| /* |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| /* Targeted fuzzer that targets specific codecs depending on two |
| compile-time flags. |
| INSTRUCTIONS: |
| |
| * Get the very fresh clang, e.g. see http://libfuzzer.info#versions |
| * Get and build libFuzzer: |
| svn co http://llvm.org/svn/llvm-project/llvm/trunk/lib/Fuzzer |
| ./Fuzzer/build.sh |
| * build ffmpeg for fuzzing: |
| FLAGS="-fsanitize=address -fsanitize-coverage=trace-pc-guard,trace-cmp -g" CC="clang $FLAGS" CXX="clang++ $FLAGS" ./configure --disable-x86asm |
| make clean && make -j |
| * build the fuzz target. |
| Choose the value of FFMPEG_CODEC (e.g. AV_CODEC_ID_DVD_SUBTITLE) and |
| choose one of FUZZ_FFMPEG_VIDEO, FUZZ_FFMPEG_AUDIO, FUZZ_FFMPEG_SUBTITLE. |
| 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 |
| * create a corpus directory and put some samples there (empty dir is ok too): |
| mkdir CORPUS && cp some-files CORPUS |
| |
| * Run fuzzing: |
| ./target_dec_fuzzer -max_len=100000 CORPUS |
| |
| More info: |
| http://libfuzzer.info |
| http://tutorial.libfuzzer.info |
| https://github.com/google/oss-fuzz |
| http://lcamtuf.coredump.cx/afl/ |
| https://security.googleblog.com/2016/08/guided-in-process-fuzzing-of-chrome.html |
| */ |
| |
| #include "config.h" |
| #include "libavutil/avassert.h" |
| #include "libavutil/imgutils.h" |
| #include "libavutil/intreadwrite.h" |
| |
| #include "libavcodec/avcodec.h" |
| #include "libavcodec/bytestream.h" |
| #include "libavformat/avformat.h" |
| |
| int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size); |
| |
| extern AVCodec * codec_list[]; |
| |
| static void error(const char *err) |
| { |
| fprintf(stderr, "%s", err); |
| exit(1); |
| } |
| |
| static AVCodec *c = NULL; |
| static AVCodec *AVCodecInitialize(enum AVCodecID codec_id) |
| { |
| AVCodec *res; |
| |
| res = avcodec_find_decoder(codec_id); |
| if (!res) |
| error("Failed to find decoder"); |
| return res; |
| } |
| |
| static int subtitle_handler(AVCodecContext *avctx, void *frame, |
| int *got_sub_ptr, AVPacket *avpkt) |
| { |
| AVSubtitle sub; |
| int ret = avcodec_decode_subtitle2(avctx, &sub, got_sub_ptr, avpkt); |
| if (ret >= 0 && *got_sub_ptr) |
| avsubtitle_free(&sub); |
| return ret; |
| } |
| |
| // Class to handle buffer allocation and resize for each frame |
| typedef struct FuzzDataBuffer { |
| size_t size_; |
| uint8_t *data_; |
| } FuzzDataBuffer; |
| |
| static void FDBCreate(FuzzDataBuffer *FDB) { |
| FDB->size_ = 0x1000; |
| FDB->data_ = av_malloc(FDB->size_); |
| if (!FDB->data_) |
| error("Failed memory allocation"); |
| } |
| |
| static void FDBDesroy(FuzzDataBuffer *FDB) { av_free(FDB->data_); } |
| |
| static void FDBRealloc(FuzzDataBuffer *FDB, size_t size) { |
| size_t needed = size + AV_INPUT_BUFFER_PADDING_SIZE; |
| av_assert0(needed > size); |
| if (needed > FDB->size_) { |
| av_free(FDB->data_); |
| FDB->size_ = needed; |
| FDB->data_ = av_malloc(FDB->size_); |
| if (!FDB->data_) |
| error("Failed memory allocation"); |
| } |
| } |
| |
| static void FDBPrepare(FuzzDataBuffer *FDB, AVPacket *dst, const uint8_t *data, |
| size_t size) |
| { |
| FDBRealloc(FDB, size); |
| memcpy(FDB->data_, data, size); |
| size_t padd = FDB->size_ - size; |
| if (padd > AV_INPUT_BUFFER_PADDING_SIZE) |
| padd = AV_INPUT_BUFFER_PADDING_SIZE; |
| memset(FDB->data_ + size, 0, padd); |
| av_init_packet(dst); |
| dst->data = FDB->data_; |
| dst->size = size; |
| } |
| |
| // Ensure we don't loop forever |
| const uint32_t maxiteration = 8096; |
| |
| static const uint64_t FUZZ_TAG = 0x4741542D5A5A5546ULL; |
| |
| int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { |
| const uint64_t fuzz_tag = FUZZ_TAG; |
| FuzzDataBuffer buffer; |
| const uint8_t *last = data; |
| const uint8_t *end = data + size; |
| uint32_t it = 0; |
| int (*decode_handler)(AVCodecContext *avctx, AVFrame *picture, |
| int *got_picture_ptr, |
| const AVPacket *avpkt) = NULL; |
| AVCodecParserContext *parser = NULL; |
| |
| |
| if (!c) { |
| #ifdef FFMPEG_DECODER |
| #define DECODER_SYMBOL0(CODEC) ff_##CODEC##_decoder |
| #define DECODER_SYMBOL(CODEC) DECODER_SYMBOL0(CODEC) |
| extern AVCodec DECODER_SYMBOL(FFMPEG_DECODER); |
| codec_list[0] = &DECODER_SYMBOL(FFMPEG_DECODER); |
| avcodec_register(&DECODER_SYMBOL(FFMPEG_DECODER)); |
| |
| c = &DECODER_SYMBOL(FFMPEG_DECODER); |
| #else |
| avcodec_register_all(); |
| c = AVCodecInitialize(FFMPEG_CODEC); // Done once. |
| #endif |
| av_log_set_level(AV_LOG_PANIC); |
| } |
| |
| switch (c->type) { |
| case AVMEDIA_TYPE_AUDIO : decode_handler = avcodec_decode_audio4; break; |
| case AVMEDIA_TYPE_VIDEO : decode_handler = avcodec_decode_video2; break; |
| case AVMEDIA_TYPE_SUBTITLE: decode_handler = subtitle_handler ; break; |
| } |
| |
| AVCodecContext* ctx = avcodec_alloc_context3(NULL); |
| AVCodecContext* parser_avctx = avcodec_alloc_context3(NULL); |
| if (!ctx || !parser_avctx) |
| error("Failed memory allocation"); |
| |
| ctx->max_pixels = 4096 * 4096; //To reduce false positive OOM and hangs |
| |
| if (size > 1024) { |
| GetByteContext gbc; |
| bytestream2_init(&gbc, data + size - 1024, 1024); |
| ctx->width = bytestream2_get_le32(&gbc); |
| ctx->height = bytestream2_get_le32(&gbc); |
| ctx->bit_rate = bytestream2_get_le64(&gbc); |
| ctx->bits_per_coded_sample = bytestream2_get_le32(&gbc); |
| // Try to initialize a parser for this codec, note, this may fail which just means we test without one |
| if (bytestream2_get_byte(&gbc) & 1) |
| parser = av_parser_init(c->id); |
| if (av_image_check_size(ctx->width, ctx->height, 0, ctx)) |
| ctx->width = ctx->height = 0; |
| size -= 1024; |
| } |
| |
| int res = avcodec_open2(ctx, c, NULL); |
| if (res < 0) { |
| av_free(ctx); |
| av_free(parser_avctx); |
| return 0; // Failure of avcodec_open2() does not imply that a issue was found |
| } |
| parser_avctx->codec_id = ctx->codec_id; |
| |
| FDBCreate(&buffer); |
| int got_frame; |
| AVFrame *frame = av_frame_alloc(); |
| if (!frame) |
| error("Failed memory allocation"); |
| |
| // Read very simple container |
| AVPacket avpkt, parsepkt; |
| while (data < end && it < maxiteration) { |
| // Search for the TAG |
| while (data + sizeof(fuzz_tag) < end) { |
| if (data[0] == (fuzz_tag & 0xFF) && AV_RN64(data) == fuzz_tag) |
| break; |
| data++; |
| } |
| if (data + sizeof(fuzz_tag) > end) |
| data = end; |
| |
| FDBPrepare(&buffer, &parsepkt, last, data - last); |
| data += sizeof(fuzz_tag); |
| last = data; |
| |
| while (parsepkt.size > 0) { |
| |
| if (parser) { |
| av_init_packet(&avpkt); |
| int ret = av_parser_parse2(parser, parser_avctx, &avpkt.data, &avpkt.size, |
| parsepkt.data, parsepkt.size, |
| parsepkt.pts, parsepkt.dts, parsepkt.pos); |
| parsepkt.data += ret; |
| parsepkt.size -= ret; |
| parsepkt.pos += ret; |
| avpkt.pts = parser->pts; |
| avpkt.dts = parser->dts; |
| avpkt.pos = parser->pos; |
| if ( parser->key_frame == 1 || |
| (parser->key_frame == -1 && parser->pict_type == AV_PICTURE_TYPE_I)) |
| avpkt.flags |= AV_PKT_FLAG_KEY; |
| avpkt.flags |= parsepkt.flags & AV_PKT_FLAG_DISCARD; |
| } else { |
| avpkt = parsepkt; |
| parsepkt.size = 0; |
| } |
| |
| // Iterate through all data |
| while (avpkt.size > 0 && it++ < maxiteration) { |
| av_frame_unref(frame); |
| int ret = decode_handler(ctx, frame, &got_frame, &avpkt); |
| |
| if (it > 20) |
| ctx->error_concealment = 0; |
| |
| if (ret <= 0 || ret > avpkt.size) |
| break; |
| if (ctx->codec_type != AVMEDIA_TYPE_AUDIO) |
| ret = avpkt.size; |
| avpkt.data += ret; |
| avpkt.size -= ret; |
| } |
| } |
| } |
| |
| av_init_packet(&avpkt); |
| avpkt.data = NULL; |
| avpkt.size = 0; |
| |
| do { |
| got_frame = 0; |
| decode_handler(ctx, frame, &got_frame, &avpkt); |
| } while (got_frame == 1 && it++ < maxiteration); |
| |
| av_frame_free(&frame); |
| avcodec_free_context(&ctx); |
| av_freep(&ctx); |
| avcodec_free_context(&parser_avctx); |
| av_freep(&parser_avctx); |
| av_parser_close(parser); |
| FDBDesroy(&buffer); |
| return 0; |
| } |