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

[Michael Niedermayer]

ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Fri Sep 17 21:40:59 2021 +0200| [6825af5c077e40794ea9cb4e8477858007bdb9df] | committer: Michael Niedermayer

avcodec/apedec: Fix integer overflow in filter_fast_3320()

Fixes: signed integer overflow: 2145649668 + 3956526 cannot be represented in type 'int'
Fixes: 38351/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-4647077926273024

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 0e45886e6ea272f453cb949e95c3bfd8380974c5)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6825af5c077e40794ea9cb4e8477858007bdb9df
---

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

diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
index 181b7fe22d..904e433a3d 100644
--- a/libavcodec/apedec.c
+++ b/libavcodec/apedec.c
@@ -879,7 +879,7 @@ static av_always_inline int filter_fast_3320(APEPredictor *p,
     }
 
     predictionA = p->buf[delayA] * 2U - p->buf[delayA - 1];
-    p->lastA[filter] = decoded + ((int32_t)(predictionA  * p->coeffsA[filter][0]) >> 9);
+    p->lastA[filter] = decoded + (unsigned)((int32_t)(predictionA  * p->coeffsA[filter][0]) >> 9);
 
     if ((decoded ^ predictionA) > 0)
         p->coeffsA[filter][0]++;