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Fix potential endless loop in custom_mutator_stage

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Co-authored-by: Ivan Gulakov <gulakov@ispras.ru>
This commit is contained in:
Vitalii Akolzin
2020-09-24 18:25:32 +03:00
parent 60ef1f7305
commit 888d63748a
4 changed files with 50 additions and 29 deletions
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3
include/afl-fuzz.h
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@ -657,6 +657,9 @@ typedef struct afl_state {
* they do not call another function */ * they do not call another function */
u8 *map_tmp_buf; u8 *map_tmp_buf;
/* queue entries ready for splicing count (len > 1) */
u32 ready_for_splicing_count;
} afl_state_t; } afl_state_t;
struct custom_mutator { struct custom_mutator {

20
src/afl-fuzz-one.c
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@ -1696,7 +1696,12 @@ custom_mutator_stage:
struct queue_entry *target; struct queue_entry *target;
u32 tid; u32 tid;
u8 * new_buf; u8 * new_buf = NULL;
u32 target_len = 0;
if (afl->ready_for_splicing_count > 1 ||
(afl->ready_for_splicing_count == 1 &&
afl->queue_cur->len == 1)) {
retry_external_pick: retry_external_pick:
/* Pick a random other queue entry for passing to external API */ /* Pick a random other queue entry for passing to external API */
@ -1713,7 +1718,7 @@ custom_mutator_stage:
/* Make sure that the target has a reasonable length. */ /* Make sure that the target has a reasonable length. */
while (target && (target->len < 2 || target == afl->queue_cur) && while (target && (target->len < 2 || target == afl->queue_cur) &&
afl->queued_paths > 3) { afl->queued_paths > 2) {
target = target->next; target = target->next;
++afl->splicing_with; ++afl->splicing_with;
@ -1734,12 +1739,15 @@ custom_mutator_stage:
if (unlikely(!new_buf)) { PFATAL("alloc"); } if (unlikely(!new_buf)) { PFATAL("alloc"); }
ck_read(fd, new_buf, target->len, target->fname); ck_read(fd, new_buf, target->len, target->fname);
close(fd); close(fd);
target_len = target->len;
}
u8 *mutated_buf = NULL; u8 *mutated_buf = NULL;
size_t mutated_size = size_t mutated_size =
el->afl_custom_fuzz(el->data, out_buf, len, &mutated_buf, new_buf, el->afl_custom_fuzz(el->data, out_buf, len, &mutated_buf, new_buf,
target->len, max_seed_size); target_len, max_seed_size);
if (unlikely(!mutated_buf)) { if (unlikely(!mutated_buf)) {
@ -2738,6 +2746,8 @@ static u8 mopt_common_fuzzing(afl_state_t *afl, MOpt_globals_t MOpt_globals) {
if (!afl->non_instrumented_mode && !afl->queue_cur->trim_done) { if (!afl->non_instrumented_mode && !afl->queue_cur->trim_done) {
u32 old_len = afl->queue_cur->len;
u8 res = trim_case(afl, afl->queue_cur, in_buf); u8 res = trim_case(afl, afl->queue_cur, in_buf);
if (res == FSRV_RUN_ERROR) { if (res == FSRV_RUN_ERROR) {
@ -2759,6 +2769,10 @@ static u8 mopt_common_fuzzing(afl_state_t *afl, MOpt_globals_t MOpt_globals) {
len = afl->queue_cur->len; len = afl->queue_cur->len;
/* maybe current entry stop being ready for splicing */
if (old_len > 1 && afl->queue_cur->len == 1)
afl->ready_for_splicing_count--;
} }
memcpy(out_buf, in_buf, len); memcpy(out_buf, in_buf, len);

2
src/afl-fuzz-queue.c
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@ -234,6 +234,8 @@ void add_to_queue(afl_state_t *afl, u8 *fname, u32 len, u8 passed_det) {
} }
if (q->len > 1) afl->ready_for_splicing_count++;
++afl->queued_paths; ++afl->queued_paths;
++afl->pending_not_fuzzed; ++afl->pending_not_fuzzed;

2
src/afl-fuzz-state.c
View File

@ -155,6 +155,8 @@ void afl_state_init(afl_state_t *afl, uint32_t map_size) {
afl->stats_last_execs = 0; afl->stats_last_execs = 0;
afl->stats_avg_exec = -1; afl->stats_avg_exec = -1;
afl->ready_for_splicing_count = 0;
init_mopt_globals(afl); init_mopt_globals(afl);
list_append(&afl_states, afl); list_append(&afl_states, afl);