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/**
* Copyright (c) 2016-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
/**
* This fuzz target performs a zstd round-trip test (compress & decompress),
* compares the result with the original, and calls abort() on corruption.
*/
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "fuzz_helpers.h"
#include "zstd.h"
static const int kMaxClevel = 19;
static ZSTD_CStream *cstream = NULL;
static ZSTD_DCtx *dctx = NULL;
static uint8_t* cBuf = NULL;
static uint8_t* rBuf = NULL;
static size_t bufSize = 0;
static uint32_t seed;
static ZSTD_outBuffer makeOutBuffer(uint8_t *dst, size_t capacity)
{
ZSTD_outBuffer buffer = { dst, 0, 0 };
FUZZ_ASSERT(capacity > 0);
buffer.size = (FUZZ_rand(&seed) % capacity) + 1;
FUZZ_ASSERT(buffer.size <= capacity);
return buffer;
}
static ZSTD_inBuffer makeInBuffer(const uint8_t **src, size_t *size)
{
ZSTD_inBuffer buffer = { *src, 0, 0 };
FUZZ_ASSERT(*size > 0);
buffer.size = (FUZZ_rand(&seed) % *size) + 1;
FUZZ_ASSERT(buffer.size <= *size);
*src += buffer.size;
*size -= buffer.size;
return buffer;
}
static size_t compress(uint8_t *dst, size_t capacity,
const uint8_t *src, size_t srcSize)
{
int cLevel = FUZZ_rand(&seed) % kMaxClevel;
size_t dstSize = 0;
FUZZ_ASSERT(!ZSTD_isError(ZSTD_initCStream(cstream, cLevel)));
while (srcSize > 0) {
ZSTD_inBuffer in = makeInBuffer(&src, &srcSize);
/* Mode controls the action. If mode == -1 we pick a new mode */
int mode = -1;
while (in.pos < in.size) {
ZSTD_outBuffer out = makeOutBuffer(dst, capacity);
/* Previous action finished, pick a new mode. */
if (mode == -1) mode = FUZZ_rand(&seed) % 10;
switch (mode) {
case 0: /* fall-though */
case 1: /* fall-though */
case 2: {
size_t const ret = ZSTD_flushStream(cstream, &out);
FUZZ_ASSERT_MSG(!ZSTD_isError(ret), ZSTD_getErrorName(ret));
if (ret == 0) mode = -1;
break;
}
case 3: {
size_t ret = ZSTD_endStream(cstream, &out);
FUZZ_ASSERT_MSG(!ZSTD_isError(ret), ZSTD_getErrorName(ret));
/* Reset the compressor when the frame is finished */
if (ret == 0) {
cLevel = FUZZ_rand(&seed) % kMaxClevel;
ret = ZSTD_initCStream(cstream, cLevel);
FUZZ_ASSERT(!ZSTD_isError(ret));
mode = -1;
}
break;
}
default: {
size_t const ret = ZSTD_compressStream(cstream, &out, &in);
FUZZ_ASSERT_MSG(!ZSTD_isError(ret), ZSTD_getErrorName(ret));
mode = -1;
}
}
dst += out.pos;
dstSize += out.pos;
capacity -= out.pos;
}
}
for (;;) {
ZSTD_outBuffer out = makeOutBuffer(dst, capacity);
size_t const ret = ZSTD_endStream(cstream, &out);
FUZZ_ASSERT_MSG(!ZSTD_isError(ret), ZSTD_getErrorName(ret));
dst += out.pos;
dstSize += out.pos;
capacity -= out.pos;
if (ret == 0) break;
}
return dstSize;
}
int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
{
size_t const neededBufSize = ZSTD_compressBound(size) * 2;
seed = FUZZ_seed(src, size);
/* Allocate all buffers and contexts if not already allocated */
if (neededBufSize > bufSize) {
free(cBuf);
free(rBuf);
cBuf = (uint8_t*)malloc(neededBufSize);
rBuf = (uint8_t*)malloc(neededBufSize);
bufSize = neededBufSize;
FUZZ_ASSERT(cBuf && rBuf);
}
if (!cstream) {
cstream = ZSTD_createCStream();
FUZZ_ASSERT(cstream);
}
if (!dctx) {
dctx = ZSTD_createDCtx();
FUZZ_ASSERT(dctx);
}
{
size_t const cSize = compress(cBuf, neededBufSize, src, size);
size_t const rSize =
ZSTD_decompressDCtx(dctx, rBuf, neededBufSize, cBuf, cSize);
FUZZ_ASSERT_MSG(!ZSTD_isError(rSize), ZSTD_getErrorName(rSize));
FUZZ_ASSERT_MSG(rSize == size, "Incorrect regenerated size");
FUZZ_ASSERT_MSG(!memcmp(src, rBuf, size), "Corruption!");
}
#ifndef STATEFULL_FUZZING
ZSTD_freeCStream(cstream); cstream = NULL;
ZSTD_freeDCtx(dctx); dctx = NULL;
#endif
return 0;
}
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