[FFmpeg-cvslog] avcodec/wmaprodec: Check if the channel sum of all internal contexts match the external

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue Nov 12 18:39:08 2019 +0100| [090ac5799751c6f52358da4e5201a3845760db93] | committer: Michael Niedermayer

avcodec/wmaprodec: Check if the channel sum of all internal contexts match the external

Fixes: NULL pointer dereference
Fixes: 18689/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_XMA1_fuzzer-5715114640015360

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=090ac5799751c6f52358da4e5201a3845760db93
---

 libavcodec/wmaprodec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/wmaprodec.c b/libavcodec/wmaprodec.c
index 87e2ead693..6a22e2f552 100644
--- a/libavcodec/wmaprodec.c
+++ b/libavcodec/wmaprodec.c
@@ -1930,6 +1930,8 @@ static av_cold int xma_decode_init(AVCodecContext *avctx)
         s->start_channel[i] = start_channels;
         start_channels += s->xma[i].nb_channels;
     }
+    if (start_channels != avctx->channels)
+        return AVERROR_INVALIDDATA;
 
     return ret;
 }