[FFmpeg-devel] [PATCH 4/7] avformat/nistspheredec: Check bits_per_coded_sample and channels

[Anton Khirnov]

Quoting Michael Niedermayer (2021-01-17 00:07:26)
> Fixes: signed integer overflow: 80 * 92233009 cannot be represented in type 'int'
> Fixes: 26910/clusterfuzz-testcase-minimized-ffmpeg_dem_NISTSPHERE_fuzzer-6669100654919680
> 
> 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/nistspheredec.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/libavformat/nistspheredec.c b/libavformat/nistspheredec.c
> index 079369929f..fec5c88892 100644
> --- a/libavformat/nistspheredec.c
> +++ b/libavformat/nistspheredec.c
> @@ -80,7 +80,9 @@ static int nist_read_header(AVFormatContext *s)
>  
>              avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
>  
> -            st->codecpar->block_align = st->codecpar->bits_per_coded_sample * st->codecpar->channels / 8;
> +            if (st->codecpar->bits_per_coded_sample * (uint64_t)st->codecpar->channels / 8 > INT_MAX)
> +                return AVERROR_INVALIDDATA;
> +            st->codecpar->block_align = st->codecpar->bits_per_coded_sample * (uint64_t)st->codecpar->channels / 8;
>  
>              if (avio_tell(s->pb) > header_size)
>                  return AVERROR_INVALIDDATA;
> -- 
> 2.17.1

Both bits_per_coded_sample and channels seem to be arbitrary ints, so
you are assuming sizeof(int) < sizeof(int64)

-- 
Anton Khirnov