Adjust buffers to prevent overflow (#15025)

* Adjust buffers to prevent overflow

* Adjust strncat parameter to prevent buffer overflow

collectors/cgroups.plugin/sys_fs_cgroup.c

@@ -1952,7 +1952,7 @@ static void is_cgroup_procs_exist(netdata_ebpf_cgroup_shm_body_t *out, char *id)
 }
 
 static inline void convert_cgroup_to_systemd_service(struct cgroup *cg) {
-    char buffer[CGROUP_CHARTID_LINE_MAX];
+    char buffer[CGROUP_CHARTID_LINE_MAX + 1];
     cg->options |= CGROUP_OPTIONS_SYSTEM_SLICE_SERVICE;
     strncpyz(buffer, cg->id, CGROUP_CHARTID_LINE_MAX);
     char *s = buffer;
@@ -2607,7 +2607,7 @@ static inline void discovery_process_first_time_seen_cgroup(struct cgroup *cg) {
     }
     cg->first_time_seen = 0;
 
-    char comm[TASK_COMM_LEN];
+    char comm[TASK_COMM_LEN + 1];
 
     if (cg->container_orchestrator == CGROUPS_ORCHESTRATOR_UNSET) {
         if (strstr(cg->id, "kubepods")) {

collectors/proc.plugin/proc_diskstats.c

@@ -348,7 +348,7 @@ static inline int get_disk_name_from_path(const char *path, char *result, size_t
 
     int found = 0, preferred = 0;
 
-    char *first_result = mallocz(result_size);
+    char *first_result = mallocz(result_size + 1);
 
     DIR *dir = opendir(path);
     if (!dir) {
@@ -454,7 +454,7 @@ failed:
 }
 
 static inline char *get_disk_name(unsigned long major, unsigned long minor, char *disk) {
-    char result[FILENAME_MAX + 1] = "";
+    char result[FILENAME_MAX + 2] = "";
 
     if(!path_to_device_mapper || !*path_to_device_mapper || !get_disk_name_from_path(path_to_device_mapper, result, FILENAME_MAX + 1, major, minor, disk, NULL, 0))
         if(!path_to_device_label || !*path_to_device_label || !get_disk_name_from_path(path_to_device_label, result, FILENAME_MAX + 1, major, minor, disk, NULL, 0))
@@ -615,8 +615,8 @@ static struct disk *get_disk(unsigned long major, unsigned long minor, char *dis
     // read device uuid if it is an LVM volume
     if (!strncmp(d->device, "dm-", 3)) {
         char uuid_filename[FILENAME_MAX + 1];
-        snprintfz(uuid_filename, FILENAME_MAX, path_to_sys_devices_virtual_block_device, disk);
-        strncat(uuid_filename, "/dm/uuid", FILENAME_MAX);
+        int size = snprintfz(uuid_filename, FILENAME_MAX, path_to_sys_devices_virtual_block_device, disk);
+        strncat(uuid_filename, "/dm/uuid", FILENAME_MAX - size);
 
         char device_uuid[RRD_ID_LENGTH_MAX + 1];
         if (!read_file(uuid_filename, device_uuid, RRD_ID_LENGTH_MAX) && !strncmp(device_uuid, "LVM-", 4)) {

database/rrdset.c

@@ -2207,7 +2207,7 @@ bool rrdset_memory_load_or_create_map_save(RRDSET *st, RRD_MEMORY_MODE memory_mo
     memset(st_on_file, 0, size);
 
     // set the values we need
-    strncpyz(st_on_file->id, rrdset_id(st), RRD_ID_LENGTH_MAX_V019 + 1);
+    strncpyz(st_on_file->id, rrdset_id(st), RRD_ID_LENGTH_MAX_V019);
     strcpy(st_on_file->cache_filename, fullfilename);
     strcpy(st_on_file->magic, RRDSET_MAGIC_V019);
     st_on_file->memsize = size;