[FFmpeg-cvslog] avcodec/mpeg12dec: Fix runtime error: left shift of negative value

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Feb 19 18:47:13 2017 +0100| [706757d26dd5e606c1745a4bb53fe45f6d6493cf] | committer: Michael Niedermayer

avcodec/mpeg12dec: Fix runtime error: left shift of negative value

Fixes: 608/clusterfuzz-testcase-603978286392934

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=706757d26dd5e606c1745a4bb53fe45f6d6493cf
---

 libavcodec/mpeg12dec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
index f3cf6eb..5f86029 100644
--- a/libavcodec/mpeg12dec.c
+++ b/libavcodec/mpeg12dec.c
@@ -865,8 +865,8 @@ static int mpeg_decode_mb(MpegEncContext *s, int16_t block[12][64])
                                                    s->last_mv[i][0][1]);
                             /* full_pel: only for MPEG-1 */
                             if (s->full_pel[i]) {
-                                s->mv[i][0][0] <<= 1;
-                                s->mv[i][0][1] <<= 1;
+                                s->mv[i][0][0] *= 2;
+                                s->mv[i][0][1] *= 2;
                             }
                         }
                     }