zstd/tests/fuzz/simple_round_trip.c
Nick Terrell c5d70b7dbb [fuzzer] Sometimes fuzz with one less output byte
Zstd compression sometimes does different stuff when it has at least
`ZSTD_compressBound()` output bytes, or not. Half of the time fuzz with
`ZSTD_compressBound() - 1` output bytes. Ensure that we have at least
one byte of overhead by disabling either the dictionary ID or checksum.
2019-04-09 16:47:59 -07:00

88 lines
2.5 KiB
C

/*
* Copyright (c) 2016-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
*/
/**
* This fuzz target performs a zstd round-trip test (compress & decompress),
* compares the result with the original, and calls abort() on corruption.
*/
#define ZSTD_STATIC_LINKING_ONLY
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "fuzz_helpers.h"
#include "zstd_helpers.h"
static const int kMaxClevel = 19;
static ZSTD_CCtx *cctx = NULL;
static ZSTD_DCtx *dctx = NULL;
static uint32_t seed;
static size_t roundTripTest(void *result, size_t resultCapacity,
void *compressed, size_t compressedCapacity,
const void *src, size_t srcSize)
{
size_t cSize;
if (FUZZ_rand(&seed) & 1) {
FUZZ_setRandomParameters(cctx, srcSize, &seed);
cSize = ZSTD_compress2(cctx, compressed, compressedCapacity, src, srcSize);
} else {
int const cLevel = FUZZ_rand(&seed) % kMaxClevel;
cSize = ZSTD_compressCCtx(
cctx, compressed, compressedCapacity, src, srcSize, cLevel);
}
FUZZ_ZASSERT(cSize);
return ZSTD_decompressDCtx(dctx, result, resultCapacity, compressed, cSize);
}
int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
{
size_t const rBufSize = size;
void* rBuf = malloc(rBufSize);
size_t cBufSize = ZSTD_compressBound(size);
void* cBuf;
seed = FUZZ_seed(&src, &size);
/* Half of the time fuzz with a 1 byte smaller output size.
* This will still succeed because we don't use a dictionary, so the dictID
* field is empty, giving us 4 bytes of overhead.
*/
cBufSize -= FUZZ_rand32(&seed, 0, 1);
cBuf = malloc(cBufSize);
FUZZ_ASSERT(cBuf && rBuf);
if (!cctx) {
cctx = ZSTD_createCCtx();
FUZZ_ASSERT(cctx);
}
if (!dctx) {
dctx = ZSTD_createDCtx();
FUZZ_ASSERT(dctx);
}
{
size_t const result =
roundTripTest(rBuf, rBufSize, cBuf, cBufSize, src, size);
FUZZ_ZASSERT(result);
FUZZ_ASSERT_MSG(result == size, "Incorrect regenerated size");
FUZZ_ASSERT_MSG(!memcmp(src, rBuf, size), "Corruption!");
}
free(rBuf);
free(cBuf);
#ifndef STATEFUL_FUZZING
ZSTD_freeCCtx(cctx); cctx = NULL;
ZSTD_freeDCtx(dctx); dctx = NULL;
#endif
return 0;
}