| 1 | /* |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * This source code is licensed under both the BSD-style license (found in the |
| 6 | * LICENSE file in the root directory of this source tree) and the GPLv2 (found |
| 7 | * in the COPYING file in the root directory of this source tree). |
| 8 | * You may select, at your option, one of the above-listed licenses. |
| 9 | */ |
| 10 | |
| 11 | // This fuzz target validates decompression of magicless-format compressed data. |
| 12 | |
| 13 | #include <stddef.h> |
| 14 | #include <stdlib.h> |
| 15 | #include <stdio.h> |
| 16 | #include <string.h> |
| 17 | #include "fuzz_helpers.h" |
| 18 | #define ZSTD_STATIC_LINKING_ONLY |
| 19 | #include "zstd.h" |
| 20 | #include "fuzz_data_producer.h" |
| 21 | |
| 22 | static ZSTD_DCtx *dctx = NULL; |
| 23 | |
| 24 | int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size) |
| 25 | { |
| 26 | // Give a random portion of src data to the producer, to use for parameter generation. |
| 27 | // The rest will be interpreted as magicless compressed data. |
| 28 | FUZZ_dataProducer_t *producer = FUZZ_dataProducer_create(src, size); |
| 29 | size_t magiclessSize = FUZZ_dataProducer_reserveDataPrefix(producer); |
| 30 | const uint8_t* const magiclessSrc = src; |
| 31 | size_t const dstSize = FUZZ_dataProducer_uint32Range(producer, 0, 10 * size); |
| 32 | uint8_t* const standardDst = (uint8_t*)FUZZ_malloc(dstSize); |
| 33 | uint8_t* const magiclessDst = (uint8_t*)FUZZ_malloc(dstSize); |
| 34 | |
| 35 | // Create standard-format src from magicless-format src |
| 36 | const uint32_t zstd_magic = ZSTD_MAGICNUMBER; |
| 37 | size_t standardSize = sizeof(zstd_magic) + magiclessSize; |
| 38 | uint8_t* const standardSrc = (uint8_t*)FUZZ_malloc(standardSize); |
| 39 | memcpy(standardSrc, &zstd_magic, sizeof(zstd_magic)); // assume fuzzing on little-endian machine |
| 40 | memcpy(standardSrc + sizeof(zstd_magic), magiclessSrc, magiclessSize); |
| 41 | |
| 42 | // Truncate to a single frame |
| 43 | { |
| 44 | const size_t standardFrameCompressedSize = ZSTD_findFrameCompressedSize(standardSrc, standardSize); |
| 45 | if (ZSTD_isError(standardFrameCompressedSize)) { |
| 46 | goto cleanup_and_return; |
| 47 | } |
| 48 | standardSize = standardFrameCompressedSize; |
| 49 | magiclessSize = standardFrameCompressedSize - sizeof(zstd_magic); |
| 50 | } |
| 51 | |
| 52 | // Create DCtx if needed |
| 53 | if (!dctx) { |
| 54 | dctx = ZSTD_createDCtx(); |
| 55 | FUZZ_ASSERT(dctx); |
| 56 | } |
| 57 | |
| 58 | // Test one-shot decompression |
| 59 | { |
| 60 | FUZZ_ZASSERT(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_and_parameters)); |
| 61 | FUZZ_ZASSERT(ZSTD_DCtx_setParameter(dctx, ZSTD_d_format, ZSTD_f_zstd1)); |
| 62 | const size_t standardRet = ZSTD_decompressDCtx( |
| 63 | dctx, standardDst, dstSize, standardSrc, standardSize); |
| 64 | |
| 65 | FUZZ_ZASSERT(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_and_parameters)); |
| 66 | FUZZ_ZASSERT(ZSTD_DCtx_setParameter(dctx, ZSTD_d_format, ZSTD_f_zstd1_magicless)); |
| 67 | const size_t magiclessRet = ZSTD_decompressDCtx( |
| 68 | dctx, magiclessDst, dstSize, magiclessSrc, magiclessSize); |
| 69 | |
| 70 | // Standard accepts => magicless should accept |
| 71 | if (!ZSTD_isError(standardRet)) FUZZ_ZASSERT(magiclessRet); |
| 72 | |
| 73 | // Magicless accepts => standard should accept |
| 74 | // NOTE: this is nice-to-have, please disable this check if it is difficult to satisfy. |
| 75 | if (!ZSTD_isError(magiclessRet)) FUZZ_ZASSERT(standardRet); |
| 76 | |
| 77 | // If both accept, decompressed size and data should match |
| 78 | if (!ZSTD_isError(standardRet) && !ZSTD_isError(magiclessRet)) { |
| 79 | FUZZ_ASSERT(standardRet == magiclessRet); |
| 80 | if (standardRet > 0) { |
| 81 | FUZZ_ASSERT( |
| 82 | memcmp(standardDst, magiclessDst, standardRet) == 0 |
| 83 | ); |
| 84 | } |
| 85 | } |
| 86 | } |
| 87 | |
| 88 | // Test streaming decompression |
| 89 | { |
| 90 | ZSTD_inBuffer standardIn = { standardSrc, standardSize, 0 }; |
| 91 | ZSTD_inBuffer magiclessIn = { magiclessSrc, magiclessSize, 0 }; |
| 92 | ZSTD_outBuffer standardOut = { standardDst, dstSize, 0 }; |
| 93 | ZSTD_outBuffer magiclessOut = { magiclessDst, dstSize, 0 }; |
| 94 | |
| 95 | FUZZ_ZASSERT(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_and_parameters)); |
| 96 | FUZZ_ZASSERT(ZSTD_DCtx_setParameter(dctx, ZSTD_d_format, ZSTD_f_zstd1)); |
| 97 | const size_t standardRet = ZSTD_decompressStream(dctx, &standardOut, &standardIn); |
| 98 | |
| 99 | FUZZ_ZASSERT(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_and_parameters)); |
| 100 | FUZZ_ZASSERT(ZSTD_DCtx_setParameter(dctx, ZSTD_d_format, ZSTD_f_zstd1_magicless)); |
| 101 | const size_t magiclessRet = ZSTD_decompressStream(dctx, &magiclessOut, &magiclessIn); |
| 102 | |
| 103 | // Standard accepts => magicless should accept |
| 104 | if (standardRet == 0) FUZZ_ASSERT(magiclessRet == 0); |
| 105 | |
| 106 | // Magicless accepts => standard should accept |
| 107 | // NOTE: this is nice-to-have, please disable this check if it is difficult to satisfy. |
| 108 | if (magiclessRet == 0) FUZZ_ASSERT(standardRet == 0); |
| 109 | |
| 110 | // If both accept, decompressed size and data should match |
| 111 | if (standardRet == 0 && magiclessRet == 0) { |
| 112 | FUZZ_ASSERT(standardOut.pos == magiclessOut.pos); |
| 113 | if (standardOut.pos > 0) { |
| 114 | FUZZ_ASSERT( |
| 115 | memcmp(standardOut.dst, magiclessOut.dst, standardOut.pos) == 0 |
| 116 | ); |
| 117 | } |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | cleanup_and_return: |
| 122 | #ifndef STATEFUL_FUZZING |
| 123 | ZSTD_freeDCtx(dctx); dctx = NULL; |
| 124 | #endif |
| 125 | free(standardSrc); |
| 126 | free(standardDst); |
| 127 | free(magiclessDst); |
| 128 | FUZZ_dataProducer_free(producer); |
| 129 | return 0; |
| 130 | } |