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 /**
12 * This fuzz target attempts to decompress the fuzzed data with the simple
13 * decompression function to ensure the decompressor never crashes.
14 */
15
16 #define ZSTD_STATIC_LINKING_ONLY
17
18 #include <stddef.h>
19 #include <stdlib.h>
20 #include <stdio.h>
21 #include "fuzz_helpers.h"
22 #include "zstd.h"
23 #include "fuzz_data_producer.h"
24
25 static ZSTD_DStream *dstream = NULL;
26 uint32_t seed;
27
makeOutBuffer(FUZZ_dataProducer_t * producer,void * buf,size_t bufSize)28 static ZSTD_outBuffer makeOutBuffer(FUZZ_dataProducer_t *producer, void* buf, size_t bufSize)
29 {
30 ZSTD_outBuffer buffer = { buf, 0, 0 };
31
32 if (FUZZ_dataProducer_empty(producer)) {
33 buffer.size = bufSize;
34 } else {
35 buffer.size = (FUZZ_dataProducer_uint32Range(producer, 0, bufSize));
36 }
37 FUZZ_ASSERT(buffer.size <= bufSize);
38
39 if (buffer.size == 0) {
40 buffer.dst = NULL;
41 }
42
43 return buffer;
44 }
45
makeInBuffer(const uint8_t ** src,size_t * size,FUZZ_dataProducer_t * producer)46 static ZSTD_inBuffer makeInBuffer(const uint8_t **src, size_t *size,
47 FUZZ_dataProducer_t *producer)
48 {
49 ZSTD_inBuffer buffer = { *src, 0, 0 };
50
51 FUZZ_ASSERT(*size > 0);
52 if (FUZZ_dataProducer_empty(producer)) {
53 buffer.size = *size;
54 } else {
55 buffer.size = (FUZZ_dataProducer_uint32Range(producer, 0, *size));
56 }
57 FUZZ_ASSERT(buffer.size <= *size);
58 *src += buffer.size;
59 *size -= buffer.size;
60
61 if (buffer.size == 0) {
62 buffer.src = NULL;
63 }
64
65 return buffer;
66 }
67
LLVMFuzzerTestOneInput(const uint8_t * src,size_t size)68 int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
69 {
70 /* Give a random portion of src data to the producer, to use for
71 parameter generation. The rest will be used for (de)compression */
72 FUZZ_dataProducer_t *producer = FUZZ_dataProducer_create(src, size);
73 int stableOutBuffer;
74 ZSTD_outBuffer out;
75 void* buf;
76 size_t bufSize;
77 size = FUZZ_dataProducer_reserveDataPrefix(producer);
78 bufSize = MAX(10 * size, ZSTD_BLOCKSIZE_MAX);
79
80 /* Allocate all buffers and contexts if not already allocated */
81 buf = FUZZ_malloc(bufSize);
82
83 if (!dstream) {
84 dstream = ZSTD_createDStream();
85 FUZZ_ASSERT(dstream);
86 } else {
87 FUZZ_ZASSERT(ZSTD_DCtx_reset(dstream, ZSTD_reset_session_only));
88 }
89
90 stableOutBuffer = FUZZ_dataProducer_uint32Range(producer, 0, 10) == 5;
91 if (stableOutBuffer) {
92 FUZZ_ZASSERT(ZSTD_DCtx_setParameter(dstream, ZSTD_d_stableOutBuffer, 1));
93 out.dst = buf;
94 out.size = bufSize;
95 out.pos = 0;
96 } else {
97 out = makeOutBuffer(producer, buf, bufSize);
98 }
99
100 while (size > 0) {
101 ZSTD_inBuffer in = makeInBuffer(&src, &size, producer);
102 do {
103 size_t const rc = ZSTD_decompressStream(dstream, &out, &in);
104 if (ZSTD_isError(rc)) goto error;
105 if (out.pos == out.size) {
106 if (stableOutBuffer) goto error;
107 out = makeOutBuffer(producer, buf, bufSize);
108 }
109 } while (in.pos != in.size);
110 }
111
112 error:
113 #ifndef STATEFUL_FUZZING
114 ZSTD_freeDStream(dstream); dstream = NULL;
115 #endif
116 FUZZ_dataProducer_free(producer);
117 free(buf);
118 return 0;
119 }
120