[FFmpeg-devel] [PATCH] avcodec/mpeg12dec: Fix uninitialized data in fate-sub-cc-scte20

[lance.lmwang at gmail.com]

On Sat, Jun 27, 2020 at 05:54:52PM +0200, Carl Eugen Hoyos wrote:
> Am Sa., 27. Juni 2020 um 17:46 Uhr schrieb <lance.lmwang at gmail.com>:
> >
> > From: Limin Wang <lance.lmwang at gmail.com>
> >
> > The issue is introduced from a705bcd763e344fa, please tested with below command line:
> > make V=1 fate-sub-cc-scte20 TARGET_EXEC="valgrind --error-exitcode=1"
> >
> > Reported-by:   Martin Storsjö <martin at martin.st>
> > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > ---
> >  libavcodec/mpeg12dec.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
> > index f0f92ac..2562027 100644
> > --- a/libavcodec/mpeg12dec.c
> > +++ b/libavcodec/mpeg12dec.c
> > @@ -2276,6 +2276,8 @@ static int mpeg_decode_a53_cc(AVCodecContext *avctx,
> >              if (ret >= 0) {
> >                  uint8_t field, cc1, cc2;
> >                  uint8_t *cap = s1->a53_buf_ref->data;
> > +
> 
> > +                memset(s1->a53_buf_ref->data + old_size, 0, cc_count * UINT64_C(3));
> 
> Why is the promotion (?) to uint64 useful?

I can't tell what's the real reason as the original code is coming in 80ea66112817c719b476de8f7
for h264, HEVC and mpeg2 are following the same way.

> 
> Carl Eugen
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-- 
Thanks,
Limin Wang