/* american fuzzy lop++ - instrumentation bootstrap ------------------------------------------------ Copyright 2015, 2016 Google Inc. All rights reserved. Copyright 2019-2020 AFLplusplus Project. All rights reserved. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0 */ #ifdef __ANDROID__ #include "android-ashmem.h" #endif #include "config.h" #include "types.h" #include "cmplog.h" #include "llvm-ngram-coverage.h" #include #include #include #include #include #include #include #include #include #include #include #ifndef __HAIKU__ #include #endif #include #include #if !__GNUC__ #include "llvm/Config/llvm-config.h" #endif #ifdef __linux__ #include "snapshot-inl.h" #endif /* This is a somewhat ugly hack for the experimental 'trace-pc-guard' mode. Basically, we need to make sure that the forkserver is initialized after the LLVM-generated runtime initialization pass, not before. */ #ifndef MAP_FIXED_NOREPLACE #ifdef MAP_EXCL #define MAP_FIXED_NOREPLACE MAP_EXCL | MAP_FIXED #else #define MAP_FIXED_NOREPLACE MAP_FIXED #endif #endif #define CTOR_PRIO 3 #include #include /* Globals needed by the injected instrumentation. The __afl_area_initial region is used for instrumentation output before __afl_map_shm() has a chance to run. It will end up as .comm, so it shouldn't be too wasteful. */ #if MAP_SIZE <= 65536 #define MAP_INITIAL_SIZE 256000 #else #define MAP_INITIAL_SIZE MAP_SIZE #endif u8 __afl_area_initial[MAP_INITIAL_SIZE]; u8 * __afl_area_ptr_dummy = __afl_area_initial; u8 * __afl_area_ptr = __afl_area_initial; u8 * __afl_area_ptr_backup = __afl_area_initial; u8 * __afl_dictionary; u8 * __afl_fuzz_ptr; u32 __afl_fuzz_len_dummy; u32 *__afl_fuzz_len = &__afl_fuzz_len_dummy; u32 __afl_final_loc; u32 __afl_map_size = MAP_SIZE; u32 __afl_dictionary_len; u64 __afl_map_addr; // for the __AFL_COVERAGE_ON/__AFL_COVERAGE_OFF features to work: int __afl_selective_coverage __attribute__((weak)); int __afl_selective_coverage_start_off __attribute__((weak)); int __afl_selective_coverage_temp = 1; #if defined(__ANDROID__) || defined(__HAIKU__) PREV_LOC_T __afl_prev_loc[NGRAM_SIZE_MAX]; u32 __afl_prev_ctx; u32 __afl_cmp_counter; #else __thread PREV_LOC_T __afl_prev_loc[NGRAM_SIZE_MAX]; __thread u32 __afl_prev_ctx; __thread u32 __afl_cmp_counter; #endif int __afl_sharedmem_fuzzing __attribute__((weak)); struct cmp_map *__afl_cmp_map; struct cmp_map *__afl_cmp_map_backup; /* Child pid? */ static s32 child_pid; static void (*old_sigterm_handler)(int) = 0; /* Running in persistent mode? */ static u8 is_persistent; /* Are we in sancov mode? */ static u8 _is_sancov; /* ensure we kill the child on termination */ void at_exit(int signal) { if (child_pid > 0) { kill(child_pid, SIGKILL); } } /* Uninspired gcc plugin instrumentation */ void __afl_trace(const u32 x) { PREV_LOC_T prev = __afl_prev_loc[0]; __afl_prev_loc[0] = (x >> 1); u8 *p = &__afl_area_ptr[prev ^ x]; #if 1 /* enable for neverZero feature. */ #if __GNUC__ u8 c = __builtin_add_overflow(*p, 1, p); *p += c; #else *p += 1 + ((u8)(1 + *p) == 0); #endif #else ++*p; #endif return; } /* Error reporting to forkserver controller */ void send_forkserver_error(int error) { u32 status; if (!error || error > 0xffff) return; status = (FS_OPT_ERROR | FS_OPT_SET_ERROR(error)); if (write(FORKSRV_FD + 1, (char *)&status, 4) != 4) { return; } } /* SHM fuzzing setup. */ static void __afl_map_shm_fuzz() { char *id_str = getenv(SHM_FUZZ_ENV_VAR); if (getenv("AFL_DEBUG")) { fprintf(stderr, "DEBUG: fuzzcase shmem %s\n", id_str ? id_str : "none"); } if (id_str) { u8 *map = NULL; #ifdef USEMMAP const char *shm_file_path = id_str; int shm_fd = -1; /* create the shared memory segment as if it was a file */ shm_fd = shm_open(shm_file_path, O_RDWR, 0600); if (shm_fd == -1) { fprintf(stderr, "shm_open() failed for fuzz\n"); send_forkserver_error(FS_ERROR_SHM_OPEN); exit(1); } map = (u8 *)mmap(0, MAX_FILE + sizeof(u32), PROT_READ, MAP_SHARED, shm_fd, 0); #else u32 shm_id = atoi(id_str); map = (u8 *)shmat(shm_id, NULL, 0); #endif /* Whooooops. */ if (!map || map == (void *)-1) { perror("Could not access fuzzing shared memory"); send_forkserver_error(FS_ERROR_SHM_OPEN); exit(1); } __afl_fuzz_len = (u32 *)map; __afl_fuzz_ptr = map + sizeof(u32); if (getenv("AFL_DEBUG")) { fprintf(stderr, "DEBUG: successfully got fuzzing shared memory\n"); } } else { fprintf(stderr, "Error: variable for fuzzing shared memory is not set\n"); send_forkserver_error(FS_ERROR_SHM_OPEN); exit(1); } } /* SHM setup. */ static void __afl_map_shm(void) { // if we are not running in afl ensure the map exists if (!__afl_area_ptr) { __afl_area_ptr = __afl_area_ptr_dummy; } char *id_str = getenv(SHM_ENV_VAR); if (__afl_final_loc) { if (__afl_final_loc % 32) __afl_final_loc = (((__afl_final_loc + 31) >> 5) << 5); __afl_map_size = __afl_final_loc; if (__afl_final_loc > MAP_SIZE) { char *ptr; u32 val = 0; if ((ptr = getenv("AFL_MAP_SIZE")) != NULL) val = atoi(ptr); if (val < __afl_final_loc) { if (__afl_final_loc > FS_OPT_MAX_MAPSIZE) { if (!getenv("AFL_QUIET")) fprintf(stderr, "Error: AFL++ tools *require* to set AFL_MAP_SIZE to %u " "to be able to run this instrumented program!\n", __afl_final_loc); if (id_str) { send_forkserver_error(FS_ERROR_MAP_SIZE); exit(-1); } } else { if (!getenv("AFL_QUIET")) fprintf(stderr, "Warning: AFL++ tools will need to set AFL_MAP_SIZE to %u " "to be able to run this instrumented program!\n", __afl_final_loc); } } } } /* If we're running under AFL, attach to the appropriate region, replacing the early-stage __afl_area_initial region that is needed to allow some really hacky .init code to work correctly in projects such as OpenSSL. */ if (getenv("AFL_DEBUG")) fprintf(stderr, "DEBUG: id_str %s, __afl_area_ptr %p, __afl_area_initial %p, " "__afl_map_addr 0x%llx, MAP_SIZE %u, __afl_final_loc %u, " "max_size_forkserver %u/0x%x\n", id_str == NULL ? "" : id_str, __afl_area_ptr, __afl_area_initial, __afl_map_addr, MAP_SIZE, __afl_final_loc, FS_OPT_MAX_MAPSIZE, FS_OPT_MAX_MAPSIZE); if (id_str) { if (__afl_area_ptr && __afl_area_ptr != __afl_area_initial) { if (__afl_map_addr) { munmap((void *)__afl_map_addr, __afl_final_loc); } else { free(__afl_area_ptr); } __afl_area_ptr = __afl_area_ptr_dummy; } #ifdef USEMMAP const char * shm_file_path = id_str; int shm_fd = -1; unsigned char *shm_base = NULL; /* create the shared memory segment as if it was a file */ shm_fd = shm_open(shm_file_path, O_RDWR, 0600); if (shm_fd == -1) { fprintf(stderr, "shm_open() failed\n"); send_forkserver_error(FS_ERROR_SHM_OPEN); exit(1); } /* map the shared memory segment to the address space of the process */ if (__afl_map_addr) { shm_base = mmap((void *)__afl_map_addr, __afl_map_size, PROT_READ | PROT_WRITE, MAP_FIXED_NOREPLACE | MAP_SHARED, shm_fd, 0); } else { shm_base = mmap(0, __afl_map_size, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0); } if (shm_base == MAP_FAILED) { close(shm_fd); shm_fd = -1; fprintf(stderr, "mmap() failed\n"); if (__afl_map_addr) send_forkserver_error(FS_ERROR_MAP_ADDR); else send_forkserver_error(FS_ERROR_MMAP); perror("mmap for map"); exit(2); } __afl_area_ptr = shm_base; #else u32 shm_id = atoi(id_str); if (__afl_map_size && __afl_map_size > MAP_SIZE) { u8 *map_env = getenv("AFL_MAP_SIZE"); if (!map_env || atoi(map_env) < MAP_SIZE) { send_forkserver_error(FS_ERROR_MAP_SIZE); _exit(1); } } __afl_area_ptr = shmat(shm_id, (void *)__afl_map_addr, 0); /* Whooooops. */ if (!__afl_area_ptr || __afl_area_ptr == (void *)-1) { if (__afl_map_addr) send_forkserver_error(FS_ERROR_MAP_ADDR); else send_forkserver_error(FS_ERROR_SHMAT); perror("shmat for map"); _exit(1); } #endif /* Write something into the bitmap so that even with low AFL_INST_RATIO, our parent doesn't give up on us. */ __afl_area_ptr[0] = 1; } else if ((!__afl_area_ptr || __afl_area_ptr == __afl_area_initial) && __afl_map_addr) { __afl_area_ptr = mmap((void *)__afl_map_addr, __afl_map_size, PROT_READ | PROT_WRITE, MAP_FIXED_NOREPLACE | MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (__afl_area_ptr == MAP_FAILED) { fprintf(stderr, "can not acquire mmap for address %p\n", (void *)__afl_map_addr); send_forkserver_error(FS_ERROR_SHM_OPEN); exit(1); } } else if (_is_sancov && __afl_area_ptr != __afl_area_initial) { free(__afl_area_ptr); __afl_area_ptr = NULL; if (__afl_final_loc > MAP_INITIAL_SIZE) { __afl_area_ptr = malloc(__afl_final_loc); } if (!__afl_area_ptr) { __afl_area_ptr = __afl_area_ptr_dummy; } } __afl_area_ptr_backup = __afl_area_ptr; if (__afl_selective_coverage) { if (__afl_map_size > MAP_INITIAL_SIZE) { __afl_area_ptr_dummy = malloc(__afl_map_size); if (__afl_area_ptr_dummy) { if (__afl_selective_coverage_start_off) { __afl_area_ptr = __afl_area_ptr_dummy; } } else { fprintf(stderr, "Error: __afl_selective_coverage failed!\n"); __afl_selective_coverage = 0; // continue; } } } id_str = getenv(CMPLOG_SHM_ENV_VAR); if (getenv("AFL_DEBUG")) { fprintf(stderr, "DEBUG: cmplog id_str %s\n", id_str == NULL ? "" : id_str); } if (id_str) { #ifdef USEMMAP const char * shm_file_path = id_str; int shm_fd = -1; struct cmp_map *shm_base = NULL; /* create the shared memory segment as if it was a file */ shm_fd = shm_open(shm_file_path, O_RDWR, 0600); if (shm_fd == -1) { perror("shm_open() failed\n"); send_forkserver_error(FS_ERROR_SHM_OPEN); exit(1); } /* map the shared memory segment to the address space of the process */ shm_base = mmap(0, sizeof(struct cmp_map), PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0); if (shm_base == MAP_FAILED) { close(shm_fd); shm_fd = -1; fprintf(stderr, "mmap() failed\n"); send_forkserver_error(FS_ERROR_SHM_OPEN); exit(2); } __afl_cmp_map = shm_base; #else u32 shm_id = atoi(id_str); __afl_cmp_map = shmat(shm_id, NULL, 0); #endif __afl_cmp_map_backup = __afl_cmp_map; if (!__afl_cmp_map || __afl_cmp_map == (void *)-1) { perror("shmat for cmplog"); send_forkserver_error(FS_ERROR_SHM_OPEN); _exit(1); } } } #ifdef __linux__ static void __afl_start_snapshots(void) { static u8 tmp[4] = {0, 0, 0, 0}; u32 status = 0; u32 already_read_first = 0; u32 was_killed; u8 child_stopped = 0; void (*old_sigchld_handler)(int) = 0; // = signal(SIGCHLD, SIG_DFL); /* Phone home and tell the parent that we're OK. If parent isn't there, assume we're not running in forkserver mode and just execute program. */ status |= (FS_OPT_ENABLED | FS_OPT_SNAPSHOT); if (__afl_sharedmem_fuzzing != 0) status |= FS_OPT_SHDMEM_FUZZ; if (__afl_map_size <= FS_OPT_MAX_MAPSIZE) status |= (FS_OPT_SET_MAPSIZE(__afl_map_size) | FS_OPT_MAPSIZE); if (__afl_dictionary_len && __afl_dictionary) status |= FS_OPT_AUTODICT; memcpy(tmp, &status, 4); if (write(FORKSRV_FD + 1, tmp, 4) != 4) { return; } if (__afl_sharedmem_fuzzing || (__afl_dictionary_len && __afl_dictionary)) { if (read(FORKSRV_FD, &was_killed, 4) != 4) { _exit(1); } if (getenv("AFL_DEBUG")) { fprintf(stderr, "target forkserver recv: %08x\n", was_killed); } if ((was_killed & (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) == (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) { __afl_map_shm_fuzz(); } if ((was_killed & (FS_OPT_ENABLED | FS_OPT_AUTODICT)) == (FS_OPT_ENABLED | FS_OPT_AUTODICT) && __afl_dictionary_len && __afl_dictionary) { // great lets pass the dictionary through the forkserver FD u32 len = __afl_dictionary_len, offset = 0; s32 ret; if (write(FORKSRV_FD + 1, &len, 4) != 4) { write(2, "Error: could not send dictionary len\n", strlen("Error: could not send dictionary len\n")); _exit(1); } while (len != 0) { ret = write(FORKSRV_FD + 1, __afl_dictionary + offset, len); if (ret < 1) { write(2, "Error: could not send dictionary\n", strlen("Error: could not send dictionary\n")); _exit(1); } len -= ret; offset += ret; } } else { // uh this forkserver does not understand extended option passing // or does not want the dictionary if (!__afl_fuzz_ptr) already_read_first = 1; } } while (1) { int status; if (already_read_first) { already_read_first = 0; } else { /* Wait for parent by reading from the pipe. Abort if read fails. */ if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1); } #ifdef _AFL_DOCUMENT_MUTATIONS if (__afl_fuzz_ptr) { static uint32_t counter = 0; char fn[32]; sprintf(fn, "%09u:forkserver", counter); s32 fd_doc = open(fn, O_WRONLY | O_CREAT | O_TRUNC, 0600); if (fd_doc >= 0) { if (write(fd_doc, __afl_fuzz_ptr, *__afl_fuzz_len) != *__afl_fuzz_len) { fprintf(stderr, "write of mutation file failed: %s\n", fn); unlink(fn); } close(fd_doc); } counter++; } #endif /* If we stopped the child in persistent mode, but there was a race condition and afl-fuzz already issued SIGKILL, write off the old process. */ if (child_stopped && was_killed) { child_stopped = 0; if (waitpid(child_pid, &status, 0) < 0) _exit(1); } if (!child_stopped) { /* Once woken up, create a clone of our process. */ child_pid = fork(); if (child_pid < 0) _exit(1); /* In child process: close fds, resume execution. */ if (!child_pid) { //(void)nice(-20); // does not seem to improve signal(SIGCHLD, old_sigchld_handler); signal(SIGTERM, old_sigterm_handler); close(FORKSRV_FD); close(FORKSRV_FD + 1); if (!afl_snapshot_take(AFL_SNAPSHOT_MMAP | AFL_SNAPSHOT_FDS | AFL_SNAPSHOT_REGS | AFL_SNAPSHOT_EXIT)) { raise(SIGSTOP); } __afl_area_ptr[0] = 1; memset(__afl_prev_loc, 0, NGRAM_SIZE_MAX * sizeof(PREV_LOC_T)); return; } } else { /* Special handling for persistent mode: if the child is alive but currently stopped, simply restart it with SIGCONT. */ kill(child_pid, SIGCONT); child_stopped = 0; } /* In parent process: write PID to pipe, then wait for child. */ if (write(FORKSRV_FD + 1, &child_pid, 4) != 4) _exit(1); if (waitpid(child_pid, &status, WUNTRACED) < 0) _exit(1); /* In persistent mode, the child stops itself with SIGSTOP to indicate a successful run. In this case, we want to wake it up without forking again. */ if (WIFSTOPPED(status)) child_stopped = 1; /* Relay wait status to pipe, then loop back. */ if (write(FORKSRV_FD + 1, &status, 4) != 4) _exit(1); } } #endif /* Fork server logic. */ static void __afl_start_forkserver(void) { struct sigaction orig_action; sigaction(SIGTERM, NULL, &orig_action); old_sigterm_handler = orig_action.sa_handler; signal(SIGTERM, at_exit); #ifdef __linux__ if (/*!is_persistent &&*/ !__afl_cmp_map && !getenv("AFL_NO_SNAPSHOT") && afl_snapshot_init() >= 0) { __afl_start_snapshots(); return; } #endif u8 tmp[4] = {0, 0, 0, 0}; u32 status_for_fsrv = 0; u32 already_read_first = 0; u32 was_killed; u8 child_stopped = 0; void (*old_sigchld_handler)(int) = 0; // = signal(SIGCHLD, SIG_DFL); if (__afl_map_size <= FS_OPT_MAX_MAPSIZE) { status_for_fsrv |= (FS_OPT_SET_MAPSIZE(__afl_map_size) | FS_OPT_MAPSIZE); } if (__afl_dictionary_len && __afl_dictionary) { status_for_fsrv |= FS_OPT_AUTODICT; } if (__afl_sharedmem_fuzzing != 0) { status_for_fsrv |= FS_OPT_SHDMEM_FUZZ; } if (status_for_fsrv) { status_for_fsrv |= (FS_OPT_ENABLED); } memcpy(tmp, &status_for_fsrv, 4); /* Phone home and tell the parent that we're OK. If parent isn't there, assume we're not running in forkserver mode and just execute program. */ if (write(FORKSRV_FD + 1, tmp, 4) != 4) { return; } if (__afl_sharedmem_fuzzing || (__afl_dictionary_len && __afl_dictionary)) { if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1); if (getenv("AFL_DEBUG")) { fprintf(stderr, "target forkserver recv: %08x\n", was_killed); } if ((was_killed & (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) == (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) { __afl_map_shm_fuzz(); } if ((was_killed & (FS_OPT_ENABLED | FS_OPT_AUTODICT)) == (FS_OPT_ENABLED | FS_OPT_AUTODICT) && __afl_dictionary_len && __afl_dictionary) { // great lets pass the dictionary through the forkserver FD u32 len = __afl_dictionary_len, offset = 0; if (write(FORKSRV_FD + 1, &len, 4) != 4) { write(2, "Error: could not send dictionary len\n", strlen("Error: could not send dictionary len\n")); _exit(1); } while (len != 0) { s32 ret; ret = write(FORKSRV_FD + 1, __afl_dictionary + offset, len); if (ret < 1) { write(2, "Error: could not send dictionary\n", strlen("Error: could not send dictionary\n")); _exit(1); } len -= ret; offset += ret; } } else { // uh this forkserver does not understand extended option passing // or does not want the dictionary if (!__afl_fuzz_ptr) already_read_first = 1; } } while (1) { int status; /* Wait for parent by reading from the pipe. Abort if read fails. */ if (already_read_first) { already_read_first = 0; } else { if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1); } #ifdef _AFL_DOCUMENT_MUTATIONS if (__afl_fuzz_ptr) { static uint32_t counter = 0; char fn[32]; sprintf(fn, "%09u:forkserver", counter); s32 fd_doc = open(fn, O_WRONLY | O_CREAT | O_TRUNC, 0600); if (fd_doc >= 0) { if (write(fd_doc, __afl_fuzz_ptr, *__afl_fuzz_len) != *__afl_fuzz_len) { fprintf(stderr, "write of mutation file failed: %s\n", fn); unlink(fn); } close(fd_doc); } counter++; } #endif /* If we stopped the child in persistent mode, but there was a race condition and afl-fuzz already issued SIGKILL, write off the old process. */ if (child_stopped && was_killed) { child_stopped = 0; if (waitpid(child_pid, &status, 0) < 0) _exit(1); } if (!child_stopped) { /* Once woken up, create a clone of our process. */ child_pid = fork(); if (child_pid < 0) _exit(1); /* In child process: close fds, resume execution. */ if (!child_pid) { //(void)nice(-20); signal(SIGCHLD, old_sigchld_handler); signal(SIGTERM, old_sigterm_handler); close(FORKSRV_FD); close(FORKSRV_FD + 1); return; } } else { /* Special handling for persistent mode: if the child is alive but currently stopped, simply restart it with SIGCONT. */ kill(child_pid, SIGCONT); child_stopped = 0; } /* In parent process: write PID to pipe, then wait for child. */ if (write(FORKSRV_FD + 1, &child_pid, 4) != 4) _exit(1); if (waitpid(child_pid, &status, is_persistent ? WUNTRACED : 0) < 0) _exit(1); /* In persistent mode, the child stops itself with SIGSTOP to indicate a successful run. In this case, we want to wake it up without forking again. */ if (WIFSTOPPED(status)) child_stopped = 1; /* Relay wait status to pipe, then loop back. */ if (write(FORKSRV_FD + 1, &status, 4) != 4) _exit(1); } } /* A simplified persistent mode handler, used as explained in * README.llvm.md. */ int __afl_persistent_loop(unsigned int max_cnt) { static u8 first_pass = 1; static u32 cycle_cnt; if (first_pass) { /* Make sure that every iteration of __AFL_LOOP() starts with a clean slate. On subsequent calls, the parent will take care of that, but on the first iteration, it's our job to erase any trace of whatever happened before the loop. */ if (is_persistent) { memset(__afl_area_ptr, 0, __afl_map_size); __afl_area_ptr[0] = 1; memset(__afl_prev_loc, 0, NGRAM_SIZE_MAX * sizeof(PREV_LOC_T)); } cycle_cnt = max_cnt; first_pass = 0; __afl_selective_coverage_temp = 1; return 1; } if (is_persistent) { if (--cycle_cnt) { raise(SIGSTOP); __afl_area_ptr[0] = 1; memset(__afl_prev_loc, 0, NGRAM_SIZE_MAX * sizeof(PREV_LOC_T)); __afl_selective_coverage_temp = 1; return 1; } else { /* When exiting __AFL_LOOP(), make sure that the subsequent code that follows the loop is not traced. We do that by pivoting back to the dummy output region. */ __afl_area_ptr = __afl_area_ptr_dummy; } } return 0; } /* This one can be called from user code when deferred forkserver mode is enabled. */ void __afl_manual_init(void) { static u8 init_done; if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) { init_done = 1; is_persistent = 0; __afl_sharedmem_fuzzing = 0; if (__afl_area_ptr == NULL) __afl_area_ptr = __afl_area_ptr_dummy; if (getenv("AFL_DEBUG")) fprintf(stderr, "DEBUG: disabled instrumentation because of " "AFL_DISABLE_LLVM_INSTRUMENTATION\n"); } if (!init_done) { __afl_start_forkserver(); init_done = 1; } } /* Initialization of the forkserver - latest possible */ __attribute__((constructor())) void __afl_auto_init(void) { if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return; if (getenv(DEFER_ENV_VAR)) return; __afl_manual_init(); } /* Initialization of the shmem - earliest possible because of LTO fixed mem. */ __attribute__((constructor(CTOR_PRIO))) void __afl_auto_early(void) { is_persistent = !!getenv(PERSIST_ENV_VAR); if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return; __afl_map_shm(); } /* preset __afl_area_ptr #2 */ __attribute__((constructor(1))) void __afl_auto_second(void) { if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return; u8 *ptr; if (__afl_final_loc) { if (__afl_area_ptr && __afl_area_ptr != __afl_area_initial) free(__afl_area_ptr); if (__afl_map_addr) ptr = (u8 *)mmap((void *)__afl_map_addr, __afl_final_loc, PROT_READ | PROT_WRITE, MAP_FIXED_NOREPLACE | MAP_SHARED | MAP_ANONYMOUS, -1, 0); else ptr = (u8 *)malloc(__afl_final_loc); if (ptr && (ssize_t)ptr != -1) { __afl_area_ptr = ptr; __afl_area_ptr_backup = __afl_area_ptr; } } } /* preset __afl_area_ptr #1 - at constructor level 0 global variables have not been set */ __attribute__((constructor(0))) void __afl_auto_first(void) { if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return; u8 *ptr; ptr = (u8 *)malloc(1024000); if (ptr && (ssize_t)ptr != -1) { __afl_area_ptr = ptr; __afl_area_ptr_backup = __afl_area_ptr; } } /* The following stuff deals with supporting -fsanitize-coverage=trace-pc-guard. It remains non-operational in the traditional, plugin-backed LLVM mode. For more info about 'trace-pc-guard', see README.llvm.md. The first function (__sanitizer_cov_trace_pc_guard) is called back on every edge (as opposed to every basic block). */ void __sanitizer_cov_trace_pc_guard(uint32_t *guard) { // For stability analysis, if you want to know to which function unstable // edge IDs belong - uncomment, recompile+install llvm_mode, recompile // the target. libunwind and libbacktrace are better solutions. // Set AFL_DEBUG_CHILD=1 and run afl-fuzz with 2>file to capture // the backtrace output /* uint32_t unstable[] = { ... unstable edge IDs }; uint32_t idx; char bt[1024]; for (idx = 0; i < sizeof(unstable)/sizeof(uint32_t); i++) { if (unstable[idx] == __afl_area_ptr[*guard]) { int bt_size = backtrace(bt, 256); if (bt_size > 0) { char **bt_syms = backtrace_symbols(bt, bt_size); if (bt_syms) { fprintf(stderr, "DEBUG: edge=%u caller=%s\n", unstable[idx], bt_syms[0]); free(bt_syms); } } } } */ #if (LLVM_VERSION_MAJOR < 9) __afl_area_ptr[*guard]++; #else __afl_area_ptr[*guard] = __afl_area_ptr[*guard] + 1 + (__afl_area_ptr[*guard] == 255 ? 1 : 0); #endif } /* Init callback. Populates instrumentation IDs. Note that we're using ID of 0 as a special value to indicate non-instrumented bits. That may still touch the bitmap, but in a fairly harmless way. */ void __sanitizer_cov_trace_pc_guard_init(uint32_t *start, uint32_t *stop) { u32 inst_ratio = 100; char *x; _is_sancov = 1; if (getenv("AFL_DEBUG")) { fprintf(stderr, "Running __sanitizer_cov_trace_pc_guard_init: %p-%p\n", start, stop); } if (start == stop || *start) return; x = getenv("AFL_INST_RATIO"); if (x) inst_ratio = (u32)atoi(x); if (!inst_ratio || inst_ratio > 100) { fprintf(stderr, "[-] ERROR: Invalid AFL_INST_RATIO (must be 1-100).\n"); abort(); } /* Make sure that the first element in the range is always set - we use that to avoid duplicate calls (which can happen as an artifact of the underlying implementation in LLVM). */ *(start++) = ++__afl_final_loc; while (start < stop) { if (R(100) < inst_ratio) *start = ++__afl_final_loc; else *start = 0; start++; } } ///// CmpLog instrumentation void __cmplog_ins_hook1(uint8_t arg1, uint8_t arg2, uint8_t attr) { // fprintf(stderr, "hook1 arg0=%02x arg1=%02x attr=%u\n", // (u8) arg1, (u8) arg2, attr); if (unlikely(!__afl_cmp_map || arg1 == arg2)) return; uintptr_t k = (uintptr_t)__builtin_return_address(0); k = (k >> 4) ^ (k << 8); k &= CMP_MAP_W - 1; u32 hits; if (__afl_cmp_map->headers[k].type != CMP_TYPE_INS) { __afl_cmp_map->headers[k].type = CMP_TYPE_INS; hits = 0; __afl_cmp_map->headers[k].hits = 1; __afl_cmp_map->headers[k].shape = 0; } else { hits = __afl_cmp_map->headers[k].hits++; } __afl_cmp_map->headers[k].attribute = attr; hits &= CMP_MAP_H - 1; __afl_cmp_map->log[k][hits].v0 = arg1; __afl_cmp_map->log[k][hits].v1 = arg2; } void __cmplog_ins_hook2(uint16_t arg1, uint16_t arg2, uint8_t attr) { if (unlikely(!__afl_cmp_map || arg1 == arg2)) return; uintptr_t k = (uintptr_t)__builtin_return_address(0); k = (k >> 4) ^ (k << 8); k &= CMP_MAP_W - 1; u32 hits; if (__afl_cmp_map->headers[k].type != CMP_TYPE_INS) { __afl_cmp_map->headers[k].type = CMP_TYPE_INS; hits = 0; __afl_cmp_map->headers[k].hits = 1; __afl_cmp_map->headers[k].shape = 1; } else { hits = __afl_cmp_map->headers[k].hits++; if (!__afl_cmp_map->headers[k].shape) { __afl_cmp_map->headers[k].shape = 1; } } __afl_cmp_map->headers[k].attribute = attr; hits &= CMP_MAP_H - 1; __afl_cmp_map->log[k][hits].v0 = arg1; __afl_cmp_map->log[k][hits].v1 = arg2; } void __cmplog_ins_hook4(uint32_t arg1, uint32_t arg2, uint8_t attr) { // fprintf(stderr, "hook4 arg0=%x arg1=%x attr=%u\n", arg1, arg2, attr); if (unlikely(!__afl_cmp_map || arg1 == arg2)) return; uintptr_t k = (uintptr_t)__builtin_return_address(0); k = (k >> 4) ^ (k << 8); k &= CMP_MAP_W - 1; u32 hits; if (__afl_cmp_map->headers[k].type != CMP_TYPE_INS) { __afl_cmp_map->headers[k].type = CMP_TYPE_INS; hits = 0; __afl_cmp_map->headers[k].hits = 1; __afl_cmp_map->headers[k].shape = 3; } else { hits = __afl_cmp_map->headers[k].hits++; if (__afl_cmp_map->headers[k].shape < 3) { __afl_cmp_map->headers[k].shape = 3; } } __afl_cmp_map->headers[k].attribute = attr; hits &= CMP_MAP_H - 1; __afl_cmp_map->log[k][hits].v0 = arg1; __afl_cmp_map->log[k][hits].v1 = arg2; } void __cmplog_ins_hook8(uint64_t arg1, uint64_t arg2, uint8_t attr) { // fprintf(stderr, "hook8 arg0=%lx arg1=%lx attr=%u\n", arg1, arg2, attr); if (unlikely(!__afl_cmp_map || arg1 == arg2)) return; uintptr_t k = (uintptr_t)__builtin_return_address(0); k = (k >> 4) ^ (k << 8); k &= CMP_MAP_W - 1; u32 hits; if (__afl_cmp_map->headers[k].type != CMP_TYPE_INS) { __afl_cmp_map->headers[k].type = CMP_TYPE_INS; hits = 0; __afl_cmp_map->headers[k].hits = 1; __afl_cmp_map->headers[k].shape = 7; } else { hits = __afl_cmp_map->headers[k].hits++; if (__afl_cmp_map->headers[k].shape < 7) { __afl_cmp_map->headers[k].shape = 7; } } __afl_cmp_map->headers[k].attribute = attr; hits &= CMP_MAP_H - 1; __afl_cmp_map->log[k][hits].v0 = arg1; __afl_cmp_map->log[k][hits].v1 = arg2; } #ifdef WORD_SIZE_64 // support for u24 to u120 via llvm _ExitInt(). size is in bytes minus 1 void __cmplog_ins_hookN(uint128_t arg1, uint128_t arg2, uint8_t attr, uint8_t size) { // fprintf(stderr, "hookN arg0=%llx:%llx arg1=%llx:%llx bytes=%u attr=%u\n", // (u64)(arg1 >> 64), (u64)arg1, (u64)(arg2 >> 64), (u64)arg2, size + 1, // attr); if (unlikely(!__afl_cmp_map || arg1 == arg2)) return; uintptr_t k = (uintptr_t)__builtin_return_address(0); k = (k >> 4) ^ (k << 8); k &= CMP_MAP_W - 1; u32 hits; if (__afl_cmp_map->headers[k].type != CMP_TYPE_INS) { __afl_cmp_map->headers[k].type = CMP_TYPE_INS; hits = 0; __afl_cmp_map->headers[k].hits = 1; __afl_cmp_map->headers[k].shape = size; } else { hits = __afl_cmp_map->headers[k].hits++; if (__afl_cmp_map->headers[k].shape < size) { __afl_cmp_map->headers[k].shape = size; } } __afl_cmp_map->headers[k].attribute = attr; hits &= CMP_MAP_H - 1; __afl_cmp_map->log[k][hits].v0 = (u64)arg1; __afl_cmp_map->log[k][hits].v1 = (u64)arg2; if (size > 7) { __afl_cmp_map->log[k][hits].v0_128 = (u64)(arg1 >> 64); __afl_cmp_map->log[k][hits].v1_128 = (u64)(arg2 >> 64); } } void __cmplog_ins_hook16(uint128_t arg1, uint128_t arg2, uint8_t attr) { if (unlikely(!__afl_cmp_map)) return; uintptr_t k = (uintptr_t)__builtin_return_address(0); k = (k >> 4) ^ (k << 8); k &= CMP_MAP_W - 1; u32 hits; if (__afl_cmp_map->headers[k].type != CMP_TYPE_INS) { __afl_cmp_map->headers[k].type = CMP_TYPE_INS; hits = 0; __afl_cmp_map->headers[k].hits = 1; __afl_cmp_map->headers[k].shape = 15; } else { hits = __afl_cmp_map->headers[k].hits++; if (__afl_cmp_map->headers[k].shape < 15) { __afl_cmp_map->headers[k].shape = 15; } } __afl_cmp_map->headers[k].attribute = attr; hits &= CMP_MAP_H - 1; __afl_cmp_map->log[k][hits].v0 = (u64)arg1; __afl_cmp_map->log[k][hits].v1 = (u64)arg2; __afl_cmp_map->log[k][hits].v0_128 = (u64)(arg1 >> 64); __afl_cmp_map->log[k][hits].v1_128 = (u64)(arg2 >> 64); } #endif #if defined(__APPLE__) #pragma weak __sanitizer_cov_trace_const_cmp1 = __cmplog_ins_hook1 #pragma weak __sanitizer_cov_trace_const_cmp2 = __cmplog_ins_hook2 #pragma weak __sanitizer_cov_trace_const_cmp4 = __cmplog_ins_hook4 #pragma weak __sanitizer_cov_trace_const_cmp8 = __cmplog_ins_hook8 #pragma weak __sanitizer_cov_trace_const_cmp16 = __cmplog_ins_hook16 #pragma weak __sanitizer_cov_trace_cmp1 = __cmplog_ins_hook1 #pragma weak __sanitizer_cov_trace_cmp2 = __cmplog_ins_hook2 #pragma weak __sanitizer_cov_trace_cmp4 = __cmplog_ins_hook4 #pragma weak __sanitizer_cov_trace_cmp8 = __cmplog_ins_hook8 #pragma weak __sanitizer_cov_trace_cmp16 = __cmplog_ins_hook16 #else void __sanitizer_cov_trace_const_cmp1(uint8_t arg1, uint8_t arg2) __attribute__((alias("__cmplog_ins_hook1"))); void __sanitizer_cov_trace_const_cmp2(uint16_t arg1, uint16_t arg2) __attribute__((alias("__cmplog_ins_hook2"))); void __sanitizer_cov_trace_const_cmp4(uint32_t arg1, uint32_t arg2) __attribute__((alias("__cmplog_ins_hook4"))); void __sanitizer_cov_trace_const_cmp8(uint64_t arg1, uint64_t arg2) __attribute__((alias("__cmplog_ins_hook8"))); #ifdef WORD_SIZE_64 void __sanitizer_cov_trace_const_cmp16(uint128_t arg1, uint128_t arg2) __attribute__((alias("__cmplog_ins_hook16"))); #endif void __sanitizer_cov_trace_cmp1(uint8_t arg1, uint8_t arg2) __attribute__((alias("__cmplog_ins_hook1"))); void __sanitizer_cov_trace_cmp2(uint16_t arg1, uint16_t arg2) __attribute__((alias("__cmplog_ins_hook2"))); void __sanitizer_cov_trace_cmp4(uint32_t arg1, uint32_t arg2) __attribute__((alias("__cmplog_ins_hook4"))); void __sanitizer_cov_trace_cmp8(uint64_t arg1, uint64_t arg2) __attribute__((alias("__cmplog_ins_hook8"))); #ifdef WORD_SIZE_64 void __sanitizer_cov_trace_cmp16(uint128_t arg1, uint128_t arg2) __attribute__((alias("__cmplog_ins_hook16"))); #endif #endif /* defined(__APPLE__) */ void __sanitizer_cov_trace_switch(uint64_t val, uint64_t *cases) { if (unlikely(!__afl_cmp_map)) return; for (uint64_t i = 0; i < cases[0]; i++) { uintptr_t k = (uintptr_t)__builtin_return_address(0) + i; k = (k >> 4) ^ (k << 8); k &= CMP_MAP_W - 1; u32 hits; if (__afl_cmp_map->headers[k].type != CMP_TYPE_INS) { __afl_cmp_map->headers[k].type = CMP_TYPE_INS; hits = 0; __afl_cmp_map->headers[k].hits = 1; __afl_cmp_map->headers[k].shape = 7; } else { hits = __afl_cmp_map->headers[k].hits++; if (__afl_cmp_map->headers[k].shape < 7) { __afl_cmp_map->headers[k].shape = 7; } } __afl_cmp_map->headers[k].attribute = 1; hits &= CMP_MAP_H - 1; __afl_cmp_map->log[k][hits].v0 = val; __afl_cmp_map->log[k][hits].v1 = cases[i + 2]; } } // POSIX shenanigan to see if an area is mapped. // If it is mapped as X-only, we have a problem, so maybe we should add a check // to avoid to call it on .text addresses static int area_is_mapped(void *ptr, size_t len) { char *p = ptr; char *page = (char *)((uintptr_t)p & ~(sysconf(_SC_PAGE_SIZE) - 1)); int r = msync(page, (p - page) + len, MS_ASYNC); if (r < 0) return errno != ENOMEM; return 1; } void __cmplog_rtn_hook(u8 *ptr1, u8 *ptr2) { /* u32 i; if (!area_is_mapped(ptr1, 32) || !area_is_mapped(ptr2, 32)) return; fprintf(stderr, "rtn arg0="); for (i = 0; i < 24; i++) fprintf(stderr, "%02x", ptr1[i]); fprintf(stderr, " arg1="); for (i = 0; i < 24; i++) fprintf(stderr, "%02x", ptr2[i]); fprintf(stderr, "\n"); */ if (unlikely(!__afl_cmp_map)) return; if (!area_is_mapped(ptr1, 32) || !area_is_mapped(ptr2, 32)) return; uintptr_t k = (uintptr_t)__builtin_return_address(0); k = (k >> 4) ^ (k << 8); k &= CMP_MAP_W - 1; u32 hits; if (__afl_cmp_map->headers[k].type != CMP_TYPE_RTN) { __afl_cmp_map->headers[k].type = CMP_TYPE_RTN; hits = 0; __afl_cmp_map->headers[k].hits = 1; __afl_cmp_map->headers[k].shape = 31; } else { hits = __afl_cmp_map->headers[k].hits++; if (__afl_cmp_map->headers[k].shape < 31) { __afl_cmp_map->headers[k].shape = 31; } } hits &= CMP_MAP_RTN_H - 1; __builtin_memcpy(((struct cmpfn_operands *)__afl_cmp_map->log[k])[hits].v0, ptr1, 32); __builtin_memcpy(((struct cmpfn_operands *)__afl_cmp_map->log[k])[hits].v1, ptr2, 32); } // gcc libstdc++ // _ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE7compareEPKc static u8 *get_gcc_stdstring(u8 *string) { u32 *len = (u32 *)(string + 8); if (*len < 16) { // in structure return (string + 16); } else { // in memory u8 **ptr = (u8 **)string; return (*ptr); } } // llvm libc++ _ZNKSt3__112basic_stringIcNS_11char_traitsIcEENS_9allocator // IcEEE7compareEmmPKcm static u8 *get_llvm_stdstring(u8 *string) { // length is in: if ((string[0] & 1) == 0) u8 len = (string[0] >> 1); // or: if (string[0] & 1) u32 *len = (u32 *) (string + 8); if (string[0] & 1) { // in memory u8 **ptr = (u8 **)(string + 16); return (*ptr); } else { // in structure return (string + 1); } } void __cmplog_rtn_gcc_stdstring_cstring(u8 *stdstring, u8 *cstring) { __cmplog_rtn_hook(get_gcc_stdstring(stdstring), cstring); } void __cmplog_rtn_gcc_stdstring_stdstring(u8 *stdstring1, u8 *stdstring2) { __cmplog_rtn_hook(get_gcc_stdstring(stdstring1), get_gcc_stdstring(stdstring2)); } void __cmplog_rtn_llvm_stdstring_cstring(u8 *stdstring, u8 *cstring) { __cmplog_rtn_hook(get_llvm_stdstring(stdstring), cstring); } void __cmplog_rtn_llvm_stdstring_stdstring(u8 *stdstring1, u8 *stdstring2) { __cmplog_rtn_hook(get_llvm_stdstring(stdstring1), get_llvm_stdstring(stdstring2)); } /* COVERAGE manipulation features */ // this variable is then used in the shm setup to create an additional map // if __afl_map_size > MAP_SIZE or cmplog is used. // Especially with cmplog this would result in a ~260MB mem increase per // target run. // disable coverage from this point onwards until turned on again void __afl_coverage_off() { if (likely(__afl_selective_coverage)) { __afl_area_ptr = __afl_area_ptr_dummy; __afl_cmp_map = NULL; } } // enable coverage void __afl_coverage_on() { if (likely(__afl_selective_coverage && __afl_selective_coverage_temp)) { __afl_area_ptr = __afl_area_ptr_backup; __afl_cmp_map = __afl_cmp_map_backup; } } // discard all coverage up to this point void __afl_coverage_discard() { memset(__afl_area_ptr_backup, 0, __afl_map_size); __afl_area_ptr_backup[0] = 1; if (__afl_cmp_map) { memset(__afl_cmp_map, 0, sizeof(struct cmp_map)); } } // discard the testcase void __afl_coverage_skip() { __afl_coverage_discard(); if (likely(is_persistent && __afl_selective_coverage)) { __afl_coverage_off(); __afl_selective_coverage_temp = 0; } else { exit(0); } } // mark this area as especially interesting void __afl_coverage_interesting(u8 val, u32 id) { __afl_area_ptr[id] = val; }