[FFmpeg-devel] [PATCH 2/2] avformat/mvdec: Check stream numbers

[Andreas Rheinhardt]

Michael Niedermayer:
> Fixes: null pointer dereference
> Fixes: 20768/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5638648978735104.fuzz
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavformat/mvdec.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/libavformat/mvdec.c b/libavformat/mvdec.c
> index f9f7e38137..64166a84b1 100644
> --- a/libavformat/mvdec.c
> +++ b/libavformat/mvdec.c
> @@ -363,6 +363,12 @@ static int mv_read_header(AVFormatContext *avctx)
>          if ((ret = read_table(avctx, NULL, parse_global_var)) < 0)
>              return ret;
>  
> +        if (mv->nb_audio_tracks < 0  || mv->nb_video_tracks < 0 ||
> +           (mv->nb_audio_tracks == 0 && mv->nb_video_tracks == 0)) {
> +            av_log(avctx, AV_LOG_ERROR, "Stream count is invalid.\n");
> +            return AVERROR_INVALIDDATA;
> +        }
> +
>          if (mv->nb_audio_tracks > 1) {
>              avpriv_request_sample(avctx, "Multiple audio streams support");
>              return AVERROR_PATCHWELCOME;
> 
LGTM.

- Andreas

PS: Is it actually allowed to set the channel_layout to stereo if
there are more than two channels (as set_channels() does)?