diff options
Diffstat (limited to 'instrumentation/afl-compiler-rt.o.c')
| -rw-r--r-- | instrumentation/afl-compiler-rt.o.c | 188 |
1 files changed, 143 insertions, 45 deletions
diff --git a/instrumentation/afl-compiler-rt.o.c b/instrumentation/afl-compiler-rt.o.c index d583e246..ff14b966 100644 --- a/instrumentation/afl-compiler-rt.o.c +++ b/instrumentation/afl-compiler-rt.o.c @@ -125,6 +125,17 @@ static u8 is_persistent; static u8 _is_sancov; +/* Debug? */ + +static u32 __afl_debug; + +/* Already initialized markers */ + +u32 __afl_already_initialized_shm; +u32 __afl_already_initialized_forkserver; +u32 __afl_already_initialized_first; +u32 __afl_already_initialized_second; + /* Dummy pipe for area_is_valid() */ static int __afl_dummy_fd[2] = {2, 2}; @@ -178,7 +189,7 @@ static void __afl_map_shm_fuzz() { char *id_str = getenv(SHM_FUZZ_ENV_VAR); - if (getenv("AFL_DEBUG")) { + if (__afl_debug) { fprintf(stderr, "DEBUG: fuzzcase shmem %s\n", id_str ? id_str : "none"); @@ -224,7 +235,7 @@ static void __afl_map_shm_fuzz() { __afl_fuzz_len = (u32 *)map; __afl_fuzz_ptr = map + sizeof(u32); - if (getenv("AFL_DEBUG")) { + if (__afl_debug) { fprintf(stderr, "DEBUG: successfully got fuzzing shared memory\n"); @@ -244,7 +255,6 @@ static void __afl_map_shm_fuzz() { static void __afl_map_shm(void) { - static u32 __afl_already_initialized_shm = 0; if (__afl_already_initialized_shm) return; __afl_already_initialized_shm = 1; @@ -305,7 +315,7 @@ static void __afl_map_shm(void) { 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")) + if (__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, " @@ -361,17 +371,18 @@ static void __afl_map_shm(void) { } - if (shm_base == MAP_FAILED) { + close(shm_fd); + shm_fd = -1; - close(shm_fd); - shm_fd = -1; + if (shm_base == MAP_FAILED) { fprintf(stderr, "mmap() failed\n"); + perror("mmap for map"); + if (__afl_map_addr) send_forkserver_error(FS_ERROR_MAP_ADDR); else send_forkserver_error(FS_ERROR_MMAP); - perror("mmap for map"); exit(2); @@ -478,7 +489,7 @@ static void __afl_map_shm(void) { id_str = getenv(CMPLOG_SHM_ENV_VAR); - if (getenv("AFL_DEBUG")) { + if (__afl_debug) { fprintf(stderr, "DEBUG: cmplog id_str %s\n", id_str == NULL ? "<null>" : id_str); @@ -543,6 +554,58 @@ static void __afl_map_shm(void) { } +/* unmap SHM. */ + +static void __afl_unmap_shm(void) { + + if (!__afl_already_initialized_shm) return; + + char *id_str = getenv(SHM_ENV_VAR); + + if (id_str) { + +#ifdef USEMMAP + + munmap((void *)__afl_area_ptr, __afl_map_size); + +#else + + shmdt((void *)__afl_area_ptr); + +#endif + + } else if ((!__afl_area_ptr || __afl_area_ptr == __afl_area_initial) && + + __afl_map_addr) { + + munmap((void *)__afl_map_addr, __afl_map_size); + + } + + __afl_area_ptr = __afl_area_ptr_dummy; + + id_str = getenv(CMPLOG_SHM_ENV_VAR); + + if (id_str) { + +#ifdef USEMMAP + + munmap((void *)__afl_cmp_map, __afl_map_size); + +#else + + shmdt((void *)__afl_cmp_map); + +#endif + + __afl_cmp_map = NULL; + + } + + __afl_already_initialized_shm = 0; + +} + #ifdef __linux__ static void __afl_start_snapshots(void) { @@ -571,7 +634,7 @@ static void __afl_start_snapshots(void) { if (read(FORKSRV_FD, &was_killed, 4) != 4) { _exit(1); } - if (getenv("AFL_DEBUG")) { + if (__afl_debug) { fprintf(stderr, "target forkserver recv: %08x\n", was_killed); @@ -748,7 +811,6 @@ static void __afl_start_snapshots(void) { static void __afl_start_forkserver(void) { - static u32 __afl_already_initialized_forkserver = 0; if (__afl_already_initialized_forkserver) return; __afl_already_initialized_forkserver = 1; @@ -802,7 +864,7 @@ static void __afl_start_forkserver(void) { if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1); - if (getenv("AFL_DEBUG")) { + if (__afl_debug) { fprintf(stderr, "target forkserver recv: %08x\n", was_killed); @@ -1037,7 +1099,7 @@ void __afl_manual_init(void) { __afl_sharedmem_fuzzing = 0; if (__afl_area_ptr == NULL) __afl_area_ptr = __afl_area_ptr_dummy; - if (getenv("AFL_DEBUG")) + if (__afl_debug) fprintf(stderr, "DEBUG: disabled instrumentation because of " "AFL_DISABLE_LLVM_INSTRUMENTATION\n"); @@ -1081,10 +1143,11 @@ __attribute__((constructor(CTOR_PRIO))) void __afl_auto_early(void) { __attribute__((constructor(1))) void __afl_auto_second(void) { - static u32 __afl_already_initialized_second = 0; if (__afl_already_initialized_second) return; __afl_already_initialized_second = 1; + if (getenv("AFL_DEBUG")) { __afl_debug = 1; } + if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return; u8 *ptr; @@ -1109,21 +1172,18 @@ __attribute__((constructor(1))) void __afl_auto_second(void) { } -} +} // ptr memleak report is a false positive /* preset __afl_area_ptr #1 - at constructor level 0 global variables have not been set */ __attribute__((constructor(0))) void __afl_auto_first(void) { - static u32 __afl_already_initialized_first = 0; if (__afl_already_initialized_first) return; __afl_already_initialized_first = 1; if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return; - u8 *ptr; - - ptr = (u8 *)malloc(MAP_INITIAL_SIZE); + u8 *ptr = (u8 *)malloc(MAP_INITIAL_SIZE); if (ptr && (ssize_t)ptr != -1) { @@ -1132,7 +1192,7 @@ __attribute__((constructor(0))) void __afl_auto_first(void) { } -} +} // ptr memleak report is a false positive /* The following stuff deals with supporting -fsanitize-coverage=trace-pc-guard. It remains non-operational in the traditional, plugin-backed LLVM mode. @@ -1200,11 +1260,13 @@ void __sanitizer_cov_trace_pc_guard_init(uint32_t *start, uint32_t *stop) { _is_sancov = 1; - if (getenv("AFL_DEBUG")) { + if (__afl_debug) { fprintf(stderr, - "Running __sanitizer_cov_trace_pc_guard_init: %p-%p (%lu edges)\n", - start, stop, (unsigned long)(stop - start)); + "Running __sanitizer_cov_trace_pc_guard_init: %p-%p (%lu edges) " + "after_fs=%u\n", + start, stop, (unsigned long)(stop - start), + __afl_already_initialized_forkserver); } @@ -1220,6 +1282,36 @@ void __sanitizer_cov_trace_pc_guard_init(uint32_t *start, uint32_t *stop) { } + /* instrumented code is loaded *after* our forkserver is up. this is a + problem. We cannot prevent collisions then :( */ + if (__afl_already_initialized_forkserver && + __afl_final_loc + 1 + stop - start > __afl_map_size) { + + if (__afl_debug) + fprintf(stderr, "Warning: new instrumneted code after the forkserver!\n"); + __afl_final_loc = 2; + + if (1 + stop - start > __afl_map_size) { + + *(start++) = ++__afl_final_loc; + + while (start < stop) { + + if (R(100) < inst_ratio) + *start = ++__afl_final_loc % __afl_map_size; + else + *start = 0; + + start++; + + } + + return; + + } + + } + /* 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). */ @@ -1237,6 +1329,28 @@ void __sanitizer_cov_trace_pc_guard_init(uint32_t *start, uint32_t *stop) { } + if (__afl_debug) { + + fprintf(stderr, + "Done __sanitizer_cov_trace_pc_guard_init: __afl_final_loc = %u\n", + __afl_final_loc); + + } + + if (__afl_already_initialized_shm && __afl_final_loc > __afl_map_size) { + + if (__afl_debug) { + + fprintf(stderr, "Reinit shm necessary (+%u)\n", + __afl_final_loc - __afl_map_size); + + } + + __afl_unmap_shm(); + __afl_map_shm(); + + } + } ///// CmpLog instrumentation @@ -1591,41 +1705,25 @@ __attribute__((weak)) void *__asan_region_is_poisoned(void *beg, size_t size) { // to avoid to call it on .text addresses static int area_is_valid(void *ptr, size_t len) { - void *ret_ptr = __asan_region_is_poisoned(ptr, len); - - if (ret_ptr) { // region is poisoned - - ssize_t ret_diff = ret_ptr - ptr; - - if (ret_diff <= 0) { - - return 0; - - } else { - - return ret_diff; // only partially poisoned - - } - - } + if (unlikely(__asan_region_is_poisoned(ptr, len))) { return 0; } - int r = syscall(__afl_dummy_fd[1], SYS_write, ptr, len); + long r = syscall(__afl_dummy_fd[1], SYS_write, ptr, len); - if (r <= 0) { // maybe this is going over an asan boundary + if (unlikely(r <= 0 || r > len)) { // fail - maybe hitting asan boundary? char *p = (char *)ptr; long page_size = sysconf(_SC_PAGE_SIZE); char *page = (char *)((uintptr_t)p & ~(page_size - 1)) + page_size; - if (page < p + len) { return 0; } + if (page < p + len) { return 0; } // no isnt, return fail len -= (p + len - page); r = syscall(__afl_dummy_fd[1], SYS_write, p, len); } // partial writes - we return what was written. - if (r > 0) { + if (likely(r >= 0 && r <= len)) { - return r; + return (int)r; } else { |