[FFmpeg-cvslog] avcodec/wmaprodec: ensure channel count in the private context and decoder context are consistent

[James Almer]

ffmpeg | branch: master | James Almer <jamrial at gmail.com> | Thu Mar 17 22:04:35 2022 -0300| [6bab6afecc513bfd242b5992547e8050cac8f95c] | committer: James Almer

avcodec/wmaprodec: ensure channel count in the private context and decoder context are consistent

avctx->ch_layout will be reinitialized using channel_mask later in the
function.

Fixes: 45736/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMAPRO_fuzzer-5769886813519872

Signed-off-by: James Almer <jamrial at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6bab6afecc513bfd242b5992547e8050cac8f95c
---

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

diff --git a/libavcodec/wmaprodec.c b/libavcodec/wmaprodec.c
index a2ee9b0440..8e1675dc78 100644
--- a/libavcodec/wmaprodec.c
+++ b/libavcodec/wmaprodec.c
@@ -403,7 +403,7 @@ static av_cold int decode_init(WMAProDecodeCtx *s, AVCodecContext *avctx, int nu
         s->decode_flags    = AV_RL16(edata_ptr+14);
         channel_mask       = AV_RL32(edata_ptr+2);
         s->bits_per_sample = AV_RL16(edata_ptr);
-        s->nb_channels     = avctx->ch_layout.nb_channels;
+        s->nb_channels     = channel_mask ? av_popcount(channel_mask) : avctx->ch_layout.nb_channels;
 
         if (s->bits_per_sample > 32 || s->bits_per_sample < 1) {
             avpriv_request_sample(avctx, "bits per sample is %d", s->bits_per_sample);