[FFmpeg-cvslog] libavcodec/wmalosslessdec: prevent sum of positive numbers from becoming negative

[Michael Niedermayer]

ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Sun Feb  9 18:09:24 2020 +0100| [1c200201cd58b68586eb9ea2219f48db1050b669] | committer: Michael Niedermayer

libavcodec/wmalosslessdec: prevent sum of positive numbers from becoming negative

Fixes: left shift of negative value -8321365
Fixes: 20506/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMALOSSLESS_fuzzer-4798062906310656

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 62e4003780cad60ac1371fef892da08c27069964)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1c200201cd58b68586eb9ea2219f48db1050b669
---

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

diff --git a/libavcodec/wmalosslessdec.c b/libavcodec/wmalosslessdec.c
index 9888ea43d6..0921c16fe5 100644
--- a/libavcodec/wmalosslessdec.c
+++ b/libavcodec/wmalosslessdec.c
@@ -163,7 +163,7 @@ typedef struct WmallDecodeCtx {
     int transient_pos[WMALL_MAX_CHANNELS];
     int seekable_tile;
 
-    int ave_sum[WMALL_MAX_CHANNELS];
+    unsigned ave_sum[WMALL_MAX_CHANNELS];
 
     int channel_residues[WMALL_MAX_CHANNELS][WMALL_BLOCK_MAX_SIZE];