fix warnings from GCC 4.6's "-Wunused-but-set-variable" option.
      Fixes bug 3208.
    - Always NUL-terminate the sun_path field of a sockaddr_un before
      passing it to the kernel. (Not a security issue: kernels are
      smart enough to reject bad sockaddr_uns.) Found by Coverity;
      CID #428. Bugfix on Tor 0.2.0.3-alpha.
    - Don't stack-allocate the list of supplementary GIDs when we're
      about to log them. Stack-allocating NGROUPS_MAX gid_t elements
      could take up to 256K, which is way too much stack. Found by
      Coverity; CID #450. Bugfix on 0.2.1.7-alpha.

  o Minor bugfixes (only in 0.2.1.x):
    - Resume using micro-version numbers in 0.2.1.x: our Debian packages
      rely on them. Bugfix on 0.2.1.30.
    - Use git revisions instead of svn revisions when generating our
      micro-version numbers. Bugfix on 0.2.1.15-rc; fixes bug 2402.

  o Minor features (also included in 0.2.2.x):
    - Adjust the expiration time on our SSL session certificates to
      better match SSL certs seen in the wild. Resolves ticket 4014.
    - Allow nameservers with IPv6 address. Resolves bug 2574.
    - Update to the October 4 2011 Maxmind GeoLite Country database.


Changes in version 0.2.2.33 - 2011-09-13
  Tor 0.2.2.33 fixes several bugs, and includes a slight tweak to Tor's
  TLS handshake that makes relays and bridges that run this new version
  reachable from Iran again.

  o Major bugfixes:
    - Avoid an assertion failure when reloading a configuration with
      TrackExitHosts changes. Found and fixed by 'laruldan'. Fixes bug
      3923; bugfix on 0.2.2.25-alpha.

  o Minor features (security):
    - Check for replays of the public-key encrypted portion of an
      INTRODUCE1 cell, in addition to the current check for replays of
      the g^x value. This prevents a possible class of active attacks
      by an attacker who controls both an introduction point and a
      rendezvous point, and who uses the malleability of AES-CTR to
      alter the encrypted g^x portion of the INTRODUCE1 cell. We think
      that these attacks are infeasible (requiring the attacker to send
      on the order of zettabytes of altered cells in a short interval),
      but we'd rather block them off in case there are any classes of
      this attack that we missed. Reported by Willem Pinckaers.

  o Minor features:
    - Adjust the expiration time on our SSL session certificates to
      better match SSL certs seen in the wild. Resolves ticket 4014.
    - Change the default required uptime for a relay to be accepted as
      a HSDir (hidden service directory) from 24 hours to 25 hours.
      Improves on 0.2.0.10-alpha; resolves ticket 2649.
    - Add a VoteOnHidServDirectoriesV2 config option to allow directory
      authorities to abstain from voting on assignment of the HSDir
      consensus flag. Related to bug 2649.
    - Update to the September 6 2011 Maxmind GeoLite Country database.

  o Minor bugfixes (documentation and log messages):
    - Correct the man page to explain that HashedControlPassword and
      CookieAuthentication can both be set, in which case either method
      is sufficient to authenticate to Tor. Bugfix on 0.2.0.7-alpha,
      when we decided to allow these config options to both be set. Issue
      raised by bug 3898.
    - Demote the 'replay detected' log message emitted when a hidden
      service receives the same Diffie-Hellman public key in two different
      INTRODUCE2 cells to info level. A normal Tor client can cause that
      log message during its normal operation. Bugfix on 0.2.1.6-alpha;
      fixes part of bug 2442.
    - Demote the 'INTRODUCE2 cell is too {old,new}' log message to info
      level. There is nothing that a hidden service's operator can do
      to fix its clients' clocks. Bugfix on 0.2.1.6-alpha; fixes part
      of bug 2442.
    - Clarify a log message specifying the characters permitted in
      HiddenServiceAuthorizeClient client names. Previously, the log
      message said that "[A-Za-z0-9+-_]" were permitted; that could have
      given the impression that every ASCII character between "+" and "_"
      was permitted. Now we say "[A-Za-z0-9+_-]". Bugfix on 0.2.1.5-alpha.

  o Build fixes:
    - Provide a substitute implementation of lround() for MSVC, which
      apparently lacks it. Patch from Gisle Vanem.
    - Clean up some code issues that prevented Tor from building on older
      BSDs. Fixes bug 3894; reported by "grarpamp".
    - Search for a platform-specific version of "ar" when cross-compiling.
      Should fix builds on iOS. Resolves bug 3909, found by Marco Bonetti.


Changes in version 0.2.2.32 - 2011-08-27
  The Tor 0.2.2 release series is dedicated to the memory of Andreas
  Pfitzmann (1958-2010), a pioneer in anonymity and privacy research,
  a founder of the PETS community, a leader in our field, a mentor,
  and a friend. He left us with these words: "I had the possibility
  to contribute to this world that is not as it should be. I hope I
  could help in some areas to make the world a better place, and that
  I could also encourage other people to be engaged in improving the
  world. Please, stay engaged. This world needs you, your love, your
  initiative -- now I cannot be part of that anymore."

  Tor 0.2.2.32, the first stable release in the 0.2.2 branch, is finally
  ready. More than two years in the making, this release features improved
  client performance and hidden service reliability, better compatibility
  for Android, correct behavior for bridges that listen on more than
  one address, more extensible and flexible directory object handling,
  better reporting of network statistics, improved code security, and
  many many other features and bugfixes.

  o Major features (client performance):
    - When choosing which cells to relay first, relays now favor circuits
      that have been quiet recently, to provide lower latency for
      low-volume circuits. By default, relays enable or disable this
      feature based on a setting in the consensus. They can override
      this default by using the new "CircuitPriorityHalflife" config
      option. Design and code by Ian Goldberg, Can Tang, and Chris
      Alexander.
    - Directory authorities now compute consensus weightings that instruct
      clients how to weight relays flagged as Guard, Exit, Guard+Exit,
      and no flag. Clients use these weightings to distribute network load
      more evenly across these different relay types. The weightings are
      in the consensus so we can change them globally in the future. Extra
      thanks to "outofwords" for finding some nasty security bugs in
      the first implementation of this feature.

  o Major features (client performance, circuit build timeout):
    - Tor now tracks how long it takes to build client-side circuits
      over time, and adapts its timeout to local network performance.
      Since a circuit that takes a long time to build will also provide
      bad performance, we get significant latency improvements by
      discarding the slowest 20% of circuits. Specifically, Tor creates
      circuits more aggressively than usual until it has enough data
      points for a good timeout estimate. Implements proposal 151.
    - Circuit build timeout constants can be controlled by consensus
      parameters. We set good defaults for these parameters based on
      experimentation on broadband and simulated high-latency links.
    - Circuit build time learning can be disabled via consensus parameter
      or by the client via a LearnCircuitBuildTimeout config option. We
      also automatically disable circuit build time calculation if either
      AuthoritativeDirectory is set, or if we fail to write our state
      file. Implements ticket 1296.

  o Major features (relays use their capacity better):
    - Set SO_REUSEADDR socket option on all sockets, not just
      listeners. This should help busy exit nodes avoid running out of
      useable ports just because all the ports have been used in the
      near past. Resolves issue 2850.
    - Relays now save observed peak bandwidth throughput rates to their
      state file (along with total usage, which was already saved),
      so that they can determine their correct estimated bandwidth on
      restart. Resolves bug 1863, where Tor relays would reset their
      estimated bandwidth to 0 after restarting.
    - Lower the maximum weighted-fractional-uptime cutoff to 98%. This
      should give us approximately 40-50% more Guard-flagged nodes,
      improving the anonymity the Tor network can provide and also
      decreasing the dropoff in throughput that relays experience when
      they first get the Guard flag.
    - Directory authorities now take changes in router IP address and
      ORPort into account when determining router stability. Previously,
      if a router changed its IP or ORPort, the authorities would not
      treat it as having any downtime for the purposes of stability
      calculation, whereas clients would experience downtime since the
      change would take a while to propagate to them. Resolves issue 1035.
    - New AccelName and AccelDir options add support for dynamic OpenSSL
      hardware crypto acceleration engines.

  o Major features (relays control their load better):
    - Exit relays now try harder to block exit attempts from unknown
      relays, to make it harder for people to use them as one-hop proxies
      a la tortunnel. Controlled by the refuseunknownexits consensus
      parameter (currently enabled), or you can override it on your
      relay with the RefuseUnknownExits torrc option. Resolves bug 1751;
      based on a variant of proposal 163.
    - Add separate per-conn write limiting to go with the per-conn read
      limiting. We added a global write limit in Tor 0.1.2.5-alpha,
      but never per-conn write limits.
    - New consensus params "bwconnrate" and "bwconnburst" to let us
      rate-limit client connections as they enter the network. It's
      controlled in the consensus so we can turn it on and off for
      experiments. It's starting out off. Based on proposal 163.

  o Major features (controllers):
    - Export GeoIP information on bridge usage to controllers even if we
      have not yet been running for 24 hours. Now Vidalia bridge operators
      can get more accurate and immediate feedback about their
      contributions to the network.
    - Add an __OwningControllerProcess configuration option and a
      TAKEOWNERSHIP control-port command. Now a Tor controller can ensure
      that when it exits, Tor will shut down. Implements feature 3049.

  o Major features (directory authorities):
    - Directory authorities now create, vote on, and serve multiple
      parallel formats of directory data as part of their voting process.
      Partially implements Proposal 162: "Publish the consensus in
      multiple flavors".
    - Directory authorities now agree on and publish small summaries
      of router information that clients can use in place of regular
      server descriptors. This transition will allow Tor 0.2.3 clients
      to use far less bandwidth for downloading information about the
      network. Begins the implementation of Proposal 158: "Clients
      download consensus + microdescriptors".
    - The directory voting system is now extensible to use multiple hash
      algorithms for signatures and resource selection. Newer formats
      are signed with SHA256, with a possibility for moving to a better
      hash algorithm in the future.
    - Directory authorities can now vote on arbitary integer values as
      part of the consensus process. This is designed to help set
      network-wide parameters. Implements proposal 167.

  o Major features and bugfixes (node selection):
    - Revise and reconcile the meaning of the ExitNodes, EntryNodes,
      ExcludeEntryNodes, ExcludeExitNodes, ExcludeNodes, and Strict*Nodes
      options. Previously, we had been ambiguous in describing what
      counted as an "exit" node, and what operations exactly "StrictNodes
      0" would permit. This created confusion when people saw nodes built
      through unexpected circuits, and made it hard to tell real bugs from
      surprises. Now the intended behavior is:
        . "Exit", in the context of ExitNodes and ExcludeExitNodes, means
          a node that delivers user traffic outside the Tor network.
        . "Entry", in the context of EntryNodes, means a node used as the
          first hop of a multihop circuit. It doesn't include direct
          connections to directory servers.
        . "ExcludeNodes" applies to all nodes.
        . "StrictNodes" changes the behavior of ExcludeNodes only. When
          StrictNodes is set, Tor should avoid all nodes listed in
          ExcludeNodes, even when it will make user requests fail. When
          StrictNodes is *not* set, then Tor should follow ExcludeNodes
          whenever it can, except when it must use an excluded node to
          perform self-tests, connect to a hidden service, provide a
          hidden service, fulfill a .exit request, upload directory
          information, or fetch directory information.
      Collectively, the changes to implement the behavior fix bug 1090.
    - If EntryNodes, ExitNodes, ExcludeNodes, or ExcludeExitNodes
      change during a config reload, mark and discard all our origin
      circuits. This fix should address edge cases where we change the
      config options and but then choose a circuit that we created before
      the change.
    - Make EntryNodes config option much more aggressive even when
      StrictNodes is not set. Before it would prepend your requested
      entrynodes to your list of guard nodes, but feel free to use others
      after that. Now it chooses only from your EntryNodes if any of
      those are available, and only falls back to others if a) they're
      all down and b) StrictNodes is not set.
    - Now we refresh your entry guards from EntryNodes at each consensus
      fetch -- rather than just at startup and then they slowly rot as
      the network changes.
    - Add support for the country code "{??}" in torrc options like
      ExcludeNodes, to indicate all routers of unknown country. Closes
      bug 1094.
    - ExcludeNodes now takes precedence over EntryNodes and ExitNodes: if
      a node is listed in both, it's treated as excluded.
    - ExcludeNodes now applies to directory nodes -- as a preference if
      StrictNodes is 0, or an absolute requirement if StrictNodes is 1.
      Don't exclude all the directory authorities and set StrictNodes to 1
      unless you really want your Tor to break.
    - ExcludeNodes and ExcludeExitNodes now override exit enclaving.
    - ExcludeExitNodes now overrides .exit requests.
    - We don't use bridges listed in ExcludeNodes.
    - When StrictNodes is 1:
       . We now apply ExcludeNodes to hidden service introduction points
         and to rendezvous points selected by hidden service users. This
         can make your hidden service less reliable: use it with caution!
       . If we have used ExcludeNodes on ourself, do not try relay
         reachability self-tests.
       . If we have excluded all the directory authorities, we will not
         even try to upload our descriptor if we're a relay.
       . Do not honor .exit requests to an excluded node.
    - When the set of permitted nodes changes, we now remove any mappings
      introduced via TrackExitHosts to now-excluded nodes. Bugfix on
      0.1.0.1-rc.
    - We never cannibalize a circuit that had excluded nodes on it, even
      if StrictNodes is 0. Bugfix on 0.1.0.1-rc.
    - Improve log messages related to excluded nodes.

  o Major features (misc):
    - Numerous changes, bugfixes, and workarounds from Nathan Freitas
      to help Tor build correctly for Android phones.
    - The options SocksPort, ControlPort, and so on now all accept a
      value "auto" that opens a socket on an OS-selected port. A
      new ControlPortWriteToFile option tells Tor to write its
      actual control port or ports to a chosen file. If the option
      ControlPortFileGroupReadable is set, the file is created as
      group-readable. Now users can run two Tor clients on the same
      system without needing to manually mess with parameters. Resolves
      part of ticket 3076.
    - Tor now supports tunneling all of its outgoing connections over
      a SOCKS proxy, using the SOCKS4Proxy and/or SOCKS5Proxy
      configuration options. Code by Christopher Davis.

  o Code security improvements:
    - Replace all potentially sensitive memory comparison operations
      with versions whose runtime does not depend on the data being
      compared. This will help resist a class of attacks where an
      adversary can use variations in timing information to learn
      sensitive data. Fix for one case of bug 3122. (Safe memcmp
      implementation by Robert Ransom based partially on code by DJB.)
    - Enable Address Space Layout Randomization (ASLR) and Data Execution
      Prevention (DEP) by default on Windows to make it harder for
      attackers to exploit vulnerabilities. Patch from John Brooks.
    - New "--enable-gcc-hardening" ./configure flag (off by default)
      to turn on gcc compile time hardening options. It ensures
      that signed ints have defined behavior (-fwrapv), enables
      -D_FORTIFY_SOURCE=2 (requiring -O2), adds stack smashing protection
      with canaries (-fstack-protector-all), turns on ASLR protection if
      supported by the kernel (-fPIE, -pie), and adds additional security
      related warnings. Verified to work on Mac OS X and Debian Lenny.
    - New "--enable-linker-hardening" ./configure flag (off by default)
      to turn on ELF specific hardening features (relro, now). This does
      not work with Mac OS X or any other non-ELF binary format.
    - Always search the Windows system directory for system DLLs, and
      nowhere else. Bugfix on 0.1.1.23; fixes bug 1954.
    - New DisableAllSwap option. If set to 1, Tor will attempt to lock all
      current and future memory pages via mlockall(). On supported
      platforms (modern Linux and probably BSD but not Windows or OS X),
      this should effectively disable any and all attempts to page out
      memory. This option requires that you start your Tor as root --
      if you use DisableAllSwap, please consider using the User option
      to properly reduce the privileges of your Tor.

  o Major bugfixes (crashes):
    - Fix crash bug on platforms where gmtime and localtime can return
      NULL. Windows 7 users were running into this one. Fixes part of bug
      2077. Bugfix on all versions of Tor. Found by boboper.
    - Introduce minimum/maximum values that clients will believe
      from the consensus. Now we'll have a better chance to avoid crashes
      or worse when a consensus param has a weird value.
    - Fix a rare crash bug that could occur when a client was configured
      with a large number of bridges. Fixes bug 2629; bugfix on
      0.2.1.2-alpha. Bugfix by trac user "shitlei".
    - Do not crash when our configuration file becomes unreadable, for
      example due to a permissions change, between when we start up
      and when a controller calls SAVECONF. Fixes bug 3135; bugfix
      on 0.0.9pre6.
    - If we're in the pathological case where there's no exit bandwidth
      but there is non-exit bandwidth, or no guard bandwidth but there
      is non-guard bandwidth, don't crash during path selection. Bugfix
      on 0.2.0.3-alpha.
    - Fix a crash bug when trying to initialize the evdns module in
      Libevent 2. Bugfix on 0.2.1.16-rc.

  o Major bugfixes (stability):
    - Fix an assert in parsing router descriptors containing IPv6
      addresses. This one took down the directory authorities when
      somebody tried some experimental code. Bugfix on 0.2.1.3-alpha.
    - Fix an uncommon assertion failure when running with DNSPort under
      heavy load. Fixes bug 2933; bugfix on 0.2.0.1-alpha.
    - Treat an unset $HOME like an empty $HOME rather than triggering an
      assert. Bugfix on 0.0.8pre1; fixes bug 1522.
    - More gracefully handle corrupt state files, removing asserts
      in favor of saving a backup and resetting state.
    - Instead of giving an assertion failure on an internal mismatch
      on estimated freelist size, just log a BUG warning and try later.
      Mitigates but does not fix bug 1125.
    - Fix an assert that got triggered when using the TestingTorNetwork
      configuration option and then issuing a GETINFO config-text control
      command. Fixes bug 2250; bugfix on 0.2.1.2-alpha.
    - If the cached cert file is unparseable, warn but don't exit.

  o Privacy fixes (relays/bridges):
    - Don't list Windows capabilities in relay descriptors. We never made
      use of them, and maybe it's a bad idea to publish them. Bugfix
      on 0.1.1.8-alpha.
    - If the Nickname configuration option isn't given, Tor would pick a
      nickname based on the local hostname as the nickname for a relay.
      Because nicknames are not very important in today's Tor and the
      "Unnamed" nickname has been implemented, this is now problematic
      behavior: It leaks information about the hostname without being
      useful at all. Fixes bug 2979; bugfix on 0.1.2.2-alpha, which
      introduced the Unnamed nickname. Reported by tagnaq.
    - Maintain separate TLS contexts and certificates for incoming and
      outgoing connections in bridge relays. Previously we would use the
      same TLS contexts and certs for incoming and outgoing connections.
      Bugfix on 0.2.0.3-alpha; addresses bug 988.
    - Maintain separate identity keys for incoming and outgoing TLS
      contexts in bridge relays. Previously we would use the same
      identity keys for incoming and outgoing TLS contexts. Bugfix on
      0.2.0.3-alpha; addresses the other half of bug 988.
    - Make the bridge directory authority refuse to answer directory
      requests for "all descriptors". It used to include bridge
      descriptors in its answer, which was a major information leak.
      Found by "piebeer". Bugfix on 0.2.0.3-alpha.

  o Privacy fixes (clients):
    - When receiving a hidden service descriptor, check that it is for
      the hidden service we wanted. Previously, Tor would store any
      hidden service descriptors that a directory gave it, whether it
      wanted them or not. This wouldn't have let an attacker impersonate
      a hidden service, but it did let directories pre-seed a client
      with descriptors that it didn't want. Bugfix on 0.0.6.
    - Start the process of disabling ".exit" address notation, since it
      can be used for a variety of esoteric application-level attacks
      on users. To reenable it, set "AllowDotExit 1" in your torrc. Fix
      on 0.0.9rc5.
    - Reject attempts at the client side to open connections to private
      IP addresses (like 127.0.0.1, 10.0.0.1, and so on) with
      a randomly chosen exit node. Attempts to do so are always
      ill-defined, generally prevented by exit policies, and usually
      in error. This will also help to detect loops in transparent
      proxy configurations. You can disable this feature by setting
      "ClientRejectInternalAddresses 0" in your torrc.
    - Log a notice when we get a new control connection. Now it's easier
      for security-conscious users to recognize when a local application
      is knocking on their controller door. Suggested by bug 1196.

  o Privacy fixes (newnym):
    - Avoid linkability based on cached hidden service descriptors: forget
      all hidden service descriptors cached as a client when processing a
      SIGNAL NEWNYM command. Fixes bug 3000; bugfix on 0.0.6.
    - On SIGHUP, do not clear out all TrackHostExits mappings, client
      DNS cache entries, and virtual address mappings: that's what
      NEWNYM is for. Fixes bug 1345; bugfix on 0.1.0.1-rc.
    - Don't attach new streams to old rendezvous circuits after SIGNAL
      NEWNYM. Previously, we would keep using an existing rendezvous
      circuit if it remained open (i.e. if it were kept open by a
      long-lived stream, or if a new stream were attached to it before
      Tor could notice that it was old and no longer in use). Bugfix on
      0.1.1.15-rc; fixes bug 3375.

  o Major bugfixes (relay bandwidth accounting):
    - Fix a bug that could break accounting on 64-bit systems with large
      time_t values, making them hibernate for impossibly long intervals.
      Fixes bug 2146. Bugfix on 0.0.9pre6; fix by boboper.
    - Fix a bug in bandwidth accounting that could make us use twice
      the intended bandwidth when our interval start changes due to
      daylight saving time. Now we tolerate skew in stored vs computed
      interval starts: if the start of the period changes by no more than
      50% of the period's duration, we remember bytes that we transferred
      in the old period. Fixes bug 1511; bugfix on 0.0.9pre5.

  o Major bugfixes (bridges):
    - Bridges now use "reject *:*" as their default exit policy. Bugfix
      on 0.2.0.3-alpha. Fixes bug 1113.
    - If you configure your bridge with a known identity fingerprint,
      and the bridge authority is unreachable (as it is in at least
      one country now), fall back to directly requesting the descriptor
      from the bridge. Finishes the feature started in 0.2.0.10-alpha;
      closes bug 1138.
    - Fix a bug where bridge users who configure the non-canonical
      address of a bridge automatically switch to its canonical
      address. If a bridge listens at more than one address, it
      should be able to advertise those addresses independently and
      any non-blocked addresses should continue to work. Bugfix on Tor
      0.2.0.3-alpha. Fixes bug 2510.
    - If you configure Tor to use bridge A, and then quit and
      configure Tor to use bridge B instead (or if you change Tor
      to use bridge B via the controller), it would happily continue
      to use bridge A if it's still reachable. While this behavior is
      a feature if your goal is connectivity, in some scenarios it's a
      dangerous bug. Bugfix on Tor 0.2.0.1-alpha; fixes bug 2511.
    - When the controller configures a new bridge, don't wait 10 to 60
      seconds before trying to fetch its descriptor. Bugfix on
      0.2.0.3-alpha; fixes bug 3198 (suggested by 2355).

  o Major bugfixes (directory authorities):
    - Many relays have been falling out of the consensus lately because
      not enough authorities know about their descriptor for them to get
      a majority of votes. When we deprecated the v2 directory protocol,
      we got rid of the only way that v3 authorities can hear from each
      other about other descriptors. Now authorities examine every v3
      vote for new descriptors, and fetch them from that authority. Bugfix
      on 0.2.1.23.
    - Authorities could be tricked into giving out the Exit flag to relays
      that didn't allow exiting to any ports. This bug could screw
      with load balancing and stats. Bugfix on 0.1.1.6-alpha; fixes bug
      1238. Bug discovered by Martin Kowalczyk.
    - If all authorities restart at once right before a consensus vote,
      nobody will vote about "Running", and clients will get a consensus
      with no usable relays. Instead, authorities refuse to build a
      consensus if this happens. Bugfix on 0.2.0.10-alpha; fixes bug 1066.

  o Major bugfixes (stream-level fairness):
    - When receiving a circuit-level SENDME for a blocked circuit, try
      to package cells fairly from all the streams that had previously
      been blocked on that circuit. Previously, we had started with the
      oldest stream, and allowed each stream to potentially exhaust
      the circuit's package window. This gave older streams on any
      given circuit priority over newer ones. Fixes bug 1937. Detected
      originally by Camilo Viecco. This bug was introduced before the
      first Tor release, in svn commit r152: it is the new winner of
      the longest-lived bug prize.
    - Fix a stream fairness bug that would cause newer streams on a given
      circuit to get preference when reading bytes from the origin or
      destination. Fixes bug 2210. Fix by Mashael AlSabah. This bug was
      introduced before the first Tor release, in svn revision r152.
    - When the exit relay got a circuit-level sendme cell, it started
      reading on the exit streams, even if had 500 cells queued in the
      circuit queue already, so the circuit queue just grew and grew in
      some cases. We fix this by not re-enabling reading on receipt of a
      sendme cell when the cell queue is blocked. Fixes bug 1653. Bugfix
      on 0.2.0.1-alpha. Detected by Mashael AlSabah. Original patch by
      "yetonetime".
    - Newly created streams were allowed to read cells onto circuits,
      even if the circuit's cell queue was blocked and waiting to drain.
      This created potential unfairness, as older streams would be
      blocked, but newer streams would gladly fill the queue completely.
      We add code to detect this situation and prevent any stream from
      getting more than one free cell. Bugfix on 0.2.0.1-alpha. Partially
      fixes bug 1298.

  o Major bugfixes (hidden services):
    - Apply circuit timeouts to opened hidden-service-related circuits
      based on the correct start time. Previously, we would apply the
      circuit build timeout based on time since the circuit's creation;
      it was supposed to be applied based on time since the circuit
      entered its current state. Bugfix on 0.0.6; fixes part of bug 1297.
    - Improve hidden service robustness: When we find that we have
      extended a hidden service's introduction circuit to a relay not
      listed as an introduction point in the HS descriptor we currently
      have, retry with an introduction point from the current
      descriptor. Previously we would just give up. Fixes bugs 1024 and
      1930; bugfix on 0.2.0.10-alpha.
    - Directory authorities now use data collected from their own
      uptime observations when choosing whether to assign the HSDir flag
      to relays, instead of trusting the uptime value the relay reports in
      its descriptor. This change helps prevent an attack where a small
      set of nodes with frequently-changing identity keys can blackhole
      a hidden service. (Only authorities need upgrade; others will be
      fine once they do.) Bugfix on 0.2.0.10-alpha; fixes bug 2709.
    - Stop assigning the HSDir flag to relays that disable their
      DirPort (and thus will refuse to answer directory requests). This
      fix should dramatically improve the reachability of hidden services:
      hidden services and hidden service clients pick six HSDir relays
      to store and retrieve the hidden service descriptor, and currently
      about half of the HSDir relays will refuse to work. Bugfix on
      0.2.0.10-alpha; fixes part of bug 1693.

  o Major bugfixes (misc):
    - Clients now stop trying to use an exit node associated with a given
      destination by TrackHostExits if they fail to reach that exit node.
      Fixes bug 2999. Bugfix on 0.2.0.20-rc.
    - Fix a regression that caused Tor to rebind its ports if it receives
      SIGHUP while hibernating. Bugfix in 0.1.1.6-alpha; closes bug 919.
    - Remove an extra pair of quotation marks around the error
      message in control-port STATUS_GENERAL BUG events. Bugfix on
      0.1.2.6-alpha; fixes bug 3732.

  o Minor features (relays):
    - Ensure that no empty [dirreq-](read|write)-history lines are added
      to an extrainfo document. Implements ticket 2497.
    - When bandwidth accounting is enabled, be more generous with how
      much bandwidth we'll use up before entering "soft hibernation".
      Previously, we'd refuse new connections and circuits once we'd
      used up 95% of our allotment. Now, we use up 95% of our allotment,
      AND make sure that we have no more than 500MB (or 3 hours of
      expected traffic, whichever is lower) remaining before we enter
      soft hibernation.
    - Relays now log the reason for publishing a new relay descriptor,
      so we have a better chance of hunting down instances of bug 1810.
      Resolves ticket 3252.
    - Log a little more clearly about the times at which we're no longer
      accepting new connections (e.g. due to hibernating). Resolves
      bug 2181.
    - When AllowSingleHopExits is set, print a warning to explain to the
      relay operator why most clients are avoiding her relay.
    - Send END_STREAM_REASON_NOROUTE in response to EHOSTUNREACH errors.
      Clients before 0.2.1.27 didn't handle NOROUTE correctly, but such
      clients are already deprecated because of security bugs.

  o Minor features (network statistics):
    - Directory mirrors that set "DirReqStatistics 1" write statistics
      about directory requests to disk every 24 hours. As compared to the
      "--enable-geoip-stats" ./configure flag in 0.2.1.x, there are a few
      improvements: 1) stats are written to disk exactly every 24 hours;
      2) estimated shares of v2 and v3 requests are determined as mean
      values, not at the end of a measurement period; 3) unresolved
      requests are listed with country code '??'; 4) directories also
      measure download times.
    - Exit nodes that set "ExitPortStatistics 1" write statistics on the
      number of exit streams and transferred bytes per port to disk every
      24 hours.
    - Relays that set "CellStatistics 1" write statistics on how long
      cells spend in their circuit queues to disk every 24 hours.
    - Entry nodes that set "EntryStatistics 1" write statistics on the
      rough number and origins of connecting clients to disk every 24
      hours.
    - Relays that write any of the above statistics to disk and set
      "ExtraInfoStatistics 1" include the past 24 hours of statistics in
      their extra-info documents. Implements proposal 166.

  o Minor features (GeoIP and statistics):
    - Provide a log message stating which geoip file we're parsing
      instead of just stating that we're parsing the geoip file.
      Implements ticket 2432.
    - Make sure every relay writes a state file at least every 12 hours.
      Previously, a relay could go for weeks without writing its state
      file, and on a crash could lose its bandwidth history, capacity
      estimates, client country statistics, and so on. Addresses bug 3012.
    - Relays report the number of bytes spent on answering directory
      requests in extra-info descriptors similar to {read,write}-history.
      Implements enhancement 1790.
    - Report only the top 10 ports in exit-port stats in order not to
      exceed the maximum extra-info descriptor length of 50 KB. Implements
      task 2196.
    - If writing the state file to disk fails, wait up to an hour before
      retrying again, rather than trying again each second. Fixes bug
      2346; bugfix on Tor 0.1.1.3-alpha.
    - Delay geoip stats collection by bridges for 6 hours, not 2 hours,
      when we switch from being a public relay to a bridge. Otherwise
      there will still be clients that see the relay in their consensus,
      and the stats will end up wrong. Bugfix on 0.2.1.15-rc; fixes
      bug 932.
    - Update to the August 2 2011 Maxmind GeoLite Country database.

  o Minor features (clients):
    - When expiring circuits, use microsecond timers rather than
      one-second timers. This can avoid an unpleasant situation where a
      circuit is launched near the end of one second and expired right
      near the beginning of the next, and prevent fluctuations in circuit
      timeout values.
    - If we've configured EntryNodes and our network goes away and/or all
      our entrynodes get marked down, optimistically retry them all when
      a new socks application request appears. Fixes bug 1882.
    - Always perform router selections using weighted relay bandwidth,
      even if we don't need a high capacity circuit at the time. Non-fast
      circuits now only differ from fast ones in that they can use relays
      not marked with the Fast flag. This "feature" could turn out to
      be a horrible bug; we should investigate more before it goes into
      a stable release.
    - When we run out of directory information such that we can't build
      circuits, but then get enough that we can build circuits, log when
      we actually construct a circuit, so the user has a better chance of
      knowing what's going on. Fixes bug 1362.
    - Log SSL state transitions at debug level during handshake, and
      include SSL states in error messages. This may help debug future
      SSL handshake issues.

  o Minor features (directory authorities):
    - When a router changes IP address or port, authorities now launch
      a new reachability test for it. Implements ticket 1899.
    - Directory authorities now reject relays running any versions of
      Tor between 0.2.1.3-alpha and 0.2.1.18 inclusive; they have
      known bugs that keep RELAY_EARLY cells from working on rendezvous
      circuits. Followup to fix for bug 2081.
    - Directory authorities now reject relays running any version of Tor
      older than 0.2.0.26-rc. That version is the earliest that fetches
      current directory information correctly. Fixes bug 2156.
    - Directory authorities now do an immediate reachability check as soon
      as they hear about a new relay. This change should slightly reduce
      the time between setting up a relay and getting listed as running
      in the consensus. It should also improve the time between setting
      up a bridge and seeing use by bridge users.
    - Directory authorities no longer launch a TLS connection to every
      relay as they startup. Now that we have 2k+ descriptors cached,
      the resulting network hiccup is becoming a burden. Besides,
      authorities already avoid voting about Running for the first half
      hour of their uptime.
    - Directory authorities now log the source of a rejected POSTed v3
      networkstatus vote, so we can track failures better.
    - Backport code from 0.2.3.x that allows directory authorities to
      clean their microdescriptor caches. Needed to resolve bug 2230.

  o Minor features (hidden services):
    - Use computed circuit-build timeouts to decide when to launch
      parallel introduction circuits for hidden services. (Previously,
      we would retry after 15 seconds.)
    - Don't allow v0 hidden service authorities to act as clients.
      Required by fix for bug 3000.
    - Ignore SIGNAL NEWNYM commands on relay-only Tor instances. Required
      by fix for bug 3000.
    - Make hidden services work better in private Tor networks by not
      requiring any uptime to join the hidden service descriptor
      DHT. Implements ticket 2088.
    - Log (at info level) when purging pieces of hidden-service-client
      state because of SIGNAL NEWNYM.

  o Minor features (controller interface):
    - New "GETINFO net/listeners/(type)" controller command to return
      a list of addresses and ports that are bound for listeners for a
      given connection type. This is useful when the user has configured
      "SocksPort auto" and the controller needs to know which port got
      chosen. Resolves another part of ticket 3076.
    - Have the controller interface give a more useful message than
      "Internal Error" in response to failed GETINFO requests.
    - Add a TIMEOUT_RATE keyword to the BUILDTIMEOUT_SET control port
      event, to give information on the current rate of circuit timeouts
      over our stored history.
    - The 'EXTENDCIRCUIT' control port command can now be used with
      a circ id of 0 and no path. This feature will cause Tor to build
      a new 'fast' general purpose circuit using its own path selection
      algorithms.
    - Added a BUILDTIMEOUT_SET controller event to describe changes
      to the circuit build timeout.
    - New controller command "getinfo config-text". It returns the
      contents that Tor would write if you send it a SAVECONF command,
      so the controller can write the file to disk itself.

  o Minor features (controller protocol):
    - Add a new ControlSocketsGroupWritable configuration option: when
      it is turned on, ControlSockets are group-writeable by the default
      group of the current user. Patch by Jérémy Bobbio; implements
      ticket 2972.
    - Tor now refuses to create a ControlSocket in a directory that is
      world-readable (or group-readable if ControlSocketsGroupWritable
      is 0). This is necessary because some operating systems do not
      enforce permissions on an AF_UNIX sockets. Permissions on the
      directory holding the socket, however, seems to work everywhere.
    - Warn when CookieAuthFileGroupReadable is set but CookieAuthFile is
      not. This would lead to a cookie that is still not group readable.
      Closes bug 1843. Suggested by katmagic.
    - Future-proof the controller protocol a bit by ignoring keyword
      arguments we do not recognize.

  o Minor features (more useful logging):
    - Revise most log messages that refer to nodes by nickname to
      instead use the "$key=nickname at address" format. This should be
      more useful, especially since nicknames are less and less likely
      to be unique. Resolves ticket 3045.
    - When an HTTPS proxy reports "403 Forbidden", we now explain
      what it means rather than calling it an unexpected status code.
      Closes bug 2503. Patch from Michael Yakubovich.
    - Rate-limit a warning about failures to download v2 networkstatus
      documents. Resolves part of bug 1352.
    - Rate-limit the "your application is giving Tor only an IP address"
      warning. Addresses bug 2000; bugfix on 0.0.8pre2.
    - Rate-limit "Failed to hand off onionskin" warnings.
    - When logging a rate-limited warning, we now mention how many messages
      got suppressed since the last warning.
    - Make the formerly ugly "2 unknown, 7 missing key, 0 good, 0 bad,
      2 no signature, 4 required" messages about consensus signatures
      easier to read, and make sure they get logged at the same severity
      as the messages explaining which keys are which. Fixes bug 1290.
    - Don't warn when we have a consensus that we can't verify because
      of missing certificates, unless those certificates are ones
      that we have been trying and failing to download. Fixes bug 1145.

  o Minor features (log domains):
    - Add documentation for configuring logging at different severities in
      different log domains. We've had this feature since 0.2.1.1-alpha,
      but for some reason it never made it into the manpage. Fixes
      bug 2215.
    - Make it simpler to specify "All log domains except for A and B".
      Previously you needed to say "[*,~A,~B]". Now you can just say
      "[~A,~B]".
    - Add a "LogMessageDomains 1" option to include the domains of log
      messages along with the messages. Without this, there's no way
      to use log domains without reading the source or doing a lot
      of guessing.
    - Add a new "Handshake" log domain for activities that happen
      during the TLS handshake.

  o Minor features (build process):
    - Make compilation with clang possible when using
      "--enable-gcc-warnings" by removing two warning options that clang
      hasn't implemented yet and by fixing a few warnings. Resolves
      ticket 2696.
    - Detect platforms that brokenly use a signed size_t, and refuse to
      build there. Found and analyzed by doorss and rransom.
    - Fix a bunch of compile warnings revealed by mingw with gcc 4.5.
      Resolves bug 2314.
    - Add support for statically linking zlib by specifying
      "--enable-static-zlib", to go with our support for statically
      linking openssl and libevent. Resolves bug 1358.
    - Instead of adding the svn revision to the Tor version string, report
      the git commit (when we're building from a git checkout).
    - Rename the "log.h" header to "torlog.h" so as to conflict with fewer
      system headers.
    - New --digests command-line switch to output the digests of the
      source files Tor was built with.
    - Generate our manpage and HTML documentation using Asciidoc. This
      change should make it easier to maintain the documentation, and
      produce nicer HTML. The build process fails if asciidoc cannot
      be found and building with asciidoc isn't disabled (via the
      "--disable-asciidoc" argument to ./configure. Skipping the manpage
      speeds up the build considerably.

  o Minor features (options / torrc):
    - Warn when the same option is provided more than once in a torrc
      file, on the command line, or in a single SETCONF statement, and
      the option is one that only accepts a single line. Closes bug 1384.
    - Warn when the user configures two HiddenServiceDir lines that point
      to the same directory. Bugfix on 0.0.6 (the version introducing
      HiddenServiceDir); fixes bug 3289.
    - Add new "perconnbwrate" and "perconnbwburst" consensus params to
      do individual connection-level rate limiting of clients. The torrc
      config options with the same names trump the consensus params, if
      both are present. Replaces the old "bwconnrate" and "bwconnburst"
      consensus params which were broken from 0.2.2.7-alpha through
      0.2.2.14-alpha. Closes bug 1947.
    - New config option "WarnUnsafeSocks 0" disables the warning that
      occurs whenever Tor receives a socks handshake using a version of
      the socks protocol that can only provide an IP address (rather
      than a hostname). Setups that do DNS locally over Tor are fine,
      and we shouldn't spam the logs in that case.
    - New config option "CircuitStreamTimeout" to override our internal
      timeout schedule for how many seconds until we detach a stream from
      a circuit and try a new circuit. If your network is particularly
      slow, you might want to set this to a number like 60.
    - New options for SafeLogging to allow scrubbing only log messages
      generated while acting as a relay. Specify "SafeLogging relay" if
      you want to ensure that only messages known to originate from
      client use of the Tor process will be logged unsafely.
    - Time and memory units in the configuration file can now be set to
      fractional units. For example, "2.5 GB" is now a valid value for
      AccountingMax.
    - Support line continuations in the torrc config file. If a line
      ends with a single backslash character, the newline is ignored, and
      the configuration value is treated as continuing on the next line.
      Resolves bug 1929.

  o Minor features (unit tests):
    - Revise our unit tests to use the "tinytest" framework, so we
      can run tests in their own processes, have smarter setup/teardown
      code, and so on. The unit test code has moved to its own
      subdirectory, and has been split into multiple modules.
    - Add a unit test for cross-platform directory-listing code.
    - Add some forgotten return value checks during unit tests. Found
      by coverity.
    - Use GetTempDir to find the proper temporary directory location on
      Windows when generating temporary files for the unit tests. Patch
      by Gisle Vanem.

  o Minor features (misc):
    - The "torify" script now uses torsocks where available.
    - Make Libevent log messages get delivered to controllers later,
      and not from inside the Libevent log handler. This prevents unsafe
      reentrant Libevent calls while still letting the log messages
      get through.
    - Certain Tor clients (such as those behind check.torproject.org) may
      want to fetch the consensus in an extra early manner. To enable this
      a user may now set FetchDirInfoExtraEarly to 1. This also depends on
      setting FetchDirInfoEarly to 1. Previous behavior will stay the same
      as only certain clients who must have this information sooner should
      set this option.
    - Expand homedirs passed to tor-checkkey. This should silence a
      coverity complaint about passing a user-supplied string into
      open() without checking it.
    - Make sure to disable DirPort if running as a bridge. DirPorts aren't
      used on bridges, and it makes bridge scanning somewhat easier.
    - Create the /var/run/tor directory on startup on OpenSUSE if it is
      not already created. Patch from Andreas Stieger. Fixes bug 2573.

  o Minor bugfixes (relays):
    - When a relay decides that its DNS is too broken for it to serve
      as an exit server, it advertised itself as a non-exit, but
      continued to act as an exit. This could create accidental
      partitioning opportunities for users. Instead, if a relay is
      going to advertise reject *:* as its exit policy, it should
      really act with exit policy "reject *:*". Fixes bug 2366.
      Bugfix on Tor 0.1.2.5-alpha. Bugfix by user "postman" on trac.
    - Publish a router descriptor even if generating an extra-info
      descriptor fails. Previously we would not publish a router
      descriptor without an extra-info descriptor; this can cause fast
      exit relays collecting exit-port statistics to drop from the
      consensus. Bugfix on 0.1.2.9-rc; fixes bug 2195.
    - When we're trying to guess whether we know our IP address as
      a relay, we would log various ways that we failed to guess
      our address, but never log that we ended up guessing it
      successfully. Now add a log line to help confused and anxious
      relay operators. Bugfix on 0.1.2.1-alpha; fixes bug 1534.
    - For bandwidth accounting, calculate our expected bandwidth rate
      based on the time during which we were active and not in
      soft-hibernation during the last interval. Previously, we were
      also considering the time spent in soft-hibernation. If this
      was a long time, we would wind up underestimating our bandwidth
      by a lot, and skewing our wakeup time towards the start of the
      accounting interval. Fixes bug 1789. Bugfix on 0.0.9pre5.
    - Demote a confusing TLS warning that relay operators might get when
      someone tries to talk to their ORPort. It is not the operator's
      fault, nor can they do anything about it. Fixes bug 1364; bugfix
      on 0.2.0.14-alpha.
    - Change "Application request when we're believed to be offline."
      notice to "Application request when we haven't used client
      functionality lately.", to clarify that it's not an error. Bugfix
      on 0.0.9.3; fixes bug 1222.

  o Minor bugfixes (bridges):
    - When a client starts or stops using bridges, never use a circuit
      that was built before the configuration change. This behavior could
      put at risk a user who uses bridges to ensure that her traffic
      only goes to the chosen addresses. Bugfix on 0.2.0.3-alpha; fixes
      bug 3200.
    - Do not reset the bridge descriptor download status every time we
      re-parse our configuration or get a configuration change. Fixes
      bug 3019; bugfix on 0.2.0.3-alpha.
    - Users couldn't configure a regular relay to be their bridge. It
      didn't work because when Tor fetched the bridge descriptor, it found
      that it already had it, and didn't realize that the purpose of the
      descriptor had changed. Now we replace routers with a purpose other
      than bridge with bridge descriptors when fetching them. Bugfix on
      0.1.1.9-alpha. Fixes bug 1776.
    - In the special case where you configure a public exit relay as your
      bridge, Tor would be willing to use that exit relay as the last
      hop in your circuit as well. Now we fail that circuit instead.
      Bugfix on 0.2.0.12-alpha. Fixes bug 2403. Reported by "piebeer".

  o Minor bugfixes (clients):
    - We now ask the other side of a stream (the client or the exit)
      for more data on that stream when the amount of queued data on
      that stream dips low enough. Previously, we wouldn't ask the
      other side for more data until either it sent us more data (which
      it wasn't supposed to do if it had exhausted its window!) or we
      had completely flushed all our queued data. This flow control fix
      should improve throughput. Fixes bug 2756; bugfix on the earliest
      released versions of Tor (svn commit r152).
    - When a client finds that an origin circuit has run out of 16-bit
      stream IDs, we now mark it as unusable for new streams. Previously,
      we would try to close the entire circuit. Bugfix on 0.0.6.
    - Make it explicit that we don't cannibalize one-hop circuits. This
      happens in the wild, but doesn't turn out to be a problem because
      we fortunately don't use those circuits. Many thanks to outofwords
      for the initial analysis and to swissknife who confirmed that
      two-hop circuits are actually created.
    - Resolve an edge case in path weighting that could make us misweight
      our relay selection. Fixes bug 1203; bugfix on 0.0.8rc1.
    - Make the DNSPort option work with libevent 2.x. Don't alter the
      behaviour for libevent 1.x. Fixes bug 1143. Found by SwissTorExit.

  o Minor bugfixes (directory authorities):
    - Make directory authorities more accurate at recording when
      relays that have failed several reachability tests became
      unreachable, so we can provide more accuracy at assigning Stable,
      Guard, HSDir, etc flags. Bugfix on 0.2.0.6-alpha. Resolves bug 2716.
    - Directory authorities are now more robust to hops back in time
      when calculating router stability. Previously, if a run of uptime
      or downtime appeared to be negative, the calculation could give
      incorrect results. Bugfix on 0.2.0.6-alpha; noticed when fixing
      bug 1035.
    - Directory authorities will now attempt to download consensuses
      if their own efforts to make a live consensus have failed. This
      change means authorities that restart will fetch a valid
      consensus, and it means authorities that didn't agree with the
      current consensus will still fetch and serve it if it has enough
      signatures. Bugfix on 0.2.0.9-alpha; fixes bug 1300.
    - Never vote for a server as "Running" if we have a descriptor for
      it claiming to be hibernating, and that descriptor was published
      more recently than our last contact with the server. Bugfix on
      0.2.0.3-alpha; fixes bug 911.
    - Directory authorities no longer change their opinion of, or vote on,
      whether a router is Running, unless they have themselves been
      online long enough to have some idea. Bugfix on 0.2.0.6-alpha.
      Fixes bug 1023.

  o Minor bugfixes (hidden services):
    - Log malformed requests for rendezvous descriptors as protocol
      warnings, not warnings. Also, use a more informative log message
      in case someone sees it at log level warning without prior
      info-level messages. Fixes bug 2748; bugfix on 0.2.0.10-alpha.
    - Accept hidden service descriptors if we think we might be a hidden
      service directory, regardless of what our consensus says. This
      helps robustness, since clients and hidden services can sometimes
      have a more up-to-date view of the network consensus than we do,
      and if they think that the directory authorities list us a HSDir,
      we might actually be one. Related to bug 2732; bugfix on
      0.2.0.10-alpha.
    - Correct the warning displayed when a rendezvous descriptor exceeds
      the maximum size. Fixes bug 2750; bugfix on 0.2.1.5-alpha. Found by
      John Brooks.
    - Clients and hidden services now use HSDir-flagged relays for hidden
      service descriptor downloads and uploads even if the relays have no
      DirPort set and the client has disabled TunnelDirConns. This will
      eventually allow us to give the HSDir flag to relays with no
      DirPort. Fixes bug 2722; bugfix on 0.2.1.6-alpha.
    - Only limit the lengths of single HS descriptors, even when multiple
      HS descriptors are published to an HSDir relay in a single POST
      operation. Fixes bug 2948; bugfix on 0.2.1.5-alpha. Found by hsdir.

  o Minor bugfixes (controllers):
    - Allow GETINFO fingerprint to return a fingerprint even when
      we have not yet built a router descriptor. Fixes bug 3577;
      bugfix on 0.2.0.1-alpha.
    - Send a SUCCEEDED stream event to the controller when a reverse
      resolve succeeded. Fixes bug 3536; bugfix on 0.0.8pre1. Issue
      discovered by katmagic.
    - Remove a trailing asterisk from "exit-policy/default" in the
      output of the control port command "GETINFO info/names". Bugfix
      on 0.1.2.5-alpha.
    - Make the SIGNAL DUMP controller command work on FreeBSD. Fixes bug
      2917. Bugfix on 0.1.1.1-alpha.
    - When we restart our relay, we might get a successful connection
      from the outside before we've started our reachability tests,
      triggering a warning: "ORPort found reachable, but I have no
      routerinfo yet. Failing to inform controller of success." This
      bug was harmless unless Tor is running under a controller
      like Vidalia, in which case the controller would never get a
      REACHABILITY_SUCCEEDED status event. Bugfix on 0.1.2.6-alpha;
      fixes bug 1172.
    - When a controller changes TrackHostExits, remove mappings for
      hosts that should no longer have their exits tracked. Bugfix on
      0.1.0.1-rc.
    - When a controller changes VirtualAddrNetwork, remove any mappings
      for hosts that were automapped to the old network. Bugfix on
      0.1.1.19-rc.
    - When a controller changes one of the AutomapHosts* options, remove
      any mappings for hosts that should no longer be automapped. Bugfix
      on 0.2.0.1-alpha.
    - Fix an off-by-one error in calculating some controller command
      argument lengths. Fortunately, this mistake is harmless since
      the controller code does redundant NUL termination too. Found by
      boboper. Bugfix on 0.1.1.1-alpha.
    - Fix a bug in the controller interface where "GETINFO ns/asdaskljkl"
      would return "551 Internal error" rather than "552 Unrecognized key
      ns/asdaskljkl". Bugfix on 0.1.2.3-alpha.
    - Don't spam the controller with events when we have no file
      descriptors available. Bugfix on 0.2.1.5-alpha. (Rate-limiting
      for log messages was already solved from bug 748.)
    - Emit a GUARD DROPPED controller event for a case we missed.
    - Ensure DNS requests launched by "RESOLVE" commands from the
      controller respect the __LeaveStreamsUnattached setconf options. The
      same goes for requests launched via DNSPort or transparent
      proxying. Bugfix on 0.2.0.1-alpha; fixes bug 1525.

  o Minor bugfixes (config options):
    - Tor used to limit HttpProxyAuthenticator values to 48 characters.
      Change the limit to 512 characters by removing base64 newlines.
      Fixes bug 2752. Fix by Michael Yakubovich.
    - Complain if PublishServerDescriptor is given multiple arguments that
      include 0 or 1. This configuration will be rejected in the future.
      Bugfix on 0.2.0.1-alpha; closes bug 1107.
    - Disallow BridgeRelay 1 and ORPort 0 at once in the configuration.
      Bugfix on 0.2.0.13-alpha; closes bug 928.

  o Minor bugfixes (log subsystem fixes):
    - When unable to format an address as a string, report its value
      as "???" rather than reusing the last formatted address. Bugfix
      on 0.2.1.5-alpha.
    - Be more consistent in our treatment of file system paths. "~" should
      get expanded to the user's home directory in the Log config option.
      Fixes bug 2971; bugfix on 0.2.0.1-alpha, which introduced the
      feature for the -f and --DataDirectory options.

  o Minor bugfixes (memory management):
    - Don't stack-allocate the list of supplementary GIDs when we're
      about to log them. Stack-allocating NGROUPS_MAX gid_t elements
      could take up to 256K, which is way too much stack. Found by
      Coverity; CID #450. Bugfix on 0.2.1.7-alpha.
    - Save a couple bytes in memory allocation every time we escape
      certain characters in a string. Patch from Florian Zumbiehl.

  o Minor bugfixes (protocol correctness):
    - When checking for 1024-bit keys, check for 1024 bits, not 128
      bytes. This allows Tor to correctly discard keys of length 1017
      through 1023. Bugfix on 0.0.9pre5.
    - Require that introduction point keys and onion handshake keys
      have a public exponent of 65537. Starts to fix bug 3207; bugfix
      on 0.2.0.10-alpha.
    - Handle SOCKS messages longer than 128 bytes long correctly, rather
      than waiting forever for them to finish. Fixes bug 2330; bugfix
      on 0.2.0.16-alpha. Found by doorss.
    - Never relay a cell for a circuit we have already destroyed.
      Between marking a circuit as closeable and finally closing it,
      it may have been possible for a few queued cells to get relayed,
      even though they would have been immediately dropped by the next
      OR in the circuit. Fixes bug 1184; bugfix on 0.2.0.1-alpha.
    - Never queue a cell for a circuit that's already been marked
      for close.
    - Fix a spec conformance issue: the network-status-version token
      must be the first token in a v3 consensus or vote. Discovered by
      "parakeep". Bugfix on 0.2.0.3-alpha.
    - A networkstatus vote must contain exactly one signature. Spec
      conformance issue. Bugfix on 0.2.0.3-alpha.
    - When asked about a DNS record type we don't support via a
      client DNSPort, reply with NOTIMPL rather than an empty
      reply. Patch by intrigeri. Fixes bug 3369; bugfix on 2.0.1-alpha.
    - Make more fields in the controller protocol case-insensitive, since
      control-spec.txt said they were.

  o Minor bugfixes (log messages):
    - Fix a log message that said "bits" while displaying a value in
      bytes. Found by wanoskarnet. Fixes bug 3318; bugfix on
      0.2.0.1-alpha.
    - Downgrade "no current certificates known for authority" message from
      Notice to Info. Fixes bug 2899; bugfix on 0.2.0.10-alpha.
    - Correctly describe errors that occur when generating a TLS object.
      Previously we would attribute them to a failure while generating a
      TLS context. Patch by Robert Ransom. Bugfix on 0.1.0.4-rc; fixes
      bug 1994.
    - Fix an instance where a Tor directory mirror might accidentally
      log the IP address of a misbehaving Tor client. Bugfix on
      0.1.0.1-rc.
    - Stop logging at severity 'warn' when some other Tor client tries
      to establish a circuit with us using weak DH keys. It's a protocol
      violation, but that doesn't mean ordinary users need to hear about
      it. Fixes the bug part of bug 1114. Bugfix on 0.1.0.13.
    - If your relay can't keep up with the number of incoming create
      cells, it would log one warning per failure into your logs. Limit
      warnings to 1 per minute. Bugfix on 0.0.2pre10; fixes bug 1042.

  o Minor bugfixes (build fixes):
    - Fix warnings from GCC 4.6's "-Wunused-but-set-variable" option.
    - When warning about missing zlib development packages during compile,
      give the correct package names. Bugfix on 0.2.0.1-alpha.
    - Fix warnings that newer versions of autoconf produce during
      ./autogen.sh. These warnings appear to be harmless in our case,
      but they were extremely verbose. Fixes bug 2020.
    - Squash a compile warning on OpenBSD. Reported by Tas; fixes
      bug 1848.

  o Minor bugfixes (portability):
    - Write several files in text mode, on OSes that distinguish text
      mode from binary mode (namely, Windows). These files are:
      'buffer-stats', 'dirreq-stats', and 'entry-stats' on relays
      that collect those statistics; 'client_keys' and 'hostname' for
      hidden services that use authentication; and (in the tor-gencert
      utility) newly generated identity and signing keys. Previously,
      we wouldn't specify text mode or binary mode, leading to an
      assertion failure. Fixes bug 3607. Bugfix on 0.2.1.1-alpha (when
      the DirRecordUsageByCountry option which would have triggered
      the assertion failure was added), although this assertion failure
      would have occurred in tor-gencert on Windows in 0.2.0.1-alpha.
    - Selectively disable deprecation warnings on OS X because Lion
      started deprecating the shipped copy of openssl. Fixes bug 3643.
    - Use a wide type to hold sockets when built for 64-bit Windows.
      Fixes bug 3270.
    - Fix an issue that prevented static linking of libevent on
      some platforms (notably Linux). Fixes bug 2698; bugfix on 0.2.1.23,
      where we introduced the "--with-static-libevent" configure option.
    - Fix a bug with our locking implementation on Windows that couldn't
      correctly detect when a file was already locked. Fixes bug 2504,
      bugfix on 0.2.1.6-alpha.
    - Build correctly on OSX with zlib 1.2.4 and higher with all warnings
      enabled.
    - Fix IPv6-related connect() failures on some platforms (BSD, OS X).
      Bugfix on 0.2.0.3-alpha; fixes first part of bug 2660. Patch by
      "piebeer".

  o Minor bugfixes (code correctness):
    - Always NUL-terminate the sun_path field of a sockaddr_un before
      passing it to the kernel. (Not a security issue: kernels are
      smart enough to reject bad sockaddr_uns.) Found by Coverity;
      CID #428. Bugfix on Tor 0.2.0.3-alpha.
    - Make connection_printf_to_buf()'s behaviour sane. Its callers
      expect it to emit a CRLF iff the format string ends with CRLF;
      it actually emitted a CRLF iff (a) the format string ended with
      CRLF or (b) the resulting string was over 1023 characters long or
      (c) the format string did not end with CRLF *and* the resulting
      string was 1021 characters long or longer. Bugfix on 0.1.1.9-alpha;
      fixes part of bug 3407.
    - Make send_control_event_impl()'s behaviour sane. Its callers
      expect it to always emit a CRLF at the end of the string; it
      might have emitted extra control characters as well. Bugfix on
      0.1.1.9-alpha; fixes another part of bug 3407.
    - Make crypto_rand_int() check the value of its input correctly.
      Previously, it accepted values up to UINT_MAX, but could return a
      negative number if given a value above INT_MAX+1. Found by George
      Kadianakis. Fixes bug 3306; bugfix on 0.2.2pre14.
    - Fix a potential null-pointer dereference while computing a
      consensus. Bugfix on tor-0.2.0.3-alpha, found with the help of
      clang's analyzer.
    - If we fail to compute the identity digest of a v3 legacy keypair,
      warn, and don't use a buffer-full of junk instead. Bugfix on
      0.2.1.1-alpha; fixes bug 3106.
    - Resolve an untriggerable issue in smartlist_string_num_isin(),
      where if the function had ever in the future been used to check
      for the presence of a too-large number, it would have given an
      incorrect result. (Fortunately, we only used it for 16-bit
      values.) Fixes bug 3175; bugfix on 0.1.0.1-rc.
    - Be more careful about reporting the correct error from a failed
      connect() system call. Under some circumstances, it was possible to
      look at an incorrect value for errno when sending the end reason.
      Bugfix on 0.1.0.1-rc.
    - Correctly handle an "impossible" overflow cases in connection byte
      counting, where we write or read more than 4GB on an edge connection
      in a single second. Bugfix on 0.1.2.8-beta.
    - Avoid a double mark-for-free warning when failing to attach a
      transparent proxy connection. Bugfix on 0.1.2.1-alpha. Fixes
      bug 2279.
    - Correctly detect failure to allocate an OpenSSL BIO. Fixes bug 2378;
      found by "cypherpunks". This bug was introduced before the first
      Tor release, in svn commit r110.
    - Fix a bug in bandwidth history state parsing that could have been
      triggered if a future version of Tor ever changed the timing
      granularity at which bandwidth history is measured. Bugfix on
      Tor 0.1.1.11-alpha.
    - Add assertions to check for overflow in arguments to
      base32_encode() and base32_decode(); fix a signed-unsigned
      comparison there too. These bugs are not actually reachable in Tor,
      but it's good to prevent future errors too. Found by doorss.
    - Avoid a bogus overlapped memcpy in tor_addr_copy(). Reported by
      "memcpyfail".
    - Set target port in get_interface_address6() correctly. Bugfix
      on 0.1.1.4-alpha and 0.2.0.3-alpha; fixes second part of bug 2660.
    - Fix an impossible-to-actually-trigger buffer overflow in relay
      descriptor generation. Bugfix on 0.1.0.15.
    - Fix numerous small code-flaws found by Coverity Scan Rung 3.

  o Minor bugfixes (code improvements):
    - After we free an internal connection structure, overwrite it
      with a different memory value than we use for overwriting a freed
      internal circuit structure. Should help with debugging. Suggested
      by bug 1055.
    - If OpenSSL fails to make a duplicate of a private or public key, log
      an error message and try to exit cleanly. May help with debugging
      if bug 1209 ever remanifests.
    - Some options used different conventions for uppercasing of acronyms
      when comparing manpage and source. Fix those in favor of the
      manpage, as it makes sense to capitalize acronyms.
    - Take a first step towards making or.h smaller by splitting out
      function definitions for all source files in src/or/. Leave
      structures and defines in or.h for now.
    - Remove a few dead assignments during router parsing. Found by
      coverity.
    - Don't use 1-bit wide signed bit fields. Found by coverity.
    - Avoid signed/unsigned comparisons by making SIZE_T_CEILING unsigned.
      None of the cases where we did this before were wrong, but by making
      this change we avoid warnings. Fixes bug 2475; bugfix on 0.2.1.28.
    - The memarea code now uses a sentinel value at the end of each area
      to make sure nothing writes beyond the end of an area. This might
      help debug some conceivable causes of bug 930.
    - Always treat failure to allocate an RSA key as an unrecoverable
      allocation error.
    - Add some more defensive programming for architectures that can't
      handle unaligned integer accesses. We don't know of any actual bugs
      right now, but that's the best time to fix them. Fixes bug 1943.

  o Minor bugfixes (misc):
    - Fix a rare bug in rend_fn unit tests: we would fail a test when
      a randomly generated port is 0. Diagnosed by Matt Edman. Bugfix
      on 0.2.0.10-alpha; fixes bug 1808.
    - Where available, use Libevent 2.0's periodic timers so that our
      once-per-second cleanup code gets called even more closely to
      once per second than it would otherwise. Fixes bug 943.
    - Ignore OutboundBindAddress when connecting to localhost.
      Connections to localhost need to come _from_ localhost, or else
      local servers (like DNS and outgoing HTTP/SOCKS proxies) will often
      refuse to listen.
    - Update our OpenSSL 0.9.8l fix so that it works with OpenSSL 0.9.8m
      too.
    - If any of the v3 certs we download are unparseable, we should
      actually notice the failure so we don't retry indefinitely. Bugfix
      on 0.2.0.x; reported by "rotator".
    - When Tor fails to parse a descriptor of any kind, dump it to disk.
      Might help diagnosing bug 1051.
    - Make our 'torify' script more portable; if we have only one of
      'torsocks' or 'tsocks' installed, don't complain to the user;
      and explain our warning about tsocks better.
    - Fix some urls in the exit notice file and make it XHTML1.1 strict
      compliant. Based on a patch from Christian Kujau.

  o Documentation changes:
    - Modernize the doxygen configuration file slightly. Fixes bug 2707.
    - Resolve all doxygen warnings except those for missing documentation.
      Fixes bug 2705.
    - Add doxygen documentation for more functions, fields, and types.
    - Convert the HACKING file to asciidoc, and add a few new sections
      to it, explaining how we use Git, how we make changelogs, and
      what should go in a patch.
    - Document the default socks host and port (127.0.0.1:9050) for
      tor-resolve.
    - Removed some unnecessary files from the source distribution. The
      AUTHORS file has now been merged into the people page on the
      website. The roadmaps and design doc can now be found in the
      projects directory in svn.

  o Deprecated and removed features (config):
    - Remove the torrc.complete file. It hasn't been kept up to date
      and users will have better luck checking out the manpage.
    - Remove the HSAuthorityRecordStats option that version 0 hidden
      service authorities could use to track statistics of overall v0
      hidden service usage.
    - Remove the obsolete "NoPublish" option; it has been flagged
      as obsolete and has produced a warning since 0.1.1.18-rc.
    - Caches no longer download and serve v2 networkstatus documents
      unless FetchV2Networkstatus flag is set: these documents haven't
      haven't been used by clients or relays since 0.2.0.x. Resolves
      bug 3022.

  o Deprecated and removed features (controller):
    - The controller no longer accepts the old obsolete "addr-mappings/"
      or "unregistered-servers-" GETINFO values.
    - The EXTENDED_EVENTS and VERBOSE_NAMES controller features are now
      always on; using them is necessary for correct forward-compatible
      controllers.

  o Deprecated and removed features (misc):
    - Hidden services no longer publish version 0 descriptors, and clients
      do not request or use version 0 descriptors. However, the old hidden
      service authorities still accept and serve version 0 descriptors
      when contacted by older hidden services/clients.
    - Remove undocumented option "-F" from tor-resolve: it hasn't done
      anything since 0.2.1.16-rc.
    - Remove everything related to building the expert bundle for OS X.
      It has confused many users, doesn't work right on OS X 10.6,
      and is hard to get rid of once installed. Resolves bug 1274.
    - Remove support for .noconnect style addresses. Nobody was using
      them, and they provided another avenue for detecting Tor users
      via application-level web tricks.
    - When we fixed bug 1038 we had to put in a restriction not to send
      RELAY_EARLY cells on rend circuits. This was necessary as long
      as relays using Tor 0.2.1.3-alpha through 0.2.1.18-alpha were
      active. Now remove this obsolete check. Resolves bug 2081.
    - Remove workaround code to handle directory responses from servers
      that had bug 539 (they would send HTTP status 503 responses _and_
      send a body too). Since only server versions before
      0.2.0.16-alpha/0.1.2.19 were affected, there is no longer reason to
      keep the workaround in place.
    - Remove the old 'fuzzy time' logic. It was supposed to be used for
      handling calculations where we have a known amount of clock skew and
      an allowed amount of unknown skew. But we only used it in three
      places, and we never adjusted the known/unknown skew values. This is
      still something we might want to do someday, but if we do, we'll
      want to do it differently.
    - Remove the "--enable-iphone" option to ./configure. According to
      reports from Marco Bonetti, Tor builds fine without any special
      tweaking on recent iPhone SDK versions.


Changes in version 0.2.1.30 - 2011-02-23
  Tor 0.2.1.30 fixes a variety of less critical bugs. The main other
  change is a slight tweak to Tor's TLS handshake that makes relays
  and bridges that run this new version reachable from Iran again.
  We don't expect this tweak will win the arms race long-term, but it
  buys us time until we roll out a better solution.

  o Major bugfixes:
    - Stop sending a CLOCK_SKEW controller status event whenever
      we fetch directory information from a relay that has a wrong clock.
      Instead, only inform the controller when it's a trusted authority
      that claims our clock is wrong. Bugfix on 0.1.2.6-alpha; fixes
      the rest of bug 1074.
    - Fix a bounds-checking error that could allow an attacker to
      remotely crash a directory authority. Bugfix on 0.2.1.5-alpha.
      Found by "piebeer".
    - If relays set RelayBandwidthBurst but not RelayBandwidthRate,
      Tor would ignore their RelayBandwidthBurst setting,
      potentially using more bandwidth than expected. Bugfix on
      0.2.0.1-alpha. Reported by Paul Wouters. Fixes bug 2470.
    - Ignore and warn if the user mistakenly sets "PublishServerDescriptor
      hidserv" in her torrc. The 'hidserv' argument never controlled
      publication of hidden service descriptors. Bugfix on 0.2.0.1-alpha.

  o Minor features:
    - Adjust our TLS Diffie-Hellman parameters to match those used by
      Apache's mod_ssl.
    - Update to the February 1 2011 Maxmind GeoLite Country database.

  o Minor bugfixes:
    - Check for and reject overly long directory certificates and
      directory tokens before they have a chance to hit any assertions.
      Bugfix on 0.2.1.28. Found by "doorss".
    - Bring the logic that gathers routerinfos and assesses the
      acceptability of circuits into line. This prevents a Tor OP from
      getting locked in a cycle of choosing its local OR as an exit for a
      path (due to a .exit request) and then rejecting the circuit because
      its OR is not listed yet. It also prevents Tor clients from using an
      OR running in the same instance as an exit (due to a .exit request)
      if the OR does not meet the same requirements expected of an OR
      running elsewhere. Fixes bug 1859; bugfix on 0.1.0.1-rc.

  o Packaging changes:
    - Stop shipping the Tor specs files and development proposal documents
      in the tarball. They are now in a separate git repository at
      git://git.torproject.org/torspec.git
    - Do not include Git version tags as though they are SVN tags when
      generating a tarball from inside a repository that has switched
      between branches. Bugfix on 0.2.1.15-rc; fixes bug 2402.


Changes in version 0.2.1.29 - 2011-01-15
  Tor 0.2.1.29 continues our recent code security audit work. The main
  fix resolves a remote heap overflow vulnerability that can allow remote
  code execution. Other fixes address a variety of assert and crash bugs,
  most of which we think are hard to exploit remotely.

  o Major bugfixes (security):
    - Fix a heap overflow bug where an adversary could cause heap
      corruption. This bug probably allows remote code execution
      attacks. Reported by "debuger". Fixes CVE-2011-0427. Bugfix on
      0.1.2.10-rc.
    - Prevent a denial-of-service attack by disallowing any
      zlib-compressed data whose compression factor is implausibly
      high. Fixes part of bug 2324; reported by "doorss".
    - Zero out a few more keys in memory before freeing them. Fixes
      bug 2384 and part of bug 2385. These key instances found by
      "cypherpunks", based on Andrew Case's report about being able
      to find sensitive data in Tor's memory space if you have enough
      permissions. Bugfix on 0.0.2pre9.

  o Major bugfixes (crashes):
    - Prevent calls to Libevent from inside Libevent log handlers.
      This had potential to cause a nasty set of crashes, especially
      if running Libevent with debug logging enabled, and running
      Tor with a controller watching for low-severity log messages.
      Bugfix on 0.1.0.2-rc. Fixes bug 2190.
    - Add a check for SIZE_T_MAX to tor_realloc() to try to avoid
      underflow errors there too. Fixes the other part of bug 2324.
    - Fix a bug where we would assert if we ever had a
      cached-descriptors.new file (or another file read directly into
      memory) of exactly SIZE_T_CEILING bytes. Fixes bug 2326; bugfix
      on 0.2.1.25. Found by doorss.
    - Fix some potential asserts and parsing issues with grossly
      malformed router caches. Fixes bug 2352; bugfix on Tor 0.2.1.27.
      Found by doorss.

  o Minor bugfixes (other):
    - Fix a bug with handling misformed replies to reverse DNS lookup
      requests in DNSPort. Bugfix on Tor 0.2.0.1-alpha. Related to a
      bug reported by doorss.
    - Fix compilation on mingw when a pthreads compatibility library
      has been installed. (We don't want to use it, so we shouldn't
      be including pthread.h.) Fixes bug 2313; bugfix on 0.1.0.1-rc.
    - Fix a bug where we would declare that we had run out of virtual
      addresses when the address space was only half-exhausted. Bugfix
      on 0.1.2.1-alpha.
    - Correctly handle the case where AutomapHostsOnResolve is set but
      no virtual addresses are available. Fixes bug 2328; bugfix on
      0.1.2.1-alpha. Bug found by doorss.
    - Correctly handle wrapping around when we run out of virtual
      address space. Found by cypherpunks; bugfix on 0.2.0.5-alpha.

  o Minor features:
    - Update to the January 1 2011 Maxmind GeoLite Country database.
    - Introduce output size checks on all of our decryption functions.

  o Build changes:
    - Tor does not build packages correctly with Automake 1.6 and earlier;
      added a check to Makefile.am to make sure that we're building with
      Automake 1.7 or later.
    - The 0.2.1.28 tarball was missing src/common/OpenBSD_malloc_Linux.c
      because we built it with a too-old version of automake. Thus that
      release broke ./configure --enable-openbsd-malloc, which is popular
      among really fast exit relays on Linux.


Changes in version 0.2.1.28 - 2010-12-17
  Tor 0.2.1.28 does some code cleanup to reduce the risk of remotely
  exploitable bugs. We also took this opportunity to change the IP address
  for one of our directory authorities, and to update the geoip database
  we ship.

  o Major bugfixes:
    - Fix a remotely exploitable bug that could be used to crash instances
      of Tor remotely by overflowing on the heap. Remote-code execution
      hasn't been confirmed, but can't be ruled out. Everyone should
      upgrade. Bugfix on the 0.1.1 series and later.

  o Directory authority changes:
    - Change IP address and ports for gabelmoo (v3 directory authority).

  o Minor features:
    - Update to the December 1 2010 Maxmind GeoLite Country database.


Changes in version 0.2.1.27 - 2010-11-23
  Yet another OpenSSL security patch broke its compatibility with Tor:
  Tor 0.2.1.27 makes relays work with openssl 0.9.8p and 1.0.0.b. We
  also took this opportunity to fix several crash bugs, integrate a new
  directory authority, and update the bundled GeoIP database.

  o Major bugfixes:
    - Resolve an incompatibility with OpenSSL 0.9.8p and OpenSSL 1.0.0b:
      No longer set the tlsext_host_name extension on server SSL objects;
      but continue to set it on client SSL objects. Our goal in setting
      it was to imitate a browser, not a vhosting server. Fixes bug 2204;
      bugfix on 0.2.1.1-alpha.
    - Do not log messages to the controller while shrinking buffer
      freelists. Doing so would sometimes make the controller connection
      try to allocate a buffer chunk, which would mess up the internals
      of the freelist and cause an assertion failure. Fixes bug 1125;
      fixed by Robert Ransom. Bugfix on 0.2.0.16-alpha.
    - Learn our external IP address when we're a relay or bridge, even if
      we set PublishServerDescriptor to 0. Bugfix on 0.2.0.3-alpha,
      where we introduced bridge relays that don't need to publish to
      be useful. Fixes bug 2050.
    - Do even more to reject (and not just ignore) annotations on
      router descriptors received anywhere but from the cache. Previously
      we would ignore such annotations at first, but cache them to disk
      anyway. Bugfix on 0.2.0.8-alpha. Found by piebeer.
    - When you're using bridges and your network goes away and your
      bridges get marked as down, recover when you attempt a new socks
      connection (if the network is back), rather than waiting up to an
      hour to try fetching new descriptors for your bridges. Bugfix on
      0.2.0.3-alpha; fixes bug 1981.

  o Major features:
    - Move to the November 2010 Maxmind GeoLite country db (rather
      than the June 2009 ip-to-country GeoIP db) for our statistics that
      count how many users relays are seeing from each country. Now we'll
      have more accurate data, especially for many African countries.

  o New directory authorities:
    - Set up maatuska (run by Linus Nordberg) as the eighth v3 directory
      authority.

  o Minor bugfixes:
    - Fix an assertion failure that could occur in directory caches or
      bridge users when using a very short voting interval on a testing
      network. Diagnosed by Robert Hogan. Fixes bug 1141; bugfix on
      0.2.0.8-alpha.
    - Enforce multiplicity rules when parsing annotations. Bugfix on
      0.2.0.8-alpha. Found by piebeer.
    - Allow handshaking OR connections to take a full KeepalivePeriod
      seconds to handshake. Previously, we would close them after
      IDLE_OR_CONN_TIMEOUT (180) seconds, the same timeout as if they
      were open. Bugfix on 0.2.1.26; fixes bug 1840. Thanks to mingw-san
      for analysis help.
    - When building with --enable-gcc-warnings on OpenBSD, disable
      warnings in system headers. This makes --enable-gcc-warnings
      pass on OpenBSD 4.8.

  o Minor features:
    - Exit nodes didn't recognize EHOSTUNREACH as a plausible error code,
      and so sent back END_STREAM_REASON_MISC. Clients now recognize a new
      stream ending reason for this case: END_STREAM_REASON_NOROUTE.
      Servers can start sending this code when enough clients recognize
      it. Bugfix on 0.1.0.1-rc; fixes part of bug 1793.
    - Build correctly on mingw with more recent versions of OpenSSL 0.9.8.
      Patch from mingw-san.

  o Removed files:
    - Remove the old debian/ directory from the main Tor distribution.
      The official Tor-for-debian git repository lives at the URL
      https://git.torproject.org/debian/tor.git
    - Stop shipping the old doc/website/ directory in the tarball. We
      changed the website format in late 2010, and what we shipped in
      0.2.1.26 really wasn't that useful anyway.


Changes in version 0.2.1.26 - 2010-05-02
  Tor 0.2.1.26 addresses the recent connection and memory overload
  problems we've been seeing on relays, especially relays with their
  DirPort open. If your relay has been crashing, or you turned it off
  because it used too many resources, give this release a try.

  This release also fixes yet another instance of broken OpenSSL libraries
  that was causing some relays to drop out of the consensus.

  o Major bugfixes:
    - Teach relays to defend themselves from connection overload. Relays
      now close idle circuits early if it looks like they were intended
      for directory fetches. Relays are also more aggressive about closing
      TLS connections that have no circuits on them. Such circuits are
      unlikely to be re-used, and tens of thousands of them were piling
      up at the fast relays, causing the relays to run out of sockets
      and memory. Bugfix on 0.2.0.22-rc (where clients started tunneling
      their directory fetches over TLS).
    - Fix SSL renegotiation behavior on OpenSSL versions like on Centos
      that claim to be earlier than 0.9.8m, but which have in reality
      backported huge swaths of 0.9.8m or 0.9.8n renegotiation
      behavior. Possible fix for some cases of bug 1346.
    - Directory mirrors were fetching relay descriptors only from v2
      directory authorities, rather than v3 authorities like they should.
      Only 2 v2 authorities remain (compared to 7 v3 authorities), leading
      to a serious bottleneck. Bugfix on 0.2.0.9-alpha. Fixes bug 1324.

  o Minor bugfixes:
    - Finally get rid of the deprecated and now harmful notion of "clique
      mode", where directory authorities maintain TLS connections to
      every other relay.

  o Testsuite fixes:
    - In the util/threads test, no longer free the test_mutex before all
      worker threads have finished. Bugfix on 0.2.1.6-alpha.
    - The master thread could starve the worker threads quite badly on
      certain systems, causing them to run only partially in the allowed
      window. This resulted in test failures. Now the master thread sleeps
      occasionally for a few microseconds while the two worker-threads
      compete for the mutex. Bugfix on 0.2.0.1-alpha.


Changes in version 0.2.1.25 - 2010-03-16
  Tor 0.2.1.25 fixes a regression introduced in 0.2.1.23 that could
  prevent relays from guessing their IP address correctly. It also fixes
  several minor potential security bugs.

  o Major bugfixes:
    - Fix a regression from our patch for bug 1244 that caused relays
      to guess their IP address incorrectly if they didn't set Address
      in their torrc and/or their address fails to resolve. Bugfix on
      0.2.1.23; fixes bug 1269.
    - When freeing a session key, zero it out completely. We only zeroed
      the first ptrsize bytes. Bugfix on 0.0.2pre8. Discovered and
      patched by ekir. Fixes bug 1254.

  o Minor bugfixes:
    - Fix a dereference-then-NULL-check sequence when publishing
      descriptors. Bugfix on 0.2.1.5-alpha. Discovered by ekir; fixes
      bug 1255.
    - Fix another dereference-then-NULL-check sequence. Bugfix on
      0.2.1.14-rc. Discovered by ekir; fixes bug 1256.
    - Make sure we treat potentially not NUL-terminated strings correctly.
      Bugfix on 0.1.1.13-alpha. Discovered by rieo; fixes bug 1257.


Changes in version 0.2.1.24 - 2010-02-21
  Tor 0.2.1.24 makes Tor work again on the latest OS X -- this time
  for sure!

  o Minor bugfixes:
    - Work correctly out-of-the-box with even more vendor-patched versions
      of OpenSSL. In particular, make it so Debian and OS X don't need
      customized patches to run/build.


Changes in version 0.2.1.23 - 2010-02-13
  Tor 0.2.1.23 fixes a huge client-side performance bug, makes Tor work
  again on the latest OS X, and updates the location of a directory
  authority.

  o Major bugfixes (performance):
    - We were selecting our guards uniformly at random, and then weighting
      which of our guards we'd use uniformly at random. This imbalance
      meant that Tor clients were severely limited on throughput (and
      probably latency too) by the first hop in their circuit. Now we
      select guards weighted by currently advertised bandwidth. We also
      automatically discard guards picked using the old algorithm. Fixes
      bug 1217; bugfix on 0.2.1.3-alpha. Found by Mike Perry.

  o Major bugfixes:
    - Make Tor work again on the latest OS X: when deciding whether to
      use strange flags to turn TLS renegotiation on, detect the OpenSSL
      version at run-time, not compile time. We need to do this because
      Apple doesn't update its dev-tools headers when it updates its
      libraries in a security patch.
    - Fix a potential buffer overflow in lookup_last_hid_serv_request()
      that could happen on 32-bit platforms with 64-bit time_t. Also fix
      a memory leak when requesting a hidden service descriptor we've
      requested before. Fixes bug 1242, bugfix on 0.2.0.18-alpha. Found
      by aakova.

  o Minor bugfixes:
    - Refactor resolve_my_address() to not use gethostbyname() anymore.
      Fixes bug 1244; bugfix on 0.0.2pre25. Reported by Mike Mestnik.

  o Minor features:
    - Avoid a mad rush at the beginning of each month when each client
      rotates half of its guards. Instead we spread the rotation out
      throughout the month, but we still avoid leaving a precise timestamp
      in the state file about when we first picked the guard. Improves
      over the behavior introduced in 0.1.2.17.


Changes in version 0.2.1.22 - 2010-01-19
  Tor 0.2.1.22 fixes a critical privacy problem in bridge directory
  authorities -- it would tell you its whole history of bridge descriptors
  if you make the right directory request. This stable update also
  rotates two of the seven v3 directory authority keys and locations.

  o Directory authority changes:
    - Rotate keys (both v3 identity and relay identity) for moria1
      and gabelmoo.

  o Major bugfixes:
    - Stop bridge directory authorities from answering dbg-stability.txt
      directory queries, which would let people fetch a list of all
      bridge identities they track. Bugfix on 0.2.1.6-alpha.


Changes in version 0.2.1.21 - 2009-12-21
  Tor 0.2.1.21 fixes an incompatibility with the most recent OpenSSL
  library. If you use Tor on Linux / Unix and you're getting SSL
  renegotiation errors, upgrading should help. We also recommend an
  upgrade if you're an exit relay.

  o Major bugfixes:
    - Work around a security feature in OpenSSL 0.9.8l that prevents our
      handshake from working unless we explicitly tell OpenSSL that we
      are using SSL renegotiation safely. We are, of course, but OpenSSL
      0.9.8l won't work unless we say we are.
    - Avoid crashing if the client is trying to upload many bytes and the
      circuit gets torn down at the same time, or if the flip side
      happens on the exit relay. Bugfix on 0.2.0.1-alpha; fixes bug 1150.

  o Minor bugfixes:
    - Do not refuse to learn about authority certs and v2 networkstatus
      documents that are older than the latest consensus. This bug might
      have degraded client bootstrapping. Bugfix on 0.2.0.10-alpha.
      Spotted and fixed by xmux.
    - Fix a couple of very-hard-to-trigger memory leaks, and one hard-to-
      trigger platform-specific option misparsing case found by Coverity
      Scan.
    - Fix a compilation warning on Fedora 12 by removing an impossible-to-
      trigger assert. Fixes bug 1173.


Changes in version 0.2.1.20 - 2009-10-15
  Tor 0.2.1.20 fixes a crash bug when you're accessing many hidden
  services at once, prepares for more performance improvements, and
  fixes a bunch of smaller bugs.

  The Windows and OS X bundles also include a more recent Vidalia,
  and switch from Privoxy to Polipo.

  The OS X installers are now drag and drop. It's best to un-install
  Tor/Vidalia and then install this new bundle, rather than upgrade. If
  you want to upgrade, you'll need to update the paths for Tor and Polipo
  in the Vidalia Settings window.

  o Major bugfixes:
    - Send circuit or stream sendme cells when our window has decreased
      by 100 cells, not when it has decreased by 101 cells. Bug uncovered
      by Karsten when testing the "reduce circuit window" performance
      patch. Bugfix on the 54th commit on Tor -- from July 2002,
      before the release of Tor 0.0.0. This is the new winner of the
      oldest-bug prize.
    - Fix a remotely triggerable memory leak when a consensus document
      contains more than one signature from the same voter. Bugfix on
      0.2.0.3-alpha.
    - Avoid segfault in rare cases when finishing an introduction circuit
      as a client and finding out that we don't have an introduction key
      for it. Fixes bug 1073. Reported by Aaron Swartz.

  o Major features:
    - Tor now reads the "circwindow" parameter out of the consensus,
      and uses that value for its circuit package window rather than the
      default of 1000 cells. Begins the implementation of proposal 168.

  o New directory authorities:
    - Set up urras (run by Jacob Appelbaum) as the seventh v3 directory
      authority.
    - Move moria1 and tonga to alternate IP addresses.

  o Minor bugfixes:
    - Fix a signed/unsigned compile warning in 0.2.1.19.
    - Fix possible segmentation fault on directory authorities. Bugfix on
      0.2.1.14-rc.
    - Fix an extremely rare infinite recursion bug that could occur if
      we tried to log a message after shutting down the log subsystem.
      Found by Matt Edman. Bugfix on 0.2.0.16-alpha.
    - Fix an obscure bug where hidden services on 64-bit big-endian
      systems might mis-read the timestamp in v3 introduce cells, and
      refuse to connect back to the client. Discovered by "rotor".
      Bugfix on 0.2.1.6-alpha.
    - We were triggering a CLOCK_SKEW controller status event whenever
      we connect via the v2 connection protocol to any relay that has
      a wrong clock. Instead, we should only inform the controller when
      it's a trusted authority that claims our clock is wrong. Bugfix
      on 0.2.0.20-rc; starts to fix bug 1074. Reported by SwissTorExit.
    - We were telling the controller about CHECKING_REACHABILITY and
      REACHABILITY_FAILED status events whenever we launch a testing
      circuit or notice that one has failed. Instead, only tell the
      controller when we want to inform the user of overall success or
      overall failure. Bugfix on 0.1.2.6-alpha. Fixes bug 1075. Reported
      by SwissTorExit.
    - Don't warn when we're using a circuit that ends with a node
      excluded in ExcludeExitNodes, but the circuit is not used to access
      the outside world. This should help fix bug 1090. Bugfix on
      0.2.1.6-alpha.
    - Work around a small memory leak in some versions of OpenSSL that
      stopped the memory used by the hostname TLS extension from being
      freed.

  o Minor features:
    - Add a "getinfo status/accepted-server-descriptor" controller
      command, which is the recommended way for controllers to learn
      whether our server descriptor has been successfully received by at
      least on directory authority. Un-recommend good-server-descriptor
      getinfo and status events until we have a better design for them.


Changes in version 0.2.1.19 - 2009-07-28
  Tor 0.2.1.19 fixes a major bug with accessing and providing hidden
  services.

  o Major bugfixes:
    - Make accessing hidden services on 0.2.1.x work right again.
      Bugfix on 0.2.1.3-alpha; workaround for bug 1038. Diagnosis and
      part of patch provided by "optimist".

  o Minor features:
    - When a relay/bridge is writing out its identity key fingerprint to
      the "fingerprint" file and to its logs, write it without spaces. Now
      it will look like the fingerprints in our bridges documentation,
      and confuse fewer users.

  o Minor bugfixes:
    - Relays no longer publish a new server descriptor if they change
      their MaxAdvertisedBandwidth config option but it doesn't end up
      changing their advertised bandwidth numbers. Bugfix on 0.2.0.28-rc;
      fixes bug 1026. Patch from Sebastian.
    - Avoid leaking memory every time we get a create cell but we have
      so many already queued that we refuse it. Bugfix on 0.2.0.19-alpha;
      fixes bug 1034. Reported by BarkerJr.


Changes in version 0.2.1.18 - 2009-07-24
  Tor 0.2.1.18 lays the foundations for performance improvements,
  adds status events to help users diagnose bootstrap problems, adds
  optional authentication/authorization for hidden services, fixes a
  variety of potential anonymity problems, and includes a huge pile of
  other features and bug fixes.

  o Major features (clients):
    - Start sending "bootstrap phase" status events to the controller,
      so it can keep the user informed of progress fetching directory
      information and establishing circuits. Also inform the controller
      if we think we're stuck at a particular bootstrap phase. Implements
      proposal 137.
    - Clients replace entry guards that were chosen more than a few months
      ago. This change should significantly improve client performance,
      especially once more people upgrade, since relays that have been
      a guard for a long time are currently overloaded.
    - Network status consensus documents and votes now contain bandwidth
      information for each relay. Clients use the bandwidth values
      in the consensus, rather than the bandwidth values in each
      relay descriptor. This approach opens the door to more accurate
      bandwidth estimates once the directory authorities start doing
      active measurements. Implements part of proposal 141.

  o Major features (relays):
    - Disable and refactor some debugging checks that forced a linear scan
      over the whole server-side DNS cache. These accounted for over 50%
      of CPU time on a relatively busy exit node's gprof profile. Also,
      disable some debugging checks that appeared in exit node profile
      data. Found by Jacob.
    - New DirPortFrontPage option that takes an html file and publishes
      it as "/" on the DirPort. Now relay operators can provide a
      disclaimer without needing to set up a separate webserver. There's
      a sample disclaimer in contrib/tor-exit-notice.html.

  o Major features (hidden services):
    - Make it possible to build hidden services that only certain clients
      are allowed to connect to. This is enforced at several points,
      so that unauthorized clients are unable to send INTRODUCE cells
      to the service, or even (depending on the type of authentication)
      to learn introduction points. This feature raises the bar for
      certain kinds of active attacks against hidden services. Design
      and code by Karsten Loesing. Implements proposal 121.
    - Relays now store and serve v2 hidden service descriptors by default,
      i.e., the new default value for HidServDirectoryV2 is 1. This is
      the last step in proposal 114, which aims to make hidden service
      lookups more reliable.

  o Major features (path selection):
    - ExitNodes and Exclude*Nodes config options now allow you to restrict
      by country code ("{US}") or IP address or address pattern
      ("255.128.0.0/16"). Patch from Robert Hogan. It still needs some
      refinement to decide what config options should take priority if
      you ask to both use a particular node and exclude it.

  o Major features (misc):
    - When building a consensus, do not include routers that are down.
      This cuts down 30% to 40% on consensus size. Implements proposal
      138.
    - New TestingTorNetwork config option to allow adjustment of
      previously constant values that could slow bootstrapping. Implements
      proposal 135. Patch from Karsten.
    - Convert many internal address representations to optionally hold
      IPv6 addresses. Generate and accept IPv6 addresses in many protocol
      elements. Make resolver code handle nameservers located at IPv6
      addresses.
    - More work on making our TLS handshake blend in: modify the list
      of ciphers advertised by OpenSSL in client mode to even more
      closely resemble a common web browser. We cheat a little so that
      we can advertise ciphers that the locally installed OpenSSL doesn't
      know about.
    - Use the TLS1 hostname extension to more closely resemble browser
      behavior.

  o Security fixes (anonymity/entropy):
    - Never use a connection with a mismatched address to extend a
      circuit, unless that connection is canonical. A canonical
      connection is one whose address is authenticated by the router's
      identity key, either in a NETINFO cell or in a router descriptor.
    - Implement most of proposal 110: The first K cells to be sent
      along a circuit are marked as special "early" cells; only K "early"
      cells will be allowed. Once this code is universal, we can block
      certain kinds of denial-of-service attack by requiring that EXTEND
      commands must be sent using an "early" cell.
    - Resume using OpenSSL's RAND_poll() for better (and more portable)
      cross-platform entropy collection again. We used to use it, then
      stopped using it because of a bug that could crash systems that
      called RAND_poll when they had a lot of fds open. It looks like the
      bug got fixed in late 2006. Our new behavior is to call RAND_poll()
      at startup, and to call RAND_poll() when we reseed later only if
      we have a non-buggy OpenSSL version.
    - When the client is choosing entry guards, now it selects at most
      one guard from a given relay family. Otherwise we could end up with
      all of our entry points into the network run by the same operator.
      Suggested by Camilo Viecco. Fix on 0.1.1.11-alpha.
    - Do not use or believe expired v3 authority certificates. Patch
      from Karsten. Bugfix in 0.2.0.x. Fixes bug 851.
    - Drop begin cells to a hidden service if they come from the middle
      of a circuit. Patch from lark.
    - When we erroneously receive two EXTEND cells for the same circuit
      ID on the same connection, drop the second. Patch from lark.
    - Authorities now vote for the Stable flag for any router whose
      weighted MTBF is at least 5 days, regardless of the mean MTBF.
    - Clients now never report any stream end reason except 'MISC'.
      Implements proposal 148.

  o Major bugfixes (crashes):
    - Parse dates and IPv4 addresses in a locale- and libc-independent
      manner, to avoid platform-dependent behavior on malformed input.
    - Fix a crash that occurs on exit nodes when a nameserver request
      timed out. Bugfix on 0.1.2.1-alpha; our CLEAR debugging code had
      been suppressing the bug since 0.1.2.10-alpha. Partial fix for
      bug 929.
    - Do not assume that a stack-allocated character array will be
      64-bit aligned on platforms that demand that uint64_t access is
      aligned. Possible fix for bug 604.
    - Resolve a very rare crash bug that could occur when the user forced
      a nameserver reconfiguration during the middle of a nameserver
      probe. Fixes bug 526. Bugfix on 0.1.2.1-alpha.
    - Avoid a "0 divided by 0" calculation when calculating router uptime
      at directory authorities. Bugfix on 0.2.0.8-alpha.
    - Fix an assertion bug in parsing policy-related options; possible fix
      for bug 811.
    - Rate-limit too-many-sockets messages: when they happen, they happen
      a lot and end up filling up the disk. Resolves bug 748.
    - Fix a race condition that could cause crashes or memory corruption
      when running as a server with a controller listening for log
      messages.
    - Avoid crashing when we have a policy specified in a DirPolicy or
      SocksPolicy or ReachableAddresses option with ports set on it,
      and we re-load the policy. May fix bug 996.
    - Fix an assertion failure on 64-bit platforms when we allocated
      memory right up to the end of a memarea, then realigned the memory
      one step beyond the end. Fixes a possible cause of bug 930.
    - Protect the count of open sockets with a mutex, so we can't
      corrupt it when two threads are closing or opening sockets at once.
      Fix for bug 939. Bugfix on 0.2.0.1-alpha.

  o Major bugfixes (clients):
    - Discard router descriptors as we load them if they are more than
      five days old. Otherwise if Tor is off for a long time and then
      starts with cached descriptors, it will try to use the onion keys
      in those obsolete descriptors when building circuits. Fixes bug 887.
    - When we choose to abandon a new entry guard because we think our
      older ones might be better, close any circuits pending on that
      new entry guard connection. This fix should make us recover much
      faster when our network is down and then comes back. Bugfix on
      0.1.2.8-beta; found by lodger.
    - When Tor clients restart after 1-5 days, they discard all their
      cached descriptors as too old, but they still use the cached
      consensus document. This approach is good for robustness, but
      bad for performance: since they don't know any bandwidths, they
      end up choosing at random rather than weighting their choice by
      speed. Fixed by the above feature of putting bandwidths in the
      consensus.

  o Major bugfixes (relays):
    - Relays were falling out of the networkstatus consensus for
      part of a day if they changed their local config but the
      authorities discarded their new descriptor as "not sufficiently
      different". Now directory authorities accept a descriptor as changed
      if BandwidthRate or BandwidthBurst changed. Partial fix for bug 962;
      patch by Sebastian.
    - Ensure that two circuits can never exist on the same connection
      with the same circuit ID, even if one is marked for close. This
      is conceivably a bugfix for bug 779; fixes a bug on 0.1.0.4-rc.
    - Directory authorities were neglecting to mark relays down in their
      internal histories if the relays fall off the routerlist without
      ever being found unreachable. So there were relays in the histories
      that haven't been seen for eight months, and are listed as being
      up for eight months. This wreaked havoc on the "median wfu" and
      "median mtbf" calculations, in turn making Guard and Stable flags
      wrong, hurting network performance. Fixes bugs 696 and 969. Bugfix
      on 0.2.0.6-alpha.

  o Major bugfixes (hidden services):
    - When establishing a hidden service, introduction points that
      originate from cannibalized circuits were completely ignored
      and not included in rendezvous service descriptors. This might
      have been another reason for delay in making a hidden service
      available. Bugfix from long ago (0.0.9.x?)

  o Major bugfixes (memory and resource management):
    - Fixed some memory leaks -- some quite frequent, some almost
      impossible to trigger -- based on results from Coverity.
    - Speed up parsing and cut down on memory fragmentation by using
      stack-style allocations for parsing directory objects. Previously,
      this accounted for over 40% of allocations from within Tor's code
      on a typical directory cache.
    - Use a Bloom filter rather than a digest-based set to track which
      descriptors we need to keep around when we're cleaning out old
      router descriptors. This speeds up the computation significantly,
      and may reduce fragmentation.

  o New/changed config options:
    - Now NodeFamily and MyFamily config options allow spaces in
      identity fingerprints, so it's easier to paste them in.
      Suggested by Lucky Green.
    - Allow ports 465 and 587 in the default exit policy again. We had
      rejected them in 0.1.0.15, because back in 2005 they were commonly
      misconfigured and ended up as spam targets. We hear they are better
      locked down these days.
    - Make TrackHostExit mappings expire a while after their last use, not
      after their creation. Patch from Robert Hogan.
    - Add an ExcludeExitNodes option so users can list a set of nodes
      that should be be excluded from the exit node position, but
      allowed elsewhere. Implements proposal 151.
    - New --hush command-line option similar to --quiet. While --quiet
      disables all logging to the console on startup, --hush limits the
      output to messages of warning and error severity.
    - New configure/torrc options (--enable-geoip-stats,
      DirRecordUsageByCountry) to record how many IPs we've served
      directory info to in each country code, how many status documents
      total we've sent to each country code, and what share of the total
      directory requests we should expect to see.
    - Make outbound DNS packets respect the OutboundBindAddress setting.
      Fixes the bug part of bug 798. Bugfix on 0.1.2.2-alpha.
    - Allow separate log levels to be configured for different logging
      domains. For example, this allows one to log all notices, warnings,
      or errors, plus all memory management messages of level debug or
      higher, with: Log [MM] debug-err [*] notice-err file /var/log/tor.
    - Update to the "June 3 2009" ip-to-country file.

  o Minor features (relays):
    - Raise the minimum rate limiting to be a relay from 20000 bytes
      to 20480 bytes (aka 20KB/s), to match our documentation. Also
      update directory authorities so they always assign the Fast flag
      to relays with 20KB/s of capacity. Now people running relays won't
      suddenly find themselves not seeing any use, if the network gets
      faster on average.
    - If we're a relay and we change our IP address, be more verbose
      about the reason that made us change. Should help track down
      further bugs for relays on dynamic IP addresses.
    - Exit servers can now answer resolve requests for ip6.arpa addresses.
    - Implement most of Proposal 152: allow specialized servers to permit
      single-hop circuits, and clients to use those servers to build
      single-hop circuits when using a specialized controller. Patch
      from Josh Albrecht. Resolves feature request 768.
    - When relays do their initial bandwidth measurement, don't limit
      to just our entry guards for the test circuits. Otherwise we tend
      to have multiple test circuits going through a single entry guard,
      which makes our bandwidth test less accurate. Fixes part of bug 654;
      patch contributed by Josh Albrecht.

  o Minor features (directory authorities):
    - Try not to open more than one descriptor-downloading connection
      to an authority at once. This should reduce load on directory
      authorities. Fixes bug 366.
    - Add cross-certification to newly generated certificates, so that
      a signing key is enough information to look up a certificate. Start
      serving certificates by <identity digest, signing key digest>
      pairs. Implements proposal 157.
    - When a directory authority downloads a descriptor that it then
      immediately rejects, do not retry downloading it right away. Should
      save some bandwidth on authorities. Fix for bug 888. Patch by
      Sebastian Hahn.
    - Directory authorities now serve a /tor/dbg-stability.txt URL to
      help debug WFU and MTBF calculations.
    - In directory authorities' approved-routers files, allow
      fingerprints with or without space.

  o Minor features (directory mirrors):
    - When a download gets us zero good descriptors, do not notify
      Tor that new directory information has arrived.
    - Servers support a new URL scheme for consensus downloads that
      allows the client to specify which authorities are trusted.
      The server then only sends the consensus if the client will trust
      it. Otherwise a 404 error is sent back. Clients use this
      new scheme when the server supports it (meaning it's running
      0.2.1.1-alpha or later). Implements proposal 134.

  o Minor features (bridges):
    - If the bridge config line doesn't specify a port, assume 443.
      This makes bridge lines a bit smaller and easier for users to
      understand.
    - If we're using bridges and our network goes away, be more willing
      to forgive our bridges and try again when we get an application
      request.

  o Minor features (hidden services):
    - When the client launches an introduction circuit, retry with a
      new circuit after 30 seconds rather than 60 seconds.
    - Launch a second client-side introduction circuit in parallel
      after a delay of 15 seconds (based on work by Christian Wilms).
    - Hidden services start out building five intro circuits rather
      than three, and when the first three finish they publish a service
      descriptor using those. Now we publish our service descriptor much
      faster after restart.
    - Drop the requirement to have an open dir port for storing and
      serving v2 hidden service descriptors.

  o Minor features (build and packaging):
    - On Linux, use the prctl call to re-enable core dumps when the User
      option is set.
    - Try to make sure that the version of Libevent we're running with
      is binary-compatible with the one we built with. May address bug
      897 and others.
    - Add a new --enable-local-appdata configuration switch to change
      the default location of the datadir on win32 from APPDATA to
      LOCAL_APPDATA. In the future, we should migrate to LOCAL_APPDATA
      entirely. Patch from coderman.
    - Build correctly against versions of OpenSSL 0.9.8 or later that
      are built without support for deprecated functions.
    - On platforms with a maximum syslog string length, truncate syslog
      messages to that length ourselves, rather than relying on the
      system to do it for us.
    - Automatically detect MacOSX versions earlier than 10.4.0, and
      disable kqueue from inside Tor when running with these versions.
      We previously did this from the startup script, but that was no
      help to people who didn't use the startup script. Resolves bug 863.
    - Build correctly when configured to build outside the main source
      path. Patch from Michael Gold.
    - Disable GCC's strict alias optimization by default, to avoid the
      likelihood of its introducing subtle bugs whenever our code violates
      the letter of C99's alias rules.
    - Change the contrib/tor.logrotate script so it makes the new
      logs as "_tor:_tor" rather than the default, which is generally
      "root:wheel". Fixes bug 676, reported by Serge Koksharov.
    - Change our header file guard macros to be less likely to conflict
      with system headers. Adam Langley noticed that we were conflicting
      with log.h on Android.
    - Add a couple of extra warnings to --enable-gcc-warnings for GCC 4.3,
      and stop using a warning that had become unfixably verbose under
      GCC 4.3.
    - Use a lockfile to make sure that two Tor processes are not
      simultaneously running with the same datadir.
    - Allow OpenSSL to use dynamic locks if it wants.
    - Add LIBS=-lrt to Makefile.am so the Tor RPMs use a static libevent.

  o Minor features (controllers):
    - When generating circuit events with verbose nicknames for
      controllers, try harder to look up nicknames for routers on a
      circuit. (Previously, we would look in the router descriptors we had
      for nicknames, but not in the consensus.) Partial fix for bug 941.
    - New controller event NEWCONSENSUS that lists the networkstatus
      lines for every recommended relay. Now controllers like Torflow
      can keep up-to-date on which relays they should be using.
    - New controller event "clients_seen" to report a geoip-based summary
      of which countries we've seen clients from recently. Now controllers
      like Vidalia can show bridge operators that they're actually making
      a difference.
    - Add a 'getinfo status/clients-seen' controller command, in case
      controllers want to hear clients_seen events but connect late.
    - New CONSENSUS_ARRIVED event to note when a new consensus has
      been fetched and validated.
    - Add an internal-use-only __ReloadTorrcOnSIGHUP option for
      controllers to prevent SIGHUP from reloading the configuration.
      Fixes bug 856.
    - Return circuit purposes in response to GETINFO circuit-status.
      Fixes bug 858.
    - Serve the latest v3 networkstatus consensus via the control
      port. Use "getinfo dir/status-vote/current/consensus" to fetch it.
    - Add a "GETINFO /status/bootstrap-phase" controller option, so the
      controller can query our current bootstrap state in case it attaches
      partway through and wants to catch up.
    - Provide circuit purposes along with circuit events to the controller.

  o Minor features (tools):
    - Do not have tor-resolve automatically refuse all .onion addresses;
      if AutomapHostsOnResolve is set in your torrc, this will work fine.
    - Add a -p option to tor-resolve for specifying the SOCKS port: some
      people find host:port too confusing.
    - Print the SOCKS5 error message string as well as the error code
      when a tor-resolve request fails. Patch from Jacob.

  o Minor bugfixes (memory and resource management):
    - Clients no longer cache certificates for authorities they do not
      recognize. Bugfix on 0.2.0.9-alpha.
    - Do not use C's stdio library for writing to log files. This will
      improve logging performance by a minute amount, and will stop
      leaking fds when our disk is full. Fixes bug 861.
    - Stop erroneous use of O_APPEND in cases where we did not in fact
      want to re-seek to the end of a file before every last write().
    - Fix a small alignment and memory-wasting bug on buffer chunks.
      Spotted by rovv.
    - Add a malloc_good_size implementation to OpenBSD_malloc_linux.c,
      to avoid unused RAM in buffer chunks and memory pools.
    - Reduce the default smartlist size from 32 to 16; it turns out that
      most smartlists hold around 8-12 elements tops.
    - Make dumpstats() log the fullness and size of openssl-internal
      buffers.
    - If the user has applied the experimental SSL_MODE_RELEASE_BUFFERS
      patch to their OpenSSL, turn it on to save memory on servers. This
      patch will (with any luck) get included in a mainline distribution
      before too long.
    - Fix a memory leak when v3 directory authorities load their keys
      and cert from disk. Bugfix on 0.2.0.1-alpha.
    - Stop using malloc_usable_size() to use more area than we had
      actually allocated: it was safe, but made valgrind really unhappy.
    - Make the assert_circuit_ok() function work correctly on circuits that
      have already been marked for close.
    - Fix uninitialized size field for memory area allocation: may improve
      memory performance during directory parsing.

  o Minor bugfixes (clients):
    - Stop reloading the router list from disk for no reason when we
      run out of reachable directory mirrors. Once upon a time reloading
      it would set the 'is_running' flag back to 1 for them. It hasn't
      done that for a long time.
    - When we had picked an exit node for a connection, but marked it as
      "optional", and it turned out we had no onion key for the exit,
      stop wanting that exit and try again. This situation may not
      be possible now, but will probably become feasible with proposal
      158. Spotted by rovv. Fixes another case of bug 752.
    - Fix a bug in address parsing that was preventing bridges or hidden
      service targets from being at IPv6 addresses.
    - Do not remove routers as too old if we do not have any consensus
      document. Bugfix on 0.2.0.7-alpha.
    - When an exit relay resolves a stream address to a local IP address,
      do not just keep retrying that same exit relay over and
      over. Instead, just close the stream. Addresses bug 872. Bugfix
      on 0.2.0.32. Patch from rovv.
    - Made Tor a little less aggressive about deleting expired
      certificates. Partial fix for bug 854.
    - Treat duplicate certificate fetches as failures, so that we do
      not try to re-fetch an expired certificate over and over and over.
    - Do not say we're fetching a certificate when we'll in fact skip it
      because of a pending download.
    - If we have correct permissions on $datadir, we complain to stdout
      and fail to start. But dangerous permissions on
      $datadir/cached-status/ would cause us to open a log and complain
      there. Now complain to stdout and fail to start in both cases. Fixes
      bug 820, reported by seeess.

  o Minor bugfixes (bridges):
    - When we made bridge authorities stop serving bridge descriptors over
      unencrypted links, we also broke DirPort reachability testing for
      bridges. So bridges with a non-zero DirPort were printing spurious
      warns to their logs. Bugfix on 0.2.0.16-alpha. Fixes bug 709.
    - Don't allow a bridge to publish its router descriptor to a
      non-bridge directory authority. Fixes part of bug 932.
    - When we change to or from being a bridge, reset our counts of
      client usage by country. Fixes bug 932.

  o Minor bugfixes (relays):
    - Log correct error messages for DNS-related network errors on
      Windows.
    - Actually return -1 in the error case for read_bandwidth_usage().
      Harmless bug, since we currently don't care about the return value
      anywhere. Bugfix on 0.2.0.9-alpha.
    - Provide a more useful log message if bug 977 (related to buffer
      freelists) ever reappears, and do not crash right away.
    - We were already rejecting relay begin cells with destination port
      of 0. Now also reject extend cells with destination port or address
      of 0. Suggested by lark.
    - When we can't transmit a DNS request due to a network error, retry
      it after a while, and eventually transmit a failing response to
      the RESOLVED cell. Bugfix on 0.1.2.5-alpha.
    - Solve a bug that kept hardware crypto acceleration from getting
      enabled when accounting was turned on. Fixes bug 907. Bugfix on
      0.0.9pre6.
    - When a canonical connection appears later in our internal list
      than a noncanonical one for a given OR ID, always use the
      canonical one. Bugfix on 0.2.0.12-alpha. Fixes bug 805.
      Spotted by rovv.
    - Avoid some nasty corner cases in the logic for marking connections
      as too old or obsolete or noncanonical for circuits. Partial
      bugfix on bug 891.
    - Fix another interesting corner-case of bug 891 spotted by rovv:
      Previously, if two hosts had different amounts of clock drift, and
      one of them created a new connection with just the wrong timing,
      the other might decide to deprecate the new connection erroneously.
      Bugfix on 0.1.1.13-alpha.
    - If one win32 nameserver fails to get added, continue adding the
      rest, and don't automatically fail.
    - Fix a bug where an unreachable relay would establish enough
      reachability testing circuits to do a bandwidth test -- if
      we already have a connection to the middle hop of the testing
      circuit, then it could establish the last hop by using the existing
      connection. Bugfix on 0.1.2.2-alpha, exposed when we made testing
      circuits no longer use entry guards in 0.2.1.3-alpha.

  o Minor bugfixes (directory authorities):
    - Limit uploaded directory documents to be 16M rather than 500K.
      The directory authorities were refusing v3 consensus votes from
      other authorities, since the votes are now 504K. Fixes bug 959;
      bugfix on 0.0.2pre17 (where we raised it from 50K to 500K ;).
    - Directory authorities should never send a 503 "busy" response to
      requests for votes or keys. Bugfix on 0.2.0.8-alpha; exposed by
      bug 959.
    - Fix code so authorities _actually_ send back X-Descriptor-Not-New
      headers. Bugfix on 0.2.0.10-alpha.

  o Minor bugfixes (hidden services):
    - When we can't find an intro key for a v2 hidden service descriptor,
      fall back to the v0 hidden service descriptor and log a bug message.
      Workaround for bug 1024.
    - In very rare situations new hidden service descriptors were
      published earlier than 30 seconds after the last change to the
      service. (We currently think that a hidden service descriptor
      that's been stable for 30 seconds is worth publishing.)
    - If a hidden service sends us an END cell, do not consider
      retrying the connection; just close it. Patch from rovv.
    - If we are not using BEGIN_DIR cells, don't attempt to contact hidden
      service directories if they have no advertised dir port. Bugfix
      on 0.2.0.10-alpha.

  o Minor bugfixes (tools):
    - In the torify(1) manpage, mention that tsocks will leak your
      DNS requests.

  o Minor bugfixes (controllers):
    - If the controller claimed responsibility for a stream, but that
      stream never finished making its connection, it would live
      forever in circuit_wait state. Now we close it after SocksTimeout
      seconds. Bugfix on 0.1.2.7-alpha; reported by Mike Perry.
    - Make DNS resolved controller events into "CLOSED", not
      "FAILED". Bugfix on 0.1.2.5-alpha. Fix by Robert Hogan. Resolves
      bug 807.
    - The control port would close the connection before flushing long
      replies, such as the network consensus, if a QUIT command was issued
      before the reply had completed. Now, the control port flushes all
      pending replies before closing the connection. Also fix a spurious
      warning when a QUIT command is issued after a malformed or rejected
      AUTHENTICATE command, but before the connection was closed. Patch
      by Marcus Griep. Fixes bugs 1015 and 1016.
    - Fix a bug that made stream bandwidth get misreported to the
      controller.

  o Deprecated and removed features:
    - The old "tor --version --version" command, which would print out
      the subversion "Id" of most of the source files, is now removed. It
      turned out to be less useful than we'd expected, and harder to
      maintain.
    - RedirectExits has been removed. It was deprecated since
      0.2.0.3-alpha.
    - Finally remove deprecated "EXTENDED_FORMAT" controller feature. It
      has been called EXTENDED_EVENTS since 0.1.2.4-alpha.
    - Cell pools are now always enabled; --disable-cell-pools is ignored.
    - Directory mirrors no longer fetch the v1 directory or
      running-routers files. They are obsolete, and nobody asks for them
      anymore. This is the first step to making v1 authorities obsolete.
    - Take out the TestVia config option, since it was a workaround for
      a bug that was fixed in Tor 0.1.1.21.
    - Mark RendNodes, RendExcludeNodes, HiddenServiceNodes, and
      HiddenServiceExcludeNodes as obsolete: they never worked properly,
      and nobody seems to be using them. Fixes bug 754. Bugfix on
      0.1.0.1-rc. Patch from Christian Wilms.
    - Remove all backward-compatibility code for relays running
      versions of Tor so old that they no longer work at all on the
      Tor network.

  o Code simplifications and refactoring:
    - Tool-assisted documentation cleanup. Nearly every function or
      static variable in Tor should have its own documentation now.
    - Rename the confusing or_is_obsolete field to the more appropriate
      is_bad_for_new_circs, and move it to or_connection_t where it
      belongs.
    - Move edge-only flags from connection_t to edge_connection_t: not
      only is this better coding, but on machines of plausible alignment,
      it should save 4-8 bytes per connection_t. "Every little bit helps."
    - Rename ServerDNSAllowBrokenResolvConf to ServerDNSAllowBrokenConfig
      for consistency; keep old option working for backward compatibility.
    - Simplify the code for finding connections to use for a circuit.
    - Revise the connection_new functions so that a more typesafe variant
      exists. This will work better with Coverity, and let us find any
      actual mistakes we're making here.
    - Refactor unit testing logic so that dmalloc can be used sensibly
      with unit tests to check for memory leaks.
    - Move all hidden-service related fields from connection and circuit
      structure to substructures: this way they won't eat so much memory.
    - Squeeze 2-5% out of client performance (according to oprofile) by
      improving the implementation of some policy-manipulation functions.
    - Change the implementation of ExcludeNodes and ExcludeExitNodes to
      be more efficient. Formerly it was quadratic in the number of
      servers; now it should be linear. Fixes bug 509.
    - Save 16-22 bytes per open circuit by moving the n_addr, n_port,
      and n_conn_id_digest fields into a separate structure that's
      only needed when the circuit has not yet attached to an n_conn.
    - Optimize out calls to time(NULL) that occur for every IO operation,
      or for every cell. On systems like Windows where time() is a
      slow syscall, this fix will be slightly helpful.


Changes in version 0.2.0.35 - 2009-06-24
  o Security fix:
    - Avoid crashing in the presence of certain malformed descriptors.
      Found by lark, and by automated fuzzing.
    - Fix an edge case where a malicious exit relay could convince a
      controller that the client's DNS question resolves to an internal IP
      address. Bug found and fixed by "optimist"; bugfix on 0.1.2.8-beta.

  o Major bugfixes:
    - Finally fix the bug where dynamic-IP relays disappear when their
      IP address changes: directory mirrors were mistakenly telling
      them their old address if they asked via begin_dir, so they
      never got an accurate answer about their new address, so they
      just vanished after a day. For belt-and-suspenders, relays that
      don't set Address in their config now avoid using begin_dir for
      all direct connections. Should fix bugs 827, 883, and 900.
    - Fix a timing-dependent, allocator-dependent, DNS-related crash bug
      that would occur on some exit nodes when DNS failures and timeouts
      occurred in certain patterns. Fix for bug 957.

  o Minor bugfixes:
    - When starting with a cache over a few days old, do not leak
      memory for the obsolete router descriptors in it. Bugfix on
      0.2.0.33; fixes bug 672.
    - Hidden service clients didn't use a cached service descriptor that
      was older than 15 minutes, but wouldn't fetch a new one either,
      because there was already one in the cache. Now, fetch a v2
      descriptor unless the same descriptor was added to the cache within
      the last 15 minutes. Fixes bug 997; reported by Marcus Griep.


Changes in version 0.2.0.34 - 2009-02-08
  Tor 0.2.0.34 features several more security-related fixes. You should
  upgrade, especially if you run an exit relay (remote crash) or a
  directory authority (remote infinite loop), or you're on an older
  (pre-XP) or not-recently-patched Windows (remote exploit).

  This release marks end-of-life for Tor 0.1.2.x. Those Tor versions
  have many known flaws, and nobody should be using them. You should
  upgrade. If you're using a Linux or BSD and its packages are obsolete,
  stop using those packages and upgrade anyway.

  o Security fixes:
    - Fix an infinite-loop bug on handling corrupt votes under certain
      circumstances. Bugfix on 0.2.0.8-alpha.
    - Fix a temporary DoS vulnerability that could be performed by
      a directory mirror. Bugfix on 0.2.0.9-alpha; reported by lark.
    - Avoid a potential crash on exit nodes when processing malformed
      input. Remote DoS opportunity. Bugfix on 0.2.0.33.
    - Do not accept incomplete ipv4 addresses (like 192.168.0) as valid.
      Spec conformance issue. Bugfix on Tor 0.0.2pre27.

  o Minor bugfixes:
    - Fix compilation on systems where time_t is a 64-bit integer.
      Patch from Matthias Drochner.
    - Don't consider expiring already-closed client connections. Fixes
      bug 893. Bugfix on 0.0.2pre20.


Changes in version 0.2.0.33 - 2009-01-21
  Tor 0.2.0.33 fixes a variety of bugs that were making relays less
  useful to users. It also finally fixes a bug where a relay or client
  that's been off for many days would take a long time to bootstrap.

  This update also fixes an important security-related bug reported by
  Ilja van Sprundel. You should upgrade. (We'll send out more details
  about the bug once people have had some time to upgrade.)

  o Security fixes:
    - Fix a heap-corruption bug that may be remotely triggerable on
      some platforms. Reported by Ilja van Sprundel.

  o Major bugfixes:
    - When a stream at an exit relay is in state "resolving" or
      "connecting" and it receives an "end" relay cell, the exit relay
      would silently ignore the end cell and not close the stream. If
      the client never closes the circuit, then the exit relay never
      closes the TCP connection. Bug introduced in Tor 0.1.2.1-alpha;
      reported by "wood".
    - When sending CREATED cells back for a given circuit, use a 64-bit
      connection ID to find the right connection, rather than an addr:port
      combination. Now that we can have multiple OR connections between
      the same ORs, it is no longer possible to use addr:port to uniquely
      identify a connection.
    - Bridge relays that had DirPort set to 0 would stop fetching
      descriptors shortly after startup, and then briefly resume
      after a new bandwidth test and/or after publishing a new bridge
      descriptor. Bridge users that try to bootstrap from them would
      get a recent networkstatus but would get descriptors from up to
      18 hours earlier, meaning most of the descriptors were obsolete
      already. Reported by Tas; bugfix on 0.2.0.13-alpha.
    - Prevent bridge relays from serving their 'extrainfo' document
      to anybody who asks, now that extrainfo docs include potentially
      sensitive aggregated client geoip summaries. Bugfix on
      0.2.0.13-alpha.
    - If the cached networkstatus consensus is more than five days old,
      discard it rather than trying to use it. In theory it could be
      useful because it lists alternate directory mirrors, but in practice
      it just means we spend many minutes trying directory mirrors that
      are long gone from the network. Also discard router descriptors as
      we load them if they are more than five days old, since the onion
      key is probably wrong by now. Bugfix on 0.2.0.x. Fixes bug 887.

  o Minor bugfixes:
    - Do not mark smartlist_bsearch_idx() function as ATTR_PURE. This bug
      could make gcc generate non-functional binary search code. Bugfix
      on 0.2.0.10-alpha.
    - Build correctly on platforms without socklen_t.
    - Compile without warnings on solaris.
    - Avoid potential crash on internal error during signature collection.
      Fixes bug 864. Patch from rovv.
    - Correct handling of possible malformed authority signing key
      certificates with internal signature types. Fixes bug 880.
      Bugfix on 0.2.0.3-alpha.
    - Fix a hard-to-trigger resource leak when logging credential status.
      CID 349.
    - When we can't initialize DNS because the network is down, do not
      automatically stop Tor from starting. Instead, we retry failed
      dns_init() every 10 minutes, and change the exit policy to reject
      *:* until one succeeds. Fixes bug 691.
    - Use 64 bits instead of 32 bits for connection identifiers used with
      the controller protocol, to greatly reduce risk of identifier reuse.
    - When we're choosing an exit node for a circuit, and we have
      no pending streams, choose a good general exit rather than one that
      supports "all the pending streams". Bugfix on 0.1.1.x. Fix by rovv.
    - Fix another case of assuming, when a specific exit is requested,
      that we know more than the user about what hosts it allows.
      Fixes one case of bug 752. Patch from rovv.
    - Clip the MaxCircuitDirtiness config option to a minimum of 10
      seconds. Warn the user if lower values are given in the
      configuration. Bugfix on 0.1.0.1-rc. Patch by Sebastian.
    - Clip the CircuitBuildTimeout to a minimum of 30 seconds. Warn the
      user if lower values are given in the configuration. Bugfix on
      0.1.1.17-rc. Patch by Sebastian.
    - Fix a memory leak when we decline to add a v2 rendezvous descriptor to
      the cache because we already had a v0 descriptor with the same ID.
      Bugfix on 0.2.0.18-alpha.
    - Fix a race condition when freeing keys shared between main thread
      and CPU workers that could result in a memory leak. Bugfix on
      0.1.0.1-rc. Fixes bug 889.
    - Send a valid END cell back when a client tries to connect to a
      nonexistent hidden service port. Bugfix on 0.1.2.15. Fixes bug
      840. Patch from rovv.
    - Check which hops rendezvous stream cells are associated with to
      prevent possible guess-the-streamid injection attacks from
      intermediate hops. Fixes another case of bug 446. Based on patch
      from rovv.
    - If a broken client asks a non-exit router to connect somewhere,
      do not even do the DNS lookup before rejecting the connection.
      Fixes another case of bug 619. Patch from rovv.
    - When a relay gets a create cell it can't decrypt (e.g. because it's
      using the wrong onion key), we were dropping it and letting the
      client time out. Now actually answer with a destroy cell. Fixes
      bug 904. Bugfix on 0.0.2pre8.

  o Minor bugfixes (hidden services):
    - Do not throw away existing introduction points on SIGHUP. Bugfix on
      0.0.6pre1. Patch by Karsten. Fixes bug 874.

  o Minor features:
    - Report the case where all signatures in a detached set are rejected
      differently than the case where there is an error handling the
      detached set.
    - When we realize that another process has modified our cached
      descriptors, print out a more useful error message rather than
      triggering an assertion. Fixes bug 885. Patch from Karsten.
    - Implement the 0x20 hack to better resist DNS poisoning: set the
      case on outgoing DNS requests randomly, and reject responses that do
      not match the case correctly. This logic can be disabled with the
      ServerDNSRamdomizeCase setting, if you are using one of the 0.3%
      of servers that do not reliably preserve case in replies. See
      "Increased DNS Forgery Resistance through 0x20-Bit Encoding"
      for more info.
    - Check DNS replies for more matching fields to better resist DNS
      poisoning.
    - Never use OpenSSL compression: it wastes RAM and CPU trying to
      compress cells, which are basically all encrypted, compressed, or
      both.


Changes in version 0.2.0.32 - 2008-11-20
  Tor 0.2.0.32 fixes a major security problem in Debian and Ubuntu
  packages (and maybe other packages) noticed by Theo de Raadt, fixes
  a smaller security flaw that might allow an attacker to access local
  services, further improves hidden service performance, and fixes a
  variety of other issues.

  o Security fixes:
    - The "User" and "Group" config options did not clear the
      supplementary group entries for the Tor process. The "User" option
      is now more robust, and we now set the groups to the specified
      user's primary group. The "Group" option is now ignored. For more
      detailed logging on credential switching, set CREDENTIAL_LOG_LEVEL
      in common/compat.c to LOG_NOTICE or higher. Patch by Jacob Appelbaum
      and Steven Murdoch. Bugfix on 0.0.2pre14. Fixes bug 848 and 857.
    - The "ClientDNSRejectInternalAddresses" config option wasn't being
      consistently obeyed: if an exit relay refuses a stream because its
      exit policy doesn't allow it, we would remember what IP address
      the relay said the destination address resolves to, even if it's
      an internal IP address. Bugfix on 0.2.0.7-alpha; patch by rovv.

  o Major bugfixes:
    - Fix a DOS opportunity during the voting signature collection process
      at directory authorities. Spotted by rovv. Bugfix on 0.2.0.x.

  o Major bugfixes (hidden services):
    - When fetching v0 and v2 rendezvous service descriptors in parallel,
      we were failing the whole hidden service request when the v0
      descriptor fetch fails, even if the v2 fetch is still pending and
      might succeed. Similarly, if the last v2 fetch fails, we were
      failing the whole hidden service request even if a v0 fetch is
      still pending. Fixes bug 814. Bugfix on 0.2.0.10-alpha.
    - When extending a circuit to a hidden service directory to upload a
      rendezvous descriptor using a BEGIN_DIR cell, almost 1/6 of all
      requests failed, because the router descriptor has not been
      downloaded yet. In these cases, do not attempt to upload the
      rendezvous descriptor, but wait until the router descriptor is
      downloaded and retry. Likewise, do not attempt to fetch a rendezvous
      descriptor from a hidden service directory for which the router
      descriptor has not yet been downloaded. Fixes bug 767. Bugfix
      on 0.2.0.10-alpha.

  o Minor bugfixes:
    - Fix several infrequent memory leaks spotted by Coverity.
    - When testing for libevent functions, set the LDFLAGS variable
      correctly. Found by Riastradh.
    - Avoid a bug where the FastFirstHopPK 0 option would keep Tor from
      bootstrapping with tunneled directory connections. Bugfix on
      0.1.2.5-alpha. Fixes bug 797. Found by Erwin Lam.
    - When asked to connect to A.B.exit:80, if we don't know the IP for A
      and we know that server B rejects most-but-not all connections to
      port 80, we would previously reject the connection. Now, we assume
      the user knows what they were asking for. Fixes bug 752. Bugfix
      on 0.0.9rc5. Diagnosed by BarkerJr.
    - If we overrun our per-second write limits a little, count this as
      having used up our write allocation for the second, and choke
      outgoing directory writes. Previously, we had only counted this when
      we had met our limits precisely. Fixes bug 824. Patch from by rovv.
      Bugfix on 0.2.0.x (??).
    - Remove the old v2 directory authority 'lefkada' from the default
      list. It has been gone for many months.
    - Stop doing unaligned memory access that generated bus errors on
      sparc64. Bugfix on 0.2.0.10-alpha. Fixes bug 862.
    - Make USR2 log-level switch take effect immediately. Bugfix on
      0.1.2.8-beta.

  o Minor bugfixes (controller):
    - Make DNS resolved events into "CLOSED", not "FAILED". Bugfix on
      0.1.2.5-alpha. Fix by Robert Hogan. Resolves bug 807.


Changes in version 0.2.0.31 - 2008-09-03
  Tor 0.2.0.31 addresses two potential anonymity issues, starts to fix
  a big bug we're seeing where in rare cases traffic from one Tor stream
  gets mixed into another stream, and fixes a variety of smaller issues.

  o Major bugfixes:
    - Make sure that two circuits can never exist on the same connection
      with the same circuit ID, even if one is marked for close. This
      is conceivably a bugfix for bug 779. Bugfix on 0.1.0.4-rc.
    - Relays now reject risky extend cells: if the extend cell includes
      a digest of all zeroes, or asks to extend back to the relay that
      sent the extend cell, tear down the circuit. Ideas suggested
      by rovv.
    - If not enough of our entry guards are available so we add a new
      one, we might use the new one even if it overlapped with the
      current circuit's exit relay (or its family). Anonymity bugfix
      pointed out by rovv.

  o Minor bugfixes:
    - Recover 3-7 bytes that were wasted per memory chunk. Fixes bug
      794; bug spotted by rovv. Bugfix on 0.2.0.1-alpha.
    - Correctly detect the presence of the linux/netfilter_ipv4.h header
      when building against recent kernels. Bugfix on 0.1.2.1-alpha.
    - Pick size of default geoip filename string correctly on windows.
      Fixes bug 806. Bugfix on 0.2.0.30.
    - Make the autoconf script accept the obsolete --with-ssl-dir
      option as an alias for the actually-working --with-openssl-dir
      option. Fix the help documentation to recommend --with-openssl-dir.
      Based on a patch by "Dave". Bugfix on 0.2.0.1-alpha.
    - When using the TransPort option on OpenBSD, and using the User
      option to change UID and drop privileges, make sure to open
      /dev/pf before dropping privileges. Fixes bug 782. Patch from
      Christopher Davis. Bugfix on 0.1.2.1-alpha.
    - Try to attach connections immediately upon receiving a RENDEZVOUS2
      or RENDEZVOUS_ESTABLISHED cell. This can save a second or two
      on the client side when connecting to a hidden service. Bugfix
      on 0.0.6pre1. Found and fixed by Christian Wilms; resolves bug 743.
    - When closing an application-side connection because its circuit is
      getting torn down, generate the stream event correctly. Bugfix on
      0.1.2.x. Anonymous patch.


Changes in version 0.2.0.30 - 2008-07-15
  This new stable release switches to a more efficient directory
  distribution design, adds features to make connections to the Tor
  network harder to block, allows Tor to act as a DNS proxy, adds separate
  rate limiting for relayed traffic to make it easier for clients to
  become relays, fixes a variety of potential anonymity problems, and
  includes the usual huge pile of other features and bug fixes.

  o New v3 directory design:
    - Tor now uses a new way to learn about and distribute information
      about the network: the directory authorities vote on a common
      network status document rather than each publishing their own
      opinion. Now clients and caches download only one networkstatus
      document to bootstrap, rather than downloading one for each
      authority. Clients only download router descriptors listed in
      the consensus. Implements proposal 101; see doc/spec/dir-spec.txt
      for details.
    - Set up moria1, tor26, and dizum as v3 directory authorities
      in addition to being v2 authorities. Also add three new ones:
      ides (run by Mike Perry), gabelmoo (run by Karsten Loesing), and
      dannenberg (run by CCC).
    - Switch to multi-level keys for directory authorities: now their
      long-term identity key can be kept offline, and they periodically
      generate a new signing key. Clients fetch the "key certificates"
      to keep up to date on the right keys. Add a standalone tool
      "tor-gencert" to generate key certificates. Implements proposal 103.
    - Add a new V3AuthUseLegacyKey config option to make it easier for
      v3 authorities to change their identity keys if another bug like
      Debian's OpenSSL RNG flaw appears.
    - Authorities and caches fetch the v2 networkstatus documents
      less often, now that v3 is recommended.

  o Make Tor connections stand out less on the wire:
    - Use an improved TLS handshake designed by Steven Murdoch in proposal
      124, as revised in proposal 130. The new handshake is meant to
      be harder for censors to fingerprint, and it adds the ability
      to detect certain kinds of man-in-the-middle traffic analysis
      attacks. The new handshake format includes version negotiation for
      OR connections as described in proposal 105, which will allow us
      to improve Tor's link protocol more safely in the future.
    - Enable encrypted directory connections by default for non-relays,
      so censor tools that block Tor directory connections based on their
      plaintext patterns will no longer work. This means Tor works in
      certain censored countries by default again.
    - Stop including recognizeable strings in the commonname part of
      Tor's x509 certificates.

  o Implement bridge relays:
    - Bridge relays (or "bridges" for short) are Tor relays that aren't
      listed in the main Tor directory. Since there is no complete public
      list of them, even an ISP that is filtering connections to all the
      known Tor relays probably won't be able to block all the bridges.
      See doc/design-paper/blocking.pdf and proposal 125 for details.
    - New config option BridgeRelay that specifies you want to be a
      bridge relay rather than a normal relay. When BridgeRelay is set
      to 1, then a) you cache dir info even if your DirPort ins't on,
      and b) the default for PublishServerDescriptor is now "bridge"
      rather than "v2,v3".
    - New config option "UseBridges 1" for clients that want to use bridge
      relays instead of ordinary entry guards. Clients then specify
      bridge relays by adding "Bridge" lines to their config file. Users
      can learn about a bridge relay either manually through word of
      mouth, or by one of our rate-limited mechanisms for giving out
      bridge addresses without letting an attacker easily enumerate them
      all. See https://www.torproject.org/bridges for details.
    - Bridge relays behave like clients with respect to time intervals
      for downloading new v3 consensus documents -- otherwise they
      stand out. Bridge users now wait until the end of the interval,
      so their bridge relay will be sure to have a new consensus document.

  o Implement bridge directory authorities:
    - Bridge authorities are like normal directory authorities, except
      they don't serve a list of known bridges. Therefore users that know
      a bridge's fingerprint can fetch a relay descriptor for that bridge,
      including fetching updates e.g. if the bridge changes IP address,
      yet an attacker can't just fetch a list of all the bridges.
    - Set up Tonga as the default bridge directory authority.
    - Bridge authorities refuse to serve bridge descriptors or other
      bridge information over unencrypted connections (that is, when
      responding to direct DirPort requests rather than begin_dir cells.)
    - Bridge directory authorities do reachability testing on the
      bridges they know. They provide router status summaries to the
      controller via "getinfo ns/purpose/bridge", and also dump summaries
      to a file periodically, so we can keep internal stats about which
      bridges are functioning.
    - If bridge users set the UpdateBridgesFromAuthority config option,
      but the digest they ask for is a 404 on the bridge authority,
      they fall back to contacting the bridge directly.
    - Bridges always use begin_dir to publish their server descriptor to
      the bridge authority using an anonymous encrypted tunnel.
    - Early work on a "bridge community" design: if bridge authorities set
      the BridgePassword config option, they will serve a snapshot of
      known bridge routerstatuses from their DirPort to anybody who
      knows that password. Unset by default.
    - Tor now includes an IP-to-country GeoIP file, so bridge relays can
      report sanitized aggregated summaries in their extra-info documents
      privately to the bridge authority, listing which countries are
      able to reach them. We hope this mechanism will let us learn when
      certain countries start trying to block bridges.
    - Bridge authorities write bridge descriptors to disk, so they can
      reload them after a reboot. They can also export the descriptors
      to other programs, so we can distribute them to blocked users via
      the BridgeDB interface, e.g. via https://bridges.torproject.org/
      and bridges@torproject.org.

  o Tor can be a DNS proxy:
    - The new client-side DNS proxy feature replaces the need for
      dns-proxy-tor: Just set "DNSPort 9999", and Tor will now listen
      for DNS requests on port 9999, use the Tor network to resolve them
      anonymously, and send the reply back like a regular DNS server.
      The code still only implements a subset of DNS.
    - Add a new AutomapHostsOnResolve option: when it is enabled, any
      resolve request for hosts matching a given pattern causes Tor to
      generate an internal virtual address mapping for that host. This
      allows DNSPort to work sensibly with hidden service users. By
      default, .exit and .onion addresses are remapped; the list of
      patterns can be reconfigured with AutomapHostsSuffixes.
    - Add an "-F" option to tor-resolve to force a resolve for a .onion
      address. Thanks to the AutomapHostsOnResolve option, this is no
      longer a completely silly thing to do.

  o Major features (relay usability):
    - New config options RelayBandwidthRate and RelayBandwidthBurst:
      a separate set of token buckets for relayed traffic. Right now
      relayed traffic is defined as answers to directory requests, and
      OR connections that don't have any local circuits on them. See
      proposal 111 for details.
    - Create listener connections before we setuid to the configured
      User and Group. Now non-Windows users can choose port values
      under 1024, start Tor as root, and have Tor bind those ports
      before it changes to another UID. (Windows users could already
      pick these ports.)
    - Added a new ConstrainedSockets config option to set SO_SNDBUF and
      SO_RCVBUF on TCP sockets. Hopefully useful for Tor servers running
      on "vserver" accounts. Patch from coderman.

  o Major features (directory authorities):
    - Directory authorities track weighted fractional uptime and weighted
      mean-time-between failures for relays. WFU is suitable for deciding
      whether a node is "usually up", while MTBF is suitable for deciding
      whether a node is "likely to stay up." We need both, because
      "usually up" is a good requirement for guards, while "likely to
      stay up" is a good requirement for long-lived connections.
    - Directory authorities use a new formula for selecting which relays
      to advertise as Guards: they must be in the top 7/8 in terms of
      how long we have known about them, and above the median of those
      nodes in terms of weighted fractional uptime.
    - Directory authorities use a new formula for selecting which relays
      to advertise as Stable: when we have 4 or more days of data, use
      median measured MTBF rather than median declared uptime. Implements
      proposal 108.
    - Directory authorities accept and serve "extra info" documents for
      routers. Routers now publish their bandwidth-history lines in the
      extra-info docs rather than the main descriptor. This step saves
      60% (!) on compressed router descriptor downloads. Servers upload
      extra-info docs to any authority that accepts them; directory
      authorities now allow multiple router descriptors and/or extra
      info documents to be uploaded in a single go. Authorities, and
      caches that have been configured to download extra-info documents,
      download them as needed. Implements proposal 104.
    - Authorities now list relays who have the same nickname as
      a different named relay, but list them with a new flag:
      "Unnamed". Now we can make use of relays that happen to pick the
      same nickname as a server that registered two years ago and then
      disappeared. Implements proposal 122.
    - Store routers in a file called cached-descriptors instead of in
      cached-routers. Initialize cached-descriptors from cached-routers
      if the old format is around. The new format allows us to store
      annotations along with descriptors, to record the time we received
      each descriptor, its source, and its purpose: currently one of
      general, controller, or bridge.

  o Major features (other):
    - New config options WarnPlaintextPorts and RejectPlaintextPorts so
      Tor can warn and/or refuse connections to ports commonly used with
      vulnerable-plaintext protocols. Currently we warn on ports 23,
      109, 110, and 143, but we don't reject any. Based on proposal 129
      by Kevin Bauer and Damon McCoy.
    - Integrate Karsten Loesing's Google Summer of Code project to publish
      hidden service descriptors on a set of redundant relays that are a
      function of the hidden service address. Now we don't have to rely
      on three central hidden service authorities for publishing and
      fetching every hidden service descriptor. Implements proposal 114.
    - Allow tunnelled directory connections to ask for an encrypted
      "begin_dir" connection or an anonymized "uses a full Tor circuit"
      connection independently. Now we can make anonymized begin_dir
      connections for (e.g.) more secure hidden service posting and
      fetching.

  o Major bugfixes (crashes and assert failures):
    - Stop imposing an arbitrary maximum on the number of file descriptors
      used for busy servers. Bug reported by Olaf Selke; patch from
      Sebastian Hahn.
    - Avoid possible failures when generating a directory with routers
      with over-long versions strings, or too many flags set.
    - Fix a rare assert error when we're closing one of our threads:
      use a mutex to protect the list of logs, so we never write to the
      list as it's being freed. Fixes the very rare bug 575, which is
      kind of the revenge of bug 222.
    - Avoid segfault in the case where a badly behaved v2 versioning
      directory sends a signed networkstatus with missing client-versions.
    - When we hit an EOF on a log (probably because we're shutting down),
      don't try to remove the log from the list: just mark it as
      unusable. (Bulletproofs against bug 222.)

  o Major bugfixes (code security fixes):
    - Detect size overflow in zlib code. Reported by Justin Ferguson and
      Dan Kaminsky.
    - Rewrite directory tokenization code to never run off the end of
      a string. Fixes bug 455. Patch from croup.
    - Be more paranoid about overwriting sensitive memory on free(),
      as a defensive programming tactic to ensure forward secrecy.

  o Major bugfixes (anonymity fixes):
    - Reject requests for reverse-dns lookup of names that are in
      a private address space. Patch from lodger.
    - Never report that we've used more bandwidth than we're willing to
      relay: it leaks how much non-relay traffic we're using. Resolves
      bug 516.
    - As a client, do not believe any server that tells us that an
      address maps to an internal address space.
    - Warn about unsafe ControlPort configurations.
    - Directory authorities now call routers Fast if their bandwidth is
      at least 100KB/s, and consider their bandwidth adequate to be a
      Guard if it is at least 250KB/s, no matter the medians. This fix
      complements proposal 107.
    - Directory authorities now never mark more than 2 servers per IP as
      Valid and Running (or 5 on addresses shared by authorities).
      Implements proposal 109, by Kevin Bauer and Damon McCoy.
    - If we're a relay, avoid picking ourselves as an introduction point,
      a rendezvous point, or as the final hop for internal circuits. Bug
      reported by taranis and lodger.
    - Exit relays that are used as a client can now reach themselves
      using the .exit notation, rather than just launching an infinite
      pile of circuits. Fixes bug 641. Reported by Sebastian Hahn.
    - Fix a bug where, when we were choosing the 'end stream reason' to
      put in our relay end cell that we send to the exit relay, Tor
      clients on Windows were sometimes sending the wrong 'reason'. The
      anonymity problem is that exit relays may be able to guess whether
      the client is running Windows, thus helping partition the anonymity
      set. Down the road we should stop sending reasons to exit relays,
      or otherwise prevent future versions of this bug.
    - Only update guard status (usable / not usable) once we have
      enough directory information. This was causing us to discard all our
      guards on startup if we hadn't been running for a few weeks. Fixes
      bug 448.
    - When our directory information has been expired for a while, stop
      being willing to build circuits using it. Fixes bug 401.

  o Major bugfixes (peace of mind for relay operators)
    - Non-exit relays no longer answer "resolve" relay cells, so they
      can't be induced to do arbitrary DNS requests. (Tor clients already
      avoid using non-exit relays for resolve cells, but now servers
      enforce this too.) Fixes bug 619. Patch from lodger.
    - When we setconf ClientOnly to 1, close any current OR and Dir
      listeners. Reported by mwenge.

  o Major bugfixes (other):
    - If we only ever used Tor for hidden service lookups or posts, we
      would stop building circuits and start refusing connections after
      24 hours, since we falsely believed that Tor was dormant. Reported
      by nwf.
    - Add a new __HashedControlSessionPassword option for controllers
      to use for one-off session password hashes that shouldn't get
      saved to disk by SAVECONF --- Vidalia users were accumulating a
      pile of HashedControlPassword lines in their torrc files, one for
      each time they had restarted Tor and then clicked Save. Make Tor
      automatically convert "HashedControlPassword" to this new option but
      only when it's given on the command line. Partial fix for bug 586.
    - Patch from "Andrew S. Lists" to catch when we contact a directory
      mirror at IP address X and he says we look like we're coming from
      IP address X. Otherwise this would screw up our address detection.
    - Reject uploaded descriptors and extrainfo documents if they're
      huge. Otherwise we'll cache them all over the network and it'll
      clog everything up. Suggested by Aljosha Judmayer.
    - When a hidden service was trying to establish an introduction point,
      and Tor *did* manage to reuse one of the preemptively built
      circuits, it didn't correctly remember which one it used,
      so it asked for another one soon after, until there were no
      more preemptive circuits, at which point it launched one from
      scratch. Bugfix on 0.0.9.x.

  o Rate limiting and load balancing improvements:
    - When we add data to a write buffer in response to the data on that
      write buffer getting low because of a flush, do not consider the
      newly added data as a candidate for immediate flushing, but rather
      make it wait until the next round of writing. Otherwise, we flush
      and refill recursively, and a single greedy TLS connection can
      eat all of our bandwidth.
    - When counting the number of bytes written on a TLS connection,
      look at the BIO actually used for writing to the network, not
      at the BIO used (sometimes) to buffer data for the network.
      Looking at different BIOs could result in write counts on the
      order of ULONG_MAX. Fixes bug 614.
    - If we change our MaxAdvertisedBandwidth and then reload torrc,
      Tor won't realize it should publish a new relay descriptor. Fixes
      bug 688, reported by mfr.
    - Avoid using too little bandwidth when our clock skips a few seconds.
    - Choose which bridge to use proportional to its advertised bandwidth,
      rather than uniformly at random. This should speed up Tor for
      bridge users. Also do this for people who set StrictEntryNodes.

  o Bootstrapping faster and building circuits more intelligently:
    - Fix bug 660 that was preventing us from knowing that we should
      preemptively build circuits to handle expected directory requests.
    - When we're checking if we have enough dir info for each relay
      to begin establishing circuits, make sure that we actually have
      the descriptor listed in the consensus, not just any descriptor.
    - Correctly notify one-hop connections when a circuit build has
      failed. Possible fix for bug 669. Found by lodger.
    - Clients now hold circuitless TLS connections open for 1.5 times
      MaxCircuitDirtiness (15 minutes), since it is likely that they'll
      rebuild a new circuit over them within that timeframe. Previously,
      they held them open only for KeepalivePeriod (5 minutes).

  o Performance improvements (memory):
    - Add OpenBSD malloc code from "phk" as an optional malloc
      replacement on Linux: some glibc libraries do very poorly with
      Tor's memory allocation patterns. Pass --enable-openbsd-malloc to
      ./configure to get the replacement malloc code.
    - Switch our old ring buffer implementation for one more like that
      used by free Unix kernels. The wasted space in a buffer with 1mb
      of data will now be more like 8k than 1mb. The new implementation
      also avoids realloc();realloc(); patterns that can contribute to
      memory fragmentation.
    - Change the way that Tor buffers data that it is waiting to write.
      Instead of queueing data cells in an enormous ring buffer for each
      client->OR or OR->OR connection, we now queue cells on a separate
      queue for each circuit. This lets us use less slack memory, and
      will eventually let us be smarter about prioritizing different kinds
      of traffic.
    - Reference-count and share copies of address policy entries; only 5%
      of them were actually distinct.
    - Tune parameters for cell pool allocation to minimize amount of
      RAM overhead used.
    - Keep unused 4k and 16k buffers on free lists, rather than wasting 8k
      for every single inactive connection_t. Free items from the
      4k/16k-buffer free lists when they haven't been used for a while.
    - Make memory debugging information describe more about history
      of cell allocation, so we can help reduce our memory use.
    - Be even more aggressive about releasing RAM from small
      empty buffers. Thanks to our free-list code, this shouldn't be too
      performance-intensive.
    - Log malloc statistics from mallinfo() on platforms where it exists.
    - Use memory pools to allocate cells with better speed and memory
      efficiency, especially on platforms where malloc() is inefficient.
    - Add a --with-tcmalloc option to the configure script to link
      against tcmalloc (if present). Does not yet search for non-system
      include paths.

  o Performance improvements (socket management):
    - Count the number of open sockets separately from the number of
      active connection_t objects. This will let us avoid underusing
      our allocated connection limit.
    - We no longer use socket pairs to link an edge connection to an
      anonymous directory connection or a DirPort test connection.
      Instead, we track the link internally and transfer the data
      in-process. This saves two sockets per "linked" connection (at the
      client and at the server), and avoids the nasty Windows socketpair()
      workaround.
    - We were leaking a file descriptor if Tor started with a zero-length
      cached-descriptors file. Patch by "freddy77".

  o Performance improvements (CPU use):
    - Never walk through the list of logs if we know that no log target
      is interested in a given message.
    - Call routerlist_remove_old_routers() much less often. This should
      speed startup, especially on directory caches.
    - Base64 decoding was actually showing up on our profile when parsing
      the initial descriptor file; switch to an in-process all-at-once
      implementation that's about 3.5x times faster than calling out to
      OpenSSL.
    - Use a slightly simpler string hashing algorithm (copying Python's
      instead of Java's) and optimize our digest hashing algorithm to take
      advantage of 64-bit platforms and to remove some possibly-costly
      voodoo.
    - When implementing AES counter mode, update only the portions of the
      counter buffer that need to change, and don't keep separate
      network-order and host-order counters on big-endian hosts (where
      they are the same).
    - Add an in-place version of aes_crypt() so that we can avoid doing a
      needless memcpy() call on each cell payload.
    - Use Critical Sections rather than Mutexes for synchronizing threads
      on win32; Mutexes are heavier-weight, and designed for synchronizing
      between processes.

  o Performance improvements (bandwidth use):
    - Don't try to launch new descriptor downloads quite so often when we
      already have enough directory information to build circuits.
    - Version 1 directories are no longer generated in full. Instead,
      authorities generate and serve "stub" v1 directories that list
      no servers. This will stop Tor versions 0.1.0.x and earlier from
      working, but (for security reasons) nobody should be running those
      versions anyway.
    - Avoid going directly to the directory authorities even if you're a
      relay, if you haven't found yourself reachable yet or if you've
      decided not to advertise your dirport yet. Addresses bug 556.
    - If we've gone 12 hours since our last bandwidth check, and we
      estimate we have less than 50KB bandwidth capacity but we could
      handle more, do another bandwidth test.
    - Support "If-Modified-Since" when answering HTTP requests for
      directories, running-routers documents, and v2 and v3 networkstatus
      documents. (There's no need to support it for router descriptors,
      since those are downloaded by descriptor digest.)
    - Stop fetching directory info so aggressively if your DirPort is
      on but your ORPort is off; stop fetching v2 dir info entirely.
      You can override these choices with the new FetchDirInfoEarly
      config option.

  o Changed config option behavior (features):
    - Configuration files now accept C-style strings as values. This
      helps encode characters not allowed in the current configuration
      file format, such as newline or #. Addresses bug 557.
    - Add hidden services and DNSPorts to the list of things that make
      Tor accept that it has running ports. Change starting Tor with no
      ports from a fatal error to a warning; we might change it back if
      this turns out to confuse anybody. Fixes bug 579.
    - Make PublishServerDescriptor default to 1, so the default doesn't
      have to change as we invent new directory protocol versions.
    - Allow people to say PreferTunnelledDirConns rather than
      PreferTunneledDirConns, for those alternate-spellers out there.
    - Raise the default BandwidthRate/BandwidthBurst to 5MB/10MB, to
      accommodate the growing number of servers that use the default
      and are reaching it.
    - Make it possible to enable HashedControlPassword and
      CookieAuthentication at the same time.
    - When a TrackHostExits-chosen exit fails too many times in a row,
      stop using it. Fixes bug 437.

  o Changed config option behavior (bugfixes):
    - Do not read the configuration file when we've only been told to
      generate a password hash. Fixes bug 643. Bugfix on 0.0.9pre5. Fix
      based on patch from Sebastian Hahn.
    - Actually validate the options passed to AuthDirReject,
      AuthDirInvalid, AuthDirBadDir, and AuthDirBadExit.
    - Make "ClientOnly 1" config option disable directory ports too.
    - Don't stop fetching descriptors when FetchUselessDescriptors is
      set, even if we stop asking for circuits. Bug reported by tup
      and ioerror.
    - Servers used to decline to publish their DirPort if their
      BandwidthRate or MaxAdvertisedBandwidth were below a threshold. Now
      they look only at BandwidthRate and RelayBandwidthRate.
    - Treat "2gb" when given in torrc for a bandwidth as meaning 2gb,
      minus 1 byte: the actual maximum declared bandwidth.
    - Make "TrackHostExits ." actually work. Bugfix on 0.1.0.x.
    - Make the NodeFamilies config option work. (Reported by
      lodger -- it has never actually worked, even though we added it
      in Oct 2004.)
    - If Tor is invoked from something that isn't a shell (e.g. Vidalia),
      now we expand "-f ~/.tor/torrc" correctly. Suggested by Matt Edman.

  o New config options:
    - New configuration options AuthDirMaxServersPerAddr and
      AuthDirMaxServersperAuthAddr to override default maximum number
      of servers allowed on a single IP address. This is important for
      running a test network on a single host.
    - Three new config options (AlternateDirAuthority,
      AlternateBridgeAuthority, and AlternateHSAuthority) that let the
      user selectively replace the default directory authorities by type,
      rather than the all-or-nothing replacement that DirServer offers.
    - New config options AuthDirBadDir and AuthDirListBadDirs for
      authorities to mark certain relays as "bad directories" in the
      networkstatus documents. Also supports the "!baddir" directive in
      the approved-routers file.
    - New config option V2AuthoritativeDirectory that all v2 directory
      authorities must set. This lets v3 authorities choose not to serve
      v2 directory information.

  o Minor features (other):
    - When we're not serving v2 directory information, there is no reason
      to actually keep any around. Remove the obsolete files and directory
      on startup if they are very old and we aren't going to serve them.
    - When we negotiate a v2 link-layer connection (not yet implemented),
      accept RELAY_EARLY cells and turn them into RELAY cells if we've
      negotiated a v1 connection for their next step. Initial steps for
      proposal 110.
    - When we have no consensus, check FallbackNetworkstatusFile (defaults
      to $PREFIX/share/tor/fallback-consensus) for a consensus. This way
      we can start out knowing some directory caches. We don't ship with
      a fallback consensus by default though, because it was making
      bootstrapping take too long while we tried many down relays.
    - Authorities send back an X-Descriptor-Not-New header in response to
      an accepted-but-discarded descriptor upload. Partially implements
      fix for bug 535.
    - If we find a cached-routers file that's been sitting around for more
      than 28 days unmodified, then most likely it's a leftover from
      when we upgraded to 0.2.0.8-alpha. Remove it. It has no good
      routers anyway.
    - When we (as a cache) download a descriptor because it was listed
      in a consensus, remember when the consensus was supposed to expire,
      and don't expire the descriptor until then.
    - Optionally (if built with -DEXPORTMALLINFO) export the output
      of mallinfo via http, as tor/mallinfo.txt. Only accessible
      from localhost.
    - Tag every guard node in our state file with the version that
      we believe added it, or with our own version if we add it. This way,
      if a user temporarily runs an old version of Tor and then switches
      back to a new one, she doesn't automatically lose her guards.
    - When somebody requests a list of statuses or servers, and we have
      none of those, return a 404 rather than an empty 200.
    - Merge in some (as-yet-unused) IPv6 address manipulation code. (Patch
      from croup.)
    - Add an HSAuthorityRecordStats option that hidden service authorities
      can use to track statistics of overall hidden service usage without
      logging information that would be as useful to an attacker.
    - Allow multiple HiddenServicePort directives with the same virtual
      port; when they occur, the user is sent round-robin to one
      of the target ports chosen at random.  Partially fixes bug 393 by
      adding limited ad-hoc round-robining.
    - Revamp file-writing logic so we don't need to have the entire
      contents of a file in memory at once before we write to disk. Tor,
      meet stdio.

  o Minor bugfixes (other):
    - Alter the code that tries to recover from unhandled write
      errors, to not try to flush onto a socket that's given us
      unhandled errors.
    - Directory mirrors no longer include a guess at the client's IP
      address if the connection appears to be coming from the same /24
      network; it was producing too many wrong guesses.
    - If we're trying to flush the last bytes on a connection (for
      example, when answering a directory request), reset the
      time-to-give-up timeout every time we manage to write something
      on the socket.
    - Reject router descriptors with out-of-range bandwidthcapacity or
      bandwidthburst values.
    - If we can't expand our list of entry guards (e.g. because we're
      using bridges or we have StrictEntryNodes set), don't mark relays
      down when they fail a directory request. Otherwise we're too quick
      to mark all our entry points down.
    - Authorities no longer send back "400 you're unreachable please fix
      it" errors to Tor servers that aren't online all the time. We're
      supposed to tolerate these servers now.
    - Let directory authorities startup even when they can't generate
      a descriptor immediately, e.g. because they don't know their
      address.
    - Correctly enforce that elements of directory objects do not appear
      more often than they are allowed to appear.
    - Stop allowing hibernating servers to be "stable" or "fast".
    - On Windows, we were preventing other processes from reading
      cached-routers while Tor was running. (Reported by janbar)
    - Check return values from pthread_mutex functions.
    - When opening /dev/null in finish_daemonize(), do not pass the
      O_CREAT flag. Fortify was complaining, and correctly so. Fixes
      bug 742; fix from Michael Scherer. Bugfix on 0.0.2pre19.

  o Controller features:
    - The GETCONF command now escapes and quotes configuration values
      that don't otherwise fit into the torrc file.
    - The SETCONF command now handles quoted values correctly.
    - Add "GETINFO/desc-annotations/id/<OR digest>" so controllers can
      ask about source, timestamp of arrival, purpose, etc. We need
      something like this to help Vidalia not do GeoIP lookups on bridge
      addresses.
    - Allow multiple HashedControlPassword config lines, to support
      multiple controller passwords.
    - Accept LF instead of CRLF on controller, since some software has a
      hard time generating real Internet newlines.
    - Add GETINFO values for the server status events
      "REACHABILITY_SUCCEEDED" and "GOOD_SERVER_DESCRIPTOR". Patch from
      Robert Hogan.
    - There is now an ugly, temporary "desc/all-recent-extrainfo-hack"
      GETINFO for Torstat to use until it can switch to using extrainfos.
    - New config option CookieAuthFile to choose a new location for the
      cookie authentication file, and config option
      CookieAuthFileGroupReadable to make it group-readable.
    - Add a SOURCE_ADDR field to STREAM NEW events so that controllers can
      match requests to applications. Patch from Robert Hogan.
    - Add a RESOLVE command to launch hostname lookups. Original patch
      from Robert Hogan.
    - Add GETINFO status/enough-dir-info to let controllers tell whether
      Tor has downloaded sufficient directory information. Patch from Tup.
    - You can now use the ControlSocket option to tell Tor to listen for
      controller connections on Unix domain sockets on systems that
      support them. Patch from Peter Palfrader.
    - New "GETINFO address-mappings/*" command to get address mappings
      with expiry information. "addr-mappings/*" is now deprecated.
      Patch from Tup.
    - Add a new config option __DisablePredictedCircuits designed for
      use by the controller, when we don't want Tor to build any circuits
      preemptively.
    - Let the controller specify HOP=%d as an argument to ATTACHSTREAM,
      so we can exit from the middle of the circuit.
    - Implement "getinfo status/circuit-established".
    - Implement "getinfo status/version/..." so a controller can tell
      whether the current version is recommended, and whether any versions
      are good, and how many authorities agree. Patch from "shibz".
    - Controllers should now specify cache=no or cache=yes when using
      the +POSTDESCRIPTOR command.
    - Add a "PURPOSE=" argument to "STREAM NEW" events, as suggested by
      Robert Hogan. Fixes the first part of bug 681.
    - When reporting clock skew, and we know that the clock is _at least
      as skewed_ as some value, but we don't know the actual value,
      report the value as a "minimum skew."

  o Controller bugfixes:
    - Generate "STATUS_SERVER" events rather than misspelled
      "STATUS_SEVER" events. Caught by mwenge.
    - Reject controller commands over 1MB in length, so rogue
      processes can't run us out of memory.
    - Change the behavior of "getinfo status/good-server-descriptor"
      so it doesn't return failure when any authority disappears.
    - Send NAMESERVER_STATUS messages for a single failed nameserver
      correctly.
    - When the DANGEROUS_VERSION controller status event told us we're
      running an obsolete version, it used the string "OLD" to describe
      it. Yet the "getinfo" interface used the string "OBSOLETE". Now use
      "OBSOLETE" in both cases.
    - Respond to INT and TERM SIGNAL commands before we execute the
      signal, in case the signal shuts us down. We had a patch in
      0.1.2.1-alpha that tried to do this by queueing the response on
      the connection's buffer before shutting down, but that really
      isn't the same thing at all. Bug located by Matt Edman.
    - Provide DNS expiry times in GMT, not in local time. For backward
      compatibility, ADDRMAP events only provide GMT expiry in an extended
      field. "GETINFO address-mappings" always does the right thing.
    - Use CRLF line endings properly in NS events.
    - Make 'getinfo fingerprint' return a 551 error if we're not a
      server, so we match what the control spec claims we do. Reported
      by daejees.
    - Fix a typo in an error message when extendcircuit fails that
      caused us to not follow the \r\n-based delimiter protocol. Reported
      by daejees.
    - When tunneling an encrypted directory connection, and its first
      circuit fails, do not leave it unattached and ask the controller
      to deal. Fixes the second part of bug 681.
    - Treat some 403 responses from directory servers as INFO rather than
      WARN-severity events.

  o Portability / building / compiling:
    - When building with --enable-gcc-warnings, check for whether Apple's
      warning "-Wshorten-64-to-32" is available.
    - Support compilation to target iPhone; patch from cjacker huang.
      To build for iPhone, pass the --enable-iphone option to configure.
    - Port Tor to build and run correctly on Windows CE systems, using
      the wcecompat library. Contributed by Valerio Lupi.
    - Detect non-ASCII platforms (if any still exist) and refuse to
      build there: some of our code assumes that 'A' is 65 and so on.
    - Clear up some MIPSPro compiler warnings.
    - Make autoconf search for libevent, openssl, and zlib consistently.
    - Update deprecated macros in configure.in.
    - When warning about missing headers, tell the user to let us
      know if the compile succeeds anyway, so we can downgrade the
      warning.
    - Include the current subversion revision as part of the version
      string: either fetch it directly if we're in an SVN checkout, do
      some magic to guess it if we're in an SVK checkout, or use
      the last-detected version if we're building from a .tar.gz.
      Use this version consistently in log messages.
    - Correctly report platform name on Windows 95 OSR2 and Windows 98 SE.
    - Read resolv.conf files correctly on platforms where read() returns
      partial results on small file reads.
    - Build without verbose warnings even on gcc 4.2 and 4.3.
    - On Windows, correctly detect errors when listing the contents of
      a directory. Fix from lodger.
    - Run 'make test' as part of 'make dist', so we stop releasing so
      many development snapshots that fail their unit tests.
    - Add support to detect Libevent versions in the 1.4.x series
      on mingw.
    - Add command-line arguments to unit-test executable so that we can
      invoke any chosen test from the command line rather than having
      to run the whole test suite at once; and so that we can turn on
      logging for the unit tests.
    - Do not automatically run configure from autogen.sh. This
      non-standard behavior tended to annoy people who have built other
      programs.
    - Fix a macro/CPP interaction that was confusing some compilers:
      some GCCs don't like #if/#endif pairs inside macro arguments.
      Fixes bug 707.
    - Fix macro collision between OpenSSL 0.9.8h and Windows headers.
      Fixes bug 704; fix from Steven Murdoch.
    - Correctly detect transparent proxy support on Linux hosts that
      require in.h to be included before netfilter_ipv4.h.  Patch
      from coderman.

  o Logging improvements:
    - When we haven't had any application requests lately, don't bother
      logging that we have expired a bunch of descriptors.
    - When attempting to open a logfile fails, tell us why.
    - Only log guard node status when guard node status has changed.
    - Downgrade the 3 most common "INFO" messages to "DEBUG". This will
      make "INFO" 75% less verbose.
    - When SafeLogging is disabled, log addresses along with all TLS
      errors.
    - Report TLS "zero return" case as a "clean close" and "IO error"
      as a "close". Stop calling closes "unexpected closes": existing
      Tors don't use SSL_close(), so having a connection close without
      the TLS shutdown handshake is hardly unexpected.
    - When we receive a consensus from the future, warn about skew.
    - Make "not enough dir info yet" warnings describe *why* Tor feels
      it doesn't have enough directory info yet.
    - On the USR1 signal, when dmalloc is in use, log the top 10 memory
      consumers. (We already do this on HUP.)
    - Give more descriptive well-formedness errors for out-of-range
      hidden service descriptor/protocol versions.
    - Stop recommending that every server operator send mail to tor-ops.
      Resolves bug 597. Bugfix on 0.1.2.x.
    - Improve skew reporting: try to give the user a better log message
      about how skewed they are, and how much this matters.
    - New --quiet command-line option to suppress the default console log.
      Good in combination with --hash-password.
    - Don't complain that "your server has not managed to confirm that its
      ports are reachable" if we haven't been able to build any circuits
      yet.
    - Detect the reason for failing to mmap a descriptor file we just
      wrote, and give a more useful log message.  Fixes bug 533.
    - Always prepend "Bug: " to any log message about a bug.
    - When dumping memory usage, list bytes used in buffer memory
      free-lists.
    - When running with dmalloc, dump more stats on hup and on exit.
    - Put a platform string (e.g. "Linux i686") in the startup log
      message, so when people paste just their logs, we know if it's
      OpenBSD or Windows or what.
    - When logging memory usage, break down memory used in buffers by
      buffer type.
    - When we are reporting the DirServer line we just parsed, we were
      logging the second stanza of the key fingerprint, not the first.
    - Even though Windows is equally happy with / and \ as path separators,
      try to use \ consistently on Windows and / consistently on Unix: it
      makes the log messages nicer.
     - On OSX, stop warning the user that kqueue support in libevent is
      "experimental", since it seems to have worked fine for ages.

  o Contributed scripts and tools:
    - Update linux-tor-prio.sh script to allow QoS based on the uid of
      the Tor process. Patch from Marco Bonetti with tweaks from Mike
      Perry.
    - Include the "tor-ctrl.sh" bash script by Stefan Behte to provide
      Unix users an easy way to script their Tor process (e.g. by
      adjusting bandwidth based on the time of the day).
    - In the exitlist script, only consider the most recently published
      server descriptor for each server. Also, when the user requests
      a list of servers that _reject_ connections to a given address,
      explicitly exclude the IPs that also have servers that accept
      connections to that address. Resolves bug 405.
    - Include a new contrib/tor-exit-notice.html file that exit relay
      operators can put on their website to help reduce abuse queries.

  o Newly deprecated features:
    - The status/version/num-versioning and status/version/num-concurring
      GETINFO controller options are no longer useful in the v3 directory
      protocol: treat them as deprecated, and warn when they're used.
    - The RedirectExits config option is now deprecated.

  o Removed features:
    - Drop the old code to choke directory connections when the
      corresponding OR connections got full: thanks to the cell queue
      feature, OR conns don't get full any more.
    - Remove the old "dns worker" server DNS code: it hasn't been default
      since 0.1.2.2-alpha, and all the servers are using the new
      eventdns code.
    - Remove the code to generate the oldest (v1) directory format.
    - Remove support for the old bw_accounting file: we've been storing
      bandwidth accounting information in the state file since
      0.1.2.5-alpha. This may result in bandwidth accounting errors
      if you try to upgrade from 0.1.1.x or earlier, or if you try to
      downgrade to 0.1.1.x or earlier.
    - Drop support for OpenSSL version 0.9.6. Just about nobody was using
      it, it had no AES, and it hasn't seen any security patches since
      2004.
    - Stop overloading the circuit_t.onionskin field for both "onionskin
      from a CREATE cell that we are waiting for a cpuworker to be
      assigned" and "onionskin from an EXTEND cell that we are going to
      send to an OR as soon as we are connected". Might help with bug 600.
    - Remove the tor_strpartition() function: its logic was confused,
      and it was only used for one thing that could be implemented far
      more easily.
    - Remove the contrib scripts ExerciseServer.py, PathDemo.py,
      and TorControl.py, as they use the old v0 controller protocol,
      and are obsoleted by TorFlow anyway.
    - Drop support for v1 rendezvous descriptors, since we never used
      them anyway, and the code has probably rotted by now. Based on
      patch from Karsten Loesing.
    - Stop allowing address masks that do not correspond to bit prefixes.
      We have warned about these for a really long time; now it's time
      to reject them. (Patch from croup.)
    - Remove an optimization in the AES counter-mode code that assumed
      that the counter never exceeded 2^68. When the counter can be set
      arbitrarily as an IV (as it is by Karsten's new hidden services
      code), this assumption no longer holds.
    - Disable the SETROUTERPURPOSE controller command: it is now
      obsolete.


Changes in version 0.1.2.19 - 2008-01-17
  Tor 0.1.2.19 fixes a huge memory leak on exit relays, makes the default
  exit policy a little bit more conservative so it's safer to run an
  exit relay on a home system, and fixes a variety of smaller issues.

  o Security fixes:
    - Exit policies now reject connections that are addressed to a
      relay's public (external) IP address too, unless
      ExitPolicyRejectPrivate is turned off. We do this because too
      many relays are running nearby to services that trust them based
      on network address.

  o Major bugfixes:
    - When the clock jumps forward a lot, do not allow the bandwidth
      buckets to become negative. Fixes bug 544.
    - Fix a memory leak on exit relays; we were leaking a cached_resolve_t
      on every successful resolve. Reported by Mike Perry.
    - Purge old entries from the "rephist" database and the hidden
      service descriptor database even when DirPort is zero.
    - Stop thinking that 0.1.2.x directory servers can handle "begin_dir"
      requests. Should ease bugs 406 and 419 where 0.1.2.x relays are
      crashing or mis-answering these requests.
    - When we decide to send a 503 response to a request for servers, do
      not then also send the server descriptors: this defeats the whole
      purpose. Fixes bug 539.

  o Minor bugfixes:
    - Changing the ExitPolicyRejectPrivate setting should cause us to
      rebuild our server descriptor.
    - Fix handling of hex nicknames when answering controller requests for
      networkstatus by name, or when deciding whether to warn about
      unknown routers in a config option. (Patch from mwenge.)
    - Fix a couple of hard-to-trigger autoconf problems that could result
      in really weird results on platforms whose sys/types.h files define
      nonstandard integer types.
    - Don't try to create the datadir when running --verify-config or
      --hash-password. Resolves bug 540.
    - If we were having problems getting a particular descriptor from the
      directory caches, and then we learned about a new descriptor for
      that router, we weren't resetting our failure count. Reported
      by lodger.
    - Although we fixed bug 539 (where servers would send HTTP status 503
      responses _and_ send a body too), there are still servers out there
      that haven't upgraded. Therefore, make clients parse such bodies
      when they receive them.
    - Run correctly on systems where rlim_t is larger than unsigned long.
      This includes some 64-bit systems.
    - Run correctly on platforms (like some versions of OS X 10.5) where
      the real limit for number of open files is OPEN_FILES, not rlim_max
      from getrlimit(RLIMIT_NOFILES).
    - Avoid a spurious free on base64 failure.
    - Avoid segfaults on certain complex invocations of
      router_get_by_hexdigest().
    - Fix rare bug on REDIRECTSTREAM control command when called with no
      port set: it could erroneously report an error when none had
      happened.


Changes in version 0.1.2.18 - 2007-10-28
  Tor 0.1.2.18 fixes many problems including crash bugs, problems with
  hidden service introduction that were causing huge delays, and a big
  bug that was causing some servers to disappear from the network status
  lists for a few hours each day.

  o Major bugfixes (crashes):
    - If a connection is shut down abruptly because of something that
      happened inside connection_flushed_some(), do not call
      connection_finished_flushing(). Should fix bug 451:
      "connection_stop_writing: Assertion conn->write_event failed"
      Bugfix on 0.1.2.7-alpha.
    - Fix possible segfaults in functions called from
      rend_process_relay_cell().

  o Major bugfixes (hidden services):
    - Hidden services were choosing introduction points uniquely by
      hexdigest, but when constructing the hidden service descriptor
      they merely wrote the (potentially ambiguous) nickname.
    - Clients now use the v2 intro format for hidden service
      connections: they specify their chosen rendezvous point by identity
      digest rather than by (potentially ambiguous) nickname. These
      changes could speed up hidden service connections dramatically.

  o Major bugfixes (other):
    - Stop publishing a new server descriptor just because we get a
      HUP signal. This led (in a roundabout way) to some servers getting
      dropped from the networkstatus lists for a few hours each day.
    - When looking for a circuit to cannibalize, consider family as well
      as identity. Fixes bug 438. Bugfix on 0.1.0.x (which introduced
      circuit cannibalization).
    - When a router wasn't listed in a new networkstatus, we were leaving
      the flags for that router alone -- meaning it remained Named,
      Running, etc -- even though absence from the networkstatus means
      that it shouldn't be considered to exist at all anymore. Now we
      clear all the flags for routers that fall out of the networkstatus
      consensus. Fixes bug 529.

  o Minor bugfixes:
    - Don't try to access (or alter) the state file when running
      --list-fingerprint or --verify-config or --hash-password. Resolves
      bug 499.
    - When generating information telling us how to extend to a given
      router, do not try to include the nickname if it is
      absent. Resolves bug 467.
    - Fix a user-triggerable segfault in expand_filename(). (There isn't
      a way to trigger this remotely.)
    - When sending a status event to the controller telling it that an
      OR address is reachable, set the port correctly. (Previously we
      were reporting the dir port.)
    - Fix a minor memory leak whenever a controller sends the PROTOCOLINFO
      command. Bugfix on 0.1.2.17.
    - When loading bandwidth history, do not believe any information in
      the future. Fixes bug 434.
    - When loading entry guard information, do not believe any information
      in the future.
    - When we have our clock set far in the future and generate an
      onion key, then re-set our clock to be correct, we should not stop
      the onion key from getting rotated.
    - On some platforms, accept() can return a broken address. Detect
      this more quietly, and deal accordingly. Fixes bug 483.
    - It's not actually an error to find a non-pending entry in the DNS
      cache when canceling a pending resolve. Don't log unless stuff
      is fishy. Resolves bug 463.
    - Don't reset trusted dir server list when we set a configuration
      option. Patch from Robert Hogan.


Changes in version 0.1.2.17 - 2007-08-30
  Tor 0.1.2.17 features a new Vidalia version in the Windows and OS
  X bundles. Vidalia 0.0.14 makes authentication required for the
  ControlPort in the default configuration, which addresses important
  security risks. Everybody who uses Vidalia (or another controller)
  should upgrade.

  In addition, this Tor update fixes major load balancing problems with
  path selection, which should speed things up a lot once many people
  have upgraded.

  o Major bugfixes (security):
    - We removed support for the old (v0) control protocol. It has been
      deprecated since Tor 0.1.1.1-alpha, and keeping it secure has
      become more of a headache than it's worth.

  o Major bugfixes (load balancing):
    - When choosing nodes for non-guard positions, weight guards
      proportionally less, since they already have enough load. Patch
      from Mike Perry.
    - Raise the "max believable bandwidth" from 1.5MB/s to 10MB/s. This
      will allow fast Tor servers to get more attention.
    - When we're upgrading from an old Tor version, forget our current
      guards and pick new ones according to the new weightings. These
      three load balancing patches could raise effective network capacity
      by a factor of four. Thanks to Mike Perry for measurements.

  o Major bugfixes (stream expiration):
    - Expire not-yet-successful application streams in all cases if
      they've been around longer than SocksTimeout. Right now there are
      some cases where the stream will live forever, demanding a new
      circuit every 15 seconds. Fixes bug 454; reported by lodger.

  o Minor features (controller):
    - Add a PROTOCOLINFO controller command. Like AUTHENTICATE, it
      is valid before any authentication has been received. It tells
      a controller what kind of authentication is expected, and what
      protocol is spoken. Implements proposal 119.

  o Minor bugfixes (performance):
    - Save on most routerlist_assert_ok() calls in routerlist.c, thus
      greatly speeding up loading cached-routers from disk on startup.
    - Disable sentinel-based debugging for buffer code: we squashed all
      the bugs that this was supposed to detect a long time ago, and now
      its only effect is to change our buffer sizes from nice powers of
      two (which platform mallocs tend to like) to values slightly over
      powers of two (which make some platform mallocs sad).

  o Minor bugfixes (misc):
    - If exit bandwidth ever exceeds one third of total bandwidth, then
      use the correct formula to weight exit nodes when choosing paths.
      Based on patch from Mike Perry.
    - Choose perfectly fairly among routers when choosing by bandwidth and
      weighting by fraction of bandwidth provided by exits. Previously, we
      would choose with only approximate fairness, and correct ourselves
      if we ran off the end of the list.
    - If we require CookieAuthentication but we fail to write the
      cookie file, we would warn but not exit, and end up in a state
      where no controller could authenticate. Now we exit.
    - If we require CookieAuthentication, stop generating a new cookie
      every time we change any piece of our config.
    - Refuse to start with certain directory authority keys, and
      encourage people using them to stop.
    - Terminate multi-line control events properly. Original patch
      from tup.
    - Fix a minor memory leak when we fail to find enough suitable
      servers to choose a circuit.
    - Stop leaking part of the descriptor when we run into a particularly
      unparseable piece of it.


Changes in version 0.1.2.16 - 2007-08-01
  Tor 0.1.2.16 fixes a critical security vulnerability that allows a
  remote attacker in certain situations to rewrite the user's torrc
  configuration file. This can completely compromise anonymity of users
  in most configurations, including those running the Vidalia bundles,
  TorK, etc. Or worse.

  o Major security fixes:
    - Close immediately after missing authentication on control port;
      do not allow multiple authentication attempts.


Changes in version 0.1.2.15 - 2007-07-17
  Tor 0.1.2.15 fixes several crash bugs, fixes some anonymity-related
  problems, fixes compilation on BSD, and fixes a variety of other
  bugs. Everybody should upgrade.

  o Major bugfixes (compilation):
    - Fix compile on FreeBSD/NetBSD/OpenBSD. Oops.

  o Major bugfixes (crashes):
    - Try even harder not to dereference the first character after
      an mmap(). Reported by lodger.
    - Fix a crash bug in directory authorities when we re-number the
      routerlist while inserting a new router.
    - When the cached-routers file is an even multiple of the page size,
      don't run off the end and crash. (Fixes bug 455; based on idea
      from croup.)
    - Fix eventdns.c behavior on Solaris: It is critical to include
      orconfig.h _before_ sys/types.h, so that we can get the expected
      definition of _FILE_OFFSET_BITS.

  o Major bugfixes (security):
    - Fix a possible buffer overrun when using BSD natd support. Bug
      found by croup.
    - When sending destroy cells from a circuit's origin, don't include
      the reason for tearing down the circuit. The spec says we didn't,
      and now we actually don't. Reported by lodger.
    - Keep streamids from different exits on a circuit separate. This
      bug may have allowed other routers on a given circuit to inject
      cells into streams. Reported by lodger; fixes bug 446.
    - If there's a never-before-connected-to guard node in our list,
      never choose any guards past it. This way we don't expand our
      guard list unless we need to.

  o Minor bugfixes (guard nodes):
    - Weight guard selection by bandwidth, so that low-bandwidth nodes
      don't get overused as guards.

  o Minor bugfixes (directory):
    - Correctly count the number of authorities that recommend each
      version. Previously, we were under-counting by 1.
    - Fix a potential crash bug when we load many server descriptors at
      once and some of them make others of them obsolete. Fixes bug 458.

  o Minor bugfixes (hidden services):
    - Stop tearing down the whole circuit when the user asks for a
      connection to a port that the hidden service didn't configure.
      Resolves bug 444.

  o Minor bugfixes (misc):
    - On Windows, we were preventing other processes from reading
      cached-routers while Tor was running. Reported by janbar.
    - Fix a possible (but very unlikely) bug in picking routers by
      bandwidth. Add a log message to confirm that it is in fact
      unlikely. Patch from lodger.
    - Backport a couple of memory leak fixes.
    - Backport miscellaneous cosmetic bugfixes.


Changes in version 0.1.2.14 - 2007-05-25
  Tor 0.1.2.14 changes the addresses of two directory authorities (this
  change especially affects those who serve or use hidden services),
  and fixes several other crash- and security-related bugs.

  o Directory authority changes:
    - Two directory authorities (moria1 and moria2) just moved to new
      IP addresses. This change will particularly affect those who serve
      or use hidden services.

  o Major bugfixes (crashes):
    - If a directory server runs out of space in the connection table
      as it's processing a begin_dir request, it will free the exit stream
      but leave it attached to the circuit, leading to unpredictable
      behavior. (Reported by seeess, fixes bug 425.)
    - Fix a bug in dirserv_remove_invalid() that would cause authorities
      to corrupt memory under some really unlikely scenarios.
    - Tighten router parsing rules. (Bugs reported by Benedikt Boss.)
    - Avoid segfaults when reading from mmaped descriptor file. (Reported
      by lodger.)

  o Major bugfixes (security):
    - When choosing an entry guard for a circuit, avoid using guards
      that are in the same family as the chosen exit -- not just guards
      that are exactly the chosen exit. (Reported by lodger.)

  o Major bugfixes (resource management):
    - If a directory authority is down, skip it when deciding where to get
      networkstatus objects or descriptors. Otherwise we keep asking
      every 10 seconds forever. Fixes bug 384.
    - Count it as a failure if we fetch a valid network-status but we
      don't want to keep it. Otherwise we'll keep fetching it and keep
      not wanting to keep it. Fixes part of bug 422.
    - If all of our dirservers have given us bad or no networkstatuses
      lately, then stop hammering them once per minute even when we
      think they're failed. Fixes another part of bug 422.

  o Minor bugfixes:
    - Actually set the purpose correctly for descriptors inserted with
      purpose=controller.
    - When we have k non-v2 authorities in our DirServer config,
      we ignored the last k authorities in the list when updating our
      network-statuses.
    - Correctly back-off from requesting router descriptors that we are
      having a hard time downloading.
    - Read resolv.conf files correctly on platforms where read() returns
      partial results on small file reads.
    - Don't rebuild the entire router store every time we get 32K of
      routers: rebuild it when the journal gets very large, or when
      the gaps in the store get very large.

  o Minor features:
    - When routers publish SVN revisions in their router descriptors,
      authorities now include those versions correctly in networkstatus
      documents.
    - Warn when using a version of libevent before 1.3b to run a server on
      OSX or BSD: these versions interact badly with userspace threads.


Changes in version 0.1.2.13 - 2007-04-24
  This release features some major anonymity fixes, such as safer path
  selection; better client performance; faster bootstrapping, better
  address detection, and better DNS support for servers; write limiting as
  well as read limiting to make servers easier to run; and a huge pile of
  other features and bug fixes. The bundles also ship with Vidalia 0.0.11.

  Tor 0.1.2.13 is released in memory of Rob Levin (1955-2006), aka lilo
  of the Freenode IRC network, remembering his patience and vision for
  free speech on the Internet.

  o Major features, client performance:
    - Weight directory requests by advertised bandwidth. Now we can
      let servers enable write limiting but still allow most clients to
      succeed at their directory requests. (We still ignore weights when
      choosing a directory authority; I hope this is a feature.)
    - Stop overloading exit nodes -- avoid choosing them for entry or
      middle hops when the total bandwidth available from non-exit nodes
      is much higher than the total bandwidth available from exit nodes.
    - Rather than waiting a fixed amount of time between retrying
      application connections, we wait only 10 seconds for the first,
      10 seconds for the second, and 15 seconds for each retry after
      that. Hopefully this will improve the expected user experience.
    - Sometimes we didn't bother sending a RELAY_END cell when an attempt
      to open a stream fails; now we do in more cases. This should
      make clients able to find a good exit faster in some cases, since
      unhandleable requests will now get an error rather than timing out.

  o Major features, client functionality:
    - Implement BEGIN_DIR cells, so we can connect to a directory
      server via TLS to do encrypted directory requests rather than
      plaintext. Enable via the TunnelDirConns and PreferTunneledDirConns
      config options if you like. For now, this feature only works if
      you already have a descriptor for the destination dirserver.
    - Add support for transparent application connections: this basically
      bundles the functionality of trans-proxy-tor into the Tor
      mainline. Now hosts with compliant pf/netfilter implementations
      can redirect TCP connections straight to Tor without diverting
      through SOCKS. (Based on patch from tup.)
    - Add support for using natd; this allows FreeBSDs earlier than
      5.1.2 to have ipfw send connections through Tor without using
      SOCKS. (Patch from Zajcev Evgeny with tweaks from tup.)

  o Major features, servers:
    - Setting up a dyndns name for your server is now optional: servers
      with no hostname or IP address will learn their IP address by
      asking the directory authorities. This code only kicks in when you
      would normally have exited with a "no address" error. Nothing's
      authenticated, so use with care.
    - Directory servers now spool server descriptors, v1 directories,
      and v2 networkstatus objects to buffers as needed rather than en
      masse. They also mmap the cached-routers files. These steps save
      lots of memory.
    - Stop requiring clients to have well-formed certificates, and stop
      checking nicknames in certificates. (Clients have certificates so
      that they can look like Tor servers, but in the future we might want
      to allow them to look like regular TLS clients instead. Nicknames
      in certificates serve no purpose other than making our protocol
      easier to recognize on the wire.) Implements proposal 106.

  o Improvements on DNS support:
    - Add "eventdns" asynchronous dns library originally based on code
      from Adam Langley. Now we can discard the old rickety dnsworker
      concept, and support a wider variety of DNS functions. Allows
      multithreaded builds on NetBSD and OpenBSD again.
    - Add server-side support for "reverse" DNS lookups (using PTR
      records so clients can determine the canonical hostname for a given
      IPv4 address). Only supported by servers using eventdns; servers
      now announce in their descriptors if they don't support eventdns.
    - Workaround for name servers (like Earthlink's) that hijack failing
      DNS requests and replace the no-such-server answer with a "helpful"
      redirect to an advertising-driven search portal. Also work around
      DNS hijackers who "helpfully" decline to hijack known-invalid
      RFC2606 addresses. Config option "ServerDNSDetectHijacking 0"
      lets you turn it off.
    - Servers now check for the case when common DNS requests are going to
      wildcarded addresses (i.e. all getting the same answer), and change
      their exit policy to reject *:* if it's happening.
    - When asked to resolve a hostname, don't use non-exit servers unless
      requested to do so. This allows servers with broken DNS to be
      useful to the network.
    - Start passing "ipv4" hints to getaddrinfo(), so servers don't do
      useless IPv6 DNS resolves.
    - Specify and implement client-side SOCKS5 interface for reverse DNS
      lookups (see doc/socks-extensions.txt). Also cache them.
    - When we change nameservers or IP addresses, reset and re-launch
      our tests for DNS hijacking.

  o Improvements on reachability testing:
    - Servers send out a burst of long-range padding cells once they've
      established that they're reachable. Spread them over 4 circuits,
      so hopefully a few will be fast. This exercises bandwidth and
      bootstraps them into the directory more quickly.
    - When we find our DirPort to be reachable, publish a new descriptor
      so we'll tell the world (reported by pnx).
    - Directory authorities now only decide that routers are reachable
      if their identity keys are as expected.
    - Do DirPort reachability tests less often, since a single test
      chews through many circuits before giving up.
    - Avoid some false positives during reachability testing: don't try
      to test via a server that's on the same /24 network as us.
    - Start publishing one minute or so after we find our ORPort
      to be reachable. This will help reduce the number of descriptors
      we have for ourselves floating around, since it's quite likely
      other things (e.g. DirPort) will change during that minute too.
    - Routers no longer try to rebuild long-term connections to directory
      authorities, and directory authorities no longer try to rebuild
      long-term connections to all servers. We still don't hang up
      connections in these two cases though -- we need to look at it
      more carefully to avoid flapping, and we likely need to wait til
      0.1.1.x is obsolete.

  o Improvements on rate limiting:
    - Enable write limiting as well as read limiting. Now we sacrifice
      capacity if we're pushing out lots of directory traffic, rather
      than overrunning the user's intended bandwidth limits.
    - Include TLS overhead when counting bandwidth usage; previously, we
      would count only the bytes sent over TLS, but not the bytes used
      to send them.
    - Servers decline directory requests much more aggressively when
      they're low on bandwidth. Otherwise they end up queueing more and
      more directory responses, which can't be good for latency.
    - But never refuse directory requests from local addresses.
    - Be willing to read or write on local connections (e.g. controller
      connections) even when the global rate limiting buckets are empty.
    - Flush local controller connection buffers periodically as we're
      writing to them, so we avoid queueing 4+ megabytes of data before
      trying to flush.
    - Revise and clean up the torrc.sample that we ship with; add
      a section for BandwidthRate and BandwidthBurst.

  o Major features, NT services:
    - Install as NT_AUTHORITY\LocalService rather than as SYSTEM; add a
      command-line flag so that admins can override the default by saying
      "tor --service install --user "SomeUser"". This will not affect
      existing installed services. Also, warn the user that the service
      will look for its configuration file in the service user's
      %appdata% directory. (We can't do the "hardwire the user's appdata
      directory" trick any more, since we may not have read access to that
      directory.)
    - Support running the Tor service with a torrc not in the same
      directory as tor.exe and default to using the torrc located in
      the %appdata%\Tor\ of the user who installed the service. Patch
      from Matt Edman.
    - Add an --ignore-missing-torrc command-line option so that we can
      get the "use sensible defaults if the configuration file doesn't
      exist" behavior even when specifying a torrc location on the
      command line.
    - When stopping an NT service, wait up to 10 sec for it to actually
      stop. (Patch from Matt Edman; resolves bug 295.)

  o Directory authority improvements:
    - Stop letting hibernating or obsolete servers affect uptime and
      bandwidth cutoffs.
    - Stop listing hibernating servers in the v1 directory.
    - Authorities no longer recommend exits as guards if this would shift
      too much load to the exit nodes.
    - Authorities now specify server versions in networkstatus. This adds
      about 2% to the size of compressed networkstatus docs, and allows
      clients to tell which servers support BEGIN_DIR and which don't.
      The implementation is forward-compatible with a proposed future
      protocol version scheme not tied to Tor versions.
    - DirServer configuration lines now have an orport= option so
      clients can open encrypted tunnels to the authorities without
      having downloaded their descriptors yet. Enabled for moria1,
      moria2, tor26, and lefkada now in the default configuration.
    - Add a BadDirectory flag to network status docs so that authorities
      can (eventually) tell clients about caches they believe to be
      broken. Not used yet.
    - Allow authorities to list nodes as bad exits in their
      approved-routers file by fingerprint or by address. If most
      authorities set a BadExit flag for a server, clients don't think
      of it as a general-purpose exit. Clients only consider authorities
      that advertise themselves as listing bad exits.
    - Patch from Steve Hildrey: Generate network status correctly on
      non-versioning dirservers.
    - Have directory authorities allow larger amounts of drift in uptime
      without replacing the server descriptor: previously, a server that
      restarted every 30 minutes could have 48 "interesting" descriptors
      per day.
    - Reserve the nickname "Unnamed" for routers that can't pick
      a hostname: any router can call itself Unnamed; directory
      authorities will never allocate Unnamed to any particular router;
      clients won't believe that any router is the canonical Unnamed.

  o Directory mirrors and clients:
    - Discard any v1 directory info that's over 1 month old (for
      directories) or over 1 week old (for running-routers lists).
    - Clients track responses with status 503 from dirservers. After a
      dirserver has given us a 503, we try not to use it until an hour has
      gone by, or until we have no dirservers that haven't given us a 503.
    - When we get a 503 from a directory, and we're not a server, we no
      longer count the failure against the total number of failures
      allowed for the object we're trying to download.
    - Prepare for servers to publish descriptors less often: never
      discard a descriptor simply for being too old until either it is
      recommended by no authorities, or until we get a better one for
      the same router. Make caches consider retaining old recommended
      routers for even longer.
    - Directory servers now provide 'Pragma: no-cache' and 'Expires'
      headers for content, so that we can work better in the presence of
      caching HTTP proxies.
    - Stop fetching descriptors if you're not a dir mirror and you
      haven't tried to establish any circuits lately. (This currently
      causes some dangerous behavior, because when you start up again
      you'll use your ancient server descriptors.)

  o Major fixes, crashes:
    - Stop crashing when the controller asks us to resetconf more than
      one config option at once. (Vidalia 0.0.11 does this.)
    - Fix a longstanding obscure crash bug that could occur when we run
      out of DNS worker processes, if we're not using eventdns. (Resolves
      bug 390.)
    - Fix an assert that could trigger if a controller quickly set then
      cleared EntryNodes. (Bug found by Udo van den Heuvel.)
    - Avoid crash when telling controller about stream-status and a
      stream is detached.
    - Avoid sending junk to controllers or segfaulting when a controller
      uses EVENT_NEW_DESC with verbose nicknames.
    - Stop triggering asserts if the controller tries to extend hidden
      service circuits (reported by mwenge).
    - If we start a server with ClientOnly 1, then set ClientOnly to 0
      and hup, stop triggering an assert based on an empty onion_key.
    - Mask out all signals in sub-threads; only the libevent signal
      handler should be processing them. This should prevent some crashes
      on some machines using pthreads. (Patch from coderman.)
    - Disable kqueue on OS X 10.3 and earlier, to fix bug 371.

  o Major fixes, anonymity/security:
    - Automatically avoid picking more than one node from the same
      /16 network when constructing a circuit. Add an
      "EnforceDistinctSubnets" option to let people disable it if they
      want to operate private test networks on a single subnet.
    - When generating bandwidth history, round down to the nearest
      1k. When storing accounting data, round up to the nearest 1k.
    - When we're running as a server, remember when we last rotated onion
      keys, so that we will rotate keys once they're a week old even if
      we never stay up for a week ourselves.
    - If a client asked for a server by name, and there's a named server
      in our network-status but we don't have its descriptor yet, we
      could return an unnamed server instead.
    - Reject (most) attempts to use Tor circuits with length one. (If
      many people start using Tor as a one-hop proxy, exit nodes become
      a more attractive target for compromise.)
    - Just because your DirPort is open doesn't mean people should be
      able to remotely teach you about hidden service descriptors. Now
      only accept rendezvous posts if you've got HSAuthoritativeDir set.
    - Fix a potential race condition in the rpm installer. Found by
      Stefan Nordhausen.
    - Do not log IPs with TLS failures for incoming TLS
      connections. (Fixes bug 382.)

  o Major fixes, other:
    - If our system clock jumps back in time, don't publish a negative
      uptime in the descriptor.
    - When we start during an accounting interval before it's time to wake
      up, remember to wake up at the correct time. (May fix bug 342.)
    - Previously, we would cache up to 16 old networkstatus documents
      indefinitely, if they came from nontrusted authorities. Now we
      discard them if they are more than 10 days old.
    - When we have a state file we cannot parse, tell the user and
      move it aside. Now we avoid situations where the user starts
      Tor in 1904, Tor writes a state file with that timestamp in it,
      the user fixes her clock, and Tor refuses to start.
    - Publish a new descriptor after we hup/reload. This is important
      if our config has changed such that we'll want to start advertising
      our DirPort now, etc.
    - If we are using an exit enclave and we can't connect, e.g. because
      its webserver is misconfigured to not listen on localhost, then
      back off and try connecting from somewhere else before we fail.

  o New config options or behaviors:
    - When EntryNodes are configured, rebuild the guard list to contain,
      in order: the EntryNodes that were guards before; the rest of the
      EntryNodes; the nodes that were guards before.
    - Do not warn when individual nodes in the configuration's EntryNodes,
      ExitNodes, etc are down: warn only when all possible nodes
      are down. (Fixes bug 348.)
    - Put a lower-bound on MaxAdvertisedBandwidth.
    - Start using the state file to store bandwidth accounting data:
      the bw_accounting file is now obsolete. We'll keep generating it
      for a while for people who are still using 0.1.2.4-alpha.
    - Try to batch changes to the state file so that we do as few
      disk writes as possible while still storing important things in
      a timely fashion.
    - The state file and the bw_accounting file get saved less often when
      the AvoidDiskWrites config option is set.
    - Make PIDFile work on Windows.
    - Add internal descriptions for a bunch of configuration options:
      accessible via controller interface and in comments in saved
      options files.
    - Reject *:563 (NNTPS) in the default exit policy. We already reject
      NNTP by default, so this seems like a sensible addition.
    - Clients now reject hostnames with invalid characters. This should
      avoid some inadvertent info leaks. Add an option
      AllowNonRFC953Hostnames to disable this behavior, in case somebody
      is running a private network with hosts called @, !, and #.
    - Check for addresses with invalid characters at the exit as well,
      and warn less verbosely when they fail. You can override this by
      setting ServerDNSAllowNonRFC953Addresses to 1.
    - Remove some options that have been deprecated since at least
      0.1.0.x: AccountingMaxKB, LogFile, DebugLogFile, LogLevel, and
      SysLog. Use AccountingMax instead of AccountingMaxKB, and use Log
      to set log options. Mark PathlenCoinWeight as obsolete.
    - Stop accepting certain malformed ports in configured exit policies.
    - When the user uses bad syntax in the Log config line, stop
      suggesting other bad syntax as a replacement.
    - Add new config option "ResolvConf" to let the server operator
      choose an alternate resolve.conf file when using eventdns.
    - If one of our entry guards is on the ExcludeNodes list, or the
      directory authorities don't think it's a good guard, treat it as
      if it were unlisted: stop using it as a guard, and throw it off
      the guards list if it stays that way for a long time.
    - Allow directory authorities to be marked separately as authorities
      for the v1 directory protocol, the v2 directory protocol, and
      as hidden service directories, to make it easier to retire old
      authorities. V1 authorities should set "HSAuthoritativeDir 1"
      to continue being hidden service authorities too.
    - Remove 8888 as a LongLivedPort, and add 6697 (IRCS).
    - Make TrackExitHosts case-insensitive, and fix the behavior of
      ".suffix" TrackExitHosts items to avoid matching in the middle of
      an address.
    - New DirPort behavior: if you have your dirport set, you download
      descriptors aggressively like a directory mirror, whether or not
      your ORPort is set.

  o Docs:
    - Create a new file ReleaseNotes which was the old ChangeLog. The
      new ChangeLog file now includes the notes for all development
      versions too.
    - Add a new address-spec.txt document to describe our special-case
      addresses: .exit, .onion, and .noconnnect.
    - Fork the v1 directory protocol into its own spec document,
      and mark dir-spec.txt as the currently correct (v2) spec.

  o Packaging, porting, and contrib
    - "tor --verify-config" now exits with -1(255) or 0 depending on
      whether the config options are bad or good.
    - The Debian package now uses --verify-config when (re)starting,
      to distinguish configuration errors from other errors.
    - Adapt a patch from goodell to let the contrib/exitlist script
      take arguments rather than require direct editing.
    - Prevent the contrib/exitlist script from printing the same
      result more than once.
    - Add support to tor-resolve tool for reverse lookups and SOCKS5.
    - In the hidden service example in torrc.sample, stop recommending
      esoteric and discouraged hidden service options.
    - Patch from Michael Mohr to contrib/cross.sh, so it checks more
      values before failing, and always enables eventdns.
    - Try to detect Windows correctly when cross-compiling.
    - Libevent-1.2 exports, but does not define in its headers, strlcpy.
      Try to fix this in configure.in by checking for most functions
      before we check for libevent.
    - Update RPMs to require libevent 1.2.
    - Experimentally re-enable kqueue on OSX when using libevent 1.1b
      or later. Log when we are doing this, so we can diagnose it when
      it fails. (Also, recommend libevent 1.1b for kqueue and
      win32 methods; deprecate libevent 1.0b harder; make libevent
      recommendation system saner.)
    - Build with recent (1.3+) libevents on platforms that do not
      define the nonstandard types "u_int8_t" and friends.
    - Remove architecture from OS X builds. The official builds are
      now universal binaries.
    - Run correctly on OS X platforms with case-sensitive filesystems.
    - Correctly set maximum connection limit on Cygwin. (This time
      for sure!)
    - Start compiling on MinGW on Windows (patches from Mike Chiussi
      and many others).
    - Start compiling on MSVC6 on Windows (patches from Frediano Ziglio).
    - Finally fix the openssl warnings from newer gccs that believe that
      ignoring a return value is okay, but casting a return value and
      then ignoring it is a sign of madness.
    - On architectures where sizeof(int)>4, still clamp declarable
      bandwidth to INT32_MAX.

  o Minor features, controller:
    - Warn the user when an application uses the obsolete binary v0
      control protocol. We're planning to remove support for it during
      the next development series, so it's good to give people some
      advance warning.
    - Add STREAM_BW events to report per-entry-stream bandwidth
      use. (Patch from Robert Hogan.)
    - Rate-limit SIGNEWNYM signals in response to controllers that
      impolitely generate them for every single stream. (Patch from
      mwenge; closes bug 394.)
    - Add a REMAP status to stream events to note that a stream's
      address has changed because of a cached address or a MapAddress
      directive.
    - Make REMAP stream events have a SOURCE (cache or exit), and
      make them generated in every case where we get a successful
      connected or resolved cell.
    - Track reasons for OR connection failure; make these reasons
      available via the controller interface. (Patch from Mike Perry.)
    - Add a SOCKS_BAD_HOSTNAME client status event so controllers
      can learn when clients are sending malformed hostnames to Tor.
    - Specify and implement some of the controller status events.
    - Have GETINFO dir/status/* work on hosts with DirPort disabled.
    - Reimplement GETINFO so that info/names stays in sync with the
      actual keys.
    - Implement "GETINFO fingerprint".
    - Implement "SETEVENTS GUARD" so controllers can get updates on
      entry guard status as it changes.
    - Make all connections to addresses of the form ".noconnect"
      immediately get closed. This lets application/controller combos
      successfully test whether they're talking to the same Tor by
      watching for STREAM events.
    - Add a REASON field to CIRC events; for backward compatibility, this
      field is sent only to controllers that have enabled the extended
      event format. Also, add additional reason codes to explain why
      a given circuit has been destroyed or truncated. (Patches from
      Mike Perry)
    - Add a REMOTE_REASON field to extended CIRC events to tell the
      controller why a remote OR told us to close a circuit.
    - Stream events also now have REASON and REMOTE_REASON fields,
      working much like those for circuit events.
    - There's now a GETINFO ns/... field so that controllers can ask Tor
      about the current status of a router.
    - A new event type "NS" to inform a controller when our opinion of
      a router's status has changed.
    - Add a GETINFO events/names and GETINFO features/names so controllers
      can tell which events and features are supported.
    - A new CLEARDNSCACHE signal to allow controllers to clear the
      client-side DNS cache without expiring circuits.
    - Fix CIRC controller events so that controllers can learn the
      identity digests of non-Named servers used in circuit paths.
    - Let controllers ask for more useful identifiers for servers. Instead
      of learning identity digests for un-Named servers and nicknames
      for Named servers, the new identifiers include digest, nickname,
      and indication of Named status. Off by default; see control-spec.txt
      for more information.
    - Add a "getinfo address" controller command so it can display Tor's
      best guess to the user.
    - New controller event to alert the controller when our server
      descriptor has changed.
    - Give more meaningful errors on controller authentication failure.
    - Export the default exit policy via the control port, so controllers
      don't need to guess what it is / will be later.

  o Minor bugfixes, controller:
    - When creating a circuit via the controller, send a 'launched'
      event when we're done, so we follow the spec better.
    - Correct the control spec to match how the code actually responds
      to 'getinfo addr-mappings/*'. Reported by daejees.
    - The control spec described a GUARDS event, but the code
      implemented a GUARD event. Standardize on GUARD, but let people
      ask for GUARDS too. Reported by daejees.
    - Give the controller END_STREAM_REASON_DESTROY events _before_ we
      clear the corresponding on_circuit variable, and remember later
      that we don't need to send a redundant CLOSED event. (Resolves part
      3 of bug 367.)
    - Report events where a resolve succeeded or where we got a socks
      protocol error correctly, rather than calling both of them
      "INTERNAL".
    - Change reported stream target addresses to IP consistently when
      we finally get the IP from an exit node.
    - Send log messages to the controller even if they happen to be very
      long.
    - Flush ERR-level controller status events just like we currently
      flush ERR-level log events, so that a Tor shutdown doesn't prevent
      the controller from learning about current events.
    - Report the circuit number correctly in STREAM CLOSED events. Bug
      reported by Mike Perry.
    - Do not report bizarre values for results of accounting GETINFOs
      when the last second's write or read exceeds the allotted bandwidth.
    - Report "unrecognized key" rather than an empty string when the
      controller tries to fetch a networkstatus that doesn't exist.
    - When the controller does a "GETINFO network-status", tell it
      about even those routers whose descriptors are very old, and use
      long nicknames where appropriate.
    - Fix handling of verbose nicknames with ORCONN controller events:
      make them show up exactly when requested, rather than exactly when
      not requested.
    - Controller signals now work on non-Unix platforms that don't define
      SIGUSR1 and SIGUSR2 the way we expect.
    - Respond to SIGNAL command before we execute the signal, in case
      the signal shuts us down. Suggested by Karsten Loesing.
    - Handle reporting OR_CONN_EVENT_NEW events to the controller.

  o Minor features, code performance:
    - Major performance improvement on inserting descriptors: change
      algorithm from O(n^2) to O(n).
    - Do not rotate onion key immediately after setting it for the first
      time.
    - Call router_have_min_dir_info half as often. (This is showing up in
      some profiles, but not others.)
    - When using GCC, make log_debug never get called at all, and its
      arguments never get evaluated, when no debug logs are configured.
      (This is showing up in some profiles, but not others.)
    - Statistics dumped by -USR2 now include a breakdown of public key
      operations, for profiling.
    - Make the common memory allocation path faster on machines where
      malloc(0) returns a pointer.
    - Split circuit_t into origin_circuit_t and or_circuit_t, and
      split connection_t into edge, or, dir, control, and base structs.
      These will save quite a bit of memory on busy servers, and they'll
      also help us track down bugs in the code and bugs in the spec.
    - Use OpenSSL's AES implementation on platforms where it's faster.
      This could save us as much as 10% CPU usage.

  o Minor features, descriptors and descriptor handling:
    - Avoid duplicate entries on MyFamily line in server descriptor.
    - When Tor receives a router descriptor that it asked for, but
      no longer wants (because it has received fresh networkstatuses
      in the meantime), do not warn the user. Cache the descriptor if
      we're a cache; drop it if we aren't.
    - Servers no longer ever list themselves in their "family" line,
      even if configured to do so. This makes it easier to configure
      family lists conveniently.

  o Minor fixes, confusing/misleading log messages:
    - Display correct results when reporting which versions are
      recommended, and how recommended they are. (Resolves bug 383.)
    - Inform the server operator when we decide not to advertise a
      DirPort due to AccountingMax enabled or a low BandwidthRate.
    - Only include function names in log messages for info/debug messages.
      For notice/warn/err, the content of the message should be clear on
      its own, and printing the function name only confuses users.
    - Remove even more protocol-related warnings from Tor server logs,
      such as bad TLS handshakes and malformed begin cells.
    - Fix bug 314: Tor clients issued "unsafe socks" warnings even
      when the IP address is mapped through MapAddress to a hostname.
    - Fix misleading log messages: an entry guard that is "unlisted",
      as well as not known to be "down" (because we've never heard
      of it), is not therefore "up".

  o Minor fixes, old/obsolete behavior:
    - Start assuming we can use a create_fast cell if we don't know
      what version a router is running.
    - We no longer look for identity and onion keys in "identity.key" and
      "onion.key" -- these were replaced by secret_id_key and
      secret_onion_key in 0.0.8pre1.
    - We no longer require unrecognized directory entries to be
      preceded by "opt".
    - Drop compatibility with obsolete Tors that permit create cells
      to have the wrong circ_id_type.
    - Remove code to special-case "-cvs" ending, since it has not
      actually mattered since 0.0.9.
    - Don't re-write the fingerprint file every restart, unless it has
      changed.

  o Minor fixes, misc client-side behavior:
    - Always remove expired routers and networkstatus docs before checking
      whether we have enough information to build circuits. (Fixes
      bug 373.)
    - When computing clock skew from directory HTTP headers, consider what
      time it was when we finished asking for the directory, not what
      time it is now.
    - Make our socks5 handling more robust to broken socks clients:
      throw out everything waiting on the buffer in between socks
      handshake phases, since they can't possibly (so the theory
      goes) have predicted what we plan to respond to them.
    - Expire socks connections if they spend too long waiting for the
      handshake to finish. Previously we would let them sit around for
      days, if the connecting application didn't close them either.
    - And if the socks handshake hasn't started, don't send a
      "DNS resolve socks failed" handshake reply; just close it.
    - If the user asks to use invalid exit nodes, be willing to use
      unstable ones.
    - Track unreachable entry guards correctly: don't conflate
      'unreachable by us right now' with 'listed as down by the directory
      authorities'. With the old code, if a guard was unreachable by us
      but listed as running, it would clog our guard list forever.
    - Behave correctly in case we ever have a network with more than
      2GB/s total advertised capacity.
    - Claim a commonname of Tor, rather than TOR, in TLS handshakes.
    - Fix a memory leak when we ask for "all" networkstatuses and we
      get one we don't recognize.


Changes in version 0.1.1.26 - 2006-12-14
  o Security bugfixes:
    - Stop sending the HttpProxyAuthenticator string to directory
      servers when directory connections are tunnelled through Tor.
    - Clients no longer store bandwidth history in the state file.
    - Do not log introduction points for hidden services if SafeLogging
      is set.

  o Minor bugfixes:
    - Fix an assert failure when a directory authority sets
      AuthDirRejectUnlisted and then receives a descriptor from an
      unlisted router (reported by seeess).


Changes in version 0.1.1.25 - 2006-11-04
  o Major bugfixes:
    - When a client asks us to resolve (rather than connect to)
      an address, and we have a cached answer, give them the cached
      answer. Previously, we would give them no answer at all.
    - We were building exactly the wrong circuits when we predict
      hidden service requirements, meaning Tor would have to build all
      its circuits on demand.
    - If none of our live entry guards have a high uptime, but we
      require a guard with a high uptime, try adding a new guard before
      we give up on the requirement. This patch should make long-lived
      connections more stable on average.
    - When testing reachability of our DirPort, don't launch new
      tests when there's already one in progress -- unreachable
      servers were stacking up dozens of testing streams.

  o Security bugfixes:
    - When the user sends a NEWNYM signal, clear the client-side DNS
      cache too. Otherwise we continue to act on previous information.

  o Minor bugfixes:
    - Avoid a memory corruption bug when creating a hash table for
      the first time.
    - Avoid possibility of controller-triggered crash when misusing
      certain commands from a v0 controller on platforms that do not
      handle printf("%s",NULL) gracefully.
    - Avoid infinite loop on unexpected controller input.
    - Don't log spurious warnings when we see a circuit close reason we
      don't recognize; it's probably just from a newer version of Tor.
    - Add Vidalia to the OS X uninstaller script, so when we uninstall
      Tor/Privoxy we also uninstall Vidalia.


Changes in version 0.1.1.24 - 2006-09-29
  o Major bugfixes:
    - Allow really slow clients to not hang up five minutes into their
      directory downloads (suggested by Adam J. Richter).
    - Fix major performance regression from 0.1.0.x: instead of checking
      whether we have enough directory information every time we want to
      do something, only check when the directory information has changed.
      This should improve client CPU usage by 25-50%.
    - Don't crash if, after a server has been running for a while,
      it can't resolve its hostname.
    - When a client asks us to resolve (not connect to) an address,
      and we have a cached answer, give them the cached answer.
      Previously, we would give them no answer at all.

  o Minor bugfixes:
    - Allow Tor to start when RunAsDaemon is set but no logs are set.
    - Don't crash when the controller receives a third argument to an
      "extendcircuit" request.
    - Controller protocol fixes: fix encoding in "getinfo addr-mappings"
      response; fix error code when "getinfo dir/status/" fails.
    - Fix configure.in to not produce broken configure files with
      more recent versions of autoconf. Thanks to Clint for his auto*
      voodoo.
    - Fix security bug on NetBSD that could allow someone to force
      uninitialized RAM to be sent to a server's DNS resolver. This
      only affects NetBSD and other platforms that do not bounds-check
      tolower().
    - Warn user when using libevent 1.1a or earlier with win32 or kqueue
      methods: these are known to be buggy.
    - If we're a directory mirror and we ask for "all" network status
      documents, we would discard status documents from authorities
      we don't recognize.


Changes in version 0.1.1.23 - 2006-07-30
  o Major bugfixes:
    - Fast Tor servers, especially exit nodes, were triggering asserts
      due to a bug in handling the list of pending DNS resolves. Some
      bugs still remain here; we're hunting them.
    - Entry guards could crash clients by sending unexpected input.
    - More fixes on reachability testing: if you find yourself reachable,
      then don't ever make any client requests (so you stop predicting
      circuits), then hup or have your clock jump, then later your IP
      changes, you won't think circuits are working, so you won't try to
      test reachability, so you won't publish.

  o Minor bugfixes:
    - Avoid a crash if the controller does a resetconf firewallports
      and then a setconf fascistfirewall=1.
    - Avoid an integer underflow when the dir authority decides whether
      a router is stable: we might wrongly label it stable, and compute
      a slightly wrong median stability, when a descriptor is published
      later than now.
    - Fix a place where we might trigger an assert if we can't build our
      own server descriptor yet.


Changes in version 0.1.1.22 - 2006-07-05
  o Major bugfixes:
    - Fix a big bug that was causing servers to not find themselves
      reachable if they changed IP addresses. Since only 0.1.1.22+
      servers can do reachability testing correctly, now we automatically
      make sure to test via one of these.
    - Fix to allow clients and mirrors to learn directory info from
      descriptor downloads that get cut off partway through.
    - Directory authorities had a bug in deciding if a newly published
      descriptor was novel enough to make everybody want a copy -- a few
      servers seem to be publishing new descriptors many times a minute.
  o Minor bugfixes:
    - Fix a rare bug that was causing some servers to complain about
      "closing wedged cpuworkers" and skip some circuit create requests.
    - Make the Exit flag in directory status documents actually work.


Changes in version 0.1.1.21 - 2006-06-10
  o Crash and assert fixes from 0.1.1.20:
    - Fix a rare crash on Tor servers that have enabled hibernation.
    - Fix a seg fault on startup for Tor networks that use only one
      directory authority.
    - Fix an assert from a race condition that occurs on Tor servers
      while exiting, where various threads are trying to log that they're
      exiting, and delete the logs, at the same time.
    - Make our unit tests pass again on certain obscure platforms.

  o Other fixes:
    - Add support for building SUSE RPM packages.
    - Speed up initial bootstrapping for clients: if we are making our
      first ever connection to any entry guard, then don't mark it down
      right after that.
    - When only one Tor server in the network is labelled as a guard,
      and we've already picked him, we would cycle endlessly picking him
      again, being unhappy about it, etc. Now we specifically exclude
      current guards when picking a new guard.
    - Servers send create cells more reliably after the TLS connection
      is established: we were sometimes forgetting to send half of them
      when we had more than one pending.
    - If we get a create cell that asks us to extend somewhere, but the
      Tor server there doesn't match the expected digest, we now send
      a destroy cell back, rather than silently doing nothing.
    - Make options->RedirectExit work again.
    - Make cookie authentication for the controller work again.
    - Stop being picky about unusual characters in the arguments to
      mapaddress. It's none of our business.
    - Add a new config option "TestVia" that lets you specify preferred
      middle hops to use for test circuits. Perhaps this will let me
      debug the reachability problems better.

  o Log / documentation fixes:
    - If we're a server and some peer has a broken TLS certificate, don't
      log about it unless ProtocolWarnings is set, i.e., we want to hear
      about protocol violations by others.
    - Fix spelling of VirtualAddrNetwork in man page.
    - Add a better explanation at the top of the autogenerated torrc file
      about what happened to our old torrc.


Changes in version 0.1.1.20 - 2006-05-23
  o Crash and assert fixes from 0.1.0.17:
    - Fix assert bug in close_logs() on exit: when we close and delete
      logs, remove them all from the global "logfiles" list.
    - Fix an assert error when we're out of space in the connection_list
      and we try to post a hidden service descriptor (reported by Peter
      Palfrader).
    - Fix a rare assert error when we've tried all intro points for
      a hidden service and we try fetching the service descriptor again:
      "Assertion conn->state != AP_CONN_STATE_RENDDESC_WAIT failed".
    - Setconf SocksListenAddress kills Tor if it fails to bind. Now back
      out and refuse the setconf if it would fail.
    - If you specify a relative torrc path and you set RunAsDaemon in
      your torrc, then it chdir()'s to the new directory. If you then
      HUP, it tries to load the new torrc location, fails, and exits.
      The fix: no longer allow a relative path to torrc when using -f.
    - Check for integer overflows in more places, when adding elements
      to smartlists. This could possibly prevent a buffer overflow
      on malicious huge inputs.

  o Security fixes, major:
    - When we're printing strings from the network, don't try to print
      non-printable characters. Now we're safer against shell escape
      sequence exploits, and also against attacks to fool users into
      misreading their logs.
    - Implement entry guards: automatically choose a handful of entry
      nodes and stick with them for all circuits. Only pick new guards
      when the ones you have are unsuitable, and if the old guards
      become suitable again, switch back. This will increase security
      dramatically against certain end-point attacks. The EntryNodes
      config option now provides some hints about which entry guards you
      want to use most; and StrictEntryNodes means to only use those.
      Fixes CVE-2006-0414.
    - Implement exit enclaves: if we know an IP address for the
      destination, and there's a running Tor server at that address
      which allows exit to the destination, then extend the circuit to
      that exit first. This provides end-to-end encryption and end-to-end
      authentication. Also, if the user wants a .exit address or enclave,
      use 4 hops rather than 3, and cannibalize a general circ for it
      if you can.
    - Obey our firewall options more faithfully:
      . If we can't get to a dirserver directly, try going via Tor.
      . Don't ever try to connect (as a client) to a place our
        firewall options forbid.
      . If we specify a proxy and also firewall options, obey the
        firewall options even when we're using the proxy: some proxies
        can only proxy to certain destinations.
    - Make clients regenerate their keys when their IP address changes.
    - For the OS X package's modified privoxy config file, comment
      out the "logfile" line so we don't log everything passed
      through privoxy.
    - Our TLS handshakes were generating a single public/private
      keypair for the TLS context, rather than making a new one for
      each new connection. Oops. (But we were still rotating them
      periodically, so it's not so bad.)
    - When we were cannibalizing a circuit with a particular exit
      node in mind, we weren't checking to see if that exit node was
      already present earlier in the circuit. Now we are.
    - Require server descriptors to list IPv4 addresses -- hostnames
      are no longer allowed. This also fixes potential vulnerabilities
      to servers providing hostnames as their address and then
      preferentially resolving them so they can partition users.
    - Our logic to decide if the OR we connected to was the right guy
      was brittle and maybe open to a mitm for invalid routers.

  o Security fixes, minor:
    - Adjust tor-spec.txt to parameterize cell and key lengths. Now
      Ian Goldberg can prove things about our handshake protocol more
      easily.
    - Make directory authorities generate a separate "guard" flag to
      mean "would make a good entry guard". Clients now honor the
      is_guard flag rather than looking at is_fast or is_stable.
    - Try to list MyFamily elements by key, not by nickname, and warn
      if we've not heard of a server.
    - Start using RAND_bytes rather than RAND_pseudo_bytes from
      OpenSSL. Also, reseed our entropy every hour, not just at
      startup. And add entropy in 512-bit chunks, not 160-bit chunks.
    - Refuse server descriptors where the fingerprint line doesn't match
      the included identity key. Tor doesn't care, but other apps (and
      humans) might actually be trusting the fingerprint line.
    - We used to kill the circuit when we receive a relay command we
      don't recognize. Now we just drop that cell.
    - Fix a bug found by Lasse Overlier: when we were making internal
      circuits (intended to be cannibalized later for rendezvous and
      introduction circuits), we were picking them so that they had
      useful exit nodes. There was no need for this, and it actually
      aids some statistical attacks.
    - Start treating internal circuits and exit circuits separately.
      It's important to keep them separate because internal circuits
      have their last hops picked like middle hops, rather than like
      exit hops. So exiting on them will break the user's expectations.
    - Fix a possible way to DoS dirservers.
    - When the client asked for a rendezvous port that the hidden
      service didn't want to provide, we were sending an IP address
      back along with the end cell. Fortunately, it was zero. But stop
      that anyway.

  o Packaging improvements:
    - Implement --with-libevent-dir option to ./configure. Improve
      search techniques to find libevent, and use those for openssl too.
    - Fix a couple of bugs in OpenSSL detection. Deal better when
      there are multiple SSLs installed with different versions.
    - Avoid warnings about machine/limits.h on Debian GNU/kFreeBSD.
    - On non-gcc compilers (e.g. Solaris's cc), use "-g -O" instead of
      "-Wall -g -O2".
    - Make unit tests (and other invocations that aren't the real Tor)
      run without launching listeners, creating subdirectories, and so on.
    - The OS X installer was adding a symlink for tor_resolve but
      the binary was called tor-resolve (reported by Thomas Hardly).
    - Now we can target arch and OS in rpm builds (contributed by
      Phobos). Also make the resulting dist-rpm filename match the
      target arch.
    - Apply Matt Ghali's --with-syslog-facility patch to ./configure
      if you log to syslog and want something other than LOG_DAEMON.
    - Fix the torify (tsocks) config file to not use Tor for localhost
      connections.
    - Start shipping socks-extensions.txt, tor-doc-unix.html,
      tor-doc-server.html, and stylesheet.css in the tarball.
    - Stop shipping tor-doc.html, INSTALL, and README in the tarball.
      They are useless now.
    - Add Peter Palfrader's contributed check-tor script. It lets you
      easily check whether a given server (referenced by nickname)
      is reachable by you.
    - Add BSD-style contributed startup script "rc.subr" from Peter
      Thoenen.

  o Directory improvements -- new directory protocol:
    - See tor/doc/dir-spec.txt for all the juicy details. Key points:
    - Authorities and caches publish individual descriptors (by
      digest, by fingerprint, by "all", and by "tell me yours").
    - Clients don't download or use the old directory anymore. Now they
      download network-statuses from the directory authorities, and
      fetch individual server descriptors as needed from mirrors.
    - Clients don't download descriptors of non-running servers.
    - Download descriptors by digest, not by fingerprint. Caches try to
      download all listed digests from authorities; clients try to
      download "best" digests from caches. This avoids partitioning
      and isolating attacks better.
    - Only upload a new server descriptor when options change, 18
      hours have passed, uptime is reset, or bandwidth changes a lot.
    - Directory authorities silently throw away new descriptors that
      haven't changed much if the timestamps are similar. We do this to
      tolerate older Tor servers that upload a new descriptor every 15
      minutes. (It seemed like a good idea at the time.)
    - Clients choose directory servers from the network status lists,
      not from their internal list of router descriptors. Now they can
      go to caches directly rather than needing to go to authorities
      to bootstrap the first set of descriptors.
    - When picking a random directory, prefer non-authorities if any
      are known.
    - Add a new flag to network-status indicating whether the server
      can answer v2 directory requests too.
    - Directory mirrors now cache up to 16 unrecognized network-status
      docs, so new directory authorities will be cached too.
    - Stop parsing, storing, or using running-routers output (but
      mirrors still cache and serve it).
    - Clients consider a threshold of "versioning" directory authorities
      before deciding whether to warn the user that he's obsolete.
    - Authorities publish separate sorted lists of recommended versions
      for clients and for servers.
    - Change DirServers config line to note which dirs are v1 authorities.
    - Put nicknames on the DirServer line, so we can refer to them
      without requiring all our users to memorize their IP addresses.
    - Remove option when getting directory cache to see whether they
      support running-routers; they all do now. Replace it with one
      to see whether caches support v2 stuff.
    - Stop listing down or invalid nodes in the v1 directory. This
      reduces its bulk by about 1/3, and reduces load on mirrors.
    - Mirrors no longer cache the v1 directory as often.
    - If we as a directory mirror don't know of any v1 directory
      authorities, then don't try to cache any v1 directories.

  o Other directory improvements:
    - Add lefkada.eecs.harvard.edu and tor.dizum.com as fourth and
      fifth authoritative directory servers.
    - Directory authorities no longer require an open connection from
      a server to consider him "reachable". We need this change because
      when we add new directory authorities, old servers won't know not
      to hang up on them.
    - Dir authorities now do their own external reachability testing
      of each server, and only list as running the ones they found to
      be reachable. We also send back warnings to the server's logs if
      it uploads a descriptor that we already believe is unreachable.
    - Spread the directory authorities' reachability testing over the
      entire testing interval, so we don't try to do 500 TLS's at once
      every 20 minutes.
    - Make the "stable" router flag in network-status be the median of
      the uptimes of running valid servers, and make clients pay
      attention to the network-status flags. Thus the cutoff adapts
      to the stability of the network as a whole, making IRC, IM, etc
      connections more reliable.
    - Make the v2 dir's "Fast" flag based on relative capacity, just
      like "Stable" is based on median uptime. Name everything in the
      top 7/8 Fast, and only the top 1/2 gets to be a Guard.
    - Retry directory requests if we fail to get an answer we like
      from a given dirserver (we were retrying before, but only if
      we fail to connect).
    - Return a robots.txt on our dirport to discourage google indexing.

  o Controller protocol improvements:
    - Revised controller protocol (version 1) that uses ascii rather
      than binary: tor/doc/control-spec.txt. Add supporting libraries
      in python and java and c# so you can use the controller from your
      applications without caring how our protocol works.
    - Allow the DEBUG controller event to work again. Mark certain log
      entries as "don't tell this to controllers", so we avoid cycles.
    - New controller function "getinfo accounting", to ask how
      many bytes we've used in this time period.
    - Add a "resetconf" command so you can set config options like
      AllowUnverifiedNodes and LongLivedPorts to "". Also, if you give
      a config option in the torrc with no value, then it clears it
      entirely (rather than setting it to its default).
    - Add a "getinfo config-file" to tell us where torrc is. Also
      expose guard nodes, config options/names.
    - Add a "quit" command (when when using the controller manually).
    - Add a new signal "newnym" to "change pseudonyms" -- that is, to
      stop using any currently-dirty circuits for new streams, so we
      don't link new actions to old actions. This also occurs on HUP
      or "signal reload".
    - If we would close a stream early (e.g. it asks for a .exit that
      we know would refuse it) but the LeaveStreamsUnattached config
      option is set by the controller, then don't close it.
    - Add a new controller event type "authdir_newdescs" that allows
      controllers to get all server descriptors that were uploaded to
      a router in its role as directory authority.
    - New controller option "getinfo desc/all-recent" to fetch the
      latest server descriptor for every router that Tor knows about.
    - Fix the controller's "attachstream 0" command to treat conn like
      it just connected, doing address remapping, handling .exit and
      .onion idioms, and so on. Now we're more uniform in making sure
      that the controller hears about new and closing connections.
    - Permit transitioning from ORPort==0 to ORPort!=0, and back, from
      the controller. Also, rotate dns and cpu workers if the controller
      changes options that will affect them; and initialize the dns
      worker cache tree whether or not we start out as a server.
    - Add a new circuit purpose 'controller' to let the controller ask
      for a circuit that Tor won't try to use. Extend the "extendcircuit"
      controller command to let you specify the purpose if you're starting
      a new circuit.  Add a new "setcircuitpurpose" controller command to
      let you change a circuit's purpose after it's been created.
    - Let the controller ask for "getinfo dir/server/foo" so it can ask
      directly rather than connecting to the dir port. "getinfo
      dir/status/foo" also works, but currently only if your DirPort
      is enabled.
    - Let the controller tell us about certain router descriptors
      that it doesn't want Tor to use in circuits. Implement
      "setrouterpurpose" and modify "+postdescriptor" to do this.
    - If the controller's *setconf commands fail, collect an error
      message in a string and hand it back to the controller -- don't
      just tell them to go read their logs.

  o Scalability, resource management, and performance:
    - Fix a major load balance bug: we were round-robin reading in 16 KB
      chunks, and servers with bandwidthrate of 20 KB, while downloading
      a 600 KB directory, would starve their other connections. Now we
      try to be a bit more fair.
    - Be more conservative about whether to advertise our DirPort.
      The main change is to not advertise if we're running at capacity
      and either a) we could hibernate ever or b) our capacity is low
      and we're using a default DirPort.
    - We weren't cannibalizing circuits correctly for
      CIRCUIT_PURPOSE_C_ESTABLISH_REND and
      CIRCUIT_PURPOSE_S_ESTABLISH_INTRO, so we were being forced to
      build those from scratch. This should make hidden services faster.
    - Predict required circuits better, with an eye toward making hidden
      services faster on the service end.
    - Compress exit policies even more: look for duplicate lines and
      remove them.
    - Generate 18.0.0.0/8 address policy format in descs when we can;
      warn when the mask is not reducible to a bit-prefix.
    - There used to be two ways to specify your listening ports in a
      server descriptor: on the "router" line and with a separate "ports"
      line. Remove support for the "ports" line.
    - Reduce memory requirements in our structs by changing the order
      of fields. Replace balanced trees with hash tables. Inline
      bottleneck smartlist functions. Add a "Map from digest to void*"
      abstraction so we can do less hex encoding/decoding, and use it
      in router_get_by_digest(). Many other CPU and memory improvements.
    - Allow tor_gzip_uncompress to extract as much as possible from
      truncated compressed data. Try to extract as many
      descriptors as possible from truncated http responses (when
      purpose is DIR_PURPOSE_FETCH_ROUTERDESC).
    - Make circ->onionskin a pointer, not a static array. moria2 was using
      125000 circuit_t's after it had been up for a few weeks, which
      translates to 20+ megs of wasted space.
    - The private half of our EDH handshake keys are now chosen out
      of 320 bits, not 1024 bits. (Suggested by Ian Goldberg.)
    - Stop doing the complex voodoo overkill checking for insecure
      Diffie-Hellman keys. Just check if it's in [2,p-2] and be happy.
    - Do round-robin writes for TLS of at most 16 kB per write. This
      might be more fair on loaded Tor servers.
    - Do not use unaligned memory access on alpha, mips, or mipsel.
      It *works*, but is very slow, so we treat them as if it doesn't.

  o Other bugfixes and improvements:
    - Start storing useful information to $DATADIR/state, so we can
      remember things across invocations of Tor. Retain unrecognized
      lines so we can be forward-compatible, and write a TorVersion line
      so we can be backward-compatible.
    - If ORPort is set, Address is not explicitly set, and our hostname
      resolves to a private IP address, try to use an interface address
      if it has a public address. Now Windows machines that think of
      themselves as localhost can guess their address.
    - Regenerate our local descriptor if it's dirty and we try to use
      it locally (e.g. if it changes during reachability detection).
      This was causing some Tor servers to keep publishing the same
      initial descriptor forever.
    - Tor servers with dynamic IP addresses were needing to wait 18
      hours before they could start doing reachability testing using
      the new IP address and ports. This is because they were using
      the internal descriptor to learn what to test, yet they were only
      rebuilding the descriptor once they decided they were reachable.
    - It turns out we couldn't bootstrap a network since we added
      reachability detection in 0.1.0.1-rc. Good thing the Tor network
      has never gone down. Add an AssumeReachable config option to let
      servers and authorities bootstrap. When we're trying to build a
      high-uptime or high-bandwidth circuit but there aren't enough
      suitable servers, try being less picky rather than simply failing.
    - Newly bootstrapped Tor networks couldn't establish hidden service
      circuits until they had nodes with high uptime. Be more tolerant.
    - Really busy servers were keeping enough circuits open on stable
      connections that they were wrapping around the circuit_id
      space. (It's only two bytes.) This exposed a bug where we would
      feel free to reuse a circuit_id even if it still exists but has
      been marked for close. Try to fix this bug. Some bug remains.
    - When we fail to bind or listen on an incoming or outgoing
      socket, we now close it before refusing, rather than just
      leaking it. (Thanks to Peter Palfrader for finding.)
    - Fix a file descriptor leak in start_daemon().
    - On Windows, you can't always reopen a port right after you've
      closed it. So change retry_listeners() to only close and re-open
      ports that have changed.
    - Workaround a problem with some http proxies that refuse GET
      requests that specify "Content-Length: 0". Reported by Adrian.
    - Recover better from TCP connections to Tor servers that are
      broken but don't tell you (it happens!); and rotate TLS
      connections once a week.
    - Fix a scary-looking but apparently harmless bug where circuits
      would sometimes start out in state CIRCUIT_STATE_OR_WAIT at
      servers, and never switch to state CIRCUIT_STATE_OPEN.
    - Check for even more Windows version flags when writing the platform
      string in server descriptors, and note any we don't recognize.
    - Add reasons to DESTROY and RELAY_TRUNCATED cells, so clients can
      get a better idea of why their circuits failed. Not used yet.
    - Add TTLs to RESOLVED, CONNECTED, and END_REASON_EXITPOLICY cells.
      We don't use them yet, but maybe one day our DNS resolver will be
      able to discover them.
    - Let people type "tor --install" as well as "tor -install" when they
      want to make it an NT service.
    - Looks like we were never delivering deflated (i.e. compressed)
      running-routers lists, even when asked. Oops.
    - We were leaking some memory every time the client changed IPs.
    - Clean up more of the OpenSSL memory when exiting, so we can detect
      memory leaks better.
    - Never call free() on tor_malloc()d memory. This will help us
      use dmalloc to detect memory leaks.
    - Some Tor servers process billions of cells per day. These
      statistics are now uint64_t's.
    - Check [X-]Forwarded-For headers in HTTP requests when generating
      log messages. This lets people run dirservers (and caches) behind
      Apache but still know which IP addresses are causing warnings.
    - Fix minor integer overflow in calculating when we expect to use up
      our bandwidth allocation before hibernating.
    - Lower the minimum required number of file descriptors to 1000,
      so we can have some overhead for Valgrind on Linux, where the
      default ulimit -n is 1024.
    - Stop writing the "router.desc" file, ever. Nothing uses it anymore,
      and its existence is confusing some users.

  o Config option fixes:
    - Add a new config option ExitPolicyRejectPrivate which defaults
      to on. Now all exit policies will begin with rejecting private
      addresses, unless the server operator explicitly turns it off.
    - Bump the default bandwidthrate to 3 MB, and burst to 6 MB.
    - Add new ReachableORAddresses and ReachableDirAddresses options
      that understand address policies. FascistFirewall is now a synonym
      for "ReachableORAddresses *:443", "ReachableDirAddresses *:80".
    - Start calling it FooListenAddress rather than FooBindAddress,
      since few of our users know what it means to bind an address
      or port.
    - If the user gave Tor an odd number of command-line arguments,
      we were silently ignoring the last one. Now we complain and fail.
      This wins the oldest-bug prize -- this bug has been present since
      November 2002, as released in Tor 0.0.0.
    - If you write "HiddenServicePort 6667 127.0.0.1 6668" in your
      torrc rather than "HiddenServicePort 6667 127.0.0.1:6668",
      it would silently ignore the 6668.
    - If we get a linelist or linelist_s config option from the torrc,
      e.g. ExitPolicy, and it has no value, warn and skip rather than
      silently resetting it to its default.
    - Setconf was appending items to linelists, not clearing them.
    - Add MyFamily to torrc.sample in the server section, so operators
      will be more likely to learn that it exists.
    - Make ContactInfo mandatory for authoritative directory servers.
    - MaxConn has been obsolete for a while now. Document the ConnLimit
      config option, which is a *minimum* number of file descriptors
      that must be available else Tor refuses to start.
    - Get rid of IgnoreVersion undocumented config option, and make us
      only warn, never exit, when we're running an obsolete version.
    - Make MonthlyAccountingStart config option truly obsolete now.
    - Correct the man page entry on TrackHostExitsExpire.
    - Let directory authorities start even if they don't specify an
      Address config option.
    - Change "AllowUnverifiedNodes" to "AllowInvalidNodes", to
      reflect the updated flags in our v2 dir protocol.

  o Config option features:
    - Add a new config option FastFirstHopPK (on by default) so clients
      do a trivial crypto handshake for their first hop, since TLS has
      already taken care of confidentiality and authentication.
    - Let the user set ControlListenAddress in the torrc. This can be
      dangerous, but there are some cases (like a secured LAN) where it
      makes sense.
    - New config options to help controllers: FetchServerDescriptors
      and FetchHidServDescriptors for whether to fetch server
      info and hidserv info or let the controller do it, and
      PublishServerDescriptor and PublishHidServDescriptors.
    - Also let the controller set the __AllDirActionsPrivate config
      option if you want all directory fetches/publishes to happen via
      Tor (it assumes your controller bootstraps your circuits).
    - Add "HardwareAccel" config option: support for crypto hardware
      accelerators via OpenSSL. Off by default, until we find somebody
      smart who can test it for us. (It appears to produce seg faults
      in at least some cases.)
    - New config option "AuthDirRejectUnlisted" for directory authorities
      as a panic button: if we get flooded with unusable servers we can
      revert to only listing servers in the approved-routers file.
    - Directory authorities can now reject/invalidate by key and IP,
      with the config options "AuthDirInvalid" and "AuthDirReject", or
      by marking a fingerprint as "!reject" or "!invalid" (as its
      nickname) in the approved-routers file. This is useful since
      currently we automatically list servers as running and usable
      even if we know they're jerks.
    - Add a new config option TestSocks so people can see whether their
      applications are using socks4, socks4a, socks5-with-ip, or
      socks5-with-fqdn. This way they don't have to keep mucking
      with tcpdump and wondering if something got cached somewhere.
    - Add "private:*" as an alias in configuration for policies. Now
      you can simplify your exit policy rather than needing to list
      every single internal or nonroutable network space.
    - Accept "private:*" in routerdesc exit policies; not generated yet
      because older Tors do not understand it.
    - Add configuration option "V1AuthoritativeDirectory 1" which
      moria1, moria2, and tor26 have set.
    - Implement an option, VirtualAddrMask, to set which addresses
      get handed out in response to mapaddress requests. This works
      around a bug in tsocks where 127.0.0.0/8 is never socksified.
    - Add a new config option FetchUselessDescriptors, off by default,
      for when you plan to run "exitlist" on your client and you want
      to know about even the non-running descriptors.
    - SocksTimeout: How long do we let a socks connection wait
      unattached before we fail it?
    - CircuitBuildTimeout: Cull non-open circuits that were born
      at least this many seconds ago.
    - CircuitIdleTimeout: Cull open clean circuits that were born
      at least this many seconds ago.
    - New config option SafeSocks to reject all application connections
      using unsafe socks protocols. Defaults to off.

  o Improved and clearer log messages:
    - Reduce clutter in server logs. We're going to try to make
      them actually usable now. New config option ProtocolWarnings that
      lets you hear about how _other Tors_ are breaking the protocol. Off
      by default.
    - Divide log messages into logging domains. Once we put some sort
      of interface on this, it will let people looking at more verbose
      log levels specify the topics they want to hear more about.
    - Log server fingerprint on startup, so new server operators don't
      have to go hunting around their filesystem for it.
    - Provide dire warnings to any users who set DirServer manually;
      move it out of torrc.sample and into torrc.complete.
    - Make the log message less scary when all the dirservers are
      temporarily unreachable.
    - When tor_socketpair() fails in Windows, give a reasonable
      Windows-style errno back.
    - Improve tor_gettimeofday() granularity on windows.
    - We were printing the number of idle dns workers incorrectly when
      culling them.
    - Handle duplicate lines in approved-routers files without warning.
    - We were whining about using socks4 or socks5-with-local-lookup
      even when it's an IP address in the "virtual" range we designed
      exactly for this case.
    - Check for named servers when looking them up by nickname;
      warn when we're calling a non-named server by its nickname;
      don't warn twice about the same name.
    - Downgrade the dirserver log messages when whining about
      unreachability.
    - Correct "your server is reachable" log entries to indicate that
      it was self-testing that told us so.
    - If we're trying to be a Tor server and running Windows 95/98/ME
      as a server, explain that we'll likely crash.
    - Provide a more useful warn message when our onion queue gets full:
      the CPU is too slow or the exit policy is too liberal.
    - Don't warn when we receive a 503 from a dirserver/cache -- this
      will pave the way for them being able to refuse if they're busy.
    - When we fail to bind a listener, try to provide a more useful
      log message: e.g., "Is Tor already running?"
    - Only start testing reachability once we've established a
      circuit. This will make startup on dir authorities less noisy.
    - Don't try to upload hidden service descriptors until we have
      established a circuit.
    - Tor didn't warn when it failed to open a log file.
    - Warn when listening on a public address for socks. We suspect a
      lot of people are setting themselves up as open socks proxies,
      and they have no idea that jerks on the Internet are using them,
      since they simply proxy the traffic into the Tor network.
    - Give a useful message when people run Tor as the wrong user,
      rather than telling them to start chowning random directories.
    - Fix a harmless bug that was causing Tor servers to log
      "Got an end because of misc error, but we're not an AP. Closing."
    - Fix wrong log message when you add a "HiddenServiceNodes" config
      line without any HiddenServiceDir line (reported by Chris Thomas).
    - Directory authorities now stop whining so loudly about bad
      descriptors that they fetch from other dirservers. So when there's
      a log complaint, it's for sure from a freshly uploaded descriptor.
    - When logging via syslog, include the pid whenever we provide
      a log entry. Suggested by Todd Fries.
    - When we're shutting down and we do something like try to post a
      server descriptor or rendezvous descriptor, don't complain that
      we seem to be unreachable. Of course we are, we're shutting down.
    - Change log line for unreachability to explicitly suggest /etc/hosts
      as the culprit. Also make it clearer what IP address and ports we're
      testing for reachability.
    - Put quotes around user-supplied strings when logging so users are
      more likely to realize if they add bad characters (like quotes)
      to the torrc.
    - NT service patch from Matt Edman to improve error messages on Win32.


Changes in version 0.1.0.17 - 2006-02-17
  o Crash bugfixes on 0.1.0.x:
    - When servers with a non-zero DirPort came out of hibernation,
      sometimes they would trigger an assert.

  o Other important bugfixes:
    - On platforms that don't have getrlimit (like Windows), we were
      artificially constraining ourselves to a max of 1024
      connections. Now just assume that we can handle as many as 15000
      connections. Hopefully this won't cause other problems.

  o Backported features:
    - When we're a server, a client asks for an old-style directory,
      and our write bucket is empty, don't give it to him. This way
      small servers can continue to serve the directory *sometimes*,
      without getting overloaded.
    - Whenever you get a 503 in response to a directory fetch, try
      once more. This will become important once servers start sending
      503's whenever they feel busy.
    - Fetch a new directory every 120 minutes, not every 40 minutes.
      Now that we have hundreds of thousands of users running the old
      directory algorithm, it's starting to hurt a lot.
    - Bump up the period for forcing a hidden service descriptor upload
      from 20 minutes to 1 hour.


Changes in version 0.1.0.16 - 2006-01-02
  o Crash bugfixes on 0.1.0.x:
    - On Windows, build with a libevent patch from "I-M Weasel" to avoid
      corrupting the heap, losing FDs, or crashing when we need to resize
      the fd_sets. (This affects the Win32 binaries, not Tor's sources.)
    - It turns out sparc64 platforms crash on unaligned memory access
      too -- so detect and avoid this.
    - Handle truncated compressed data correctly (by detecting it and
      giving an error).
    - Fix possible-but-unlikely free(NULL) in control.c.
    - When we were closing connections, there was a rare case that
      stomped on memory, triggering seg faults and asserts.
    - Avoid potential infinite recursion when building a descriptor. (We
      don't know that it ever happened, but better to fix it anyway.)
    - We were neglecting to unlink marked circuits from soon-to-close OR
      connections, which caused some rare scribbling on freed memory.
    - Fix a memory stomping race bug when closing the joining point of two
      rendezvous circuits.
    - Fix an assert in time parsing found by Steven Murdoch.

  o Other bugfixes on 0.1.0.x:
    - When we're doing reachability testing, provide more useful log
      messages so the operator knows what to expect.
    - Do not check whether DirPort is reachable when we are suppressing
      advertising it because of hibernation.
    - When building with -static or on Solaris, we sometimes needed -ldl.
    - One of the dirservers (tor26) changed its IP address.
    - When we're deciding whether a stream has enough circuits around
      that can handle it, count the freshly dirty ones and not the ones
      that are so dirty they won't be able to handle it.
    - When we're expiring old circuits, we had a logic error that caused
      us to close new rendezvous circuits rather than old ones.
    - Give a more helpful log message when you try to change ORPort via
      the controller: you should upgrade Tor if you want that to work.
    - We were failing to parse Tor versions that start with "Tor ".
    - Tolerate faulty streams better: when a stream fails for reason
      exitpolicy, stop assuming that the router is lying about his exit
      policy. When a stream fails for reason misc, allow it to retry just
      as if it was resolvefailed. When a stream has failed three times,
      reset its failure count so we can try again and get all three tries.


Changes in version 0.1.0.15 - 2005-09-23
  o Bugfixes on 0.1.0.x:
    - Reject ports 465 and 587 (spam targets) in default exit policy.
    - Don't crash when we don't have any spare file descriptors and we
      try to spawn a dns or cpu worker.
    - Get rid of IgnoreVersion undocumented config option, and make us
      only warn, never exit, when we're running an obsolete version.
    - Don't try to print a null string when your server finds itself to
      be unreachable and the Address config option is empty.
    - Make the numbers in read-history and write-history into uint64s,
      so they don't overflow and publish negatives in the descriptor.
    - Fix a minor memory leak in smartlist_string_remove().
    - We were only allowing ourselves to upload a server descriptor at
      most every 20 minutes, even if it changed earlier than that.
    - Clean up log entries that pointed to old URLs.


Changes in version 0.1.0.14 - 2005-08-08
  o Bugfixes on 0.1.0.x:
      - Fix the other half of the bug with crypto handshakes
        (CVE-2005-2643).
      - Fix an assert trigger if you send a 'signal term' via the
        controller when it's listening for 'event info' messages.


Changes in version 0.1.0.13 - 2005-08-04
  o Bugfixes on 0.1.0.x:
    - Fix a critical bug in the security of our crypto handshakes.
    - Fix a size_t underflow in smartlist_join_strings2() that made
      it do bad things when you hand it an empty smartlist.
    - Fix Windows installer to ship Tor license (thanks to Aphex for
      pointing out this oversight) and put a link to the doc directory
      in the start menu.
    - Explicitly set no-unaligned-access for sparc: it turns out the
      new gcc's let you compile broken code, but that doesn't make it
      not-broken.


Changes in version 0.1.0.12 - 2005-07-18
  o New directory servers:
      - tor26 has changed IP address.

  o Bugfixes on 0.1.0.x:
    - Fix a possible double-free in tor_gzip_uncompress().
    - When --disable-threads is set, do not search for or link against
      pthreads libraries.
    - Don't trigger an assert if an authoritative directory server
      claims its dirport is 0.
    - Fix bug with removing Tor as an NT service: some people were
      getting "The service did not return an error." Thanks to Matt
      Edman for the fix.


Changes in version 0.1.0.11 - 2005-06-30
  o Bugfixes on 0.1.0.x:
    - Fix major security bug: servers were disregarding their
      exit policies if clients behaved unexpectedly.
    - Make OS X init script check for missing argument, so we don't
      confuse users who invoke it incorrectly.
    - Fix a seg fault in "tor --hash-password foo".
    - The MAPADDRESS control command was broken.


Changes in version 0.1.0.10 - 2005-06-14
  o Fixes on Win32:
    - Make NT services work and start on startup on Win32 (based on
      patch by Matt Edman). See the FAQ entry for details.
    - Make 'platform' string in descriptor more accurate for Win32
      servers, so it's not just "unknown platform".
    - REUSEADDR on normal platforms means you can rebind to the port
      right after somebody else has let it go. But REUSEADDR on Win32
      means you can bind to the port _even when somebody else already
      has it bound_! So, don't do that on Win32.
    - Clean up the log messages when starting on Win32 with no config
      file.
    - Allow seeding the RNG on Win32 even when you're not running as
      Administrator. If seeding the RNG on Win32 fails, quit.

  o Assert / crash bugs:
    - Refuse relay cells that claim to have a length larger than the
      maximum allowed. This prevents a potential attack that could read
      arbitrary memory (e.g. keys) from an exit server's process
      (CVE-2005-2050).
    - If unofficial Tor clients connect and send weird TLS certs, our
      Tor server triggers an assert. Stop asserting, and start handling
      TLS errors better in other situations too.
    - Fix a race condition that can trigger an assert when we have a
      pending create cell and an OR connection attempt fails.

  o Resource leaks:
    - Use pthreads for worker processes rather than forking. This was
      forced because when we forked, we ended up wasting a lot of
      duplicate ram over time.
      - Also switch to foo_r versions of some library calls to allow
        reentry and threadsafeness.
      - Implement --disable-threads configure option. Disable threads on
        netbsd and openbsd by default, because they have no reentrant
        resolver functions (!), and on solaris since it has other
        threading issues.
    - Fix possible bug on threading platforms (e.g. win32) which was
      leaking a file descriptor whenever a cpuworker or dnsworker died.
    - Fix a minor memory leak when somebody establishes an introduction
      point at your Tor server.
    - Fix possible memory leak in tor_lookup_hostname(). (Thanks to
      Adam Langley.)
    - Add ./configure --with-dmalloc option, to track memory leaks.
    - And try to free all memory on closing, so we can detect what
      we're leaking.

  o Protocol correctness:
    - When we've connected to an OR and handshaked but didn't like
      the result, we were closing the conn without sending destroy
      cells back for pending circuits. Now send those destroys.
    - Start sending 'truncated' cells back rather than destroy cells
      if the circuit closes in front of you. This means we won't have
      to abandon partially built circuits.
    - Handle changed router status correctly when dirserver reloads
      fingerprint file. We used to be dropping all unverified descriptors
      right then. The bug was hidden because we would immediately
      fetch a directory from another dirserver, which would include the
      descriptors we just dropped.
    - Revise tor-spec to add more/better stream end reasons.
    - Revise all calls to connection_edge_end to avoid sending 'misc',
      and to take errno into account where possible.
    - Client now retries when streams end early for 'hibernating' or
      'resource limit' reasons, rather than failing them.
    - Try to be more zealous about calling connection_edge_end when
      things go bad with edge conns in connection.c.

  o Robustness improvements:
    - Better handling for heterogeneous / unreliable nodes:
      - Annotate circuits with whether they aim to contain high uptime
        nodes and/or high capacity nodes. When building circuits, choose
        appropriate nodes.
      - This means that every single node in an intro rend circuit,
        not just the last one, will have a minimum uptime.
      - New config option LongLivedPorts to indicate application streams
        that will want high uptime circuits.
      - Servers reset uptime when a dir fetch entirely fails. This
        hopefully reflects stability of the server's network connectivity.
      - If somebody starts his tor server in Jan 2004 and then fixes his
        clock, don't make his published uptime be a year.
      - Reset published uptime when we wake up from hibernation.
    - Introduce a notion of 'internal' circs, which are chosen without
      regard to the exit policy of the last hop. Intro and rendezvous
      circs must be internal circs, to avoid leaking information. Resolve
      and connect streams can use internal circs if they want.
    - New circuit pooling algorithm: keep track of what destination ports
      we've used recently (start out assuming we'll want to use 80), and
      make sure to have enough circs around to satisfy these ports. Also
      make sure to have 2 internal circs around if we've required internal
      circs lately (and with high uptime if we've seen that lately too).
    - Turn addr_policy_compare from a tristate to a quadstate; this should
      help address our "Ah, you allow 1.2.3.4:80. You are a good choice
      for google.com" problem.
    - When a client asks us for a dir mirror and we don't have one,
      launch an attempt to get a fresh one.
    - First cut at support for "create-fast" cells. Clients can use
      these when extending to their first hop, since the TLS already
      provides forward secrecy and authentication. Not enabled on
      clients yet.

  o Reachability testing.
    - Your Tor server will automatically try to see if its ORPort and
      DirPort are reachable from the outside, and it won't upload its
      descriptor until it decides at least ORPort is reachable (when
      DirPort is not yet found reachable, publish it as zero).
    - When building testing circs for ORPort testing, use only
      high-bandwidth nodes, so fewer circuits fail.
    - Notice when our IP changes, and reset stats/uptime/reachability.
    - Authdirservers don't do ORPort reachability detection, since
      they're in clique mode, so it will be rare to find a server not
      already connected to them.
    - Authdirservers now automatically approve nodes running 0.1.0.2-rc
      or later.

  o Dirserver fixes:
    - Now we allow two unverified servers with the same nickname
      but different keys. But if a nickname is verified, only that
      nickname+key are allowed.
    - If you're an authdirserver connecting to an address:port,
      and it's not the OR you were expecting, forget about that
      descriptor. If he *was* the one you were expecting, then forget
      about all other descriptors for that address:port.
    - Allow servers to publish descriptors from 12 hours in the future.
      Corollary: only whine about clock skew from the dirserver if
      he's a trusted dirserver (since now even verified servers could
      have quite wrong clocks).
    - Require servers that use the default dirservers to have public IP
      addresses. We have too many servers that are configured with private
      IPs and their admins never notice the log entries complaining that
      their descriptors are being rejected.

  o Efficiency improvements:
    - Use libevent. Now we can use faster async cores (like epoll, kpoll,
      and /dev/poll), and hopefully work better on Windows too.
      - Apple's OS X 10.4.0 ships with a broken kqueue API, and using
        kqueue on 10.3.9 causes kernel panics. Don't use kqueue on OS X.
      - Find libevent even if it's hiding in /usr/local/ and your
        CFLAGS and LDFLAGS don't tell you to look there.
      - Be able to link with libevent as a shared library (the default
        after 1.0d), even if it's hiding in /usr/local/lib and even
        if you haven't added /usr/local/lib to your /etc/ld.so.conf,
        assuming you're running gcc. Otherwise fail and give a useful
        error message.
    - Switch to a new buffer management algorithm, which tries to avoid
      reallocing and copying quite as much. In first tests it looks like
      it uses *more* memory on average, but less cpu.
    - Switch our internal buffers implementation to use a ring buffer,
      to hopefully improve performance for fast servers a lot.
    - Reenable the part of the code that tries to flush as soon as an
      OR outbuf has a full TLS record available. Perhaps this will make
      OR outbufs not grow as huge except in rare cases, thus saving lots
      of CPU time plus memory.
    - Improve performance for dirservers: stop re-parsing the whole
      directory every time you regenerate it.
    - Keep a big splay tree of (circid,orconn)->circuit mappings to make
      it much faster to look up a circuit for each relay cell.
    - Remove most calls to assert_all_pending_dns_resolves_ok(),
      since they're eating our cpu on exit nodes.
    - Stop wasting time doing a case insensitive comparison for every
      dns name every time we do any lookup. Canonicalize the names to
      lowercase when you first see them.

  o Hidden services:
    - Handle unavailable hidden services better. Handle slow or busy
      hidden services better.
    - Cannibalize GENERAL circs to be C_REND, C_INTRO, S_INTRO, and S_REND
      circ as necessary, if there are any completed ones lying around
      when we try to launch one.
    - Make hidden services try to establish a rendezvous for 30 seconds
      after fetching the descriptor, rather than for n (where n=3)
      attempts to build a circuit.
    - Adjust maximum skew and age for rendezvous descriptors: let skew
      be 48 hours rather than 90 minutes.
    - Reject malformed .onion addresses rather then passing them on as
      normal web requests.

  o Controller:
    - More Tor controller support. See
      http://tor.eff.org/doc/control-spec.txt for all the new features,
      including signals to emulate unix signals from any platform;
      redirectstream; extendcircuit; mapaddress; getinfo; postdescriptor;
      closestream; closecircuit; etc.
    - Encode hashed controller passwords in hex instead of base64,
      to make it easier to write controllers.
    - Revise control spec and implementation to allow all log messages to
      be sent to controller with their severities intact (suggested by
      Matt Edman). Disable debug-level logs while delivering a debug-level
      log to the controller, to prevent loop. Update TorControl to handle
      new log event types.

  o New config options/defaults:
    - Begin scrubbing sensitive strings from logs by default. Turn off
      the config option SafeLogging if you need to do debugging.
    - New exit policy: accept most low-numbered ports, rather than
      rejecting most low-numbered ports.
    - Put a note in the torrc about abuse potential with the default
      exit policy.
    - Add support for CONNECTing through https proxies, with "HttpsProxy"
      config option.
    - Add HttpProxyAuthenticator and HttpsProxyAuthenticator support
      based on patch from Adam Langley (basic auth only).
    - Bump the default BandwidthRate from 1 MB to 2 MB, to accommodate
      the fast servers that have been joining lately. (Clients are now
      willing to load balance over up to 2 MB of advertised bandwidth
      capacity too.)
    - New config option MaxAdvertisedBandwidth which lets you advertise
      a low bandwidthrate (to not attract as many circuits) while still
      allowing a higher bandwidthrate in reality.
    - Require BandwidthRate to be at least 20kB/s for servers.
    - Add a NoPublish config option, so you can be a server (e.g. for
      testing running Tor servers in other Tor networks) without
      publishing your descriptor to the primary dirservers.
    - Add a new AddressMap config directive to rewrite incoming socks
      addresses. This lets you, for example, declare an implicit
      required exit node for certain sites.
    - Add a new TrackHostExits config directive to trigger addressmaps
      for certain incoming socks addresses -- for sites that break when
      your exit keeps changing (based on patch from Mike Perry).
    - Split NewCircuitPeriod option into NewCircuitPeriod (30 secs),
      which describes how often we retry making new circuits if current
      ones are dirty, and MaxCircuitDirtiness (10 mins), which describes
      how long we're willing to make use of an already-dirty circuit.
    - Change compiled-in SHUTDOWN_WAIT_LENGTH from a fixed 30 secs to
      a config option "ShutdownWaitLength" (when using kill -INT on
      servers).
    - Fix an edge case in parsing config options: if they say "--"
      on the commandline, it's not a config option (thanks weasel).
    - New config option DirAllowPrivateAddresses for authdirservers.
      Now by default they refuse router descriptors that have non-IP or
      private-IP addresses.
    - Change DirFetchPeriod/StatusFetchPeriod to have a special "Be
      smart" default value: low for servers and high for clients.
    - Some people were putting "Address  " in their torrc, and they had
      a buggy resolver that resolved " " to 0.0.0.0. Oops.
    - If DataDir is ~/.tor, and that expands to /.tor, then default to
      LOCALSTATEDIR/tor instead.
    - Implement --verify-config command-line option to check if your torrc
      is valid without actually launching Tor.

  o Logging improvements:
    - When dirservers refuse a server descriptor, we now log its
      contactinfo, platform, and the poster's IP address.
    - Only warn once per nickname from add_nickname_list_to_smartlist()
      per failure, so an entrynode or exitnode choice that's down won't
      yell so much.
    - When we're connecting to an OR and he's got a different nickname/key
      than we were expecting, only complain loudly if we're an OP or a
      dirserver. Complaining loudly to the OR admins just confuses them.
    - Whine at you if you're a server and you don't set your contactinfo.
    - Warn when exit policy implicitly allows local addresses.
    - Give a better warning when some other server advertises an
      ORPort that is actually an apache running ssl.
    - If we get an incredibly skewed timestamp from a dirserver mirror
      that isn't a verified OR, don't warn -- it's probably him that's
      wrong.
    - When a dirserver causes you to give a warn, mention which dirserver
      it was.
    - Initialize libevent later in the startup process, so the logs are
      already established by the time we start logging libevent warns.
    - Use correct errno on win32 if libevent fails.
    - Check and warn about known-bad/slow libevent versions.
    - Stop warning about sigpipes in the logs. We're going to
      pretend that getting these occassionally is normal and fine.

  o New contrib scripts:
    - New experimental script tor/contrib/exitlist: a simple python
      script to parse directories and find Tor nodes that exit to listed
      addresses/ports.
    - New experimental script tor/contrib/ExerciseServer.py (needs more
      work) that uses the controller interface to build circuits and
      fetch pages over them. This will help us bootstrap servers that
      have lots of capacity but haven't noticed it yet.
    - New experimental script tor/contrib/PathDemo.py (needs more work)
      that uses the controller interface to let you choose whole paths
      via addresses like
      "<hostname>.<path,separated by dots>.<length of path>.path"
    - New contributed script "privoxy-tor-toggle" to toggle whether
      Privoxy uses Tor. Seems to be configured for Debian by default.
    - Have torctl.in/tor.sh.in check for location of su binary (needed
      on FreeBSD)

  o Misc bugfixes:
    - chdir() to your datadirectory at the *end* of the daemonize process,
      not the beginning. This was a problem because the first time you
      run tor, if your datadir isn't there, and you have runasdaemon set
      to 1, it will try to chdir to it before it tries to create it. Oops.
    - Fix several double-mark-for-close bugs, e.g. where we were finding
      a conn for a cell even if that conn is already marked for close.
    - Stop most cases of hanging up on a socks connection without sending
      the socks reject.
    - Fix a bug in the RPM package: set home directory for _tor to
      something more reasonable when first installing.
    - Stop putting nodename in the Platform string in server descriptors.
      It doesn't actually help, and it is confusing/upsetting some people.
    - When using preferred entry or exit nodes, ignore whether the
      circuit wants uptime or capacity. They asked for the nodes, they
      get the nodes.
    - Tie MAX_DIR_SIZE to MAX_BUF_SIZE, so now directory sizes won't get
      artificially capped at 500kB.
    - Cache local dns resolves correctly even when they're .exit
      addresses.
    - If we're hibernating and we get a SIGINT, exit immediately.
    - tor-resolve requests were ignoring .exit if there was a working circuit
      they could use instead.
    - Pay more attention to the ClientOnly config option.
    - Resolve OS X installer bugs: stop claiming to be 0.0.9.2 in certain
      installer screens; and don't put stuff into StartupItems unless
      the user asks you to.

  o Misc features:
    - Rewrite address "serifos.exit" to "externalIP.serifos.exit"
      rather than just rejecting it.
    - If our clock jumps forward by 100 seconds or more, assume something
      has gone wrong with our network and abandon all not-yet-used circs.
    - When an application is using socks5, give him the whole variety of
      potential socks5 responses (connect refused, host unreachable, etc),
      rather than just "success" or "failure".
    - A more sane version numbering system. See
      http://tor.eff.org/cvs/tor/doc/version-spec.txt for details.
    - Change version parsing logic: a version is "obsolete" if it is not
      recommended and (1) there is a newer recommended version in the
      same series, or (2) there are no recommended versions in the same
      series, but there are some recommended versions in a newer series.
      A version is "new" if it is newer than any recommended version in
      the same series.
    - Report HTTP reasons to client when getting a response from directory
      servers -- so you can actually know what went wrong.
    - Reject odd-looking addresses at the client (e.g. addresses that
      contain a colon), rather than having the server drop them because
      they're malformed.
    - Stop publishing socksport in the directory, since it's not
      actually meant to be public. For compatibility, publish a 0 there
      for now.
    - Since we ship our own Privoxy on OS X, tweak it so it doesn't write
      cookies to disk and doesn't log each web request to disk. (Thanks
      to Brett Carrington for pointing this out.)
    - Add OSX uninstall instructions. An actual uninstall script will
      come later.
    - Add "opt hibernating 1" to server descriptor to make it clearer
      whether the server is hibernating.


Changes in version 0.0.9.10 - 2005-06-16
  o Bugfixes on 0.0.9.x (backported from 0.1.0.10):
    - Refuse relay cells that claim to have a length larger than the
      maximum allowed. This prevents a potential attack that could read
      arbitrary memory (e.g. keys) from an exit server's process
      (CVE-2005-2050).


Changes in version 0.0.9.9 - 2005-04-23
  o Bugfixes on 0.0.9.x:
    - If unofficial Tor clients connect and send weird TLS certs, our
      Tor server triggers an assert. This release contains a minimal
      backport from the broader fix that we put into 0.1.0.4-rc.


Changes in version 0.0.9.8 - 2005-04-07
  o Bugfixes on 0.0.9.x:
    - We have a bug that I haven't found yet. Sometimes, very rarely,
      cpuworkers get stuck in the 'busy' state, even though the cpuworker
      thinks of itself as idle. This meant that no new circuits ever got
      established. Here's a workaround to kill any cpuworker that's been
      busy for more than 100 seconds.


Changes in version 0.0.9.7 - 2005-04-01
  o Bugfixes on 0.0.9.x:
    - Fix another race crash bug (thanks to Glenn Fink for reporting).
    - Compare identity to identity, not to nickname, when extending to
      a router not already in the directory. This was preventing us from
      extending to unknown routers. Oops.
    - Make sure to create OS X Tor user in <500 range, so we aren't
      creating actual system users.
    - Note where connection-that-hasn't-sent-end was marked, and fix
      a few really loud instances of this harmless bug (it's fixed more
      in 0.1.0.x).


Changes in version 0.0.9.6 - 2005-03-24
  o Bugfixes on 0.0.9.x (crashes and asserts):
    - Add new end stream reasons to maintainance branch. Fix bug where
      reason (8) could trigger an assert.  Prevent bug from recurring.
    - Apparently win32 stat wants paths to not end with a slash.
    - Fix assert triggers in assert_cpath_layer_ok(), where we were
      blowing away the circuit that conn->cpath_layer points to, then
      checking to see if the circ is well-formed. Backport check to make
      sure we dont use the cpath on a closed connection.
    - Prevent circuit_resume_edge_reading_helper() from trying to package
      inbufs for marked-for-close streams.
    - Don't crash on hup if your options->address has become unresolvable.
    - Some systems (like OS X) sometimes accept() a connection and tell
      you the remote host is 0.0.0.0:0. If this happens, due to some
      other mis-features, we get confused; so refuse the conn for now.

  o Bugfixes on 0.0.9.x (other):
    - Fix harmless but scary "Unrecognized content encoding" warn message.
    - Add new stream error reason: TORPROTOCOL reason means "you are not
      speaking a version of Tor I understand; say bye-bye to your stream."
    - Be willing to cache directories from up to ROUTER_MAX_AGE seconds
      into the future, now that we are more tolerant of skew. This
      resolves a bug where a Tor server would refuse to cache a directory
      because all the directories it gets are too far in the future;
      yet the Tor server never logs any complaints about clock skew.
    - Mac packaging magic: make man pages useable, and do not overwrite
      existing torrc files.
    - Make OS X log happily to /var/log/tor/tor.log


Changes in version 0.0.9.5 - 2005-02-22
  o Bugfixes on 0.0.9.x:
    - Fix an assert race at exit nodes when resolve requests fail.
    - Stop picking unverified dir mirrors--it only leads to misery.
    - Patch from Matt Edman to make NT services work better. Service
      support is still not compiled into the executable by default.
    - Patch from Dmitri Bely so the Tor service runs better under
      the win32 SYSTEM account.
    - Make tor-resolve actually work (?) on Win32.
    - Fix a sign bug when getrlimit claims to have 4+ billion
      file descriptors available.
    - Stop refusing to start when bandwidthburst == bandwidthrate.
    - When create cells have been on the onion queue more than five
      seconds, just send back a destroy and take them off the list.


Changes in version 0.0.9.4 - 2005-02-03
  o Bugfixes on 0.0.9:
    - Fix an assert bug that took down most of our servers: when
      a server claims to have 1 GB of bandwidthburst, don't
      freak out.
    - Don't crash as badly if we have spawned the max allowed number
      of dnsworkers, or we're out of file descriptors.
    - Block more file-sharing ports in the default exit policy.
    - MaxConn is now automatically set to the hard limit of max
      file descriptors we're allowed (ulimit -n), minus a few for
      logs, etc.
    - Give a clearer message when servers need to raise their
      ulimit -n when they start running out of file descriptors.
    - SGI Compatibility patches from Jan Schaumann.
    - Tolerate a corrupt cached directory better.
    - When a dirserver hasn't approved your server, list which one.
    - Go into soft hibernation after 95% of the bandwidth is used,
      not 99%. This is especially important for daily hibernators who
      have a small accounting max. Hopefully it will result in fewer
      cut connections when the hard hibernation starts.
    - Load-balance better when using servers that claim more than
      800kB/s of capacity.
    - Make NT services work (experimental, only used if compiled in).


Changes in version 0.0.9.3 - 2005-01-21
  o Bugfixes on 0.0.9:
    - Backport the cpu use fixes from main branch, so busy servers won't
      need as much processor time.
    - Work better when we go offline and then come back, or when we
      run Tor at boot before the network is up. We do this by
      optimistically trying to fetch a new directory whenever an
      application request comes in and we think we're offline -- the
      human is hopefully a good measure of when the network is back.
    - Backport some minimal hidserv bugfixes: keep rend circuits open as
      long as you keep using them; actually publish hidserv descriptors
      shortly after they change, rather than waiting 20-40 minutes.
    - Enable Mac startup script by default.
    - Fix duplicate dns_cancel_pending_resolve reported by Giorgos Pallas.
    - When you update AllowUnverifiedNodes or FirewallPorts via the
      controller's setconf feature, we were always appending, never
      resetting.
    - When you update HiddenServiceDir via setconf, it was screwing up
      the order of reading the lines, making it fail.
    - Do not rewrite a cached directory back to the cache; otherwise we
      will think it is recent and not fetch a newer one on startup.
    - Workaround for webservers that lie about Content-Encoding: Tor
      now tries to autodetect compressed directories and compression
      itself. This lets us Proxypass dir fetches through apache.


Changes in version 0.0.9.2 - 2005-01-04
  o Bugfixes on 0.0.9 (crashes and asserts):
    - Fix an assert on startup when the disk is full and you're logging
      to a file.
    - If you do socks4 with an IP of 0.0.0.x but *don't* provide a socks4a
      style address, then we'd crash.
    - Fix an assert trigger when the running-routers string we get from
      a dirserver is broken.
    - Make worker threads start and run on win32. Now win32 servers
      may work better.
    - Bandaid (not actually fix, but now it doesn't crash) an assert
      where the dns worker dies mysteriously and the main Tor process
      doesn't remember anything about the address it was resolving.

  o Bugfixes on 0.0.9 (Win32):
    - Workaround for brain-damaged __FILE__ handling on MSVC: keep Nick's
      name out of the warning/assert messages.
    - Fix a superficial "unhandled error on read" bug on win32.
    - The win32 installer no longer requires a click-through for our
      license, since our Free Software license grants rights but does not
      take any away.
    - Win32: When connecting to a dirserver fails, try another one
      immediately. (This was already working for non-win32 Tors.)
    - Stop trying to parse $HOME on win32 when hunting for default
      DataDirectory.
    - Make tor-resolve.c work on win32 by calling network_init().

  o Bugfixes on 0.0.9 (other):
    - Make 0.0.9.x build on Solaris again.
    - Due to a fencepost error, we were blowing away the \n when reporting
      confvalue items in the controller. So asking for multiple config
      values at once couldn't work.
    - When listing circuits that are pending on an opening OR connection,
      if we're an OR we were listing circuits that *end* at us as
      being pending on every listener, dns/cpu worker, etc. Stop that.
    - Dirservers were failing to create 'running-routers' or 'directory'
      strings if we had more than some threshold of routers. Fix them so
      they can handle any number of routers.
    - Fix a superficial "Duplicate mark for close" bug.
    - Stop checking for clock skew for OR connections, even for servers.
    - Fix a fencepost error that was chopping off the last letter of any
      nickname that is the maximum allowed nickname length.
    - Update URLs in log messages so they point to the new website.
    - Fix a potential problem in mangling server private keys while
      writing to disk (not triggered yet, as far as we know).
    - Include the licenses for other free software we include in Tor,
      now that we're shipping binary distributions more regularly.


Changes in version 0.0.9.1 - 2004-12-15
  o Bugfixes on 0.0.9:
    - Make hibernation actually work.
    - Make HashedControlPassword config option work.
    - When we're reporting event circuit status to a controller,
      don't use the stream status code.


Changes in version 0.0.9 - 2004-12-12
  o Bugfixes on 0.0.8.1 (Crashes and asserts):
    - Catch and ignore SIGXFSZ signals when log files exceed 2GB; our
      write() call will fail and we handle it there.
    - When we run out of disk space, or other log writing error, don't
      crash. Just stop logging to that log and continue.
    - Fix isspace() and friends so they still make Solaris happy
      but also so they don't trigger asserts on win32.
    - Fix assert failure on malformed socks4a requests.
    - Fix an assert bug where a hidden service provider would fail if
      the first hop of his rendezvous circuit was down.
    - Better handling of size_t vs int, so we're more robust on 64
      bit platforms.

  o Bugfixes on 0.0.8.1 (Win32):
    - Make windows sockets actually non-blocking (oops), and handle
      win32 socket errors better.
    - Fix parse_iso_time on platforms without strptime (eg win32).
    - win32: when being multithreaded, leave parent fdarray open.
    - Better handling of winsock includes on non-MSV win32 compilers.
    - Change our file IO stuff (especially wrt OpenSSL) so win32 is
      happier.
    - Make unit tests work on win32.

  o Bugfixes on 0.0.8.1 (Path selection and streams):
    - Calculate timeout for waiting for a connected cell from the time
      we sent the begin cell, not from the time the stream started. If
      it took a long time to establish the circuit, we would time out
      right after sending the begin cell.
    - Fix router_compare_addr_to_addr_policy: it was not treating a port
      of * as always matching, so we were picking reject *:* nodes as
      exit nodes too. Oops.
    - When read() failed on a stream, we would close it without sending
      back an end. So 'connection refused' would simply be ignored and
      the user would get no response.
    - Stop a sigpipe: when an 'end' cell races with eof from the app,
      we shouldn't hold-open-until-flush if the eof arrived first.
    - Let resolve conns retry/expire also, rather than sticking around
      forever.
    - Fix more dns related bugs: send back resolve_failed and end cells
      more reliably when the resolve fails, rather than closing the
      circuit and then trying to send the cell. Also attach dummy resolve
      connections to a circuit *before* calling dns_resolve(), to fix
      a bug where cached answers would never be sent in RESOLVED cells.

  o Bugfixes on 0.0.8.1 (Circuits):
    - Finally fix a bug that's been plaguing us for a year:
      With high load, circuit package window was reaching 0. Whenever
      we got a circuit-level sendme, we were reading a lot on each
      socket, but only writing out a bit. So we would eventually reach
      eof. This would be noticed and acted on even when there were still
      bytes sitting in the inbuf.
    - Use identity comparison, not nickname comparison, to choose which
      half of circuit-ID-space each side gets to use. This is needed
      because sometimes we think of a router as a nickname, and sometimes
      as a hex ID, and we can't predict what the other side will do.

  o Bugfixes on 0.0.8.1 (Other):
    - Fix a whole slew of memory leaks.
    - Disallow NDEBUG. We don't ever want anybody to turn off debug.
    - If we are using select, make sure we stay within FD_SETSIZE.
    - When poll() is interrupted, we shouldn't believe the revents values.
    - Add a FAST_SMARTLIST define to optionally inline smartlist_get
      and smartlist_len, which are two major profiling offenders.
    - If do_hup fails, actually notice.
    - Flush the log file descriptor after we print "Tor opening log file",
      so we don't see those messages days later.
    - Hidden service operators now correctly handle version 1 style
      INTRODUCE1 cells (nobody generates them still, so not a critical
      bug).
    - Handle more errnos from accept() without closing the listener.
      Some OpenBSD machines were closing their listeners because
      they ran out of file descriptors.
    - Some people had wrapped their tor client/server in a script
      that would restart it whenever it died. This did not play well
      with our "shut down if your version is obsolete" code. Now people
      don't fetch a new directory if their local cached version is
      recent enough.
    - Make our autogen.sh work on ksh as well as bash.
    - Better torrc example lines for dirbindaddress and orbindaddress.
    - Improved bounds checking on parsed ints (e.g. config options and
      the ones we find in directories.)
    - Stop using separate defaults for no-config-file and
      empty-config-file. Now you have to explicitly turn off SocksPort,
      if you don't want it open.
    - We were starting to daemonize before we opened our logs, so if
      there were any problems opening logs, we would complain to stderr,
      which wouldn't work, and then mysteriously exit.
    - If a verified OR connects to us before he's uploaded his descriptor,
      or we verify him and hup but he still has the original TLS
      connection, then conn->nickname is still set like he's unverified.

  o Code security improvements, inspired by Ilja:
    - tor_snprintf wrapper over snprintf with consistent (though not C99)
      overflow behavior.
    - Replace sprintf with tor_snprintf. (I think they were all safe, but
      hey.)
    - Replace strcpy/strncpy with strlcpy in more places.
    - Avoid strcat; use tor_snprintf or strlcat instead.

  o Features (circuits and streams):
    - New circuit building strategy: keep a list of ports that we've
      used in the past 6 hours, and always try to have 2 circuits open
      or on the way that will handle each such port. Seed us with port
      80 so web users won't complain that Tor is "slow to start up".
    - Make kill -USR1 dump more useful stats about circuits.
    - When warning about retrying or giving up, print the address, so
      the user knows which one it's talking about.
    - If you haven't used a clean circuit in an hour, throw it away,
      just to be on the safe side. (This means after 6 hours a totally
      unused Tor client will have no circuits open.)
    - Support "foo.nickname.exit" addresses, to let Alice request the
      address "foo" as viewed by exit node "nickname". Based on a patch
      from Geoff Goodell.
    - If your requested entry or exit node has advertised bandwidth 0,
      pick it anyway.
    - Be more greedy about filling up relay cells -- we try reading again
      once we've processed the stuff we read, in case enough has arrived
      to fill the last cell completely.
    - Refuse application socks connections to port 0.
    - Use only 0.0.9pre1 and later servers for resolve cells.

  o Features (bandwidth):
    - Hibernation: New config option "AccountingMax" lets you
      set how many bytes per month (in each direction) you want to
      allow your server to consume. Rather than spreading those
      bytes out evenly over the month, we instead hibernate for some
      of the month and pop up at a deterministic time, work until
      the bytes are consumed, then hibernate again. Config option
      "MonthlyAccountingStart" lets you specify which day of the month
      your billing cycle starts on.
    - Implement weekly/monthly/daily accounting: now you specify your
      hibernation properties by
      AccountingMax N bytes|KB|MB|GB|TB
      AccountingStart day|week|month [day] HH:MM
        Defaults to "month 1 0:00".
    - Let bandwidth and interval config options be specified as 5 bytes,
      kb, kilobytes, etc; and as seconds, minutes, hours, days, weeks.

  o Features (directories):
    - New "router-status" line in directory, to better bind each verified
      nickname to its identity key.
    - Clients can ask dirservers for /dir.z to get a compressed version
      of the directory. Only works for servers running 0.0.9, of course.
    - Make clients cache directories and use them to seed their router
      lists at startup. This means clients have a datadir again.
    - Respond to content-encoding headers by trying to uncompress as
      appropriate.
    - Clients and servers now fetch running-routers; cache
      running-routers; compress running-routers; serve compressed
      running-routers.z
    - Make moria2 advertise a dirport of 80, so people behind firewalls
      will be able to get a directory.
    - Http proxy support
      - Dirservers translate requests for http://%s:%d/x to /x
      - You can specify "HttpProxy %s[:%d]" and all dir fetches will
        be routed through this host.
      - Clients ask for /tor/x rather than /x for new enough dirservers.
        This way we can one day coexist peacefully with apache.
      - Clients specify a "Host: %s%d" http header, to be compatible
        with more proxies, and so running squid on an exit node can work.
    - Protect dirservers from overzealous descriptor uploading -- wait
      10 seconds after directory gets dirty, before regenerating.

  o Features (packages and install):
    - Add NSI installer contributed by J Doe.
    - Apply NT service patch from Osamu Fujino. Still needs more work.
    - Commit VC6 and VC7 workspace/project files.
    - Commit a tor.spec for making RPM files, with help from jbash.
    - Add contrib/torctl.in contributed by Glenn Fink.
    - Make expand_filename handle ~ and ~username.
    - Use autoconf to enable largefile support where necessary. Use
      ftello where available, since ftell can fail at 2GB.
    - Ship src/win32/ in the tarball, so people can use it to build.
    - Make old win32 fall back to CWD if SHGetSpecialFolderLocation
      is broken.

  o Features (ui controller):
    - Control interface: a separate program can now talk to your
      client/server over a socket, and get/set config options, receive
      notifications of circuits and streams starting/finishing/dying,
      bandwidth used, etc. The next step is to get some GUIs working.
      Let us know if you want to help out. See doc/control-spec.txt .
    - Ship a contrib/tor-control.py as an example script to interact
      with the control port.
    - "tor --hash-password zzyxz" will output a salted password for
      use in authenticating to the control interface.
    - Implement the control-spec's SAVECONF command, to write your
      configuration to torrc.
    - Get cookie authentication for the controller closer to working.
    - When set_conf changes our server descriptor, upload a new copy.
      But don't upload it too often if there are frequent changes.

  o Features (config and command-line):
    - Deprecate unofficial config option abbreviations, and abbreviations
      not on the command line.
    - Configuration infrastructure support for warning on obsolete
      options.
    - Give a slightly more useful output for "tor -h".
    - Break DirFetchPostPeriod into:
      - DirFetchPeriod for fetching full directory,
      - StatusFetchPeriod for fetching running-routers,
      - DirPostPeriod for posting server descriptor,
      - RendPostPeriod for posting hidden service descriptors.
    - New log format in config:
      "Log minsev[-maxsev] stdout|stderr|syslog" or
      "Log minsev[-maxsev] file /var/foo"
    - DirPolicy config option, to let people reject incoming addresses
      from their dirserver.
    - "tor --list-fingerprint" will list your identity key fingerprint
      and then exit.
    - Make tor --version --version dump the cvs Id of every file.
    - New 'MyFamily nick1,...' config option for a server to
      specify other servers that shouldn't be used in the same circuit
      with it. Only believed if nick1 also specifies us.
    - New 'NodeFamily nick1,nick2,...' config option for a client to
      specify nodes that it doesn't want to use in the same circuit.
    - New 'Redirectexit pattern address:port' config option for a
      server to redirect exit connections, e.g. to a local squid.
    - Add "pass" target for RedirectExit, to make it easier to break
      out of a sequence of RedirectExit rules.
    - Make the dirservers file obsolete.
      - Include a dir-signing-key token in directories to tell the
        parsing entity which key is being used to sign.
      - Remove the built-in bulky default dirservers string.
      - New config option "Dirserver %s:%d [fingerprint]", which can be
        repeated as many times as needed. If no dirservers specified,
        default to moria1,moria2,tor26.
      - Make 'Routerfile' config option obsolete.
    - Discourage people from setting their dirfetchpostperiod more often
      than once per minute.

  o Features (other):
    - kill -USR2 now moves all logs to loglevel debug (kill -HUP to
      get back to normal.)
    - Accept *:706 (silc) in default exit policy.
    - Implement new versioning format for post 0.1.
    - Distinguish between TOR_TLS_CLOSE and TOR_TLS_ERROR, so we can
      log more informatively.
    - Check clock skew for verified servers, but allow unverified
      servers and clients to have any clock skew.
    - Make sure the hidden service descriptors are at a random offset
      from each other, to hinder linkability.
    - Clients now generate a TLS cert too, in preparation for having
      them act more like real nodes.
    - Add a pure-C tor-resolve implementation.
    - Use getrlimit and friends to ensure we can reach MaxConn (currently
      1024) file descriptors.
    - Raise the max dns workers from 50 to 100.


Changes in version 0.0.8.1 - 2004-10-13
  o Bugfixes:
    - Fix a seg fault that can be triggered remotely for Tor
      clients/servers with an open dirport.
    - Fix a rare assert trigger, where routerinfos for entries in
      our cpath would expire while we're building the path.
    - Fix a bug in OutboundBindAddress so it (hopefully) works.
    - Fix a rare seg fault for people running hidden services on
      intermittent connections.
    - Fix a bug in parsing opt keywords with objects.
    - Fix a stale pointer assert bug when a stream detaches and
      reattaches.
    - Fix a string format vulnerability (probably not exploitable)
      in reporting stats locally.
    - Fix an assert trigger: sometimes launching circuits can fail
      immediately, e.g. because too many circuits have failed recently.
    - Fix a compile warning on 64 bit platforms.


Changes in version 0.0.8 - 2004-08-25
  o Bugfixes:
    - Made our unit tests compile again on OpenBSD 3.5, and tor
      itself compile again on OpenBSD on a sparc64.
    - We were neglecting milliseconds when logging on win32, so
      everything appeared to happen at the beginning of each second.
    - Check directory signature _before_ you decide whether you're
      you're running an obsolete version and should exit.
    - Check directory signature _before_ you parse the running-routers
      list to decide who's running.
    - Check return value of fclose while writing to disk, so we don't
      end up with broken files when servers run out of disk space.
    - Port it to SunOS 5.9 / Athena
    - Fix two bugs in saving onion keys to disk when rotating, so
      hopefully we'll get fewer people using old onion keys.
    - Remove our mostly unused -- and broken -- hex_encode()
      function. Use base16_encode() instead. (Thanks to Timo Lindfors
      for pointing out this bug.)
    - Only pick and establish intro points after we've gotten a
      directory.
    - Fix assert triggers: if the other side returns an address 0.0.0.0,
      don't put it into the client dns cache.
    - If a begin failed due to exit policy, but we believe the IP
      address should have been allowed, switch that router to exitpolicy
      reject *:* until we get our next directory.

  o Protocol changes:
    - 'Extend' relay cell payloads now include the digest of the
      intended next hop's identity key. Now we can verify that we're
      extending to the right router, and also extend to routers we
      hadn't heard of before.

  o Features:
    - Tor nodes can now act as relays (with an advertised ORPort)
      without being manually verified by the dirserver operators.
      - Uploaded descriptors of unverified routers are now accepted
        by the dirservers, and included in the directory.
      - Verified routers are listed by nickname in the running-routers
        list; unverified routers are listed as "$<fingerprint>".
      - We now use hash-of-identity-key in most places rather than
        nickname or addr:port, for improved security/flexibility.
      - AllowUnverifiedNodes config option to let circuits choose no-name
        routers in entry,middle,exit,introduction,rendezvous positions.
        Allow middle and rendezvous positions by default.
      - When picking unverified routers, skip those with low uptime and/or
        low bandwidth, depending on what properties you care about.
      - ClientOnly option for nodes that never want to become servers.
    - Directory caching.
      - "AuthoritativeDir 1" option for the official dirservers.
      - Now other nodes (clients and servers) will cache the latest
        directory they've pulled down.
      - They can enable their DirPort to serve it to others.
      - Clients will pull down a directory from any node with an open
        DirPort, and check the signature/timestamp correctly.
      - Authoritative dirservers now fetch directories from other
        authdirservers, to stay better synced.
      - Running-routers list tells who's down also, along with noting
        if they're verified (listed by nickname) or unverified (listed
        by hash-of-key).
      - Allow dirservers to serve running-router list separately.
        This isn't used yet.
      - You can now fetch $DIRURL/running-routers to get just the
        running-routers line, not the whole descriptor list. (But
        clients don't use this yet.)
    - Clients choose nodes proportional to advertised bandwidth.
    - Clients avoid using nodes with low uptime as introduction points.
    - Handle servers with dynamic IP addresses: don't just replace
      options->Address with the resolved one at startup, and
      detect our address right before we make a routerinfo each time.
    - 'FascistFirewall' option to pick dirservers and ORs on specific
      ports; plus 'FirewallPorts' config option to tell FascistFirewall
      which ports are open. (Defaults to 80,443)
    - Try other dirservers immediately if the one you try is down. This
      should tolerate down dirservers better now.
    - ORs connect-on-demand to other ORs
      - If you get an extend cell to an OR you're not connected to,
        connect, handshake, and forward the create cell.
      - The authoritative dirservers stay connected to everybody,
        and everybody stays connected to 0.0.7 servers, but otherwise
        clients/servers expire unused connections after 5 minutes.
    - When servers get a sigint, they delay 30 seconds (refusing new
      connections) then exit. A second sigint causes immediate exit.
    - File and name management:
      - Look for .torrc if no CONFDIR "torrc" is found.
      - If no datadir is defined, then choose, make, and secure ~/.tor
        as datadir.
      - If torrc not found, exitpolicy reject *:*.
      - Expands ~/ in filenames to $HOME/ (but doesn't yet expand ~arma).
      - If no nickname is defined, derive default from hostname.
      - Rename secret key files, e.g. identity.key -> secret_id_key,
        to discourage people from mailing their identity key to tor-ops.
    - Refuse to build a circuit before the directory has arrived --
      it won't work anyway, since you won't know the right onion keys
      to use.
    - Parse tor version numbers so we can do an is-newer-than check
      rather than an is-in-the-list check.
    - New socks command 'resolve', to let us shim gethostbyname()
      locally.
      - A 'tor_resolve' script to access the socks resolve functionality.
      - A new socks-extensions.txt doc file to describe our
        interpretation and extensions to the socks protocols.
    - Add a ContactInfo option, which gets published in descriptor.
    - Write tor version at the top of each log file
    - New docs in the tarball:
      - tor-doc.html.
      - Document that you should proxy your SSL traffic too.
    - Log a warning if the user uses an unsafe socks variant, so people
      are more likely to learn about privoxy or socat.
    - Log a warning if you're running an unverified server, to let you
      know you might want to get it verified.
    - Change the default exit policy to reject the default edonkey,
      kazaa, gnutella ports.
    - Add replace_file() to util.[ch] to handle win32's rename().
    - Publish OR uptime in descriptor (and thus in directory) too.
    - Remember used bandwidth (both in and out), and publish 15-minute
      snapshots for the past day into our descriptor.
    - Be more aggressive about trying to make circuits when the network
      has changed (e.g. when you unsuspend your laptop).
    - Check for time skew on http headers; report date in response to
      "GET /".
    - If the entrynode config line has only one node, don't pick it as
      an exitnode.
    - Add strict{entry|exit}nodes config options. If set to 1, then
      we refuse to build circuits that don't include the specified entry
      or exit nodes.
    - OutboundBindAddress config option, to bind to a specific
      IP address for outgoing connect()s.
    - End truncated log entries (e.g. directories) with "[truncated]".


Changes in version 0.0.7.3 - 2004-08-12
  o Stop dnsworkers from triggering an assert failure when you
    ask them to resolve the host "".


Changes in version 0.0.7.2 - 2004-07-07
  o A better fix for the 0.0.0.0 problem, that will hopefully
    eliminate the remaining related assertion failures.


Changes in version 0.0.7.1 - 2004-07-04
  o When an address resolves to 0.0.0.0, treat it as a failed resolve,
    since internally we use 0.0.0.0 to signify "not yet resolved".


Changes in version 0.0.7 - 2004-06-07
  o Fixes for crashes and other obnoxious bugs:
    - Fix an epipe bug: sometimes when directory connections failed
      to connect, we would give them a chance to flush before closing
      them.
    - When we detached from a circuit because of resolvefailed, we
      would immediately try the same circuit twice more, and then
      give up on the resolve thinking we'd tried three different
      exit nodes.
    - Limit the number of intro circuits we'll attempt to build for a
      hidden service per 15-minute period.
    - Check recommended-software string *early*, before actually parsing
      the directory. Thus we can detect an obsolete version and exit,
      even if the new directory format doesn't parse.
  o Fixes for security bugs:
    - Remember which nodes are dirservers when you startup, and if a
      random OR enables his dirport, don't automatically assume he's
      a trusted dirserver.
  o Other bugfixes:
    - Directory connections were asking the wrong poll socket to
      start writing, and not asking themselves to start writing.
    - When we detached from a circuit because we sent a begin but
      didn't get a connected, we would use it again the first time;
      but after that we would correctly switch to a different one.
    - Stop warning when the first onion decrypt attempt fails; they
      will sometimes legitimately fail now that we rotate keys.
    - Override unaligned-access-ok check when $host_cpu is ia64 or
      arm. Apparently they allow it but the kernel whines.
    - Dirservers try to reconnect periodically too, in case connections
      have failed.
    - Fix some memory leaks in directory servers.
    - Allow backslash in Win32 filenames.
    - Made Tor build complain-free on FreeBSD, hopefully without
      breaking other BSD builds. We'll see.
    - Check directory signatures based on name of signer, not on whom
      we got the directory from. This will let us cache directories more
      easily.
    - Rotate dnsworkers and cpuworkers on SIGHUP, so they get new config
      settings too.
  o Features:
    - Doxygen markup on all functions and global variables.
    - Make directory functions update routerlist, not replace it. So
      now directory disagreements are not so critical a problem.
    - Remove the upper limit on number of descriptors in a dirserver's
      directory (not that we were anywhere close).
    - Allow multiple logfiles at different severity ranges.
    - Allow *BindAddress to specify ":port" rather than setting *Port
      separately. Allow multiple instances of each BindAddress config
      option, so you can bind to multiple interfaces if you want.
    - Allow multiple exit policy lines, which are processed in order.
      Now we don't need that huge line with all the commas in it.
    - Enable accept/reject policies on SOCKS connections, so you can bind
      to 0.0.0.0 but still control who can use your OP.
    - Updated the man page to reflect these features.


Changes in version 0.0.6.2 - 2004-05-16
  o Our integrity-checking digest was checking only the most recent cell,
    not the previous cells like we'd thought.
    Thanks to Stefan Mark for finding the flaw!


Changes in version 0.0.6.1 - 2004-05-06
  o Fix two bugs in our AES counter-mode implementation (this affected
    onion-level stream encryption, but not TLS-level). It turns
    out we were doing something much more akin to a 16-character
    polyalphabetic cipher. Oops.
    Thanks to Stefan Mark for finding the flaw!
  o Retire moria3 as a directory server, and add tor26 as a directory
    server.


Changes in version 0.0.6 - 2004-05-02
  o Features:
    - Hidden services and rendezvous points are implemented. Go to
      http://6sxoyfb3h2nvok2d.onion/ for an index of currently available
      hidden services. (This only works via a socks4a proxy such as
      Privoxy, and currently it's quite slow.)
    - We now rotate link (tls context) keys and onion keys.
    - CREATE cells now include oaep padding, so you can tell
      if you decrypted them correctly.
    - Retry stream correctly when we fail to connect because of
      exit-policy-reject (should try another) or can't-resolve-address.
    - When we hup a dirserver and we've *removed* a server from the
      approved-routers list, now we remove that server from the
      in-memory directories too.
    - Add bandwidthburst to server descriptor.
    - Directories now say which dirserver signed them.
    - Use a tor_assert macro that logs failed assertions too.
    - Since we don't support truncateds much, don't bother sending them;
      just close the circ.
    - Fetch randomness from /dev/urandom better (not via fopen/fread)
    - Better debugging for tls errors
    - Set Content-Type on the directory and hidserv descriptor.
    - Remove IVs from cipher code, since AES-ctr has none.
  o Bugfixes:
    - Fix an assert trigger for exit nodes that's been plaguing us since
      the days of 0.0.2prexx (thanks weasel!)
    - Fix a bug where we were closing tls connections intermittently.
      It turns out openssl keeps its errors around -- so if an error
      happens, and you don't ask about it, and then another openssl
      operation happens and succeeds, and you ask if there was an error,
      it tells you about the first error.
    - Fix a bug that's been lurking since 27 may 03 (!)
      When passing back a destroy cell, we would use the wrong circ id.
    - Don't crash if a conn that sent a begin has suddenly lost its circuit.
    - Some versions of openssl have an SSL_pending function that erroneously
      returns bytes when there is a non-application record pending.
    - Win32 fixes. Tor now compiles on win32 with no warnings/errors.
      o We were using an array of length zero in a few places.
      o Win32's gethostbyname can't resolve an IP to an IP.
      o Win32's close can't close a socket.
      o Handle windows socket errors correctly.
  o Portability:
    - check for <sys/limits.h> so we build on FreeBSD again, and
      <machine/limits.h> for NetBSD.


Changes in version 0.0.5 - 2004-03-30
  o Install torrc as torrc.sample -- we no longer clobber your
    torrc. (Woo!)
  o Fix mangled-state bug in directory fetching (was causing sigpipes).
  o Only build circuits after we've fetched the directory: clients were
    using only the directory servers before they'd fetched a directory.
    This also means longer startup time; so it goes.
  o Fix an assert trigger where an OP would fail to handshake, and we'd
    expect it to have a nickname.
  o Work around a tsocks bug: do a socks reject when AP connection dies
    early, else tsocks goes into an infinite loop.
  o Hold socks connection open until reply is flushed (if possible)
  o Make exit nodes resolve IPs to IPs immediately, rather than asking
    the dns farm to do it.
  o Fix c99 aliasing warnings in rephist.c
  o Don't include server descriptors that are older than 24 hours in the
    directory.
  o Give socks 'reject' replies their whole 15s to attempt to flush,
    rather than seeing the 60s timeout and assuming the flush had failed.
  o Clean automake droppings from the cvs repository
  o Add in a 'notice' log level for things the operator should hear
    but that aren't warnings


Changes in version 0.0.4 - 2004-03-26
  o When connecting to a dirserver or OR and the network is down,
    we would crash.


Changes in version 0.0.3 - 2004-03-26
  o Warn and fail if server chose a nickname with illegal characters
  o Port to Solaris and Sparc:
    - include missing header fcntl.h
    - have autoconf find -lsocket -lnsl automatically
    - deal with hardware word alignment
    - make uname() work (solaris has a different return convention)
    - switch from using signal() to sigaction()
  o Preliminary work on reputation system:
    - Keep statistics on success/fail of connect attempts; they're published
      by kill -USR1 currently.
    - Add a RunTesting option to try to learn link state by creating test
      circuits, even when SocksPort is off.
    - Remove unused open circuits when there are too many.


Changes in version 0.0.2 - 2004-03-19
    - Include strlcpy and strlcat for safer string ops
    - define INADDR_NONE so we compile (but still not run) on solaris


Changes in version 0.0.2pre27 - 2004-03-14
  o Bugfixes:
    - Allow internal tor networks (we were rejecting internal IPs,
      now we allow them if they're set explicitly).
    - And fix a few endian issues.


Changes in version 0.0.2pre26 - 2004-03-14
  o New features:
    - If a stream times out after 15s without a connected cell, don't
      try that circuit again: try a new one.
    - Retry streams at most 4 times. Then give up.
    - When a dirserver gets a descriptor from an unknown router, it
      logs its fingerprint (so the dirserver operator can choose to
      accept it even without mail from the server operator).
    - Inform unapproved servers when we reject their descriptors.
    - Make tor build on Windows again. It works as a client, who knows
      about as a server.
    - Clearer instructions in the torrc for how to set up a server.
    - Be more efficient about reading fd's when our global token bucket
      (used for rate limiting) becomes empty.
  o Bugfixes:
    - Stop asserting that computers always go forward in time. It's
      simply not true.
    - When we sent a cell (e.g. destroy) and then marked an OR connection
      expired, we might close it before finishing a flush if the other
      side isn't reading right then.
    - Don't allow dirservers to start if they haven't defined
      RecommendedVersions
    - We were caching transient dns failures. Oops.
    - Prevent servers from publishing an internal IP as their address.
    - Address a strcat vulnerability in circuit.c


Changes in version 0.0.2pre25 - 2004-03-04
  o New features:
    - Put the OR's IP in its router descriptor, not its fqdn. That way
      we'll stop being stalled by gethostbyname for nodes with flaky dns,
      e.g. poblano.
  o Bugfixes:
    - If the user typed in an address that didn't resolve, the server
      crashed.


Changes in version 0.0.2pre24 - 2004-03-03
  o Bugfixes:
    - Fix an assertion failure in dns.c, where we were trying to dequeue
      a pending dns resolve even if it wasn't pending
    - Fix a spurious socks5 warning about still trying to write after the
      connection is finished.
    - Hold certain marked_for_close connections open until they're finished
      flushing, rather than losing bytes by closing them too early.
    - Correctly report the reason for ending a stream
    - Remove some duplicate calls to connection_mark_for_close
    - Put switch_id and start_daemon earlier in the boot sequence, so it
      will actually try to chdir() to options.DataDirectory
    - Make 'make test' exit(1) if a test fails; fix some unit tests
    - Make tor fail when you use a config option it doesn't know about,
      rather than warn and continue.
    - Make --version work
    - Bugfixes on the rpm spec file and tor.sh, so it's more up to date


Changes in version 0.0.2pre23 - 2004-02-29
  o New features:
    - Print a statement when the first circ is finished, so the user
      knows it's working.
    - If a relay cell is unrecognized at the end of the circuit,
      send back a destroy. (So attacks to mutate cells are more
      clearly thwarted.)
    - New config option 'excludenodes' to avoid certain nodes for circuits.
    - When it daemonizes, it chdir's to the DataDirectory rather than "/",
      so you can collect coredumps there.
 o Bugfixes:
    - Fix a bug in tls flushing where sometimes data got wedged and
      didn't flush until more data got sent. Hopefully this bug was
      a big factor in the random delays we were seeing.
    - Make 'connected' cells include the resolved IP, so the client
      dns cache actually gets populated.
    - Disallow changing from ORPort=0 to ORPort>0 on hup.
    - When we time-out on a stream and detach from the circuit, send an
      end cell down it first.
    - Only warn about an unknown router (in exitnodes, entrynodes,
      excludenodes) after we've fetched a directory.


Changes in version 0.0.2pre22 - 2004-02-26
  o New features:
    - Servers publish less revealing uname information in descriptors.
    - More memory tracking and assertions, to crash more usefully when
      errors happen.
    - If the default torrc isn't there, just use some default defaults.
      Plus provide an internal dirservers file if they don't have one.
    - When the user tries to use Tor as an http proxy, give them an http
      501 failure explaining that we're a socks proxy.
    - Dump a new router.desc on hup, to help confused people who change
      their exit policies and then wonder why router.desc doesn't reflect
      it.
    - Clean up the generic tor.sh init script that we ship with.
  o Bugfixes:
    - If the exit stream is pending on the resolve, and a destroy arrives,
      then the stream wasn't getting removed from the pending list. I
      think this was the one causing recent server crashes.
    - Use a more robust poll on OSX 10.3, since their poll is flaky.
    - When it couldn't resolve any dirservers, it was useless from then on.
      Now it reloads the RouterFile (or default dirservers) if it has no
      dirservers.
    - Move the 'tor' binary back to /usr/local/bin/ -- it turns out
      many users don't even *have* a /usr/local/sbin/.


Changes in version 0.0.2pre21 - 2004-02-18
  o New features:
    - There's a ChangeLog file that actually reflects the changelog.
    - There's a 'torify' wrapper script, with an accompanying
      tor-tsocks.conf, that simplifies the process of using tsocks for
      tor. It even has a man page.
    - The tor binary gets installed to sbin rather than bin now.
    - Retry streams where the connected cell hasn't arrived in 15 seconds
    - Clean up exit policy handling -- get the default out of the torrc,
      so we can update it without forcing each server operator to fix
      his/her torrc.
    - Allow imaps and pop3s in default exit policy
  o Bugfixes:
    - Prevent picking middleman nodes as the last node in the circuit


Changes in version 0.0.2pre20 - 2004-01-30
  o New features:
    - We now have a deb package, and it's in debian unstable. Go to
      it, apt-getters. :)
    - I've split the TotalBandwidth option into BandwidthRate (how many
      bytes per second you want to allow, long-term) and
      BandwidthBurst (how many bytes you will allow at once before the cap
      kicks in).  This better token bucket approach lets you, say, set
      BandwidthRate to 10KB/s and BandwidthBurst to 10MB, allowing good
      performance while not exceeding your monthly bandwidth quota.
    - Push out a tls record's worth of data once you've got it, rather
      than waiting until you've read everything waiting to be read. This
      may improve performance by pipelining better. We'll see.
    - Add an AP_CONN_STATE_CONNECTING state, to allow streams to detach
      from failed circuits (if they haven't been connected yet) and attach
      to new ones.
    - Expire old streams that haven't managed to connect. Some day we'll
      have them reattach to new circuits instead.

  o Bugfixes:
    - Fix several memory leaks that were causing servers to become bloated
      after a while.
    - Fix a few very rare assert triggers. A few more remain.
    - Setuid to User _before_ complaining about running as root.


Changes in version 0.0.2pre19 - 2004-01-07
  o Bugfixes:
    - Fix deadlock condition in dns farm. We were telling a child to die by
      closing the parent's file descriptor to him. But newer children were
      inheriting the open file descriptor from the parent, and since they
      weren't closing it, the socket never closed, so the child never read
      eof, so he never knew to exit. Similarly, dns workers were holding
      open other sockets, leading to all sorts of chaos.
    - New cleaner daemon() code for forking and backgrounding.
    - If you log to a file, it now prints an entry at the top of the
      logfile so you know it's working.
    - The onionskin challenge length was 30 bytes longer than necessary.
    - Started to patch up the spec so it's not quite so out of date.


Changes in version 0.0.2pre18 - 2004-01-02
  o Bugfixes:
    - Fix endian issues with the 'integrity' field in the relay header.
    - Fix a potential bug where connections in state
      AP_CONN_STATE_CIRCUIT_WAIT might unexpectedly ask to write.


Changes in version 0.0.2pre17 - 2003-12-30
  o Bugfixes:
    - Made --debuglogfile (or any second log file, actually) work.
    - Resolved an edge case in get_unique_circ_id_by_conn where a smart
      adversary could force us into an infinite loop.

  o Features:
    - Each onionskin handshake now includes a hash of the computed key,
      to prove the server's identity and help perfect forward secrecy.
    - Changed cell size from 256 to 512 bytes (working toward compatibility
      with MorphMix).
    - Changed cell length to 2 bytes, and moved it to the relay header.
    - Implemented end-to-end integrity checking for the payloads of
      relay cells.
    - Separated streamid from 'recognized' (otherwise circuits will get
      messed up when we try to have streams exit from the middle). We
      use the integrity-checking to confirm that a cell is addressed to
      this hop.
    - Randomize the initial circid and streamid values, so an adversary who
      breaks into a node can't learn how many circuits or streams have
      been made so far.


Changes in version 0.0.2pre16 - 2003-12-14
  o Bugfixes:
    - Fixed a bug that made HUP trigger an assert
    - Fixed a bug where a circuit that immediately failed wasn't being
      counted as a failed circuit in counting retries.

  o Features:
    - Now we close the circuit when we get a truncated cell: otherwise we're
      open to an anonymity attack where a bad node in the path truncates
      the circuit and then we open streams at him.
    - Add port ranges to exit policies
    - Add a conservative default exit policy
    - Warn if you're running tor as root
    - on HUP, retry OR connections and close/rebind listeners
    - options.EntryNodes: try these nodes first when picking the first node
    - options.ExitNodes: if your best choices happen to include any of
      your preferred exit nodes, you choose among just those preferred
      exit nodes.
    - options.ExcludedNodes: nodes that are never picked in path building


Changes in version 0.0.2pre15 - 2003-12-03
  o Robustness and bugfixes:
    - Sometimes clients would cache incorrect DNS resolves, which would
      really screw things up.
    - An OP that goes offline would slowly leak all its sockets and stop
      working.
    - A wide variety of bugfixes in exit node selection, exit policy
      handling, and processing pending streams when a new circuit is
      established.
    - Pick nodes for a path only from those the directory says are up
    - Choose randomly from all running dirservers, not always the first one
    - Increase allowed http header size for directory fetch.
    - Stop writing to stderr (if we're daemonized it will be closed).
    - Enable -g always, so cores will be more useful to me.
    - Switch "-lcrypto -lssl" to "-lssl -lcrypto" for broken distributions.

  o Documentation:
    - Wrote a man page. It lists commonly used options.

  o Configuration:
    - Change default loglevel to warn.
    - Make PidFile default to null rather than littering in your CWD.
    - OnionRouter config option is now obsolete. Instead it just checks
      ORPort>0.
    - Moved to a single unified torrc file for both clients and servers.


Changes in version 0.0.2pre14 - 2003-11-29
  o Robustness and bugfixes:
    - Force the admin to make the DataDirectory himself
      - to get ownership/permissions right
      - so clients no longer make a DataDirectory and then never use it
    - fix bug where a client who was offline for 45 minutes would never
      pull down a directory again
    - fix (or at least hide really well) the dns assert bug that was
      causing server crashes
    - warnings and improved robustness wrt clockskew for certs
    - use the native daemon(3) to daemonize, when available
    - exit if bind() fails
    - exit if neither socksport nor orport is defined
    - include our own tor_timegm (Win32 doesn't have its own)
    - bugfix for win32 with lots of connections
    - fix minor bias in PRNG
    - make dirserver more robust to corrupt cached directory

  o Documentation:
    - Wrote the design document (woo)

  o Circuit building and exit policies:
    - Circuits no longer try to use nodes that the directory has told them
      are down.
    - Exit policies now support bitmasks (18.0.0.0/255.0.0.0) and
      bitcounts (18.0.0.0/8).
    - Make AP connections standby for a circuit if no suitable circuit
      exists, rather than failing
    - Circuits choose exit node based on addr/port, exit policies, and
      which AP connections are standing by
    - Bump min pathlen from 2 to 3
    - Relay end cells have a payload to describe why the stream ended.
    - If the stream failed because of exit policy, try again with a new
      circuit.
    - Clients have a dns cache to remember resolved addresses.
    - Notice more quickly when we have no working circuits

  o Configuration:
    - APPort is now called SocksPort
    - SocksBindAddress, ORBindAddress, DirBindAddress let you configure
      where to bind
    - RecommendedVersions is now a config variable rather than
      hardcoded (for dirservers)
    - Reloads config on HUP
    - Usage info on -h or --help
    - If you set User and Group config vars, it'll setu/gid to them.

Changes in version 0.0.2pre13 - 2003-10-19
  o General stability:
    - SSL_write no longer fails when it returns WANTWRITE and the number
      of bytes in the buf has changed by the next SSL_write call.
    - Fix segfault fetching directory when network is down
    - Fix a variety of minor memory leaks
    - Dirservers reload the fingerprints file on HUP, so I don't have
      to take down the network when I approve a new router
    - Default server config file has explicit Address line to specify fqdn

  o Buffers:
    - Buffers grow and shrink as needed (Cut process size from 20M to 2M)
    - Make listener connections not ever alloc bufs

  o Autoconf improvements:
    - don't clobber an external CFLAGS in ./configure
    - Make install now works
    - create var/lib/tor on make install
    - autocreate a tor.sh initscript to help distribs
    - autocreate the torrc and sample-server-torrc with correct paths

  o Log files and Daemonizing now work:
    - If --DebugLogFile is specified, log to it at -l debug
    - If --LogFile is specified, use it instead of commandline
    - If --RunAsDaemon is set, tor forks and backgrounds on startup