[FFmpeg-cvslog] avcodec/apedec: Fix integer overflow in filter_fast_3320()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Aug 18 00:28:34 2019 +0200| [64ac8a6e697e06880e05debd5a0e47254cd8b4ca] | committer: Michael Niedermayer

avcodec/apedec: Fix integer overflow in filter_fast_3320()

Fixes: signed integer overflow: -1094994793 * 2 cannot be represented in type 'int'
Fixes: 16139/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5663911036059648

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=64ac8a6e697e06880e05debd5a0e47254cd8b4ca
---

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

diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
index 70939abeb4..5d82ff53ff 100644
--- a/libavcodec/apedec.c
+++ b/libavcodec/apedec.c
@@ -828,7 +828,7 @@ static av_always_inline int filter_fast_3320(APEPredictor *p,
         return decoded;
     }
 
-    predictionA = p->buf[delayA] * 2 - p->buf[delayA - 1];
+    predictionA = p->buf[delayA] * 2U - p->buf[delayA - 1];
     p->lastA[filter] = decoded + ((int32_t)(predictionA  * p->coeffsA[filter][0]) >> 9);
 
     if ((decoded ^ predictionA) > 0)