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- //===-- asan_win.cpp ------------------------------------------------------===//
- //
- // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- // See https://llvm.org/LICENSE.txt for license information.
- // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- //
- //===----------------------------------------------------------------------===//
- //
- // This file is a part of AddressSanitizer, an address sanity checker.
- //
- // Windows-specific details.
- //===----------------------------------------------------------------------===//
- #include "sanitizer_common/sanitizer_platform.h"
- #if SANITIZER_WINDOWS
- #define WIN32_LEAN_AND_MEAN
- #include <windows.h>
- #include <stdlib.h>
- #include "asan_interceptors.h"
- #include "asan_internal.h"
- #include "asan_mapping.h"
- #include "asan_report.h"
- #include "asan_stack.h"
- #include "asan_thread.h"
- #include "sanitizer_common/sanitizer_libc.h"
- #include "sanitizer_common/sanitizer_mutex.h"
- #include "sanitizer_common/sanitizer_win.h"
- #include "sanitizer_common/sanitizer_win_defs.h"
- using namespace __asan;
- extern "C" {
- SANITIZER_INTERFACE_ATTRIBUTE
- int __asan_should_detect_stack_use_after_return() {
- __asan_init();
- return __asan_option_detect_stack_use_after_return;
- }
- SANITIZER_INTERFACE_ATTRIBUTE
- uptr __asan_get_shadow_memory_dynamic_address() {
- __asan_init();
- return __asan_shadow_memory_dynamic_address;
- }
- } // extern "C"
- // ---------------------- Windows-specific interceptors ---------------- {{{
- static LPTOP_LEVEL_EXCEPTION_FILTER default_seh_handler;
- static LPTOP_LEVEL_EXCEPTION_FILTER user_seh_handler;
- extern "C" SANITIZER_INTERFACE_ATTRIBUTE
- long __asan_unhandled_exception_filter(EXCEPTION_POINTERS *info) {
- EXCEPTION_RECORD *exception_record = info->ExceptionRecord;
- CONTEXT *context = info->ContextRecord;
- // FIXME: Handle EXCEPTION_STACK_OVERFLOW here.
- SignalContext sig(exception_record, context);
- ReportDeadlySignal(sig);
- UNREACHABLE("returned from reporting deadly signal");
- }
- // Wrapper SEH Handler. If the exception should be handled by asan, we call
- // __asan_unhandled_exception_filter, otherwise, we execute the user provided
- // exception handler or the default.
- static long WINAPI SEHHandler(EXCEPTION_POINTERS *info) {
- DWORD exception_code = info->ExceptionRecord->ExceptionCode;
- if (__sanitizer::IsHandledDeadlyException(exception_code))
- return __asan_unhandled_exception_filter(info);
- if (user_seh_handler)
- return user_seh_handler(info);
- // Bubble out to the default exception filter.
- if (default_seh_handler)
- return default_seh_handler(info);
- return EXCEPTION_CONTINUE_SEARCH;
- }
- INTERCEPTOR_WINAPI(LPTOP_LEVEL_EXCEPTION_FILTER, SetUnhandledExceptionFilter,
- LPTOP_LEVEL_EXCEPTION_FILTER ExceptionFilter) {
- CHECK(REAL(SetUnhandledExceptionFilter));
- if (ExceptionFilter == &SEHHandler)
- return REAL(SetUnhandledExceptionFilter)(ExceptionFilter);
- // We record the user provided exception handler to be called for all the
- // exceptions unhandled by asan.
- Swap(ExceptionFilter, user_seh_handler);
- return ExceptionFilter;
- }
- INTERCEPTOR_WINAPI(void, RtlRaiseException, EXCEPTION_RECORD *ExceptionRecord) {
- CHECK(REAL(RtlRaiseException));
- // This is a noreturn function, unless it's one of the exceptions raised to
- // communicate with the debugger, such as the one from OutputDebugString.
- if (ExceptionRecord->ExceptionCode != DBG_PRINTEXCEPTION_C)
- __asan_handle_no_return();
- REAL(RtlRaiseException)(ExceptionRecord);
- }
- INTERCEPTOR_WINAPI(void, RaiseException, void *a, void *b, void *c, void *d) {
- CHECK(REAL(RaiseException));
- __asan_handle_no_return();
- REAL(RaiseException)(a, b, c, d);
- }
- #ifdef _WIN64
- INTERCEPTOR_WINAPI(EXCEPTION_DISPOSITION, __C_specific_handler,
- _EXCEPTION_RECORD *a, void *b, _CONTEXT *c,
- _DISPATCHER_CONTEXT *d) {
- CHECK(REAL(__C_specific_handler));
- __asan_handle_no_return();
- return REAL(__C_specific_handler)(a, b, c, d);
- }
- #else
- INTERCEPTOR(int, _except_handler3, void *a, void *b, void *c, void *d) {
- CHECK(REAL(_except_handler3));
- __asan_handle_no_return();
- return REAL(_except_handler3)(a, b, c, d);
- }
- #if ASAN_DYNAMIC
- // This handler is named differently in -MT and -MD CRTs.
- #define _except_handler4 _except_handler4_common
- #endif
- INTERCEPTOR(int, _except_handler4, void *a, void *b, void *c, void *d) {
- CHECK(REAL(_except_handler4));
- __asan_handle_no_return();
- return REAL(_except_handler4)(a, b, c, d);
- }
- #endif
- static thread_return_t THREAD_CALLING_CONV asan_thread_start(void *arg) {
- AsanThread *t = (AsanThread *)arg;
- SetCurrentThread(t);
- return t->ThreadStart(GetTid());
- }
- INTERCEPTOR_WINAPI(HANDLE, CreateThread, LPSECURITY_ATTRIBUTES security,
- SIZE_T stack_size, LPTHREAD_START_ROUTINE start_routine,
- void *arg, DWORD thr_flags, DWORD *tid) {
- // Strict init-order checking is thread-hostile.
- if (flags()->strict_init_order)
- StopInitOrderChecking();
- GET_STACK_TRACE_THREAD;
- // FIXME: The CreateThread interceptor is not the same as a pthread_create
- // one. This is a bandaid fix for PR22025.
- bool detached = false; // FIXME: how can we determine it on Windows?
- u32 current_tid = GetCurrentTidOrInvalid();
- AsanThread *t =
- AsanThread::Create(start_routine, arg, current_tid, &stack, detached);
- return REAL(CreateThread)(security, stack_size, asan_thread_start, t,
- thr_flags, tid);
- }
- // }}}
- namespace __asan {
- void InitializePlatformInterceptors() {
- // The interceptors were not designed to be removable, so we have to keep this
- // module alive for the life of the process.
- HMODULE pinned;
- CHECK(GetModuleHandleExW(
- GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_PIN,
- (LPCWSTR)&InitializePlatformInterceptors, &pinned));
- ASAN_INTERCEPT_FUNC(CreateThread);
- ASAN_INTERCEPT_FUNC(SetUnhandledExceptionFilter);
- #ifdef _WIN64
- ASAN_INTERCEPT_FUNC(__C_specific_handler);
- #else
- ASAN_INTERCEPT_FUNC(_except_handler3);
- ASAN_INTERCEPT_FUNC(_except_handler4);
- #endif
- // Try to intercept kernel32!RaiseException, and if that fails, intercept
- // ntdll!RtlRaiseException instead.
- if (!::__interception::OverrideFunction("RaiseException",
- (uptr)WRAP(RaiseException),
- (uptr *)&REAL(RaiseException))) {
- CHECK(::__interception::OverrideFunction("RtlRaiseException",
- (uptr)WRAP(RtlRaiseException),
- (uptr *)&REAL(RtlRaiseException)));
- }
- }
- void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
- UNIMPLEMENTED();
- }
- void FlushUnneededASanShadowMemory(uptr p, uptr size) {
- // Since asan's mapping is compacting, the shadow chunk may be
- // not page-aligned, so we only flush the page-aligned portion.
- ReleaseMemoryPagesToOS(MemToShadow(p), MemToShadow(p + size));
- }
- // ---------------------- TSD ---------------- {{{
- static bool tsd_key_inited = false;
- static __declspec(thread) void *fake_tsd = 0;
- // https://docs.microsoft.com/en-us/windows/desktop/api/winternl/ns-winternl-_teb
- // "[This structure may be altered in future versions of Windows. Applications
- // should use the alternate functions listed in this topic.]"
- typedef struct _TEB {
- PVOID Reserved1[12];
- // PVOID ThreadLocalStoragePointer; is here, at the last field in Reserved1.
- PVOID ProcessEnvironmentBlock;
- PVOID Reserved2[399];
- BYTE Reserved3[1952];
- PVOID TlsSlots[64];
- BYTE Reserved4[8];
- PVOID Reserved5[26];
- PVOID ReservedForOle;
- PVOID Reserved6[4];
- PVOID TlsExpansionSlots;
- } TEB, *PTEB;
- constexpr size_t TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET = 11;
- BOOL IsTlsInitialized() {
- PTEB teb = (PTEB)NtCurrentTeb();
- return teb->Reserved1[TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET] !=
- nullptr;
- }
- void AsanTSDInit(void (*destructor)(void *tsd)) {
- // FIXME: we're ignoring the destructor for now.
- tsd_key_inited = true;
- }
- void *AsanTSDGet() {
- CHECK(tsd_key_inited);
- return IsTlsInitialized() ? fake_tsd : nullptr;
- }
- void AsanTSDSet(void *tsd) {
- CHECK(tsd_key_inited);
- fake_tsd = tsd;
- }
- void PlatformTSDDtor(void *tsd) { AsanThread::TSDDtor(tsd); }
- // }}}
- // ---------------------- Various stuff ---------------- {{{
- void *AsanDoesNotSupportStaticLinkage() {
- #if defined(_DEBUG)
- #error Please build the runtime with a non-debug CRT: /MD or /MT
- #endif
- return 0;
- }
- uptr FindDynamicShadowStart() {
- return MapDynamicShadow(MemToShadowSize(kHighMemEnd), ASAN_SHADOW_SCALE,
- /*min_shadow_base_alignment*/ 0, kHighMemEnd);
- }
- void AsanCheckDynamicRTPrereqs() {}
- void AsanCheckIncompatibleRT() {}
- void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
- UNIMPLEMENTED();
- }
- void AsanOnDeadlySignal(int, void *siginfo, void *context) { UNIMPLEMENTED(); }
- bool PlatformUnpoisonStacks() { return false; }
- #if SANITIZER_WINDOWS64
- // Exception handler for dealing with shadow memory.
- static LONG CALLBACK
- ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
- uptr page_size = GetPageSizeCached();
- // Only handle access violations.
- if (exception_pointers->ExceptionRecord->ExceptionCode !=
- EXCEPTION_ACCESS_VIOLATION ||
- exception_pointers->ExceptionRecord->NumberParameters < 2) {
- __asan_handle_no_return();
- return EXCEPTION_CONTINUE_SEARCH;
- }
- // Only handle access violations that land within the shadow memory.
- uptr addr =
- (uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]);
- // Check valid shadow range.
- if (!AddrIsInShadow(addr)) {
- __asan_handle_no_return();
- return EXCEPTION_CONTINUE_SEARCH;
- }
- // This is an access violation while trying to read from the shadow. Commit
- // the relevant page and let execution continue.
- // Determine the address of the page that is being accessed.
- uptr page = RoundDownTo(addr, page_size);
- // Commit the page.
- uptr result =
- (uptr)::VirtualAlloc((LPVOID)page, page_size, MEM_COMMIT, PAGE_READWRITE);
- if (result != page)
- return EXCEPTION_CONTINUE_SEARCH;
- // The page mapping succeeded, so continue execution as usual.
- return EXCEPTION_CONTINUE_EXECUTION;
- }
- #endif
- void InitializePlatformExceptionHandlers() {
- #if SANITIZER_WINDOWS64
- // On Win64, we map memory on demand with access violation handler.
- // Install our exception handler.
- CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler));
- #endif
- }
- bool IsSystemHeapAddress(uptr addr) {
- return ::HeapValidate(GetProcessHeap(), 0, (void *)addr) != FALSE;
- }
- // We want to install our own exception handler (EH) to print helpful reports
- // on access violations and whatnot. Unfortunately, the CRT initializers assume
- // they are run before any user code and drop any previously-installed EHs on
- // the floor, so we can't install our handler inside __asan_init.
- // (See crt0dat.c in the CRT sources for the details)
- //
- // Things get even more complicated with the dynamic runtime, as it finishes its
- // initialization before the .exe module CRT begins to initialize.
- //
- // For the static runtime (-MT), it's enough to put a callback to
- // __asan_set_seh_filter in the last section for C initializers.
- //
- // For the dynamic runtime (-MD), we want link the same
- // asan_dynamic_runtime_thunk.lib to all the modules, thus __asan_set_seh_filter
- // will be called for each instrumented module. This ensures that at least one
- // __asan_set_seh_filter call happens after the .exe module CRT is initialized.
- extern "C" SANITIZER_INTERFACE_ATTRIBUTE int __asan_set_seh_filter() {
- // We should only store the previous handler if it's not our own handler in
- // order to avoid loops in the EH chain.
- auto prev_seh_handler = SetUnhandledExceptionFilter(SEHHandler);
- if (prev_seh_handler != &SEHHandler)
- default_seh_handler = prev_seh_handler;
- return 0;
- }
- bool HandleDlopenInit() {
- // Not supported on this platform.
- static_assert(!SANITIZER_SUPPORTS_INIT_FOR_DLOPEN,
- "Expected SANITIZER_SUPPORTS_INIT_FOR_DLOPEN to be false");
- return false;
- }
- #if !ASAN_DYNAMIC
- // The CRT runs initializers in this order:
- // - C initializers, from XIA to XIZ
- // - C++ initializers, from XCA to XCZ
- // Prior to 2015, the CRT set the unhandled exception filter at priority XIY,
- // near the end of C initialization. Starting in 2015, it was moved to the
- // beginning of C++ initialization. We set our priority to XCAB to run
- // immediately after the CRT runs. This way, our exception filter is called
- // first and we can delegate to their filter if appropriate.
- #pragma section(".CRT$XCAB", long, read)
- __declspec(allocate(".CRT$XCAB")) int (*__intercept_seh)() =
- __asan_set_seh_filter;
- // Piggyback on the TLS initialization callback directory to initialize asan as
- // early as possible. Initializers in .CRT$XL* are called directly by ntdll,
- // which run before the CRT. Users also add code to .CRT$XLC, so it's important
- // to run our initializers first.
- static void NTAPI asan_thread_init(void *module, DWORD reason, void *reserved) {
- if (reason == DLL_PROCESS_ATTACH)
- __asan_init();
- }
- #pragma section(".CRT$XLAB", long, read)
- __declspec(allocate(".CRT$XLAB")) void(NTAPI *__asan_tls_init)(
- void *, unsigned long, void *) = asan_thread_init;
- #endif
- static void NTAPI asan_thread_exit(void *module, DWORD reason, void *reserved) {
- if (reason == DLL_THREAD_DETACH) {
- // Unpoison the thread's stack because the memory may be re-used.
- NT_TIB *tib = (NT_TIB *)NtCurrentTeb();
- uptr stackSize = (uptr)tib->StackBase - (uptr)tib->StackLimit;
- __asan_unpoison_memory_region(tib->StackLimit, stackSize);
- }
- }
- #pragma section(".CRT$XLY", long, read)
- __declspec(allocate(".CRT$XLY")) void(NTAPI *__asan_tls_exit)(
- void *, unsigned long, void *) = asan_thread_exit;
- WIN_FORCE_LINK(__asan_dso_reg_hook)
- // }}}
- } // namespace __asan
- #endif // SANITIZER_WINDOWS
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