[FFmpeg-cvslog] avcodec/shorten: Fix undefined integer overflow

[Michael Niedermayer]

ffmpeg | branch: release/4.0 | Michael Niedermayer <michael at niedermayer.cc> | Mon Jul  2 19:08:54 2018 +0200| [c4b23793d4fe679168ffba993ef1469491521233] | committer: Michael Niedermayer

avcodec/shorten: Fix undefined integer overflow

Fixes: signed integer overflow: 8454144 * 256 cannot be represented in type 'int'
Fixes: 8788/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SHORTEN_fuzzer-5728205041303552

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 70832333bba3b915040f415548518e136b44280e)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=c4b23793d4fe679168ffba993ef1469491521233
---

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

diff --git a/libavcodec/shorten.c b/libavcodec/shorten.c
index 18a12d0b97..79656e7757 100644
--- a/libavcodec/shorten.c
+++ b/libavcodec/shorten.c
@@ -177,7 +177,7 @@ static void fix_bitshift(ShortenContext *s, int32_t *buffer)
             buffer[i] = 0;
     } else if (s->bitshift != 0) {
         for (i = 0; i < s->blocksize; i++)
-            buffer[i] *= 1 << s->bitshift;
+            buffer[i] *= 1U << s->bitshift;
     }
 }