/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
* 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).
* You may select, at your option, one of the above-listed licenses.
*/
/**
* 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"
#include "fuzz_data_producer.h"
#include "fuzz_third_party_seq_prod.h"
static ZSTD_CCtx *cctx = NULL;
static ZSTD_DCtx *dctx = NULL;
static size_t getDecompressionMargin(void const* compressed, size_t cSize, size_t srcSize, int hasSmallBlocks, int maxBlockSize)
{
size_t margin = ZSTD_decompressionMargin(compressed, cSize);
if (!hasSmallBlocks) {
/* The macro should be correct in this case, but it may be smaller
* because of e.g. block splitting, so take the smaller of the two.
*/
ZSTD_frameHeader zfh;
size_t marginM;
FUZZ_ZASSERT(ZSTD_getFrameHeader(&zfh, compressed, cSize));
if (maxBlockSize == 0) {
maxBlockSize = zfh.blockSizeMax;
} else {
maxBlockSize = MIN(maxBlockSize, (int)zfh.blockSizeMax);
}
marginM = ZSTD_DECOMPRESSION_MARGIN(srcSize, maxBlockSize);
if (marginM < margin)
margin = marginM;
}
return margin;
}
static size_t roundTripTest(void *result, size_t resultCapacity,
void *compressed, size_t compressedCapacity,
const void *src, size_t srcSize,
FUZZ_dataProducer_t *producer)
{
size_t cSize;
size_t dSize;
int targetCBlockSize = 0;
int maxBlockSize = 0;
if (FUZZ_dataProducer_uint32Range(producer, 0, 1)) {
size_t const remainingBytes = FUZZ_dataProducer_remainingBytes(producer);
FUZZ_setRandomParameters(cctx, srcSize, producer);
cSize = ZSTD_compress2(cctx, compressed, compressedCapacity, src, srcSize);
FUZZ_ZASSERT(cSize);
FUZZ_ZASSERT(ZSTD_CCtx_getParameter(cctx, ZSTD_c_targetCBlockSize, &targetCBlockSize));
FUZZ_ZASSERT(ZSTD_CCtx_getParameter(cctx, ZSTD_c_maxBlockSize, &maxBlockSize));
// Compress a second time and check for determinism
{
size_t const cSize0 = cSize;
XXH64_hash_t const hash0 = XXH64(compressed, cSize, 0);
FUZZ_dataProducer_rollBack(producer, remainingBytes);
FUZZ_setRandomParameters(cctx, srcSize, producer);
cSize = ZSTD_compress2(cctx, compressed, compressedCapacity, src, srcSize);
FUZZ_ASSERT(cSize == cSize0);
FUZZ_ASSERT(XXH64(compressed, cSize, 0) == hash0);
}
} else {
int const cLevel = FUZZ_dataProducer_int32Range(producer, kMinClevel, kMaxClevel);
cSize = ZSTD_compressCCtx(
cctx, compressed, compressedCapacity, src, srcSize, cLevel);
FUZZ_ZASSERT(cSize);
// Compress a second time and check for determinism
{
size_t const cSize0 = cSize;
XXH64_hash_t const hash0 = XXH64(compressed, cSize, 0);
cSize = ZSTD_compressCCtx(
cctx, compressed, compressedCapacity, src, srcSize, cLevel);
FUZZ_ASSERT(cSize == cSize0);
FUZZ_ASSERT(XXH64(compressed, cSize, 0) == hash0);
}
}
if (FUZZ_dataProducer_uint32Range(producer, 0, 1)) {
FUZZ_ZASSERT(ZSTD_DCtx_setParameter(dctx, ZSTD_d_maxBlockSize, maxBlockSize));
}
dSize = ZSTD_decompressDCtx(dctx, result, resultCapacity, compressed, cSize);
FUZZ_ZASSERT(dSize);
FUZZ_ASSERT_MSG(dSize == srcSize, "Incorrect regenerated size");
FUZZ_ASSERT_MSG(!FUZZ_memcmp(src, result, dSize), "Corruption!");
{
size_t margin = getDecompressionMargin(compressed, cSize, srcSize, targetCBlockSize, maxBlockSize);
size_t const outputSize = srcSize + margin;
char* const output = (char*)FUZZ_malloc(outputSize);
char* const input = output + outputSize - cSize;
FUZZ_ASSERT(outputSize >= cSize);
memcpy(input, compressed, cSize);
dSize = ZSTD_decompressDCtx(dctx, output, outputSize, input, cSize);
FUZZ_ZASSERT(dSize);
FUZZ_ASSERT_MSG(dSize == srcSize, "Incorrect regenerated size");
FUZZ_ASSERT_MSG(!FUZZ_memcmp(src, output, srcSize), "Corruption!");
free(output);
}
/* When superblock is enabled make sure we don't expand the block more than expected.
* NOTE: This test is currently disabled because superblock mode can arbitrarily
* expand the block in the worst case. Once superblock mode has been improved we can
* re-enable this test.
*/
if (0 && targetCBlockSize != 0) {
size_t normalCSize;
FUZZ_ZASSERT(ZSTD_CCtx_setParameter(cctx, ZSTD_c_targetCBlockSize, 0));
normalCSize = ZSTD_compress2(cctx, compressed, compressedCapacity, src, srcSize);
FUZZ_ZASSERT(normalCSize);
{
size_t const bytesPerBlock = 3 /* block header */
+ 5 /* Literal header */
+ 6 /* Huffman jump table */
+ 3 /* number of sequences */
+ 1 /* symbol compression modes */;
size_t const expectedExpansion = bytesPerBlock * (1 + (normalCSize / MAX(1, targetCBlockSize)));
size_t const allowedExpansion = (srcSize >> 3) + 5 * expectedExpansion + 10;
FUZZ_ASSERT(cSize <= normalCSize + allowedExpansion);
}
}
return dSize;
}
int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
{
FUZZ_SEQ_PROD_SETUP();
size_t const rBufSize = size;
void* rBuf = FUZZ_malloc(rBufSize);
size_t cBufSize = ZSTD_compressBound(size);
void* cBuf;
/* Give a random portion of src data to the producer, to use for
parameter generation. The rest will be used for (de)compression */
FUZZ_dataProducer_t *producer = FUZZ_dataProducer_create(src, size);
size = FUZZ_dataProducer_reserveDataPrefix(producer);
/* 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_dataProducer_uint32Range(producer, 0, 1);
cBuf = FUZZ_malloc(cBufSize);
if (!cctx) {
cctx = ZSTD_createCCtx();
FUZZ_ASSERT(cctx);
}
if (!dctx) {
dctx = ZSTD_createDCtx();
FUZZ_ASSERT(dctx);
}
roundTripTest(rBuf, rBufSize, cBuf, cBufSize, src, size, producer);
free(rBuf);
free(cBuf);
FUZZ_dataProducer_free(producer);
#ifndef STATEFUL_FUZZING
ZSTD_freeCCtx(cctx); cctx = NULL;
ZSTD_freeDCtx(dctx); dctx = NULL;
#endif
FUZZ_SEQ_PROD_TEARDOWN();
return 0;
}