summaryrefslogtreecommitdiff
path: root/tools/target_dec_fuzzer.c (plain)
blob: cb3bc50919bea99c87c533b9b63f8eb8391ac418
1/*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19/* Targeted fuzzer that targets specific codecs depending on two
20 compile-time flags.
21 INSTRUCTIONS:
22
23 * Get the very fresh clang, e.g. see http://libfuzzer.info#versions
24 * Get and build libFuzzer:
25 svn co http://llvm.org/svn/llvm-project/llvm/trunk/lib/Fuzzer
26 ./Fuzzer/build.sh
27 * build ffmpeg for fuzzing:
28 FLAGS="-fsanitize=address -fsanitize-coverage=trace-pc-guard,trace-cmp -g" CC="clang $FLAGS" CXX="clang++ $FLAGS" ./configure --disable-yasm
29 make clean && make -j
30 * build the fuzz target.
31 Choose the value of FFMPEG_CODEC (e.g. AV_CODEC_ID_DVD_SUBTITLE) and
32 choose one of FUZZ_FFMPEG_VIDEO, FUZZ_FFMPEG_AUDIO, FUZZ_FFMPEG_SUBTITLE.
33 clang -fsanitize=address -fsanitize-coverage=trace-pc-guard,trace-cmp tools/target_dec_fuzzer.c -o target_dec_fuzzer -I. -DFFMPEG_CODEC=AV_CODEC_ID_MPEG1VIDEO -DFUZZ_FFMPEG_VIDEO ../../libfuzzer/libFuzzer.a -Llibavcodec -Llibavdevice -Llibavfilter -Llibavformat -Llibavresample -Llibavutil -Llibpostproc -Llibswscale -Llibswresample -Wl,--as-needed -Wl,-z,noexecstack -Wl,--warn-common -Wl,-rpath-link=libpostproc:libswresample:libswscale:libavfilter:libavdevice:libavformat:libavcodec:libavutil:libavresample -lavdevice -lavfilter -lavformat -lavcodec -lswresample -lswscale -lavutil -ldl -lxcb -lxcb-shm -lxcb -lxcb-xfixes -lxcb -lxcb-shape -lxcb -lX11 -lasound -lm -lbz2 -lz -pthread
34 * create a corpus directory and put some samples there (empty dir is ok too):
35 mkdir CORPUS && cp some-files CORPUS
36
37 * Run fuzzing:
38 ./target_dec_fuzzer -max_len=100000 CORPUS
39
40 More info:
41 http://libfuzzer.info
42 http://tutorial.libfuzzer.info
43 https://github.com/google/oss-fuzz
44 http://lcamtuf.coredump.cx/afl/
45 https://security.googleblog.com/2016/08/guided-in-process-fuzzing-of-chrome.html
46*/
47
48#include "libavutil/avassert.h"
49#include "libavutil/intreadwrite.h"
50
51#include "libavcodec/avcodec.h"
52#include "libavformat/avformat.h"
53
54static void error(const char *err)
55{
56 fprintf(stderr, "%s", err);
57 exit(1);
58}
59
60static AVCodec *c = NULL;
61static AVCodec *AVCodecInitialize(enum AVCodecID codec_id)
62{
63 AVCodec *res;
64 av_register_all();
65 av_log_set_level(AV_LOG_PANIC);
66 res = avcodec_find_decoder(codec_id);
67 if (!res)
68 error("Failed to find decoder");
69 return res;
70}
71
72#if defined(FUZZ_FFMPEG_VIDEO)
73#define decode_handler avcodec_decode_video2
74#elif defined(FUZZ_FFMPEG_AUDIO)
75#define decode_handler avcodec_decode_audio4
76#elif defined(FUZZ_FFMPEG_SUBTITLE)
77static int subtitle_handler(AVCodecContext *avctx, void *frame,
78 int *got_sub_ptr, AVPacket *avpkt)
79{
80 AVSubtitle sub;
81 int ret = avcodec_decode_subtitle2(avctx, &sub, got_sub_ptr, avpkt);
82 if (ret >= 0 && *got_sub_ptr)
83 avsubtitle_free(&sub);
84 return ret;
85}
86
87#define decode_handler subtitle_handler
88#else
89#error "Specify encoder type" // To catch mistakes
90#endif
91
92// Class to handle buffer allocation and resize for each frame
93typedef struct FuzzDataBuffer {
94 size_t size_;
95 uint8_t *data_;
96} FuzzDataBuffer;
97
98void FDBCreate(FuzzDataBuffer *FDB) {
99 FDB->size_ = 0x1000;
100 FDB->data_ = av_malloc(FDB->size_);
101 if (!FDB->data_)
102 error("Failed memory allocation");
103}
104
105void FDBDesroy(FuzzDataBuffer *FDB) { av_free(FDB->data_); }
106
107void FDBRealloc(FuzzDataBuffer *FDB, size_t size) {
108 size_t needed = size + FF_INPUT_BUFFER_PADDING_SIZE;
109 av_assert0(needed > size);
110 if (needed > FDB->size_) {
111 av_free(FDB->data_);
112 FDB->size_ = needed;
113 FDB->data_ = av_malloc(FDB->size_);
114 if (!FDB->data_)
115 error("Failed memory allocation");
116 }
117}
118
119void FDBPrepare(FuzzDataBuffer *FDB, AVPacket *dst, const uint8_t *data,
120 size_t size)
121{
122 FDBRealloc(FDB, size);
123 memcpy(FDB->data_, data, size);
124 size_t padd = FDB->size_ - size;
125 if (padd > FF_INPUT_BUFFER_PADDING_SIZE)
126 padd = FF_INPUT_BUFFER_PADDING_SIZE;
127 memset(FDB->data_ + size, 0, padd);
128 av_init_packet(dst);
129 dst->data = FDB->data_;
130 dst->size = size;
131}
132
133// Ensure we don't loop forever
134const uint32_t maxiteration = 8096;
135
136static const uint64_t FUZZ_TAG = 0x4741542D5A5A5546ULL;
137
138int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
139 const uint64_t fuzz_tag = FUZZ_TAG;
140 FuzzDataBuffer buffer;
141 const uint8_t *last = data;
142 const uint8_t *end = data + size;
143 uint32_t it = 0;
144
145 if (!c)
146 c = AVCodecInitialize(FFMPEG_CODEC); // Done once.
147
148 AVCodecContext* ctx = avcodec_alloc_context3(NULL);
149 if (!ctx)
150 error("Failed memory allocation");
151
152 ctx->max_pixels = 4096 * 4096; //To reduce false positive OOM and hangs
153
154 int res = avcodec_open2(ctx, c, NULL);
155 if (res < 0)
156 return res;
157
158 FDBCreate(&buffer);
159 int got_frame;
160 AVFrame *frame = av_frame_alloc();
161 if (!frame)
162 error("Failed memory allocation");
163
164 // Read very simple container
165 AVPacket avpkt;
166 while (data < end && it < maxiteration) {
167 // Search for the TAG
168 while (data + sizeof(fuzz_tag) < end) {
169 if (data[0] == (fuzz_tag & 0xFF) && AV_RN64(data) == fuzz_tag)
170 break;
171 data++;
172 }
173 if (data + sizeof(fuzz_tag) > end)
174 data = end;
175
176 FDBPrepare(&buffer, &avpkt, last, data - last);
177 data += sizeof(fuzz_tag);
178 last = data;
179
180 // Iterate through all data
181 while (avpkt.size > 0 && it++ < maxiteration) {
182 av_frame_unref(frame);
183 int ret = decode_handler(ctx, frame, &got_frame, &avpkt);
184
185 if (it > 20)
186 ctx->error_concealment = 0;
187
188 if (ret <= 0 || ret > avpkt.size)
189 break;
190 if (ctx->codec_type != AVMEDIA_TYPE_AUDIO)
191 ret = avpkt.size;
192 avpkt.data += ret;
193 avpkt.size -= ret;
194 }
195 }
196
197 av_init_packet(&avpkt);
198 avpkt.data = NULL;
199 avpkt.size = 0;
200
201 do {
202 got_frame = 0;
203 decode_handler(ctx, frame, &got_frame, &avpkt);
204 } while (got_frame == 1 && it++ < maxiteration);
205
206 av_frame_free(&frame);
207 avcodec_free_context(&ctx);
208 av_freep(&ctx);
209 FDBDesroy(&buffer);
210 return 0;
211}
212
generated by cgit at 2024-05-17 06:09:52 (GMT)