2 * This file is part of FFmpeg.
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.
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.
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
19 /* Targeted fuzzer that targets specific codecs depending on two
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
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-x86asm
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
38 ./target_dec_fuzzer -max_len=100000 CORPUS
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
49 #include "libavutil/avassert.h"
50 #include "libavutil/imgutils.h"
51 #include "libavutil/intreadwrite.h"
53 #include "libavcodec/avcodec.h"
54 #include "libavcodec/bytestream.h"
55 #include "libavformat/avformat.h"
57 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
59 extern AVCodec * codec_list[];
61 static void error(const char *err)
63 fprintf(stderr, "%s", err);
67 static AVCodec *c = NULL;
68 static AVCodec *AVCodecInitialize(enum AVCodecID codec_id)
72 res = avcodec_find_decoder(codec_id);
74 error("Failed to find decoder");
78 static int subtitle_handler(AVCodecContext *avctx, void *frame,
79 int *got_sub_ptr, AVPacket *avpkt)
82 int ret = avcodec_decode_subtitle2(avctx, &sub, got_sub_ptr, avpkt);
83 if (ret >= 0 && *got_sub_ptr)
84 avsubtitle_free(&sub);
88 // Class to handle buffer allocation and resize for each frame
89 typedef struct FuzzDataBuffer {
94 static void FDBCreate(FuzzDataBuffer *FDB) {
96 FDB->data_ = av_malloc(FDB->size_);
98 error("Failed memory allocation");
101 static void FDBDesroy(FuzzDataBuffer *FDB) { av_free(FDB->data_); }
103 static void FDBRealloc(FuzzDataBuffer *FDB, size_t size) {
104 size_t needed = size + AV_INPUT_BUFFER_PADDING_SIZE;
105 av_assert0(needed > size);
106 if (needed > FDB->size_) {
109 FDB->data_ = av_malloc(FDB->size_);
111 error("Failed memory allocation");
115 static void FDBPrepare(FuzzDataBuffer *FDB, AVPacket *dst, const uint8_t *data,
118 FDBRealloc(FDB, size);
119 memcpy(FDB->data_, data, size);
120 size_t padd = FDB->size_ - size;
121 if (padd > AV_INPUT_BUFFER_PADDING_SIZE)
122 padd = AV_INPUT_BUFFER_PADDING_SIZE;
123 memset(FDB->data_ + size, 0, padd);
125 dst->data = FDB->data_;
129 // Ensure we don't loop forever
130 const uint32_t maxiteration = 8096;
131 const uint64_t maxpixels_per_frame = 4096 * 4096;
134 static const uint64_t FUZZ_TAG = 0x4741542D5A5A5546ULL;
136 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
137 const uint64_t fuzz_tag = FUZZ_TAG;
138 FuzzDataBuffer buffer;
139 const uint8_t *last = data;
140 const uint8_t *end = data + size;
142 uint64_t ec_pixels = 0;
143 int (*decode_handler)(AVCodecContext *avctx, AVFrame *picture,
144 int *got_picture_ptr,
145 const AVPacket *avpkt) = NULL;
146 AVCodecParserContext *parser = NULL;
150 #ifdef FFMPEG_DECODER
151 #define DECODER_SYMBOL0(CODEC) ff_##CODEC##_decoder
152 #define DECODER_SYMBOL(CODEC) DECODER_SYMBOL0(CODEC)
153 extern AVCodec DECODER_SYMBOL(FFMPEG_DECODER);
154 codec_list[0] = &DECODER_SYMBOL(FFMPEG_DECODER);
155 avcodec_register(&DECODER_SYMBOL(FFMPEG_DECODER));
157 c = &DECODER_SYMBOL(FFMPEG_DECODER);
159 avcodec_register_all();
160 c = AVCodecInitialize(FFMPEG_CODEC); // Done once.
162 av_log_set_level(AV_LOG_PANIC);
166 case AVMEDIA_TYPE_AUDIO : decode_handler = avcodec_decode_audio4; break;
167 case AVMEDIA_TYPE_VIDEO : decode_handler = avcodec_decode_video2; break;
168 case AVMEDIA_TYPE_SUBTITLE: decode_handler = subtitle_handler ; break;
170 maxpixels = maxpixels_per_frame * maxiteration;
172 // Allows a small input to generate gigantic output
173 case AV_CODEC_ID_QTRLE: maxpixels /= 16;
174 case AV_CODEC_ID_GIF: maxpixels /= 16;
175 // Performs slow frame rescaling in C
176 case AV_CODEC_ID_GDV: maxpixels /= 256;
177 // Postprocessing in C
178 case AV_CODEC_ID_HNM4_VIDEO:maxpixels /= 128;
182 AVCodecContext* ctx = avcodec_alloc_context3(NULL);
183 AVCodecContext* parser_avctx = avcodec_alloc_context3(NULL);
184 if (!ctx || !parser_avctx)
185 error("Failed memory allocation");
187 ctx->max_pixels = maxpixels_per_frame; //To reduce false positive OOM and hangs
193 bytestream2_init(&gbc, data + size, 1024);
194 ctx->width = bytestream2_get_le32(&gbc);
195 ctx->height = bytestream2_get_le32(&gbc);
196 ctx->bit_rate = bytestream2_get_le64(&gbc);
197 ctx->bits_per_coded_sample = bytestream2_get_le32(&gbc);
198 // Try to initialize a parser for this codec, note, this may fail which just means we test without one
199 if (bytestream2_get_byte(&gbc) & 1)
200 parser = av_parser_init(c->id);
202 extradata_size = bytestream2_get_le32(&gbc);
203 if (extradata_size < size) {
204 ctx->extradata = av_mallocz(extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
205 if (ctx->extradata) {
206 ctx->extradata_size = extradata_size;
207 size -= ctx->extradata_size;
208 memcpy(ctx->extradata, data + size, ctx->extradata_size);
211 if (av_image_check_size(ctx->width, ctx->height, 0, ctx))
212 ctx->width = ctx->height = 0;
215 int res = avcodec_open2(ctx, c, NULL);
217 avcodec_free_context(&ctx);
218 av_free(parser_avctx);
219 av_parser_close(parser);
220 return 0; // Failure of avcodec_open2() does not imply that a issue was found
222 parser_avctx->codec_id = ctx->codec_id;
226 AVFrame *frame = av_frame_alloc();
228 error("Failed memory allocation");
230 // Read very simple container
231 AVPacket avpkt, parsepkt;
232 while (data < end && it < maxiteration) {
233 // Search for the TAG
234 while (data + sizeof(fuzz_tag) < end) {
235 if (data[0] == (fuzz_tag & 0xFF) && AV_RN64(data) == fuzz_tag)
239 if (data + sizeof(fuzz_tag) > end)
242 FDBPrepare(&buffer, &parsepkt, last, data - last);
243 data += sizeof(fuzz_tag);
246 while (parsepkt.size > 0) {
249 av_init_packet(&avpkt);
250 int ret = av_parser_parse2(parser, parser_avctx, &avpkt.data, &avpkt.size,
251 parsepkt.data, parsepkt.size,
252 parsepkt.pts, parsepkt.dts, parsepkt.pos);
253 parsepkt.data += ret;
254 parsepkt.size -= ret;
256 avpkt.pts = parser->pts;
257 avpkt.dts = parser->dts;
258 avpkt.pos = parser->pos;
259 if ( parser->key_frame == 1 ||
260 (parser->key_frame == -1 && parser->pict_type == AV_PICTURE_TYPE_I))
261 avpkt.flags |= AV_PKT_FLAG_KEY;
262 avpkt.flags |= parsepkt.flags & AV_PKT_FLAG_DISCARD;
268 // Iterate through all data
269 while (avpkt.size > 0 && it++ < maxiteration) {
270 av_frame_unref(frame);
271 int ret = decode_handler(ctx, frame, &got_frame, &avpkt);
273 ec_pixels += ctx->width * ctx->height;
274 if (it > 20 || ec_pixels > 4 * ctx->max_pixels)
275 ctx->error_concealment = 0;
276 if (ec_pixels > maxpixels)
277 goto maximums_reached;
279 if (ret <= 0 || ret > avpkt.size)
281 if (ctx->codec_type != AVMEDIA_TYPE_AUDIO)
290 av_init_packet(&avpkt);
296 decode_handler(ctx, frame, &got_frame, &avpkt);
297 } while (got_frame == 1 && it++ < maxiteration);
299 av_frame_free(&frame);
300 avcodec_free_context(&ctx);
301 avcodec_free_context(&parser_avctx);
302 av_parser_close(parser);