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@niedermayer.cc>

diff --git a/libavcodec/shorten.c b/libavcodec/shorten.c
index 18a12d0b973043d0bcc66b64ccfea11fb06a6bd0..79656e7757be23e1ef12716ce505938982c08139 100644 (file)
--- 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;
     }
 }