From aff8cf18cb0b1fa4f2e3d163c3da2f25aa6d1906 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Sat, 25 Feb 2017 21:07:24 +0100
Subject: [PATCH] avcodec/mpeg12dec: Fix runtime error: left shift of negative
value -2
671/clusterfuzz-testcase-4990381827555328
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
libavcodec/mpeg12dec.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
index 5f860296601..d44ddb20fae 100644
--- a/libavcodec/mpeg12dec.c
+++ b/libavcodec/mpeg12dec.c
@@ -948,8 +948,8 @@ static int mpeg_decode_mb(MpegEncContext *s, int16_t block[12][64])
dmy = get_dmv(s);
- s->last_mv[i][0][1] = my << my_shift;
- s->last_mv[i][1][1] = my << my_shift;
+ s->last_mv[i][0][1] = my * (1 << my_shift);
+ s->last_mv[i][1][1] = my * (1 << my_shift);
s->mv[i][0][0] = mx;
s->mv[i][0][1] = my;
--
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