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| author | Michael Niedermayer <michael@niedermayer.cc> | 2018-11-29 02:32:10 +0100 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2018-12-05 00:50:13 +0100 |
| commit | 09ec182864d41c990bc18f620eabb77444aeff57 (patch) | |
| tree | 651d50744f83b50fb64ccf5cfd647d2c6fd527cb | |
| parent | ed5680f37ed30a01933c0158b21e3bb3c8acfe4a (diff) | |
| download | ffmpeg-09ec182864d41c990bc18f620eabb77444aeff57.tar.gz | |
avcodec/msmpeg4dec: Skip frame if its smaller than 1/8 of the minimal size
Frames that small are not valid and of limited use for error concealment, while
being very computationally intensive to process.
Fixes: Timeout
Fixes: 11318/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MSMPEG4V1_fuzzer-5710884555456512
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
| -rw-r--r-- | libavcodec/msmpeg4dec.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/libavcodec/msmpeg4dec.c b/libavcodec/msmpeg4dec.c index 457a37e745..16b67192b5 100644 --- a/libavcodec/msmpeg4dec.c +++ b/libavcodec/msmpeg4dec.c @@ -412,6 +412,14 @@ int ff_msmpeg4_decode_picture_header(MpegEncContext * s) { int code; + // at minimum one bit per macroblock is required at least in a valid frame, + // we discard frames much smaller than this. Frames smaller than 1/8 of the + // smallest "black/skip" frame generally contain not much recoverable content + // while at the same time they have the highest computational requirements + // per byte + if (get_bits_left(&s->gb) * 8LL < (s->width+15)/16 * ((s->height+15)/16)) + return AVERROR_INVALIDDATA; + if(s->msmpeg4_version==1){ int start_code = get_bits_long(&s->gb, 32); if(start_code!=0x00000100){ |