[FFmpeg-devel] [PATCH 4/4] avcodec/mpegpicture: Keep ff_mpeg_framesize_alloc() failure state consistent

[Michael Niedermayer]

On Fri, Mar 19, 2021 at 04:26:11PM +0100, Michael Niedermayer wrote:
> On Thu, Mar 18, 2021 at 09:57:11PM +0100, Andreas Rheinhardt wrote:
> > Michael Niedermayer:
> > > Fixes: null pointer dereference
> > > Fixes: ff_put_pixels16_sse2.mp4
> > > 
> > > Found-by: Rafael Dutra <rafael.dutra at cispa.de>
> > > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > > ---
> > >  libavcodec/mpegpicture.c | 5 ++++-
> > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/libavcodec/mpegpicture.c b/libavcodec/mpegpicture.c
> > > index e3f648895d..0652b7c879 100644
> > > --- a/libavcodec/mpegpicture.c
> > > +++ b/libavcodec/mpegpicture.c
> > > @@ -79,8 +79,11 @@ int ff_mpeg_framesize_alloc(AVCodecContext *avctx, MotionEstContext *me,
> > >      // linesize * interlaced * MBsize
> > >      // we also use this buffer for encoding in encode_mb_internal() needig an additional 32 lines
> > >      if (!FF_ALLOCZ_TYPED_ARRAY(sc->edge_emu_buffer, alloc_size * EMU_EDGE_HEIGHT) ||
> > > -        !FF_ALLOCZ_TYPED_ARRAY(me->scratchpad,      alloc_size * 4 * 16 * 2))
> > > +        !FF_ALLOCZ_TYPED_ARRAY(me->scratchpad,      alloc_size * 4 * 16 * 2)) {
> > > +        av_freep(&sc->edge_emu_buffer);
> > >          return AVERROR(ENOMEM);
> > > +    }
> > > +
> > >      me->temp            = me->scratchpad;
> > >      sc->rd_scratchpad   = me->scratchpad;
> > >      sc->b_scratchpad    = me->scratchpad;
> > > 
> > This is a regression since 4b2863ff01b1fe93d9a518523c9098d17a9d8c6f, see
> > http://ffmpeg.org/pipermail/ffmpeg-devel/2020-December/274026.html.
> 
> Do you prefer your patchset, or do i misunderstand ?
> 
> I have no preferrance except that i want to see the bugs fixed

will apply with a reference to the commit that caused the regression

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

It is what and why we do it that matters, not just one of them.
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