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Remove reduntant copying from write_with_gap function

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This commit is contained in:
rish9101
2020-07-23 23:48:26 +05:30
parent 4898db80cb
commit 2fa31dab60
1 changed files with 46 additions and 20 deletions
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66
src/afl-fuzz-run.c
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@ -142,35 +142,55 @@ static void write_with_gap(afl_state_t *afl, void *mem, u32 len, u32 skip_at,
s32 fd = afl->fsrv.out_fd;
u32 tail_len = len - skip_at - skip_len;
/* We first copy the mem into a new memory region removing the gaps
and then carry out any post-processing work on them. Then copy them out to
shared-mem or write to file */
void *mem_trimmed =
ck_alloc(skip_at + tail_len +
1); // 1 extra size allocated to remove chance of overflow
if (skip_at) { memcpy(mem_trimmed, mem, skip_at); }
if (tail_len) {
memcpy(mem_trimmed + skip_at, (u8 *)mem + skip_at + skip_len, tail_len);
}
/*
This memory is used to carry out the post_processing(if present) after copying
the testcase by removing the gaps
*/
u8 mem_trimmed[skip_at + tail_len +
1]; // 1 extra size to remove chance of overflow
ssize_t new_size = skip_at + tail_len;
void * new_mem = mem_trimmed;
void * new_mem = mem;
u8 * new_buf = NULL;
bool post_process_skipped = true;
if (unlikely(afl->custom_mutators_count)) {
new_mem = mem_trimmed;
LIST_FOREACH(&afl->custom_mutator_list, struct custom_mutator, {
if (el->afl_custom_post_process) {
// We copy into the mem_trimmed only if we actually have custom mutators
// *with* post_processing installed
if (post_process_skipped) {
if (skip_at) { memcpy(mem_trimmed, (u8 *)mem, skip_at); }
if (tail_len) {
memcpy(mem_trimmed + skip_at, (u8 *)mem + skip_at + skip_len,
tail_len);
}
post_process_skipped = false;
}
new_size =
el->afl_custom_post_process(el->data, new_mem, new_size, &new_buf);
if (unlikely(!new_buf && (new_size <= 0))) {
FATAL("Custom_post_process failed (ret: %lu)",
(long unsigned)new_size);
}
}
new_mem = new_buf;
@ -181,7 +201,9 @@ static void write_with_gap(afl_state_t *afl, void *mem, u32 len, u32 skip_at,
if (afl->fsrv.shmem_fuzz) {
if ((new_buf)) {
if (!post_process_skipped) {
// If we did post_processing, copy directly from the new_buf bufer
memcpy(afl->fsrv.shmem_fuzz, new_buf, new_size);
@ -189,7 +211,9 @@ static void write_with_gap(afl_state_t *afl, void *mem, u32 len, u32 skip_at,
else {
memcpy(afl->fsrv.shmem_fuzz, mem_trimmed, new_size);
memcpy(afl->fsrv.shmem_fuzz, mem, skip_at);
memcpy(afl->fsrv.shmem_fuzz, mem + skip_at + skip_len, tail_len);
}
@ -237,13 +261,15 @@ static void write_with_gap(afl_state_t *afl, void *mem, u32 len, u32 skip_at,
}
if (new_buf) {
if (!post_process_skipped) {
ck_write(fd, new_buf, new_size, afl->fsrv.out_file);
} else {
ck_write(fd, mem_trimmed, new_size, afl->fsrv.out_file);
ck_write(fd, mem, skip_at, afl->fsrv.out_file);
ck_write(fd, mem + skip_at + skip_len, tail_len, afl->fsrv.out_file);
}