[FFmpeg-cvslog] avcodec/dsddec: Check channels

[Michael Niedermayer]

ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Mon May  4 00:04:49 2020 +0200| [219c025463c4e5634129b73a72a13e0f6ab70150] | committer: Michael Niedermayer

avcodec/dsddec: Check channels

Fixes: division by zero
Fixes: 21677/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DSD_MSBF_fuzzer-5712547983654912
Fixes: 21751/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DSD_LSBF_fuzzer-5197097180856320

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 2570a8777e7095358b10f679d35641e114a2ab33)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=219c025463c4e5634129b73a72a13e0f6ab70150
---

 libavcodec/dsddec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/dsddec.c b/libavcodec/dsddec.c
index 2c5c357acc..a2e038419f 100644
--- a/libavcodec/dsddec.c
+++ b/libavcodec/dsddec.c
@@ -44,6 +44,9 @@ static av_cold int decode_init(AVCodecContext *avctx)
     int i;
     uint8_t silence;
 
+    if (!avctx->channels)
+        return AVERROR_INVALIDDATA;
+
     ff_init_dsd_data();
 
     s = av_malloc_array(sizeof(DSDContext), avctx->channels);