[FFmpeg-devel] [PATCH] avcodec/wavpack: check for overflow

Michael Niedermayer michaelni at gmx.at
Wed Jul 3 02:04:13 CEST 2013


On Tue, Jul 02, 2013 at 11:05:09PM +0000, Paul B Mahol wrote:
> On 7/2/13, Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Mon, Jun 17, 2013 at 05:49:47PM +0200, Michael Niedermayer wrote:
> >> On Mon, Jun 17, 2013 at 10:54:28AM +0000, Paul B Mahol wrote:
> >> > On 6/15/13, Michael Niedermayer <michaelni at gmx.at> wrote:
> >> > > Fix integer overflow in fate
> >> > >
> >> > > Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> >> > > ---
> >> > >  libavcodec/wavpack.c |   10 ++++++++--
> >> > >  1 file changed, 8 insertions(+), 2 deletions(-)
> >> > >
> >> > > diff --git a/libavcodec/wavpack.c b/libavcodec/wavpack.c
> >> > > index 47f598a..dd273f7 100644
> >> > > --- a/libavcodec/wavpack.c
> >> > > +++ b/libavcodec/wavpack.c
> >> > > @@ -581,8 +581,14 @@ static inline int
> >> > > wv_unpack_stereo(WavpackFrameContext
> >> > > *s, GetBitContext *gb,
> >> > >                      L2 = L + ((s->decorr[i].weightA * (int64_t)A +
> >> > > 512) >>
> >> > > 10);
> >> > >                      R2 = R + ((s->decorr[i].weightB * (int64_t)B +
> >> > > 512) >>
> >> > > 10);
> >> > >                  } else {
> >> > > -                    L2 = L + ((s->decorr[i].weightA * A + 512) >>
> >> > > 10);
> >> > > -                    R2 = R + ((s->decorr[i].weightB * B + 512) >>
> >> > > 10);
> >> > > +                    int64_t Lt = s->decorr[i].weightA * (int64_t)A +
> >> > > 512;
> >> > > +                    int64_t Rt = s->decorr[i].weightB * (int64_t)B +
> >> > > 512;
> >> > > +                    if ((int32_t)Lt != Lt || (int32_t)Rt != Rt) {
> >> > > +                        av_log(s->avctx, AV_LOG_ERROR, "sample
> >> > > overflow %d
> >> >
> >> > This looks extremly ugly.
> >>
> >> Iam quite aware of that, which is part of the reason why i posted this
> >> (aka do you know a less ugly solution?)
> >
> > ping
> > anyone has a better solution ?
> > do any objections to the original patch remain ?
> 
> Yes, i see no point to apply this patch as is.

what alternative solution do you suggest?


[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

What does censorship reveal? It reveals fear. -- Julian Assange
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