Add post-process functionality in write_with_gap
MODIFY
src/afl-fuzz-run.c
src/afl-fuzz-run.c
@@ -142,18 +142,58 @@ 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;
- if (afl->fsrv.shmem_fuzz) {
+ /* 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(afl->fsrv.shmem_fuzz, mem, skip_at); }
+ if (skip_at) { memcpy(mem_trimmed, mem, skip_at); }
if (tail_len) {
- memcpy(afl->fsrv.shmem_fuzz + skip_at, (u8 *)mem + skip_at + skip_len,
- tail_len);
+ memcpy(mem_trimmed + skip_at, (u8 *)mem + skip_at + skip_len, tail_len);
+
+ }
+
+ ssize_t new_size = skip_at + tail_len;
+ void * new_mem = mem_trimmed;
+ u8 * new_buf = NULL;
+
+ if (unlikely(afl->custom_mutators_count)) {
+
+ LIST_FOREACH(&afl->custom_mutator_list, struct custom_mutator, {
+
+ if (el->afl_custom_post_process) {
+
+ new_size =
+ el->afl_custom_post_process(el->data, new_mem, new_size, &new_buf);
+
+ }
+
+ new_mem = new_buf;
+
+ });
}
- *afl->fsrv.shmem_fuzz_len = len - skip_len;
+ if (afl->fsrv.shmem_fuzz) {
+
+ if ((new_buf)) {
+
+ memcpy(afl->fsrv.shmem_fuzz, new_buf, new_size);
+
+ }
+
+ else {
+
+ memcpy(afl->fsrv.shmem_fuzz, mem_trimmed, new_size);
+
+ }
+
+ *afl->fsrv.shmem_fuzz_len = new_size;
#ifdef _DEBUG
if (afl->debug) {
@@ -197,18 +237,19 @@ static void write_with_gap(afl_state_t *afl, void *mem, u32 len, u32 skip_at,
}
- if (skip_at) { ck_write(fd, mem, skip_at, afl->fsrv.out_file); }
+ if (new_buf) {
- u8 *memu8 = mem;
- if (tail_len) {
+ ck_write(fd, new_buf, new_size, afl->fsrv.out_file);
+
+ } else {
- ck_write(fd, memu8 + skip_at + skip_len, tail_len, afl->fsrv.out_file);
+ ck_write(fd, mem_trimmed, new_size, afl->fsrv.out_file);
}
if (!afl->fsrv.out_file) {
- if (ftruncate(fd, len - skip_len)) { PFATAL("ftruncate() failed"); }
+ if (ftruncate(fd, new_size)) { PFATAL("ftruncate() failed"); }
lseek(fd, 0, SEEK_SET);
} else {

Add post-process functionality in write_with_gap