[FFmpeg-cvslog] avcodec/ituh263dec: Check cbpy in ff_h263_decode_mb()

Michael Niedermayer git at videolan.org
Mon Feb 20 02:17:49 EET 2017


ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Mon Feb 20 00:49:03 2017 +0100| [b7d9b4a1f1fcd01084ccbec6f7ef32c853681833] | committer: Michael Niedermayer

avcodec/ituh263dec: Check cbpy in ff_h263_decode_mb()

Fixes: 618/clusterfuzz-testcase-6594990333493248

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b7d9b4a1f1fcd01084ccbec6f7ef32c853681833
---

 libavcodec/ituh263dec.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/ituh263dec.c b/libavcodec/ituh263dec.c
index 2e0f395..73aaa1d 100644
--- a/libavcodec/ituh263dec.c
+++ b/libavcodec/ituh263dec.c
@@ -717,6 +717,11 @@ int ff_h263_decode_mb(MpegEncContext *s,
             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 
+        if (cbpy < 0) {
+            av_log(s->avctx, AV_LOG_ERROR, "cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
+            return SLICE_ERROR;
+        }
+
         if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
             cbpy ^= 0xF;
 



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