[FFmpeg-cvslog] avcodec/dxtory: Fix negative stride shift in dx2_decode_slice_420()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Fri Oct  2 14:59:13 2020 +0200| [3291d994b76db4b6e67c8467367ce68f79785e60] | committer: Michael Niedermayer

avcodec/dxtory: Fix negative stride shift in dx2_decode_slice_420()

Fixes: left shift of negative value -640
Fixes: 26044/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DXTORY_fuzzer-5631057602543616

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3291d994b76db4b6e67c8467367ce68f79785e60
---

 libavcodec/dxtory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/dxtory.c b/libavcodec/dxtory.c
index bc95e0e7e1..7143a11e2e 100644
--- a/libavcodec/dxtory.c
+++ b/libavcodec/dxtory.c
@@ -717,7 +717,7 @@ static int dx2_decode_slice_420(GetBitContext *gb, AVFrame *frame,
             V[huvborder] = decode_sym(gb, lru[2]) ^ 0x80;
         }
 
-        Y += ystride << 1;
+        Y += ystride * 2;
         U += ustride;
         V += vstride;
     }