/* * 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" //For FF_SANE_NB_CHANNELS, so we dont waste energy testing things that will get instantly rejected #include "libavcodec/internal.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; } // Ensure we don't loop forever const uint32_t maxiteration = 8096; const uint64_t maxpixels_per_frame = 4096 * 4096; uint64_t maxpixels; const uint64_t maxsamples_per_frame = 256*1024*32; uint64_t maxsamples; static const uint64_t FUZZ_TAG = 0x4741542D5A5A5546ULL; int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { const uint64_t fuzz_tag = FUZZ_TAG; const uint8_t *last = data; const uint8_t *end = data + size; uint32_t it = 0; uint64_t ec_pixels = 0; uint64_t nb_samples = 0; int (*decode_handler)(AVCodecContext *avctx, AVFrame *picture, int *got_picture_ptr, const AVPacket *avpkt) = NULL; AVCodecParserContext *parser = NULL; uint64_t keyframes = 0; 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; } maxpixels = maxpixels_per_frame * maxiteration; maxsamples = maxsamples_per_frame * maxiteration; switch (c->id) { // Allows a small input to generate gigantic output case AV_CODEC_ID_BINKVIDEO: maxpixels /= 32; break; case AV_CODEC_ID_CFHD: maxpixels /= 128; break; case AV_CODEC_ID_DIRAC: maxpixels /= 8192; break; case AV_CODEC_ID_DST: maxsamples /= 8192; break; case AV_CODEC_ID_DXV: maxpixels /= 32; break; case AV_CODEC_ID_FFWAVESYNTH: maxsamples /= 16384; break; case AV_CODEC_ID_MSRLE: maxpixels /= 16; break; case AV_CODEC_ID_QTRLE: maxpixels /= 16; break; case AV_CODEC_ID_RASC: maxpixels /= 16; break; case AV_CODEC_ID_SANM: maxpixels /= 16; break; case AV_CODEC_ID_G2M: maxpixels /= 64; break; case AV_CODEC_ID_GIF: maxpixels /= 16; break; // Performs slow frame rescaling in C case AV_CODEC_ID_GDV: maxpixels /= 512; break; // Postprocessing in C case AV_CODEC_ID_HNM4_VIDEO:maxpixels /= 128; break; // Cliping in C, generally slow even with small input case AV_CODEC_ID_INDEO4: maxpixels /= 128; break; case AV_CODEC_ID_LSCR: maxpixels /= 16; break; case AV_CODEC_ID_MOTIONPIXELS:maxpixels /= 256; break; case AV_CODEC_ID_MSS2: maxpixels /= 16384; break; case AV_CODEC_ID_MSZH: maxpixels /= 128; break; case AV_CODEC_ID_SCPR: maxpixels /= 32; break; case AV_CODEC_ID_SMACKVIDEO: maxpixels /= 64; break; case AV_CODEC_ID_SNOW: maxpixels /= 128; break; case AV_CODEC_ID_TGV: maxpixels /= 32; break; case AV_CODEC_ID_TRUEMOTION2: maxpixels /= 1024; break; case AV_CODEC_ID_VP7: maxpixels /= 256; break; case AV_CODEC_ID_VP9: maxpixels /= 4096; break; } AVCodecContext* ctx = avcodec_alloc_context3(c); AVCodecContext* parser_avctx = avcodec_alloc_context3(NULL); if (!ctx || !parser_avctx) error("Failed memory allocation"); if (ctx->max_pixels == 0 || ctx->max_pixels > maxpixels_per_frame) ctx->max_pixels = maxpixels_per_frame; //To reduce false positive OOM and hangs ctx->refcounted_frames = 1; //To reduce false positive timeouts and focus testing on the refcounted API ctx->max_samples = maxsamples_per_frame; if (size > 1024) { GetByteContext gbc; int extradata_size; int flags; size -= 1024; bytestream2_init(&gbc, data + size, 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 flags = bytestream2_get_byte(&gbc); if (flags & 1) parser = av_parser_init(c->id); if (flags & 2) ctx->strict_std_compliance = FF_COMPLIANCE_EXPERIMENTAL; if (flags & 4) { ctx->err_recognition = AV_EF_AGGRESSIVE | AV_EF_COMPLIANT | AV_EF_CAREFUL; if (flags & 8) ctx->err_recognition |= AV_EF_EXPLODE; } if (flags & 0x10) ctx->flags2 |= AV_CODEC_FLAG2_FAST; extradata_size = bytestream2_get_le32(&gbc); ctx->sample_rate = bytestream2_get_le32(&gbc) & 0x7FFFFFFF; ctx->channels = (unsigned)bytestream2_get_le32(&gbc) % FF_SANE_NB_CHANNELS; ctx->block_align = bytestream2_get_le32(&gbc) & 0x7FFFFFFF; ctx->codec_tag = bytestream2_get_le32(&gbc); keyframes = bytestream2_get_le64(&gbc); ctx->request_channel_layout = bytestream2_get_le64(&gbc); if (extradata_size < size) { ctx->extradata = av_mallocz(extradata_size + AV_INPUT_BUFFER_PADDING_SIZE); if (ctx->extradata) { ctx->extradata_size = extradata_size; size -= ctx->extradata_size; memcpy(ctx->extradata, data + size, ctx->extradata_size); } } if (av_image_check_size(ctx->width, ctx->height, 0, ctx)) ctx->width = ctx->height = 0; } int res = avcodec_open2(ctx, c, NULL); if (res < 0) { avcodec_free_context(&ctx); av_free(parser_avctx); av_parser_close(parser); return 0; // Failure of avcodec_open2() does not imply that a issue was found } parser_avctx->codec_id = ctx->codec_id; int got_frame; AVFrame *frame = av_frame_alloc(); if (!frame) error("Failed memory allocation"); // Read very simple container AVPacket avpkt, parsepkt; av_init_packet(&avpkt); av_init_packet(&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; res = av_new_packet(&parsepkt, data - last); if (res < 0) error("Failed memory allocation"); memcpy(parsepkt.data, last, data - last); parsepkt.flags = (keyframes & 1) * AV_PKT_FLAG_DISCARD + (!!(keyframes & 2)) * AV_PKT_FLAG_KEY; keyframes = (keyframes >> 2) + (keyframes<<62); 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); if (avpkt.data == parsepkt.data) { avpkt.buf = av_buffer_ref(parsepkt.buf); if (!avpkt.buf) error("Failed memory allocation"); } else { if (av_packet_make_refcounted(&avpkt) < 0) error("Failed memory allocation"); } 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 { av_packet_move_ref(&avpkt, &parsepkt); } // Iterate through all data while (avpkt.size > 0 && it++ < maxiteration) { av_frame_unref(frame); int ret = decode_handler(ctx, frame, &got_frame, &avpkt); ec_pixels += (ctx->width + 32LL) * (ctx->height + 32LL); if (it > 20 || ec_pixels > 4 * ctx->max_pixels) ctx->error_concealment = 0; if (ec_pixels > maxpixels) goto maximums_reached; nb_samples += frame->nb_samples; if (nb_samples > maxsamples) goto maximums_reached; if (ret <= 0 || ret > avpkt.size) break; if (ctx->codec_type != AVMEDIA_TYPE_AUDIO) ret = avpkt.size; avpkt.data += ret; avpkt.size -= ret; } av_packet_unref(&avpkt); } av_packet_unref(&parsepkt); } maximums_reached: av_packet_unref(&avpkt); do { got_frame = 0; av_frame_unref(frame); decode_handler(ctx, frame, &got_frame, &avpkt); } while (got_frame == 1 && it++ < maxiteration); fprintf(stderr, "pixels decoded: %"PRId64", samples decoded: %"PRId64", iterations: %d\n", ec_pixels, nb_samples, it); av_frame_free(&frame); avcodec_free_context(&ctx); avcodec_free_context(&parser_avctx); av_parser_close(parser); av_packet_unref(&parsepkt); return 0; }