[FFmpeg-devel] [PATCH 5/7] avformat/mvdec: Sanity check SAMPLE_WIDTH

[Michael Niedermayer]

On Wed, Feb 03, 2021 at 01:18:18PM +1100, Peter Ross wrote:
> On Wed, Feb 03, 2021 at 12:13:32AM +0100, Michael Niedermayer wrote:
> > Fixes: signed integer overflow: 999999999 * 8 cannot be represented in type 'int'
> > Fixes: 30048/clusterfuzz-testcase-minimized-ffmpeg_dem_MV_fuzzer-5864289917337600
> > 
> > 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 | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/libavformat/mvdec.c b/libavformat/mvdec.c
> > index d8f121bea5..ac96e4a808 100644
> > --- a/libavformat/mvdec.c
> > +++ b/libavformat/mvdec.c
> > @@ -159,7 +159,10 @@ static int parse_audio_var(AVFormatContext *avctx, AVStream *st,
> >          st->codecpar->sample_rate = var_read_int(pb, size);
> >          avpriv_set_pts_info(st, 33, 1, st->codecpar->sample_rate);
> >      } else if (!strcmp(name, "SAMPLE_WIDTH")) {
> > -        st->codecpar->bits_per_coded_sample = var_read_int(pb, size) * 8;
> > +        uint64_t bpc = var_read_int(pb, size) * (uint64_t)8;
> > +        if (bpc > 100)
> > +            return AVERROR_INVALIDDATA;
> > +        st->codecpar->bits_per_coded_sample = bpc;
> >      } else
> >          return AVERROR_INVALIDDATA;
> 
> ok
> 
> could tighten it further.  realistically (audio) bits per codeded sample will never >16 here.

will apply with 16

thx

[...]

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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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