[FFmpeg-cvslog] avcodec/apedec: fix a integer overflow in long_filter_high_3800()

[Michael Niedermayer]

ffmpeg | branch: release/4.3 | Michael Niedermayer <michael at niedermayer.cc> | Mon Mar 28 00:12:17 2022 +0200| [d909850308eb08f7ade9b1585ef30d997091f740] | committer: Michael Niedermayer

avcodec/apedec: fix a integer overflow in long_filter_high_3800()

Fixes: signed integer overflow: -2146549696 - 3923884 cannot be represented in type 'int'
Fixes: 45907/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5992380584558592

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 b085b400becb93ccc68d786ab738b1fc50408b89)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d909850308eb08f7ade9b1585ef30d997091f740
---

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

diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
index 43d7110c57..23f4d3a093 100644
--- a/libavcodec/apedec.c
+++ b/libavcodec/apedec.c
@@ -928,7 +928,7 @@ static void long_filter_high_3800(int32_t *buffer, int order, int shift, int len
             dotprod += delay[j] * (unsigned)coeffs[j];
             coeffs[j] += ((delay[j] >> 31) | 1) * sign;
         }
-        buffer[i] -= dotprod >> shift;
+        buffer[i] -= (unsigned)(dotprod >> shift);
         for (j = 0; j < order - 1; j++)
             delay[j] = delay[j + 1];
         delay[order - 1] = buffer[i];