4193638996
* Fix bug introduced in PR #2271 * Fix long-standing bug that is impossible to trigger inside of zstd * Add a fuzzer that makes sure the normalized count always round trips correctly
101 lines
3.4 KiB
C
101 lines
3.4 KiB
C
/*
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* Copyright (c) 2016-2020, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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*/
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/**
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* This fuzz target round trips the FSE normalized count with FSE_writeNCount()
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* and FSE_readNcount() to ensure that it can always round trip correctly.
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*/
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#define FSE_STATIC_LINKING_ONLY
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#define ZSTD_STATIC_LINKING_ONLY
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#include <stddef.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include "fuzz_helpers.h"
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#include "zstd_helpers.h"
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#include "fuzz_data_producer.h"
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#include "fse.h"
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int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
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{
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FUZZ_dataProducer_t *producer = FUZZ_dataProducer_create(src, size);
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/* Pick a random tableLog and maxSymbolValue */
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unsigned const tableLog = FUZZ_dataProducer_uint32Range(producer, FSE_MIN_TABLELOG, FSE_MAX_TABLELOG);
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unsigned const maxSymbolValue = FUZZ_dataProducer_uint32Range(producer, 0, 255);
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unsigned remainingWeight = (1u << tableLog) - 1;
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size_t dataSize;
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BYTE data[512];
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short ncount[256];
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/* Randomly fill the normalized count */
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memset(ncount, 0, sizeof(ncount));
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{
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unsigned s;
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for (s = 0; s < maxSymbolValue && remainingWeight > 0; ++s) {
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short n = (short)FUZZ_dataProducer_int32Range(producer, -1, remainingWeight);
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ncount[s] = n;
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if (n < 0) {
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remainingWeight -= 1;
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} else {
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assert((unsigned)n <= remainingWeight);
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remainingWeight -= n;
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}
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}
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/* Ensure ncount[maxSymbolValue] != 0 and the sum is (1<<tableLog) */
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ncount[maxSymbolValue] = remainingWeight + 1;
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if (ncount[maxSymbolValue] == 1 && FUZZ_dataProducer_uint32Range(producer, 0, 1) == 1) {
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ncount[maxSymbolValue] = -1;
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}
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}
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/* Write the normalized count */
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{
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FUZZ_ASSERT(sizeof(data) >= FSE_NCountWriteBound(maxSymbolValue, tableLog));
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dataSize = FSE_writeNCount(data, sizeof(data), ncount, maxSymbolValue, tableLog);
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FUZZ_ZASSERT(dataSize);
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}
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/* Read & validate the normalized count */
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{
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short rtNcount[256];
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unsigned rtMaxSymbolValue = 255;
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unsigned rtTableLog;
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/* Copy into a buffer with a random amount of random data at the end */
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size_t const buffSize = (size_t)FUZZ_dataProducer_uint32Range(producer, dataSize, sizeof(data));
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BYTE* const buff = FUZZ_malloc(buffSize);
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size_t rtDataSize;
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memcpy(buff, data, dataSize);
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{
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size_t b;
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for (b = dataSize; b < buffSize; ++b) {
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buff[b] = (BYTE)FUZZ_dataProducer_uint32Range(producer, 0, 255);
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}
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}
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rtDataSize = FSE_readNCount(rtNcount, &rtMaxSymbolValue, &rtTableLog, buff, buffSize);
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FUZZ_ZASSERT(rtDataSize);
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FUZZ_ASSERT(rtDataSize == dataSize);
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FUZZ_ASSERT(rtMaxSymbolValue == maxSymbolValue);
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FUZZ_ASSERT(rtTableLog == tableLog);
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{
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unsigned s;
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for (s = 0; s <= maxSymbolValue; ++s) {
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FUZZ_ASSERT(ncount[s] == rtNcount[s]);
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}
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}
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free(buff);
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}
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FUZZ_dataProducer_free(producer);
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return 0;
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}
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