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| author | Ronald S. Bultje <rsbultje@gmail.com> | 2012-03-13 16:26:44 -0700 |
|---|---|---|
| committer | Ronald S. Bultje <rsbultje@gmail.com> | 2012-03-14 13:24:49 -0700 |
| commit | e0febda22d0e0fab094a9c886b0e0f0f662df1ef (patch) | |
| tree | c77d610b4fc5bd6923a0ccc32f8c31562f140ef9 /libavcodec | |
| parent | 48cbe4b092113eae0b3e5d6a08b59027f913a884 (diff) | |
| download | ffmpeg-e0febda22d0e0fab094a9c886b0e0f0f662df1ef.tar.gz | |
h264: stricter reference limit enforcement.
Progressive images can have only 16 references, error out if there are
more, since the data is almost certainly corrupt, and the invalid value
will lead to random crashes or invalid writes later on.
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
Diffstat (limited to 'libavcodec')
| -rw-r--r-- | libavcodec/h264.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/libavcodec/h264.c b/libavcodec/h264.c index c3ef3f0110..64f676c4a9 100644 --- a/libavcodec/h264.c +++ b/libavcodec/h264.c @@ -3021,6 +3021,8 @@ static int decode_slice_header(H264Context *h, H264Context *h0){ h->ref_count[1]= h->pps.ref_count[1]; if(h->slice_type_nos != AV_PICTURE_TYPE_I){ + int max_refs = s->picture_structure == PICT_FRAME ? 16 : 32; + if(h->slice_type_nos == AV_PICTURE_TYPE_B){ h->direct_spatial_mv_pred= get_bits1(&s->gb); } @@ -3030,13 +3032,14 @@ static int decode_slice_header(H264Context *h, H264Context *h0){ h->ref_count[0]= get_ue_golomb(&s->gb) + 1; if(h->slice_type_nos==AV_PICTURE_TYPE_B) h->ref_count[1]= get_ue_golomb(&s->gb) + 1; + } - if(h->ref_count[0]-1 > 32-1 || h->ref_count[1]-1 > 32-1){ - av_log(h->s.avctx, AV_LOG_ERROR, "reference overflow\n"); - h->ref_count[0]= h->ref_count[1]= 1; - return -1; - } + if (h->ref_count[0] > max_refs || h->ref_count[1] > max_refs) { + av_log(h->s.avctx, AV_LOG_ERROR, "reference overflow\n"); + h->ref_count[0] = h->ref_count[1] = 1; + return AVERROR_INVALIDDATA; } + if(h->slice_type_nos == AV_PICTURE_TYPE_B) h->list_count= 2; else |