[FFmpeg-cvslog] libopusdec: default to stereo for invalid number of channels

[Andreas Cadhalpun]

ffmpeg | branch: master | Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com> | Mon Nov 14 21:41:45 2016 +0100| [f92d7bdfddfaac04b3bb31f2749d173ca1d8ba6d] | committer: Anton Khirnov

libopusdec: default to stereo for invalid number of channels

This fixes an out-of-bounds read if avc->channels is 0.

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
Signed-off-by: Anton Khirnov <anton at khirnov.net>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f92d7bdfddfaac04b3bb31f2749d173ca1d8ba6d
---

 libavcodec/libopusdec.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavcodec/libopusdec.c b/libavcodec/libopusdec.c
index c6e1573..75eaf9b 100644
--- a/libavcodec/libopusdec.c
+++ b/libavcodec/libopusdec.c
@@ -42,6 +42,12 @@ static av_cold int libopus_decode_init(AVCodecContext *avc)
     int ret, channel_map = 0, gain_db = 0, nb_streams, nb_coupled;
     uint8_t mapping_arr[8] = { 0, 1 }, *mapping;
 
+    if (avc->channels <= 0) {
+        av_log(avc, AV_LOG_WARNING,
+               "Invalid number of channels %d, defaulting to stereo\n", avc->channels);
+        avc->channels = 2;
+    }
+
     avc->sample_rate    = 48000;
     avc->sample_fmt     = avc->request_sample_fmt == AV_SAMPLE_FMT_FLT ?
                           AV_SAMPLE_FMT_FLT : AV_SAMPLE_FMT_S16;