diff options
Diffstat (limited to 'src/afl-fuzz-skipdet.c')
| -rw-r--r-- | src/afl-fuzz-skipdet.c | 403 |
1 files changed, 403 insertions, 0 deletions
diff --git a/src/afl-fuzz-skipdet.c b/src/afl-fuzz-skipdet.c new file mode 100644 index 00000000..e52d59a3 --- /dev/null +++ b/src/afl-fuzz-skipdet.c @@ -0,0 +1,403 @@ + + +#include "afl-fuzz.h" + +void flip_range(u8 *input, u32 pos, u32 size) { + + for (u32 i = 0; i < size; i++) + input[pos + i] ^= 0xFF; + + return; + +} + +#define MAX_EFF_TIMEOUT (10 * 60 * 1000) +#define MAX_DET_TIMEOUT (15 * 60 * 1000) +u8 is_det_timeout(u64 cur_ms, u8 is_flip) { + + if (is_flip) { + + if (unlikely(get_cur_time() - cur_ms > MAX_EFF_TIMEOUT)) return 1; + + } else { + + if (unlikely(get_cur_time() - cur_ms > MAX_DET_TIMEOUT)) return 1; + + } + + return 0; + +} + +/* decide if the seed should be deterministically fuzzed */ + +u8 should_det_fuzz(afl_state_t *afl, struct queue_entry *q) { + + if (!afl->skipdet_g->virgin_det_bits) { + + afl->skipdet_g->virgin_det_bits = + (u8 *)ck_alloc(sizeof(u8) * afl->fsrv.map_size); + + } + + if (!q->favored || q->passed_det) return 0; + if (!q->trace_mini) return 0; + + if (!afl->skipdet_g->last_cov_undet) + afl->skipdet_g->last_cov_undet = get_cur_time(); + + if (get_cur_time() - afl->skipdet_g->last_cov_undet >= THRESHOLD_DEC_TIME) { + + if (afl->skipdet_g->undet_bits_threshold >= 2) { + + afl->skipdet_g->undet_bits_threshold *= 0.75; + afl->skipdet_g->last_cov_undet = get_cur_time(); + + } + + } + + u32 new_det_bits = 0; + + for (u32 i = 0; i < afl->fsrv.map_size; i++) { + + if (unlikely(q->trace_mini[i >> 3] & (1 << (i & 7)))) { + + if (!afl->skipdet_g->virgin_det_bits[i]) { new_det_bits++; } + + } + + } + + if (!afl->skipdet_g->undet_bits_threshold) + afl->skipdet_g->undet_bits_threshold = new_det_bits * 0.05; + + if (new_det_bits >= afl->skipdet_g->undet_bits_threshold) { + + afl->skipdet_g->last_cov_undet = get_cur_time(); + q->skipdet_e->undet_bits = new_det_bits; + + for (u32 i = 0; i < afl->fsrv.map_size; i++) { + + if (unlikely(q->trace_mini[i >> 3] & (1 << (i & 7)))) { + + if (!afl->skipdet_g->virgin_det_bits[i]) + afl->skipdet_g->virgin_det_bits[i] = 1; + + } + + } + + return 1; + + } + + return 0; + +} + +/* + consists of two stages that + return 0 if exec failed. +*/ + +u8 skip_deterministic_stage(afl_state_t *afl, u8 *orig_buf, u8 *out_buf, + u32 len, u64 before_det_time) { + + u64 orig_hit_cnt, new_hit_cnt; + + if (afl->queue_cur->skipdet_e->done_eff) return 1; + + if (!should_det_fuzz(afl, afl->queue_cur)) return 1; + + /* Add check to make sure that for seeds without too much undet bits, + we ignore them */ + + /****************** + * SKIP INFERENCE * + ******************/ + + afl->stage_short = "inf"; + afl->stage_name = "inference"; + afl->stage_cur = 0; + orig_hit_cnt = afl->queued_items + afl->saved_crashes; + + u8 *inf_eff_map = (u8 *)ck_alloc(sizeof(u8) * len); + memset(inf_eff_map, 1, sizeof(u8) * len); + + if (common_fuzz_stuff(afl, orig_buf, len)) { return 0; } + + u64 prev_cksum = hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST); + u64 _prev_cksum = prev_cksum; + + if (MINIMAL_BLOCK_SIZE * 8 < len) { + + // u64 size_skiped = 0, quick_skip_exec = total_execs, quick_skip_time = + // get_cur_time(); + u64 pre_inf_exec = afl->fsrv.total_execs, pre_inf_time = get_cur_time(); + + /* if determine stage time / input size is too small, just go ahead */ + + u32 pos = 0, cur_block_size = MINIMAL_BLOCK_SIZE, max_block_size = len / 8; + + while (pos < len - 1) { + + cur_block_size = MINIMAL_BLOCK_SIZE; + + while (cur_block_size < max_block_size) { + + u32 flip_block_size = + (cur_block_size + pos < len) ? cur_block_size : len - 1 - pos; + + afl->stage_cur += 1; + + flip_range(out_buf, pos, flip_block_size); + + if (common_fuzz_stuff(afl, out_buf, len)) return 0; + + flip_range(out_buf, pos, flip_block_size); + + u64 cksum = + hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST); + + // printf("Now trying range %d with %d, %s.\n", pos, cur_block_size, + // (cksum == prev_cksum) ? (u8*)"Yes" : (u8*) "Not"); + + /* continue until we fail or exceed length */ + if (cksum == _prev_cksum) { + + cur_block_size *= 2; + + if (cur_block_size >= len - 1 - pos) break; + + } else { + + break; + + } + + } + + if (cur_block_size == MINIMAL_BLOCK_SIZE) { + + /* we failed early on*/ + + pos += cur_block_size; + + } else { + + u32 cur_skip_len = (cur_block_size / 2 + pos < len) + ? (cur_block_size / 2) + : (len - pos - 1); + + memset(inf_eff_map + pos, 0, cur_skip_len); + + afl->skipdet_g->inf_prof->inf_skipped_bytes += cur_skip_len; + + pos += cur_skip_len; + + } + + } + + afl->skipdet_g->inf_prof->inf_execs_cost += + (afl->fsrv.total_execs - pre_inf_exec); + afl->skipdet_g->inf_prof->inf_time_cost += (get_cur_time() - pre_inf_time); + // PFATAL("Done, now have %d bytes skipped, with exec %lld, time %lld.\n", + // afl->inf_skipped_bytes, afl->inf_execs_cost, afl->inf_time_cost); + + } else + + memset(inf_eff_map, 1, len); + + new_hit_cnt = afl->queued_items + afl->saved_crashes; + + afl->stage_finds[STAGE_INF] += new_hit_cnt - orig_hit_cnt; + afl->stage_cycles[STAGE_INF] += afl->stage_cur; + + /**************************** + * Quick Skip Effective Map * + ****************************/ + + /* Quick Effective Map Calculation */ + + afl->stage_short = "quick"; + afl->stage_name = "quick eff"; + afl->stage_cur = 0; + afl->stage_max = 32 * 1024; + + orig_hit_cnt = afl->queued_items + afl->saved_crashes; + + u32 before_skip_inf = afl->queued_items; + + /* clean all the eff bytes, since previous eff bytes are already fuzzed */ + u8 *skip_eff_map = afl->queue_cur->skipdet_e->skip_eff_map, + *done_inf_map = afl->queue_cur->skipdet_e->done_inf_map; + + if (!skip_eff_map) { + + skip_eff_map = (u8 *)ck_alloc(sizeof(u8) * len); + afl->queue_cur->skipdet_e->skip_eff_map = skip_eff_map; + + } else { + + memset(skip_eff_map, 0, sizeof(u8) * len); + + } + + /* restore the starting point */ + if (!done_inf_map) { + + done_inf_map = (u8 *)ck_alloc(sizeof(u8) * len); + afl->queue_cur->skipdet_e->done_inf_map = done_inf_map; + + } else { + + for (afl->stage_cur = 0; afl->stage_cur < len; afl->stage_cur++) { + + if (done_inf_map[afl->stage_cur] == 0) break; + + } + + } + + /* depending on the seed's performance, we could search eff bytes + for multiple rounds */ + + u8 eff_round_continue = 1, eff_round_done = 0, done_eff = 0, repeat_eff = 0, + fuzz_nearby = 0, *non_eff_bytes = 0; + + u64 before_eff_execs = afl->fsrv.total_execs; + + if (getenv("REPEAT_EFF")) repeat_eff = 1; + if (getenv("FUZZ_NEARBY")) fuzz_nearby = 1; + + if (fuzz_nearby) { + + non_eff_bytes = (u8 *)ck_alloc(sizeof(u8) * len); + + // clean exec cksum + if (common_fuzz_stuff(afl, out_buf, len)) { return 0; } + prev_cksum = hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST); + + } + + do { + + eff_round_continue = 0; + afl->stage_max = 32 * 1024; + + for (; afl->stage_cur < afl->stage_max && afl->stage_cur < len; + ++afl->stage_cur) { + + afl->stage_cur_byte = afl->stage_cur; + + if (!inf_eff_map[afl->stage_cur_byte] || + skip_eff_map[afl->stage_cur_byte]) + continue; + + if (is_det_timeout(before_det_time, 1)) { goto cleanup_skipdet; } + + u8 orig = out_buf[afl->stage_cur_byte], replace = rand_below(afl, 256); + + while (replace == orig) { + + replace = rand_below(afl, 256); + + } + + out_buf[afl->stage_cur_byte] = replace; + + before_skip_inf = afl->queued_items; + + if (common_fuzz_stuff(afl, out_buf, len)) { return 0; } + + out_buf[afl->stage_cur_byte] = orig; + + if (fuzz_nearby) { + + if (prev_cksum == + hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST)) { + + non_eff_bytes[afl->stage_cur_byte] = 1; + + } + + } + + if (afl->queued_items != before_skip_inf) { + + skip_eff_map[afl->stage_cur_byte] = 1; + afl->queue_cur->skipdet_e->quick_eff_bytes += 1; + + if (afl->stage_max < MAXIMUM_QUICK_EFF_EXECS) { afl->stage_max *= 2; } + + if (afl->stage_max == MAXIMUM_QUICK_EFF_EXECS && repeat_eff) + eff_round_continue = 1; + + } + + done_inf_map[afl->stage_cur_byte] = 1; + + } + + afl->stage_cur = 0; + done_eff = 1; + + if (++eff_round_done >= 8) break; + + } while (eff_round_continue); + + new_hit_cnt = afl->queued_items + afl->saved_crashes; + + afl->stage_finds[STAGE_QUICK] += new_hit_cnt - orig_hit_cnt; + afl->stage_cycles[STAGE_QUICK] += (afl->fsrv.total_execs - before_eff_execs); + +cleanup_skipdet: + + if (fuzz_nearby) { + + u8 *nearby_bytes = (u8 *)ck_alloc(sizeof(u8) * len); + + u32 i = 3; + while (i < len) { + + // assume DWORD size, from i - 3 -> i + 3 + if (skip_eff_map[i]) { + + u32 fill_length = (i + 3 < len) ? 7 : len - i + 2; + memset(nearby_bytes + i - 3, 1, fill_length); + i += 3; + + } else + + i += 1; + + } + + for (i = 0; i < len; i++) { + + if (nearby_bytes[i] && !non_eff_bytes[i]) skip_eff_map[i] = 1; + + } + + ck_free(nearby_bytes); + ck_free(non_eff_bytes); + + } + + if (done_eff) { + + afl->queue_cur->skipdet_e->continue_inf = 0; + afl->queue_cur->skipdet_e->done_eff = 1; + + } else { + + afl->queue_cur->skipdet_e->continue_inf = 1; + + } + + return 1; + +} + |