[FFmpeg-cvslog] avcodec/h264_cabac: Check decode_cabac_mb_mvd() for failure

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue Jan 26 02:23:31 2016 +0100| [e5655a32bc745462cb820f4ccc3eaee146dd2cdc] | committer: Michael Niedermayer

avcodec/h264_cabac: Check decode_cabac_mb_mvd() for failure

Fixes harmless integer overflow
Fixes Ticket5150

No speedloss measured, actually its slightly faster, but please benchmark & double check this

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e5655a32bc745462cb820f4ccc3eaee146dd2cdc
---

 libavcodec/h264_cabac.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libavcodec/h264_cabac.c b/libavcodec/h264_cabac.c
index 04d412b..deab35a 100644
--- a/libavcodec/h264_cabac.c
+++ b/libavcodec/h264_cabac.c
@@ -1540,8 +1540,12 @@ static int decode_cabac_mb_mvd(H264SliceContext *sl, int ctxbase, int amvd, int
     int amvd1 = sl->mvd_cache[list][scan8[n] - 1][1] +\
                 sl->mvd_cache[list][scan8[n] - 8][1];\
 \
-    mx += decode_cabac_mb_mvd(sl, 40, amvd0, &mpx);\
-    my += decode_cabac_mb_mvd(sl, 47, amvd1, &mpy);\
+    int mxd = decode_cabac_mb_mvd(sl, 40, amvd0, &mpx);\
+    int myd = decode_cabac_mb_mvd(sl, 47, amvd1, &mpy);\
+    if (mxd == INT_MIN || myd == INT_MIN) \
+        return AVERROR_INVALIDDATA; \
+    mx += mxd;\
+    my += myd;\
 }
 
 static av_always_inline int get_cabac_cbf_ctx(H264SliceContext *sl,