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![Michael Niedermayer](/assets/img/avatar_default.png)
Fixes: Timeout (131sec -> 4sec) Fixes: 15581/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_INDEO4_fuzzer-5651105515569152 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
284 lines
11 KiB
C
284 lines
11 KiB
C
/*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/* Targeted fuzzer that targets specific codecs depending on two
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compile-time flags.
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INSTRUCTIONS:
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* Get the very fresh clang, e.g. see http://libfuzzer.info#versions
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* Get and build libFuzzer:
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svn co http://llvm.org/svn/llvm-project/llvm/trunk/lib/Fuzzer
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./Fuzzer/build.sh
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* build ffmpeg for fuzzing:
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FLAGS="-fsanitize=address -fsanitize-coverage=trace-pc-guard,trace-cmp -g" CC="clang $FLAGS" CXX="clang++ $FLAGS" ./configure --disable-x86asm
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make clean && make -j
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* build the fuzz target.
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Choose the value of FFMPEG_CODEC (e.g. AV_CODEC_ID_DVD_SUBTITLE) and
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choose one of FUZZ_FFMPEG_VIDEO, FUZZ_FFMPEG_AUDIO, FUZZ_FFMPEG_SUBTITLE.
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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
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* create a corpus directory and put some samples there (empty dir is ok too):
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mkdir CORPUS && cp some-files CORPUS
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* Run fuzzing:
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./target_dec_fuzzer -max_len=100000 CORPUS
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More info:
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http://libfuzzer.info
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http://tutorial.libfuzzer.info
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https://github.com/google/oss-fuzz
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http://lcamtuf.coredump.cx/afl/
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https://security.googleblog.com/2016/08/guided-in-process-fuzzing-of-chrome.html
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*/
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#include "config.h"
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#include "libavutil/avassert.h"
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#include "libavutil/imgutils.h"
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#include "libavutil/intreadwrite.h"
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#include "libavcodec/avcodec.h"
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#include "libavcodec/bytestream.h"
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#include "libavformat/avformat.h"
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int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
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extern AVCodec * codec_list[];
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static void error(const char *err)
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{
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fprintf(stderr, "%s", err);
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exit(1);
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}
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static AVCodec *c = NULL;
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static AVCodec *AVCodecInitialize(enum AVCodecID codec_id)
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{
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AVCodec *res;
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res = avcodec_find_decoder(codec_id);
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if (!res)
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error("Failed to find decoder");
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return res;
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}
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static int subtitle_handler(AVCodecContext *avctx, void *frame,
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int *got_sub_ptr, AVPacket *avpkt)
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{
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AVSubtitle sub;
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int ret = avcodec_decode_subtitle2(avctx, &sub, got_sub_ptr, avpkt);
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if (ret >= 0 && *got_sub_ptr)
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avsubtitle_free(&sub);
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return ret;
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}
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// Ensure we don't loop forever
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const uint32_t maxiteration = 8096;
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const uint64_t maxpixels_per_frame = 4096 * 4096;
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uint64_t maxpixels;
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static const uint64_t FUZZ_TAG = 0x4741542D5A5A5546ULL;
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int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
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const uint64_t fuzz_tag = FUZZ_TAG;
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const uint8_t *last = data;
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const uint8_t *end = data + size;
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uint32_t it = 0;
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uint64_t ec_pixels = 0;
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int (*decode_handler)(AVCodecContext *avctx, AVFrame *picture,
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int *got_picture_ptr,
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const AVPacket *avpkt) = NULL;
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AVCodecParserContext *parser = NULL;
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if (!c) {
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#ifdef FFMPEG_DECODER
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#define DECODER_SYMBOL0(CODEC) ff_##CODEC##_decoder
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#define DECODER_SYMBOL(CODEC) DECODER_SYMBOL0(CODEC)
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extern AVCodec DECODER_SYMBOL(FFMPEG_DECODER);
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codec_list[0] = &DECODER_SYMBOL(FFMPEG_DECODER);
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avcodec_register(&DECODER_SYMBOL(FFMPEG_DECODER));
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c = &DECODER_SYMBOL(FFMPEG_DECODER);
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#else
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avcodec_register_all();
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c = AVCodecInitialize(FFMPEG_CODEC); // Done once.
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#endif
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av_log_set_level(AV_LOG_PANIC);
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}
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switch (c->type) {
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case AVMEDIA_TYPE_AUDIO : decode_handler = avcodec_decode_audio4; break;
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case AVMEDIA_TYPE_VIDEO : decode_handler = avcodec_decode_video2; break;
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case AVMEDIA_TYPE_SUBTITLE: decode_handler = subtitle_handler ; break;
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}
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maxpixels = maxpixels_per_frame * maxiteration;
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switch (c->id) {
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// Allows a small input to generate gigantic output
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case AV_CODEC_ID_DIRAC: maxpixels /= 8192; break;
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case AV_CODEC_ID_MSRLE: maxpixels /= 16; break;
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case AV_CODEC_ID_QTRLE: maxpixels /= 16; break;
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case AV_CODEC_ID_SANM: maxpixels /= 16; break;
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case AV_CODEC_ID_GIF: maxpixels /= 16; break;
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// Performs slow frame rescaling in C
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case AV_CODEC_ID_GDV: maxpixels /= 512; break;
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// Postprocessing in C
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case AV_CODEC_ID_HNM4_VIDEO:maxpixels /= 128; break;
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// Cliping in C, generally slow even with small input
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case AV_CODEC_ID_INDEO4: maxpixels /= 128; break;
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}
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AVCodecContext* ctx = avcodec_alloc_context3(c);
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AVCodecContext* parser_avctx = avcodec_alloc_context3(NULL);
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if (!ctx || !parser_avctx)
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error("Failed memory allocation");
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if (ctx->max_pixels == 0 || ctx->max_pixels > maxpixels_per_frame)
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ctx->max_pixels = maxpixels_per_frame; //To reduce false positive OOM and hangs
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ctx->refcounted_frames = 1; //To reduce false positive timeouts and focus testing on the refcounted API
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if (size > 1024) {
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GetByteContext gbc;
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int extradata_size;
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size -= 1024;
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bytestream2_init(&gbc, data + size, 1024);
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ctx->width = bytestream2_get_le32(&gbc);
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ctx->height = bytestream2_get_le32(&gbc);
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ctx->bit_rate = bytestream2_get_le64(&gbc);
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ctx->bits_per_coded_sample = bytestream2_get_le32(&gbc);
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// Try to initialize a parser for this codec, note, this may fail which just means we test without one
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if (bytestream2_get_byte(&gbc) & 1)
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parser = av_parser_init(c->id);
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extradata_size = bytestream2_get_le32(&gbc);
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if (extradata_size < size) {
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ctx->extradata = av_mallocz(extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
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if (ctx->extradata) {
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ctx->extradata_size = extradata_size;
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size -= ctx->extradata_size;
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memcpy(ctx->extradata, data + size, ctx->extradata_size);
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}
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}
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if (av_image_check_size(ctx->width, ctx->height, 0, ctx))
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ctx->width = ctx->height = 0;
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}
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int res = avcodec_open2(ctx, c, NULL);
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if (res < 0) {
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avcodec_free_context(&ctx);
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av_free(parser_avctx);
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av_parser_close(parser);
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return 0; // Failure of avcodec_open2() does not imply that a issue was found
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}
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parser_avctx->codec_id = ctx->codec_id;
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int got_frame;
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AVFrame *frame = av_frame_alloc();
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if (!frame)
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error("Failed memory allocation");
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// Read very simple container
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AVPacket avpkt, parsepkt;
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av_init_packet(&avpkt);
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while (data < end && it < maxiteration) {
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// Search for the TAG
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while (data + sizeof(fuzz_tag) < end) {
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if (data[0] == (fuzz_tag & 0xFF) && AV_RN64(data) == fuzz_tag)
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break;
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data++;
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}
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if (data + sizeof(fuzz_tag) > end)
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data = end;
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res = av_new_packet(&parsepkt, data - last);
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if (res < 0)
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error("Failed memory allocation");
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memcpy(parsepkt.data, last, data - last);
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data += sizeof(fuzz_tag);
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last = data;
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while (parsepkt.size > 0) {
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if (parser) {
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av_init_packet(&avpkt);
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int ret = av_parser_parse2(parser, parser_avctx, &avpkt.data, &avpkt.size,
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parsepkt.data, parsepkt.size,
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parsepkt.pts, parsepkt.dts, parsepkt.pos);
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if (avpkt.data == parsepkt.data) {
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avpkt.buf = av_buffer_ref(parsepkt.buf);
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if (!avpkt.buf)
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error("Failed memory allocation");
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} else {
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if (av_packet_make_refcounted(&avpkt) < 0)
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error("Failed memory allocation");
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}
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parsepkt.data += ret;
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parsepkt.size -= ret;
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parsepkt.pos += ret;
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avpkt.pts = parser->pts;
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avpkt.dts = parser->dts;
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avpkt.pos = parser->pos;
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if ( parser->key_frame == 1 ||
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(parser->key_frame == -1 && parser->pict_type == AV_PICTURE_TYPE_I))
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avpkt.flags |= AV_PKT_FLAG_KEY;
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avpkt.flags |= parsepkt.flags & AV_PKT_FLAG_DISCARD;
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} else {
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av_packet_move_ref(&avpkt, &parsepkt);
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}
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// Iterate through all data
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while (avpkt.size > 0 && it++ < maxiteration) {
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av_frame_unref(frame);
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int ret = decode_handler(ctx, frame, &got_frame, &avpkt);
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ec_pixels += ctx->width * ctx->height;
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if (it > 20 || ec_pixels > 4 * ctx->max_pixels)
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ctx->error_concealment = 0;
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if (ec_pixels > maxpixels)
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goto maximums_reached;
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if (ret <= 0 || ret > avpkt.size)
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break;
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if (ctx->codec_type != AVMEDIA_TYPE_AUDIO)
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ret = avpkt.size;
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avpkt.data += ret;
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avpkt.size -= ret;
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}
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av_packet_unref(&avpkt);
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}
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av_packet_unref(&parsepkt);
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}
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maximums_reached:
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av_packet_unref(&avpkt);
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do {
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got_frame = 0;
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av_frame_unref(frame);
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decode_handler(ctx, frame, &got_frame, &avpkt);
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} while (got_frame == 1 && it++ < maxiteration);
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fprintf(stderr, "pixels decoded: %"PRId64", iterations: %d\n", ec_pixels, it);
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av_frame_free(&frame);
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avcodec_free_context(&ctx);
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avcodec_free_context(&parser_avctx);
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av_parser_close(parser);
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av_packet_unref(&parsepkt);
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return 0;
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}
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