[FFmpeg-devel] [PATCH] avcodec/h264_ps: Fix copying oversized pps data

Michael Niedermayer michaelni at gmx.at
Sat Oct 3 11:44:29 CEST 2015


On Fri, Oct 02, 2015 at 11:04:10PM +0200, Hendrik Leppkes wrote:
> On Fri, Oct 2, 2015 at 9:49 PM, wm4 <nfxjfg at googlemail.com> wrote:
> > On Fri, 2 Oct 2015 21:41:59 +0200
> > Michael Niedermayer <michaelni at gmx.at> wrote:
> >
> >> On Fri, Oct 02, 2015 at 09:23:04PM +0200, wm4 wrote:
> >> > On Fri,  2 Oct 2015 21:14:57 +0200
> >> > Michael Niedermayer <michaelni at gmx.at> wrote:
> >> >
> >> > > From: Michael Niedermayer <michael at niedermayer.cc>
> >> > >
> >> > > Fixes: https://trac.ffmpeg.org/attachment/ticket/685/movie.264
> >> > >
> >> > > In the available testcase the actual PPS only uses a few bits
> >> > > while there are 7kbyte of apparently random data after it
> >> > >
> >> > > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> >> > > ---
> >> > >  libavcodec/h264_ps.c |    4 ++--
> >> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> >> > >
> >> > > diff --git a/libavcodec/h264_ps.c b/libavcodec/h264_ps.c
> >> > > index fd16a95..0dca5f0 100644
> >> > > --- a/libavcodec/h264_ps.c
> >> > > +++ b/libavcodec/h264_ps.c
> >> > > @@ -611,8 +611,8 @@ int ff_h264_decode_picture_parameter_set(H264Context *h, int bit_length)
> >> > >          return AVERROR(ENOMEM);
> >> > >      pps->data_size = h->gb.buffer_end - h->gb.buffer;
> >> > >      if (pps->data_size > sizeof(pps->data)) {
> >> > > -        ret = AVERROR_INVALIDDATA;
> >> > > -        goto fail;
> >> > > +        av_log(h->avctx, AV_LOG_WARNING, "Truncating likely oversized PPS\n");
> >> > > +        pps->data_size = sizeof(pps->data);
> >> > >      }
> >> > >      memcpy(pps->data, h->gb.buffer, pps->data_size);
> >> > >      pps->sps_id = get_ue_golomb_31(&h->gb);
> >> >
> >> > That was quick.
> >> >
> >>
> >> > Should the same be done for SPS?
> >>
> >> i dont know
> >>
> >
> > I'd say it would be good for symmetry.
> >
> 
> Its a new error condition which wouldn't affect 99% of all users, so
> its probably best to switch it to a warning as well and hope for the
> best.

ok, switched the 2nd and applied

thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Old school: Use the lowest level language in which you can solve the problem
            conveniently.
New school: Use the highest level language in which the latest supercomputer
            can solve the problem without the user falling asleep waiting.
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