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// This simple example just creates random buffer <= 100 filled with 'A'
// needs -I /path/to/AFLplusplus/include
#include "custom_mutator_helpers.h"
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#ifndef _FIXED_CHAR
#define _FIXED_CHAR 0x41
#endif
typedef struct my_mutator {
afl_t *afl;
// Reused buffers:
BUF_VAR(u8, fuzz);
} my_mutator_t;
my_mutator_t *afl_custom_init(afl_t *afl, unsigned int seed) {
srand(seed);
my_mutator_t *data = calloc(1, sizeof(my_mutator_t));
if (!data) {
perror("afl_custom_init alloc");
return NULL;
}
data->afl = afl;
return data;
}
size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf, size_t buf_size,
u8 **out_buf, uint8_t *add_buf,
size_t add_buf_size, // add_buf can be NULL
size_t max_size) {
int size = (rand() % 100) + 1;
if (size > max_size) size = max_size;
u8 *mutated_out = maybe_grow(BUF_PARAMS(data, fuzz), size);
if (!mutated_out) {
*out_buf = NULL;
perror("custom mutator allocation (maybe_grow)");
return 0; /* afl-fuzz will very likely error out after this. */
}
memset(mutated_out, _FIXED_CHAR, size);
*out_buf = mutated_out;
return size;
}
/**
* Deinitialize everything
*
* @param data The data ptr from afl_custom_init
*/
void afl_custom_deinit(my_mutator_t *data) {
free(data->fuzz_buf);
free(data);
}
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