[FFmpeg-devel] [PATCH 2/2] avcodec/h264: Check weight values to be within the specs limits.

[Ronald S. Bultje]

Hi,

On Thu, Apr 6, 2017 at 8:10 PM, Michael Niedermayer <michael at niedermayer.cc>
wrote:

> On Wed, Mar 22, 2017 at 07:09:23PM +0100, Michael Niedermayer wrote:
> > On Wed, Mar 22, 2017 at 09:06:09AM -0400, Ronald S. Bultje wrote:
> > > Hi,
> > >
> > > On Tue, Mar 21, 2017 at 9:59 PM, Michael Niedermayer
> <michael at niedermayer.cc
> > > > wrote:
> > >
> > > > @@ -59,6 +59,9 @@ int ff_h264_pred_weight_table(GetBitContext *gb,
> const
> > > > SPS *sps,
> > > >              if (luma_weight_flag) {
> > > >                  pwt->luma_weight[i][list][0] = get_se_golomb(gb);
> > > >                  pwt->luma_weight[i][list][1] = get_se_golomb(gb);
> > > > +                if (   (int8_t)pwt->luma_weight[i][list][0] !=
> > > > pwt->luma_weight[i][list][0]
> > > > +                    || (int8_t)pwt->luma_weight[i][list][1] !=
> > > > pwt->luma_weight[i][list][1])
> > > > +                    goto error;
> > > >
> > >
> > > Can we please put || on the line before? h264* and a very limited
> subset of
> > > other files in our codebase have always been an exception to the large
> > > majority of the codebase and it's about time we fix that [1].
> >
> > i find putting the operators in the first column more readable
> > but if its preferred in the last, iam happy to change it.
> >
> >
> > >
> > > It's interesting (I mean that in a positive way) how you use casting to
> > > check for the range. It's a little obscure, but it's OK.
> >
> > yes, it caused me to pause to but it was the simplest way i saw to do
> > the check
> >
> >
> > >
> > > +error:
> > > > +    avpriv_request_sample(logctx, "Out of range weight\n");
> > > > +    return AVERROR_INVALIDDATA;
> > >
> > >
> > > Same comment as previously in other, but related, threads: unless
> there is
> > > real, demonstrable evidence that this happens in real-world files,
> this is
> > > fuzz/corruption only and shouldn't be accompanied by an explicit log
> > > message. Just return AVERROR_INVALIDDATA directly and remove the
> goto/error
> > > message.
> >
> > If there is "real, demonstrable evidence that this happens in real-world
> > files" then we would likely have a sample and not ask for one with
> > avpriv_request_sample()
> >
> > I think its very plausible that a encoder would use a weight that is
> > outside the range. Printing something does make sense.
>
> i will apply this with the label chaned to out_range_weight:
> unless there are objections


OK.

Ronald