From e12acaa20367f335549c2db97b88ac5c8ffbeab7 Mon Sep 17 00:00:00 2001 From: vanhauser-thc Date: Sat, 15 Apr 2023 10:12:20 +0200 Subject: fix custom mutator C examples --- custom_mutators/examples/example.c | 116 +++++++++++++------------------------ 1 file changed, 41 insertions(+), 75 deletions(-) (limited to 'custom_mutators/examples/example.c') diff --git a/custom_mutators/examples/example.c b/custom_mutators/examples/example.c index e680ec8e..42c7469c 100644 --- a/custom_mutators/examples/example.c +++ b/custom_mutators/examples/example.c @@ -7,7 +7,7 @@ */ // You need to use -I/path/to/AFLplusplus/include -I. -#include "custom_mutator_helpers.h" +#include "afl-fuzz.h" #include #include @@ -26,19 +26,14 @@ static const char *commands[] = { typedef struct my_mutator { - afl_t *afl; + afl_state_t *afl; // any additional data here! size_t trim_size_current; int trimmming_steps; int cur_step; - // Reused buffers: - BUF_VAR(u8, fuzz); - BUF_VAR(u8, data); - BUF_VAR(u8, havoc); - BUF_VAR(u8, trim); - BUF_VAR(u8, post_process); + u8 *mutated_out, *post_process_buf, *trim_buf; } my_mutator_t; @@ -53,7 +48,7 @@ typedef struct my_mutator { * There may be multiple instances of this mutator in one afl-fuzz run! * Return NULL on error. */ -my_mutator_t *afl_custom_init(afl_t *afl, unsigned int seed) { +my_mutator_t *afl_custom_init(afl_state_t *afl, unsigned int seed) { srand(seed); // needed also by surgical_havoc_mutate() @@ -65,6 +60,27 @@ my_mutator_t *afl_custom_init(afl_t *afl, unsigned int seed) { } + if ((data->mutated_out = (u8 *)malloc(MAX_FILE)) == NULL) { + + perror("afl_custom_init malloc"); + return NULL; + + } + + if ((data->post_process_buf = (u8 *)malloc(MAX_FILE)) == NULL) { + + perror("afl_custom_init malloc"); + return NULL; + + } + + if ((data->trim_buf = (u8 *)malloc(MAX_FILE)) == NULL) { + + perror("afl_custom_init malloc"); + return NULL; + + } + data->afl = afl; return data; @@ -96,31 +112,14 @@ size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf, size_t buf_size, // the fuzzer size_t mutated_size = DATA_SIZE <= max_size ? DATA_SIZE : max_size; - // maybe_grow is optimized to be quick for reused buffers. - u8 *mutated_out = maybe_grow(BUF_PARAMS(data, fuzz), mutated_size); - if (!mutated_out) { - - *out_buf = NULL; - perror("custom mutator allocation (maybe_grow)"); - return 0; /* afl-fuzz will very likely error out after this. */ - - } + memcpy(data->mutated_out, buf, buf_size); // Randomly select a command string to add as a header to the packet - memcpy(mutated_out, commands[rand() % 3], 3); + memcpy(data->mutated_out, commands[rand() % 3], 3); - // Mutate the payload of the packet - int i; - for (i = 0; i < 8; ++i) { + if (mutated_size > max_size) { mutated_size = max_size; } - // Randomly perform one of the (no len modification) havoc mutations - surgical_havoc_mutate(mutated_out, 3, mutated_size); - - } - - if (max_size > mutated_size) { mutated_size = max_size; } - - *out_buf = mutated_out; + *out_buf = data->mutated_out; return mutated_size; } @@ -144,24 +143,16 @@ size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf, size_t buf_size, size_t afl_custom_post_process(my_mutator_t *data, uint8_t *buf, size_t buf_size, uint8_t **out_buf) { - uint8_t *post_process_buf = - maybe_grow(BUF_PARAMS(data, post_process), buf_size + 5); - if (!post_process_buf) { + if (buf_size + 5 > MAX_FILE) { buf_size = MAX_FILE - 5; } - perror("custom mutator realloc failed."); - *out_buf = NULL; - return 0; + memcpy(data->post_process_buf + 5, buf, buf_size); + data->post_process_buf[0] = 'A'; + data->post_process_buf[1] = 'F'; + data->post_process_buf[2] = 'L'; + data->post_process_buf[3] = '+'; + data->post_process_buf[4] = '+'; - } - - memcpy(post_process_buf + 5, buf, buf_size); - post_process_buf[0] = 'A'; - post_process_buf[1] = 'F'; - post_process_buf[2] = 'L'; - post_process_buf[3] = '+'; - post_process_buf[4] = '+'; - - *out_buf = post_process_buf; + *out_buf = data->post_process_buf; return buf_size + 5; @@ -197,13 +188,6 @@ int32_t afl_custom_init_trim(my_mutator_t *data, uint8_t *buf, data->cur_step = 0; - if (!maybe_grow(BUF_PARAMS(data, trim), buf_size)) { - - perror("init_trim grow"); - return -1; - - } - memcpy(data->trim_buf, buf, buf_size); data->trim_size_current = buf_size; @@ -284,27 +268,11 @@ int32_t afl_custom_post_trim(my_mutator_t *data, int success) { size_t afl_custom_havoc_mutation(my_mutator_t *data, u8 *buf, size_t buf_size, u8 **out_buf, size_t max_size) { - if (buf_size == 0) { - - *out_buf = maybe_grow(BUF_PARAMS(data, havoc), 1); - if (!*out_buf) { - - perror("custom havoc: maybe_grow"); - return 0; - - } + *out_buf = buf; // in-place mutation - **out_buf = rand() % 256; - buf_size = 1; - - } else { - - // We reuse buf here. It's legal and faster. - *out_buf = buf; - - } + if (buf_size <= sizeof(size_t)) { return buf_size; } - size_t victim = rand() % buf_size; + size_t victim = rand() % (buf_size - sizeof(size_t)); (*out_buf)[victim] += rand() % 10; return buf_size; @@ -371,9 +339,7 @@ uint8_t afl_custom_queue_new_entry(my_mutator_t *data, void afl_custom_deinit(my_mutator_t *data) { free(data->post_process_buf); - free(data->havoc_buf); - free(data->data_buf); - free(data->fuzz_buf); + free(data->mutated_out); free(data->trim_buf); free(data); -- cgit 1.4.1