[FFmpeg-cvslog] avcodec/wnv1: Fix runtime error: left shift of negative value -1

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Fri May  5 18:01:25 2017 +0200| [9fac508ca46f93450ec232299dfd15ac70b6f326] | committer: Michael Niedermayer

avcodec/wnv1: Fix runtime error: left shift of negative value -1

Fixes: 1338/clusterfuzz-testcase-minimized-6485546354343936

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=9fac508ca46f93450ec232299dfd15ac70b6f326
---

 libavcodec/wnv1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/wnv1.c b/libavcodec/wnv1.c
index 9ff99b2f98..126c01a02d 100644
--- a/libavcodec/wnv1.c
+++ b/libavcodec/wnv1.c
@@ -52,7 +52,7 @@ static inline int wnv1_get_code(WNV1Context *w, int base_value)
     if (v == 15)
         return ff_reverse[get_bits(&w->gb, 8 - w->shift)];
     else
-        return base_value + ((v - 7) << w->shift);
+        return base_value + ((v - 7U) << w->shift);
 }
 
 static int decode_frame(AVCodecContext *avctx,