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author | Michael Niedermayer <michael@niedermayer.cc> | 2018-08-26 15:57:54 +0200 |
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committer | Michael Niedermayer <michael@niedermayer.cc> | 2018-09-03 00:01:32 +0200 |
commit | 0c88a5d3eb8cd6891a52eb285b37b1458f0b4b16 (patch) | |
tree | ef7dcf8179e2aa559c89d583ded05aa9b5c13399 | |
parent | 93a203662f6ff1bb9fd2e966bf7df27e9bdb1916 (diff) | |
download | ffmpeg-0c88a5d3eb8cd6891a52eb285b37b1458f0b4b16.tar.gz |
avcodec/wmv2dec: skip frames that have only skiped MBs
This requires us to pre-parse the skip data, as we want to
detect this before allocating all the arrays
Fixes: Timeout
Fixes: 9708/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMV2_fuzzer-5729709861109760
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/wmv2dec.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/libavcodec/wmv2dec.c b/libavcodec/wmv2dec.c index ea0e0594b5..4f97d9227c 100644 --- a/libavcodec/wmv2dec.c +++ b/libavcodec/wmv2dec.c @@ -141,6 +141,21 @@ int ff_wmv2_decode_picture_header(MpegEncContext *s) if (s->qscale <= 0) return AVERROR_INVALIDDATA; + if (s->pict_type != AV_PICTURE_TYPE_I && show_bits(&s->gb, 1)) { + GetBitContext gb = s->gb; + int skip_type = get_bits(&gb, 2); + int run = skip_type == SKIP_TYPE_COL ? s->mb_width : s->mb_height; + + while (run > 0) { + int block = FFMIN(run, 25); + if (get_bits(&gb, block) + 1 != 1<<block) + break; + run -= block; + } + if (!run) + return FRAME_SKIPPED; + } + return 0; } |