[FFmpeg-devel] [PATCH 2/2] avformat/mxfdec: Use 64bit in remainder

[James Almer]

On 12/25/2022 7:03 PM, Michael Niedermayer wrote:
> Fixes: signed integer overflow: 48000 * 223587 cannot be represented in type 'int'
> Fixes: 54513/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5817594836025344
> 
> 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/mxfdec.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> index e6118e141d..6150c131ec 100644
> --- a/libavformat/mxfdec.c
> +++ b/libavformat/mxfdec.c
> @@ -3857,8 +3857,8 @@ static int64_t mxf_compute_sample_count(MXFContext *mxf, AVStream *st,
>       if ((sample_rate.num / sample_rate.den) == 48000) {
>           return av_rescale_q(edit_unit, sample_rate, track->edit_rate);
>       } else {
> -        int remainder = (sample_rate.num * time_base.num) %
> -                        (time_base.den * sample_rate.den);
> +        int64_t remainder = (sample_rate.num * (int64_t)time_base.num) %
> +                        (time_base.den * (int64_t)sample_rate.den);

Don't undo the vertical alignment, please.

>           if (remainder)
>               av_log(mxf->fc, AV_LOG_WARNING,
>                      "seeking detected on stream #%d with time base (%d/%d) and "