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

[Michael Niedermayer]

On Thu, Sep 22, 2022 at 03:18:20PM +0200, Anton Khirnov wrote:
> 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.

ok but then we fail before the actual problem is encountered
i will send a patch doing that

thx

[...]

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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No human being will ever know the Truth, for even if they happen to say it
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