[FFmpeg-devel] [PATCH 2/3] avcodec/wmalosslessdec: Check channel mask against num channels

[Michael Niedermayer]

Fixes: Out of array write
Fixes: 45613/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMALOSSLESS_fuzzer-4539073606320128

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/wmalosslessdec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/wmalosslessdec.c b/libavcodec/wmalosslessdec.c
index cd05b22689..1728920729 100644
--- a/libavcodec/wmalosslessdec.c
+++ b/libavcodec/wmalosslessdec.c
@@ -281,6 +281,9 @@ static av_cold int decode_init(AVCodecContext *avctx)
 
     av_channel_layout_uninit(&avctx->ch_layout);
     av_channel_layout_from_mask(&avctx->ch_layout, channel_mask);
+    if (s->num_channels != avctx->ch_layout.nb_channels)
+        return AVERROR_PATCHWELCOME; //are there non fuzzed files with this or is it an error ?
+
     return 0;
 }
 
-- 
2.17.1