core-lightning/tests/fuzz/libfuzz.c
Matt Morehouse 38e31d6034 fuzz: add custom cross-over functions
These can be used in custom mutators for libFuzzer targets.
2023-10-24 12:17:18 +10:30

121 lines
3.0 KiB
C

#include "config.h"
#include <assert.h>
#include <ccan/isaac/isaac64.h>
#include <common/pseudorand.h>
#include <stdlib.h>
#include <string.h>
#include <tests/fuzz/libfuzz.h>
int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
int LLVMFuzzerInitialize(int *argc, char ***argv);
/* Provide a non-random pseudo-random function to speed fuzzing. */
static isaac64_ctx isaac64;
uint64_t pseudorand(uint64_t max)
{
assert(max);
return isaac64_next_uint(&isaac64, max);
}
int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
isaac64_init(&isaac64, NULL, 0);
run(data, size);
return 0;
}
int LLVMFuzzerInitialize(int *argc, char ***argv) {
init(argc, argv);
return 0;
}
const uint8_t **get_chunks(const void *ctx, const uint8_t *data,
size_t data_size, size_t chunk_size)
{
size_t n_chunks = data_size / chunk_size;
const uint8_t **chunks = tal_arr(ctx, const uint8_t *, n_chunks);
for (size_t i = 0; i < n_chunks; i++)
chunks[i] = tal_dup_arr(chunks, const uint8_t,
data + i * chunk_size, chunk_size, 0);
return chunks;
}
char *to_string(const tal_t *ctx, const u8 *data, size_t data_size)
{
char *string = tal_arr(ctx, char, data_size + 1);
for (size_t i = 0; i < data_size; i++)
string[i] = (char) data[i] % (CHAR_MAX + 1);
string[data_size] = '\0';
return string;
}
static size_t insert_part(const u8 *in1, size_t in1_size, const u8 *in2,
size_t in2_size, u8 *out, size_t max_out_size)
{
size_t max_insert_size;
size_t insert_begin;
size_t insert_size;
size_t in2_begin;
if (in1_size >= max_out_size)
return 0;
if (in1_size == 0 || in2_size == 0)
return 0;
max_insert_size = max_out_size - in1_size;
if (max_insert_size > in2_size)
max_insert_size = in2_size;
insert_begin = rand() % in1_size;
insert_size = (rand() % max_insert_size) + 1;
in2_begin = rand() % (in2_size - insert_size + 1);
memcpy(out, in1, insert_begin);
memcpy(out + insert_begin, in2 + in2_begin, insert_size);
memcpy(out + insert_begin + insert_size, in1 + insert_begin,
in1_size - insert_begin);
return in1_size + insert_size;
}
static size_t overwrite_part(const u8 *in1, size_t in1_size, const u8 *in2,
size_t in2_size, u8 *out, size_t max_out_size)
{
size_t overwrite_begin;
size_t overwrite_size;
size_t in2_begin;
if (in1_size > max_out_size)
return 0;
if (in1_size == 0)
return 0;
overwrite_begin = rand() % in1_size;
overwrite_size = (rand() % (in1_size - overwrite_begin)) + 1;
if (overwrite_size > in2_size)
overwrite_size = in2_size;
in2_begin = rand() % (in2_size - overwrite_size + 1);
memcpy(out, in1, in1_size);
memcpy(out + overwrite_begin, in2 + in2_begin, overwrite_size);
return in1_size;
}
size_t cross_over(const u8 *in1, size_t in1_size, const u8 *in2,
size_t in2_size, u8 *out, size_t max_out_size, unsigned seed)
{
srand(seed);
if (rand() % 2)
return insert_part(in1, in1_size, in2, in2_size, out,
max_out_size);
return overwrite_part(in1, in1_size, in2, in2_size, out, max_out_size);
}