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

[Michael Niedermayer]

ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Sat Sep 16 23:36:29 2023 +0200| [bcfc9efde313ae248db04d064cbe5cac832ed145] | committer: Michael Niedermayer

avcodec/apedec: Fix an integer overflow in predictor_update_filter()

Fixes: signed integer overflow: -2147483506 + -801380 cannot be represented in type 'int'
Fixes: 62164/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-6578985923117056

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 515c0247a3062ca4639e457c81d2f58c504e9e8f)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=bcfc9efde313ae248db04d064cbe5cac832ed145
---

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

diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
index 6f9c1fb3c0..ffdd6beaf4 100644
--- a/libavcodec/apedec.c
+++ b/libavcodec/apedec.c
@@ -1198,7 +1198,7 @@ static av_always_inline int predictor_update_filter(APEPredictor64 *p,
     if (compression_level < COMPRESSION_LEVEL_INSANE) {
         predictionA = (int32_t)predictionA;
         predictionB = (int32_t)predictionB;
-        p->lastA[filter] = decoded + ((int32_t)(predictionA + (predictionB >> 1)) >> 10);
+        p->lastA[filter] = (int32_t)(decoded + (unsigned)((int32_t)(predictionA + (predictionB >> 1)) >> 10));
     } else {
         p->lastA[filter] = decoded + ((int64_t)((uint64_t)predictionA + (predictionB >> 1)) >> 10);
     }