[FFmpeg-devel] [PATCH 10/13] avformat/vividas: Check packet size

[Anton Khirnov]

Quoting Michael Niedermayer (2022-09-18 19:14:07)
> Fixes: signed integer overflow: 119760682 - -2084600173 cannot be represented in type 'int'
> Fixes: 50993/clusterfuzz-testcase-minimized-ffmpeg_dem_VIVIDAS_fuzzer-6745781167587328
> 
> 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/vividas.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/libavformat/vividas.c b/libavformat/vividas.c
> index e9954f73ed0..22f61db7576 100644
> --- a/libavformat/vividas.c
> +++ b/libavformat/vividas.c
> @@ -643,7 +643,9 @@ static int viv_read_packet(AVFormatContext *s,
>  
>      if (viv->current_audio_subpacket < viv->n_audio_subpackets) {
>          AVStream *astream;
> -        int size = viv->audio_subpackets[viv->current_audio_subpacket+1].start - viv->audio_subpackets[viv->current_audio_subpacket].start;
> +        int64_t size = viv->audio_subpackets[viv->current_audio_subpacket+1].start - (int64_t)viv->audio_subpackets[viv->current_audio_subpacket].start;
> +        if (size < 0 || size != (int)size)
> +            return AVERROR_INVALIDDATA;

These values should be checked in the loop where they are set.

-- 
Anton Khirnov