small adjustments for custom mutator

This commit is contained in:
van Hauser
2019-09-05 10:10:25 +02:00
parent 5955dd4e25
commit 760416c1a0
2 changed files with 28 additions and 15 deletions

View File

@ -3,9 +3,10 @@
Written by Khaled Yakdan <yakdan@code-intelligence.de>
This a simple mutator that assumes that the generates messages starting with one
of the three strings GET, PUT, or DEL followed by a payload. The mutator randomly
selects a commend and mutates the payload of the seed provided as input.
This a simple mutator that assumes that the generates messages starting with
one of the three strings GET, PUT, or DEL followed by a payload. The mutator
randomly selects a commend and mutates the payload of the seed provided as
input.
*/
#include <stdint.h>
@ -13,28 +14,36 @@
#include <string.h>
static const char *commands[] = {
"GET",
"PUT",
"DEL",
"GET",
"PUT",
"DEL",
};
static size_t data_size = 100;
size_t afl_custom_mutator (uint8_t *data, size_t size, uint8_t* mutated_out, size_t max_size, unsigned int seed) {
size_t afl_custom_mutator(uint8_t *data, size_t size, uint8_t *mutated_out,
size_t max_size, unsigned int seed) {
// Seed the PRNG
srand(seed);
// Make sure that the packet size does not exceed the maximum size expected by the fuzzer
// 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;
// Randomly select a command string to add as a header to the packet
memcpy(mutated_out, commands[rand() % 3], 3);
// Mutate the payload of the packet
for (int i = 3 ; i < mutated_size ; i++) {
for (int i = 3; i < mutated_size; i++) {
mutated_out[i] = (data[i] + rand() % 10) & 0xff;
}
return mutated_size;
}

View File

@ -426,20 +426,24 @@ u8* (*post_handler)(u8* buf, u32* len);
* @param data Input data to be mutated
* @param size Size of input data
* @param mutated_out Buffer to store the mutated input
* @param max_size Maximum size of the mutated output. The mutation must not produce data larger than max_size.
* @param seed Seed used for the mutation. The mutation should produce the same output given the same seed.
* @param max_size Maximum size of the mutated output. The mutation must not
* produce data larger than max_size.
* @param seed Seed used for the mutation. The mutation should produce the same
* output given the same seed.
* @return Size of the mutated output.
*/
size_t (*custom_mutator)(u8 *data, size_t size, u8* mutated_out, size_t max_size, unsigned int seed);
size_t (*custom_mutator)(u8* data, size_t size, u8* mutated_out,
size_t max_size, unsigned int seed);
/**
* A post-processing function to use right before AFL writes the test case to disk in order to execute the target.
* If this functionality is not needed, Simply don't define this function.
* A post-processing function to use right before AFL writes the test case to
* disk in order to execute the target. If this functionality is not needed,
* Simply don't define this function.
* @param data Buffer containing the test case to be executed.
* @param size Size of the test case.
* @param new_data Buffer to store the test case after processing
* @return Size of data after processing.
*/
size_t (*pre_save_handler)(u8 *data, size_t size, u8 **new_data);
size_t (*pre_save_handler)(u8* data, size_t size, u8** new_data);
/* Interesting values, as per config.h */