/* american fuzzy lop++ - redqueen implementation on top of cmplog --------------------------------------------------------------- Originally written by Michal Zalewski Forkserver design by Jann Horn Now maintained by by Marc Heuse , Heiko Eißfeldt and Andrea Fioraldi Copyright 2016, 2017 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 Shared code to handle the shared memory. This is used by the fuzzer as well the other components like afl-tmin, afl-showmap, etc... */ #include "afl-fuzz.h" #include "cmplog.h" ///// Colorization struct range { u32 start; u32 end; struct range *next; }; static struct range *add_range(struct range *ranges, u32 start, u32 end) { struct range *r = ck_alloc_nozero(sizeof(struct range)); r->start = start; r->end = end; r->next = ranges; return r; } static struct range *pop_biggest_range(struct range **ranges) { struct range *r = *ranges; struct range *prev = NULL; struct range *rmax = NULL; struct range *prev_rmax = NULL; u32 max_size = 0; while (r) { u32 s = r->end - r->start; if (s >= max_size) { max_size = s; prev_rmax = prev; rmax = r; } prev = r; r = r->next; } if (rmax) { if (prev_rmax) { prev_rmax->next = rmax->next; } else { *ranges = rmax->next; } } return rmax; } static u8 get_exec_checksum(afl_state_t *afl, u8 *buf, u32 len, u64 *cksum) { if (unlikely(common_fuzz_stuff(afl, buf, len))) { return 1; } *cksum = hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST); return 0; } static void rand_replace(afl_state_t *afl, u8 *buf, u32 len) { u32 i; for (i = 0; i < len; ++i) { buf[i] = rand_below(afl, 256); } } static u8 colorization(afl_state_t *afl, u8 *buf, u32 len, u64 exec_cksum) { struct range *ranges = add_range(NULL, 0, len); u8 * backup = ck_alloc_nozero(len); u8 needs_write = 0; u64 orig_hit_cnt, new_hit_cnt; orig_hit_cnt = afl->queued_paths + afl->unique_crashes; afl->stage_name = "colorization"; afl->stage_short = "colorization"; afl->stage_max = 1000; struct range *rng = NULL; afl->stage_cur = 0; while ((rng = pop_biggest_range(&ranges)) != NULL && afl->stage_cur < afl->stage_max) { u32 s = rng->end - rng->start; if (s != 0) { /* Range not empty */ memcpy(backup, buf + rng->start, s); rand_replace(afl, buf + rng->start, s); u64 cksum; u64 start_us = get_cur_time_us(); if (unlikely(get_exec_checksum(afl, buf, len, &cksum))) { goto checksum_fail; } u64 stop_us = get_cur_time_us(); /* Discard if the mutations change the paths or if it is too decremental in speed */ if (cksum != exec_cksum || (stop_us - start_us > 2 * afl->queue_cur->exec_us)) { ranges = add_range(ranges, rng->start, rng->start + s / 2); ranges = add_range(ranges, rng->start + s / 2 + 1, rng->end); memcpy(buf + rng->start, backup, s); } else { needs_write = 1; } } ck_free(rng); rng = NULL; ++afl->stage_cur; } if (afl->stage_cur < afl->stage_max) { afl->queue_cur->fully_colorized = 1; } new_hit_cnt = afl->queued_paths + afl->unique_crashes; afl->stage_finds[STAGE_COLORIZATION] += new_hit_cnt - orig_hit_cnt; afl->stage_cycles[STAGE_COLORIZATION] += afl->stage_cur; ck_free(backup); while (ranges) { rng = ranges; ranges = ranges->next; ck_free(rng); rng = NULL; } ck_free(rng); rng = NULL; // save the input with the high entropy if (needs_write) { s32 fd; if (afl->no_unlink) { fd = open(afl->queue_cur->fname, O_WRONLY | O_CREAT | O_TRUNC, 0600); } else { unlink(afl->queue_cur->fname); /* ignore errors */ fd = open(afl->queue_cur->fname, O_WRONLY | O_CREAT | O_EXCL, 0600); } if (fd < 0) { PFATAL("Unable to create '%s'", afl->queue_cur->fname); } ck_write(fd, buf, len, afl->queue_cur->fname); afl->queue_cur->len = len; // no-op, just to be 100% safe close(fd); } return 0; checksum_fail: if (rng) { ck_free(rng); } ck_free(backup); while (ranges) { rng = ranges; ranges = ranges->next; ck_free(rng); rng = NULL; } // TODO: clang notices a _potential_ leak of mem pointed to by rng return 1; } ///// Input to State replacement static u8 its_fuzz(afl_state_t *afl, u8 *buf, u32 len, u8 *status) { u64 orig_hit_cnt, new_hit_cnt; orig_hit_cnt = afl->queued_paths + afl->unique_crashes; if (unlikely(common_fuzz_stuff(afl, buf, len))) { return 1; } new_hit_cnt = afl->queued_paths + afl->unique_crashes; if (unlikely(new_hit_cnt != orig_hit_cnt)) { *status = 1; } else { *status = 2; } return 0; } static u8 cmp_extend_encoding(afl_state_t *afl, struct cmp_header *h, u64 pattern, u64 repl, u64 o_pattern, u32 idx, u8 *orig_buf, u8 *buf, u32 len, u8 do_reverse, u8 *status) { u64 *buf_64 = (u64 *)&buf[idx]; u32 *buf_32 = (u32 *)&buf[idx]; u16 *buf_16 = (u16 *)&buf[idx]; u8 * buf_8 = &buf[idx]; u64 *o_buf_64 = (u64 *)&orig_buf[idx]; u32 *o_buf_32 = (u32 *)&orig_buf[idx]; u16 *o_buf_16 = (u16 *)&orig_buf[idx]; u8 * o_buf_8 = &orig_buf[idx]; u32 its_len = len - idx; *status = 0; if (SHAPE_BYTES(h->shape) == 8) { if (its_len >= 8 && *buf_64 == pattern && *o_buf_64 == o_pattern) { *buf_64 = repl; if (unlikely(its_fuzz(afl, buf, len, status))) { return 1; } *buf_64 = pattern; } // reverse encoding if (do_reverse) { if (unlikely(cmp_extend_encoding(afl, h, SWAP64(pattern), SWAP64(repl), SWAP64(o_pattern), idx, orig_buf, buf, len, 0, status))) { return 1; } } } if (SHAPE_BYTES(h->shape) == 4 || *status == 2) { if (its_len >= 4 && *buf_32 == (u32)pattern && *o_buf_32 == (u32)o_pattern) { *buf_32 = (u32)repl; if (unlikely(its_fuzz(afl, buf, len, status))) { return 1; } *buf_32 = pattern; } // reverse encoding if (do_reverse) { if (unlikely(cmp_extend_encoding(afl, h, SWAP32(pattern), SWAP32(repl), SWAP32(o_pattern), idx, orig_buf, buf, len, 0, status))) { return 1; } } } if (SHAPE_BYTES(h->shape) == 2 || *status == 2) { if (its_len >= 2 && *buf_16 == (u16)pattern && *o_buf_16 == (u16)o_pattern) { *buf_16 = (u16)repl; if (unlikely(its_fuzz(afl, buf, len, status))) { return 1; } *buf_16 = (u16)pattern; } // reverse encoding if (do_reverse) { if (unlikely(cmp_extend_encoding(afl, h, SWAP16(pattern), SWAP16(repl), SWAP16(o_pattern), idx, orig_buf, buf, len, 0, status))) { return 1; } } } if (SHAPE_BYTES(h->shape) == 1 || *status == 2) { if (its_len >= 1 && *buf_8 == (u8)pattern && *o_buf_8 == (u8)o_pattern) { *buf_8 = (u8)repl; if (unlikely(its_fuzz(afl, buf, len, status))) { return 1; } *buf_8 = (u8)pattern; } } return 0; } static void try_to_add_to_dict(afl_state_t *afl, u64 v, u8 shape) { u8 *b = (u8 *)&v; u32 k; u8 cons_ff = 0, cons_0 = 0; for (k = 0; k < shape; ++k) { if (b[k] == 0) { ++cons_0; } else if (b[k] == 0xff) { ++cons_0; } else { cons_0 = cons_ff = 0; } if (cons_0 > 1 || cons_ff > 1) { return; } } maybe_add_auto((u8 *)afl, (u8 *)&v, shape); u64 rev; switch (shape) { case 1: break; case 2: rev = SWAP16((u16)v); maybe_add_auto((u8 *)afl, (u8 *)&rev, shape); break; case 4: rev = SWAP32((u32)v); maybe_add_auto((u8 *)afl, (u8 *)&rev, shape); break; case 8: rev = SWAP64(v); maybe_add_auto((u8 *)afl, (u8 *)&rev, shape); break; } } static u8 cmp_fuzz(afl_state_t *afl, u32 key, u8 *orig_buf, u8 *buf, u32 len) { struct cmp_header *h = &afl->shm.cmp_map->headers[key]; u32 i, j, idx; u32 loggeds = h->hits; if (h->hits > CMP_MAP_H) { loggeds = CMP_MAP_H; } u8 status = 0; // opt not in the paper u32 fails; u8 found_one = 0; /* loop cmps are useless, detect and blacklist them */ u64 s_v0, s_v1; u8 s_v0_fixed = 1, s_v1_fixed = 1; u8 s_v0_inc = 1, s_v1_inc = 1; u8 s_v0_dec = 1, s_v1_dec = 1; for (i = 0; i < loggeds; ++i) { fails = 0; struct cmp_operands *o = &afl->shm.cmp_map->log[key][i]; // loop detection code if (i == 0) { s_v0 = o->v0; s_v1 = o->v1; } else { if (s_v0 != o->v0) { s_v0_fixed = 0; } if (s_v1 != o->v1) { s_v1_fixed = 0; } if (s_v0 + 1 != o->v0) { s_v0_inc = 0; } if (s_v1 + 1 != o->v1) { s_v1_inc = 0; } if (s_v0 - 1 != o->v0) { s_v0_dec = 0; } if (s_v1 - 1 != o->v1) { s_v1_dec = 0; } s_v0 = o->v0; s_v1 = o->v1; } struct cmp_operands *orig_o = &afl->orig_cmp_map->log[key][i]; // opt not in the paper for (j = 0; j < i; ++j) { if (afl->shm.cmp_map->log[key][j].v0 == o->v0 && afl->shm.cmp_map->log[key][i].v1 == o->v1) { goto cmp_fuzz_next_iter; } } for (idx = 0; idx < len && fails < 8; ++idx) { if (unlikely(cmp_extend_encoding(afl, h, o->v0, o->v1, orig_o->v0, idx, orig_buf, buf, len, 1, &status))) { return 1; } if (status == 2) { ++fails; } else if (status == 1) { break; } if (unlikely(cmp_extend_encoding(afl, h, o->v1, o->v0, orig_o->v1, idx, orig_buf, buf, len, 1, &status))) { return 1; } if (status == 2) { ++fails; } else if (status == 1) { break; } } if (status == 1) { found_one = 1; } // If failed, add to dictionary if (fails == 8) { if (afl->pass_stats[key].total == 0) { try_to_add_to_dict(afl, o->v0, SHAPE_BYTES(h->shape)); try_to_add_to_dict(afl, o->v1, SHAPE_BYTES(h->shape)); } } cmp_fuzz_next_iter: afl->stage_cur++; } if (loggeds > 3 && ((s_v0_fixed && s_v1_inc) || (s_v1_fixed && s_v0_inc) || (s_v0_fixed && s_v1_dec) || (s_v1_fixed && s_v0_dec))) { afl->pass_stats[key].total = afl->pass_stats[key].faileds = 0xff; } if (!found_one && afl->pass_stats[key].faileds < 0xff) { afl->pass_stats[key].faileds++; } if (afl->pass_stats[key].total < 0xff) { afl->pass_stats[key].total++; } return 0; } static u8 rtn_extend_encoding(afl_state_t *afl, struct cmp_header *h, u8 *pattern, u8 *repl, u8 *o_pattern, u32 idx, u8 *orig_buf, u8 *buf, u32 len, u8 *status) { u32 i; u32 its_len = MIN(32, len - idx); u8 save[32]; memcpy(save, &buf[idx], its_len); *status = 0; for (i = 0; i < its_len; ++i) { if (pattern[idx + i] != buf[idx + i] || o_pattern[idx + i] != orig_buf[idx + i] || *status == 1) { break; } buf[idx + i] = repl[idx + i]; if (unlikely(its_fuzz(afl, buf, len, status))) { return 1; } } memcpy(&buf[idx], save, i); return 0; } static u8 rtn_fuzz(afl_state_t *afl, u32 key, u8 *orig_buf, u8 *buf, u32 len) { struct cmp_header *h = &afl->shm.cmp_map->headers[key]; u32 i, j, idx; u32 loggeds = h->hits; if (h->hits > CMP_MAP_RTN_H) { loggeds = CMP_MAP_RTN_H; } u8 status = 0; // opt not in the paper u32 fails = 0; u8 found_one = 0; for (i = 0; i < loggeds; ++i) { fails = 0; struct cmpfn_operands *o = &((struct cmpfn_operands *)afl->shm.cmp_map->log[key])[i]; struct cmpfn_operands *orig_o = &((struct cmpfn_operands *)afl->orig_cmp_map->log[key])[i]; // opt not in the paper for (j = 0; j < i; ++j) { if (!memcmp(&((struct cmpfn_operands *)afl->shm.cmp_map->log[key])[j], o, sizeof(struct cmpfn_operands))) { goto rtn_fuzz_next_iter; } } for (idx = 0; idx < len && fails < 8; ++idx) { if (unlikely(rtn_extend_encoding(afl, h, o->v0, o->v1, orig_o->v0, idx, orig_buf, buf, len, &status))) { return 1; } if (status == 2) { ++fails; } else if (status == 1) { break; } if (unlikely(rtn_extend_encoding(afl, h, o->v1, o->v0, orig_o->v1, idx, orig_buf, buf, len, &status))) { return 1; } if (status == 2) { ++fails; } else if (status == 1) { break; } } if (status == 1) { found_one = 1; } // If failed, add to dictionary if (fails == 8) { if (afl->pass_stats[key].total == 0) { maybe_add_auto((u8 *)afl, o->v0, SHAPE_BYTES(h->shape)); maybe_add_auto((u8 *)afl, o->v1, SHAPE_BYTES(h->shape)); } } rtn_fuzz_next_iter: afl->stage_cur++; } if (!found_one && afl->pass_stats[key].faileds < 0xff) { afl->pass_stats[key].faileds++; } if (afl->pass_stats[key].total < 0xff) { afl->pass_stats[key].total++; } return 0; } ///// Input to State stage // afl->queue_cur->exec_cksum u8 input_to_state_stage(afl_state_t *afl, u8 *orig_buf, u8 *buf, u32 len, u64 exec_cksum) { u8 r = 1; if (afl->orig_cmp_map == NULL) { afl->orig_cmp_map = ck_alloc_nozero(sizeof(struct cmp_map)); } if (afl->pass_stats == NULL) { afl->pass_stats = ck_alloc(sizeof(struct afl_pass_stat) * CMP_MAP_W); } // do it manually, forkserver clear only afl->fsrv.trace_bits memset(afl->shm.cmp_map->headers, 0, sizeof(afl->shm.cmp_map->headers)); if (unlikely(common_fuzz_cmplog_stuff(afl, buf, len))) { return 1; } memcpy(afl->orig_cmp_map, afl->shm.cmp_map, sizeof(struct cmp_map)); if (unlikely(colorization(afl, buf, len, exec_cksum))) { return 1; } // do it manually, forkserver clear only afl->fsrv.trace_bits memset(afl->shm.cmp_map->headers, 0, sizeof(afl->shm.cmp_map->headers)); if (unlikely(common_fuzz_cmplog_stuff(afl, buf, len))) { return 1; } u64 orig_hit_cnt, new_hit_cnt; u64 orig_execs = afl->fsrv.total_execs; orig_hit_cnt = afl->queued_paths + afl->unique_crashes; afl->stage_name = "input-to-state"; afl->stage_short = "its"; afl->stage_max = 0; afl->stage_cur = 0; u32 k; for (k = 0; k < CMP_MAP_W; ++k) { if (!afl->shm.cmp_map->headers[k].hits) { continue; } if (afl->pass_stats[k].total && (rand_below(afl, afl->pass_stats[k].total) >= afl->pass_stats[k].faileds || afl->pass_stats[k].total == 0xff)) { afl->shm.cmp_map->headers[k].hits = 0; // blacklist this cmp } if (afl->shm.cmp_map->headers[k].type == CMP_TYPE_INS) { afl->stage_max += MIN((u32)afl->shm.cmp_map->headers[k].hits, CMP_MAP_H); } else { afl->stage_max += MIN((u32)afl->shm.cmp_map->headers[k].hits, CMP_MAP_RTN_H); } } for (k = 0; k < CMP_MAP_W; ++k) { if (!afl->shm.cmp_map->headers[k].hits) { continue; } if (afl->shm.cmp_map->headers[k].type == CMP_TYPE_INS) { if (unlikely(cmp_fuzz(afl, k, orig_buf, buf, len))) { goto exit_its; } } else { if (unlikely(rtn_fuzz(afl, k, orig_buf, buf, len))) { goto exit_its; } } } r = 0; exit_its: new_hit_cnt = afl->queued_paths + afl->unique_crashes; afl->stage_finds[STAGE_ITS] += new_hit_cnt - orig_hit_cnt; afl->stage_cycles[STAGE_ITS] += afl->fsrv.total_execs - orig_execs; memcpy(orig_buf, buf, len); return r; }