diff options
Diffstat (limited to 'examples/custom_mutators')
| -rw-r--r-- | examples/custom_mutators/Makefile | 2 | ||||
| -rw-r--r-- | examples/custom_mutators/README.md | 2 | ||||
| -rw-r--r-- | examples/custom_mutators/custom_mutator_helpers.h | 268 | ||||
| -rw-r--r-- | examples/custom_mutators/example.c | 83 |
4 files changed, 339 insertions, 16 deletions
diff --git a/examples/custom_mutators/Makefile b/examples/custom_mutators/Makefile new file mode 100644 index 00000000..a83e87fe --- /dev/null +++ b/examples/custom_mutators/Makefile @@ -0,0 +1,2 @@ +all: + $(CC) $(CFLAGS) -fPIC -shared -g -I ../../include example.c -o libexamplemutator.so diff --git a/examples/custom_mutators/README.md b/examples/custom_mutators/README.md index ce49436e..93f824cd 100644 --- a/examples/custom_mutators/README.md +++ b/examples/custom_mutators/README.md @@ -7,7 +7,7 @@ Note that if you compile with python3.7 you must use python3 scripts, and if you use pyton2.7 to compile python2 scripts! example.c - this is a simple example written in C and should be compiled to a - shared library + shared library. Use make to compile it and produce libexamplemutator.so example.py - this is the template you can use, the functions are there but they are empty diff --git a/examples/custom_mutators/custom_mutator_helpers.h b/examples/custom_mutators/custom_mutator_helpers.h new file mode 100644 index 00000000..844ccf94 --- /dev/null +++ b/examples/custom_mutators/custom_mutator_helpers.h @@ -0,0 +1,268 @@ +#ifndef CUSTOM_MUTATOR_HELPERS +#define CUSTOM_MUTATOR_HELPERS + +#include "config.h" +#include "types.h" +#include <stdlib.h> + +#define RAND_BELOW(limit) (rand() % (limit)) + +typedef struct{} afl_t; + +static void surgical_havoc_mutate(u8 *out_buf, s32 begin, s32 end) { + + static s8 interesting_8[] = {INTERESTING_8}; + static s16 interesting_16[] = {INTERESTING_8, INTERESTING_16}; + static s32 interesting_32[] = {INTERESTING_8, INTERESTING_16, INTERESTING_32}; + + switch (RAND_BELOW(12)) { + + case 0: { + + /* Flip a single bit somewhere. Spooky! */ + + s32 bit_idx = ((RAND_BELOW(end - begin) + begin) << 3) + RAND_BELOW(8); + + out_buf[bit_idx >> 3] ^= 128 >> (bit_idx & 7); + + break; + + } + + case 1: { + + /* Set byte to interesting value. */ + + u8 val = interesting_8[RAND_BELOW(sizeof(interesting_8))]; + out_buf[(RAND_BELOW(end - begin) + begin)] = val; + + break; + + } + + case 2: { + + /* Set word to interesting value, randomly choosing endian. */ + + if (end - begin < 2) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 1) break; + + switch (RAND_BELOW(2)) { + + case 0: + *(u16 *)(out_buf + byte_idx) = + interesting_16[RAND_BELOW(sizeof(interesting_16) >> 1)]; + break; + case 1: + *(u16 *)(out_buf + byte_idx) = + SWAP16(interesting_16[RAND_BELOW(sizeof(interesting_16) >> 1)]); + break; + + } + + break; + + } + + case 3: { + + /* Set dword to interesting value, randomly choosing endian. */ + + if (end - begin < 4) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 3) break; + + switch (RAND_BELOW(2)) { + + case 0: + *(u32 *)(out_buf + byte_idx) = + interesting_32[RAND_BELOW(sizeof(interesting_32) >> 2)]; + break; + case 1: + *(u32 *)(out_buf + byte_idx) = + SWAP32(interesting_32[RAND_BELOW(sizeof(interesting_32) >> 2)]); + break; + + } + + break; + + } + + case 4: { + + /* Set qword to interesting value, randomly choosing endian. */ + + if (end - begin < 8) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 7) break; + + switch (RAND_BELOW(2)) { + + case 0: + *(u64 *)(out_buf + byte_idx) = + (s64)interesting_32[RAND_BELOW(sizeof(interesting_32) >> 2)]; + break; + case 1: + *(u64 *)(out_buf + byte_idx) = + SWAP64((s64)interesting_32[RAND_BELOW(sizeof(interesting_32) >> 2)]); + break; + + } + + break; + + } + + case 5: { + + /* Randomly subtract from byte. */ + + out_buf[(RAND_BELOW(end - begin) + begin)] -= 1 + RAND_BELOW(ARITH_MAX); + + break; + + } + + case 6: { + + /* Randomly add to byte. */ + + out_buf[(RAND_BELOW(end - begin) + begin)] += 1 + RAND_BELOW(ARITH_MAX); + + break; + + } + + case 7: { + + /* Randomly subtract from word, random endian. */ + + if (end - begin < 2) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 1) break; + + if (RAND_BELOW(2)) { + + *(u16 *)(out_buf + byte_idx) -= 1 + RAND_BELOW(ARITH_MAX); + + } else { + + u16 num = 1 + RAND_BELOW(ARITH_MAX); + + *(u16 *)(out_buf + byte_idx) = + SWAP16(SWAP16(*(u16 *)(out_buf + byte_idx)) - num); + + } + + break; + + } + + case 8: { + + /* Randomly add to word, random endian. */ + + if (end - begin < 2) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 1) break; + + if (RAND_BELOW(2)) { + + *(u16 *)(out_buf + byte_idx) += 1 + RAND_BELOW(ARITH_MAX); + + } else { + + u16 num = 1 + RAND_BELOW(ARITH_MAX); + + *(u16 *)(out_buf + byte_idx) = + SWAP16(SWAP16(*(u16 *)(out_buf + byte_idx)) + num); + + } + + break; + + } + + case 9: { + + /* Randomly subtract from dword, random endian. */ + + if (end - begin < 4) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 3) break; + + if (RAND_BELOW(2)) { + + *(u32 *)(out_buf + byte_idx) -= 1 + RAND_BELOW(ARITH_MAX); + + } else { + + u32 num = 1 + RAND_BELOW(ARITH_MAX); + + *(u32 *)(out_buf + byte_idx) = + SWAP32(SWAP32(*(u32 *)(out_buf + byte_idx)) - num); + + } + + break; + + } + + case 10: { + + /* Randomly add to dword, random endian. */ + + if (end - begin < 4) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 3) break; + + if (RAND_BELOW(2)) { + + *(u32 *)(out_buf + byte_idx) += 1 + RAND_BELOW(ARITH_MAX); + + } else { + + u32 num = 1 + RAND_BELOW(ARITH_MAX); + + *(u32 *)(out_buf + byte_idx) = + SWAP32(SWAP32(*(u32 *)(out_buf + byte_idx)) + num); + + } + + break; + + } + + case 11: { + + /* Just set a random byte to a random value. Because, + why not. We use XOR with 1-255 to eliminate the + possibility of a no-op. */ + + out_buf[(RAND_BELOW(end - begin) + begin)] ^= 1 + RAND_BELOW(255); + + break; + + } + + } + +} + +#endif diff --git a/examples/custom_mutators/example.c b/examples/custom_mutators/example.c index 127f971e..560a5919 100644 --- a/examples/custom_mutators/example.c +++ b/examples/custom_mutators/example.c @@ -3,12 +3,18 @@ Written by Khaled Yakdan <yakdan@code-intelligence.de> Andrea Fioraldi <andreafioraldi@gmail.com> Shengtuo Hu <h1994st@gmail.com> + Dominik Maier <mail@dmnk.co> */ +// You need to use -I /path/to/AFLplusplus/include +#include "custom_mutator_helpers.h" + #include <stdint.h> #include <stdlib.h> #include <string.h> +#define DATA_SIZE (100) + static const char *commands[] = { "GET", @@ -17,11 +23,35 @@ static const char *commands[] = { }; -static size_t data_size = 100; -void afl_custom_init(unsigned int seed) { +typedef struct my_mutator { + + afl_t *afl; + // any additional data here! + +} my_mutator_t; + +/** + * Initialize this custom mutator + * + * @param[in] afl a pointer to the internal state object. Can be ignored for now. + * @param[in] seed A seed for this mutator - the same seed should always mutate in the same way. + * @return Pointer to the data object this custom mutator instance should use. + * There may be multiple instances of this mutator in one afl-fuzz run! + * Returns NULL on error. + */ +my_mutator_t *afl_custom_init(afl_t *afl, unsigned int seed) { + + srand(seed); // needed also by surgical_havoc_mutate() + + my_mutator_t *data = calloc(1, sizeof(my_mutator_t)); + if (!data) { + perror("afl_custom_init alloc"); + return NULL; + } + data->afl = afl; - srand(seed); + return data; } @@ -30,6 +60,7 @@ void afl_custom_init(unsigned int seed) { * * (Optional for now. Required in the future) * + * @param[in] data pointer returned in afl_custom_init for this fuzz case * @param[in] buf Pointer to input data to be mutated * @param[in] buf_size Size of input data * @param[in] add_buf Buffer containing the additional test case @@ -38,13 +69,14 @@ void afl_custom_init(unsigned int seed) { * produce data larger than max_size. * @return Size of the mutated output. */ -size_t afl_custom_fuzz(uint8_t **buf, size_t buf_size, uint8_t *add_buf, +size_t afl_custom_fuzz(my_mutator_t *data, uint8_t **buf, size_t buf_size, + uint8_t *add_buf, size_t add_buf_size, // add_buf can be NULL size_t max_size) { // Make sure that the packet size does not exceed the maximum size expected by // the fuzzer - size_t mutated_size = data_size <= max_size ? data_size : max_size; + size_t mutated_size = DATA_SIZE <= max_size ? DATA_SIZE : max_size; if (mutated_size > buf_size) *buf = realloc(*buf, mutated_size); @@ -54,9 +86,11 @@ size_t afl_custom_fuzz(uint8_t **buf, size_t buf_size, uint8_t *add_buf, memcpy(mutated_out, commands[rand() % 3], 3); // Mutate the payload of the packet - for (int i = 3; i < mutated_size; i++) { + int i; + for (i = 0; i < 8; ++i) { - mutated_out[i] = (mutated_out[i] + rand() % 10) & 0xff; + // Randomly perform one of the (no len modification) havoc mutations + surgical_havoc_mutate(mutated_out, 3, mutated_size); } @@ -71,6 +105,7 @@ size_t afl_custom_fuzz(uint8_t **buf, size_t buf_size, uint8_t *add_buf, * (Optional) If this functionality is not needed, simply don't define this * function. * + * @param[in] data pointer returned in afl_custom_init for this fuzz case * @param[in] buf Buffer containing the test case to be executed * @param[in] buf_size Size of the test case * @param[out] out_buf Pointer to the buffer containing the test case after @@ -78,7 +113,7 @@ size_t afl_custom_fuzz(uint8_t **buf, size_t buf_size, uint8_t *add_buf, * will release the memory after saving the test case. * @return Size of the output buffer after processing */ -size_t afl_custom_pre_save(uint8_t *buf, size_t buf_size, uint8_t **out_buf) { +size_t afl_custom_pre_save(my_mutator_t *data, uint8_t *buf, size_t buf_size, uint8_t **out_buf) { size_t out_buf_size; @@ -113,11 +148,12 @@ static int cur_step; * * (Optional) * + * @param data pointer returned in afl_custom_init for this fuzz case * @param buf Buffer containing the test case * @param buf_size Size of the test case * @return The amount of possible iteration steps to trim the input */ -int afl_custom_init_trim(uint8_t *buf, size_t buf_size) { +int afl_custom_init_trim(my_mutator_t *data, uint8_t *buf, size_t buf_size) { // We simply trim once trimmming_steps = 1; @@ -141,12 +177,13 @@ int afl_custom_init_trim(uint8_t *buf, size_t buf_size) { * * (Optional) * + * @param[in] data pointer returned in afl_custom_init for this fuzz case * @param[out] out_buf Pointer to the buffer containing the trimmed test case. * External library should allocate memory for out_buf. AFL++ will release * the memory after saving the test case. * @param[out] out_buf_size Pointer to the size of the trimmed test case */ -void afl_custom_trim(uint8_t **out_buf, size_t *out_buf_size) { +void afl_custom_trim(my_mutator_t *data, uint8_t **out_buf, size_t *out_buf_size) { *out_buf_size = trim_buf_size - 1; @@ -164,11 +201,12 @@ void afl_custom_trim(uint8_t **out_buf, size_t *out_buf_size) { * * (Optional) * + * @param[in] data pointer returned in afl_custom_init for this fuzz case * @param success Indicates if the last trim operation was successful. * @return The next trim iteration index (from 0 to the maximum amount of * steps returned in init_trim) */ -int afl_custom_post_trim(int success) { +int afl_custom_post_trim(my_mutator_t *data, int success) { if (success) { @@ -187,6 +225,7 @@ int afl_custom_post_trim(int success) { * * (Optional) * + * @param[in] data pointer returned in afl_custom_init for this fuzz case * @param[inout] buf Pointer to the input data to be mutated and the mutated * output * @param[in] buf_size Size of input data @@ -194,7 +233,7 @@ int afl_custom_post_trim(int success) { * not produce data larger than max_size. * @return Size of the mutated output. */ -size_t afl_custom_havoc_mutation(uint8_t **buf, size_t buf_size, +size_t afl_custom_havoc_mutation(my_mutator_t *data, uint8_t **buf, size_t buf_size, size_t max_size) { if (buf_size == 0) { @@ -218,9 +257,10 @@ size_t afl_custom_havoc_mutation(uint8_t **buf, size_t buf_size, * * (Optional) * + * @param[in] data pointer returned in afl_custom_init for this fuzz case * @return The probability (0-100). */ -uint8_t afl_custom_havoc_mutation_probability(void) { +uint8_t afl_custom_havoc_mutation_probability(my_mutator_t *data) { return 5; // 5 % @@ -231,11 +271,12 @@ uint8_t afl_custom_havoc_mutation_probability(void) { * * (Optional) * + * @param[in] data pointer returned in afl_custom_init for this fuzz case * @param filename File name of the test case in the queue entry * @return Return True(1) if the fuzzer will fuzz the queue entry, and * False(0) otherwise. */ -uint8_t afl_custom_queue_get(const uint8_t *filename) { +uint8_t afl_custom_queue_get(my_mutator_t *data, const uint8_t *filename) { return 1; @@ -247,13 +288,25 @@ uint8_t afl_custom_queue_get(const uint8_t *filename) { * * (Optional) * + * @param data pointer returned in afl_custom_init for this fuzz case * @param filename_new_queue File name of the new queue entry * @param filename_orig_queue File name of the original queue entry */ -void afl_custom_queue_new_entry(const uint8_t *filename_new_queue, +void afl_custom_queue_new_entry(my_mutator_t *data, const uint8_t *filename_new_queue, const uint8_t *filename_orig_queue) { /* Additional analysis on the original or new test case */ } +/** + * Deinitialize everything + * + * @param data The data ptr from afl_custom_init + */ +void afl_custom_deinit(my_mutator_t *data) { + + free(data); + +} + |