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| author | Ronald S. Bultje <rsbultje@gmail.com> | 2012-03-13 16:26:44 -0700 |
|---|---|---|
| committer | Reinhard Tartler <siretart@tauware.de> | 2012-03-14 21:33:15 +0100 |
| commit | 4d343a6f47931a43fe8e4c9288a5068c76b843e0 (patch) | |
| tree | 604beedcdd9f725643d12ac448dc8371eb625e2c | |
| parent | a81a6d9c80448cfbba0d2bcdd681bf971c7055a4 (diff) | |
| download | ffmpeg-4d343a6f47931a43fe8e4c9288a5068c76b843e0.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
(cherry picked from commit e0febda22d0e0fab094a9c886b0e0f0f662df1ef)
Signed-off-by: Reinhard Tartler <siretart@tauware.de>
| -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 95a672b962..e0eb8e119d 100644 --- a/libavcodec/h264.c +++ b/libavcodec/h264.c @@ -3020,6 +3020,8 @@ 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); } @@ -3029,13 +3031,14 @@ 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 |