[FFmpeg-devel] [PATCH V4 1/2] lavf/vc1test: fix vc1test can't probe some RCV file.

[mypopy at gmail.com]

On Wed, Oct 17, 2018 at 7:23 AM Michael Niedermayer
<michael at niedermayer.cc> wrote:
>
> On Mon, Oct 15, 2018 at 10:03:59PM +0800, Jun Zhao wrote:
> > case 1:
> > use the hexdump -C SMM0005.rcv get:
> >                      size              skip (size - 4)
> >                       |                        |
> >                       V                        V
> > 00000000  18 00 00 c5 05 00 00 00  4d f1 0a 11 00 e0 01 00
> > 00000010  00 d0 02 00 00 0c 00 00  00 88 13 00 00 c0 65 52
> >                          ^
> >                        |
> >                    size + 16
> > case 2:
> > same the command for SMM0015.rcv get:
> >                     size
> >                       |
> >                       V
> > 00000000  19 00 00 c5 04 00 00 00  41 f3 80 01 40 02 00 00
> > 00000010  d0 02 00 00 0c 00 00 00  00 00 00 10 00 00 00 00
> >                       ^
> >                     |
> >                  size + 16
> >
> > There are different the RCV file format for VC-1, vc1test
> > just handle the case 2 now, this fix will support the case 1.
> > (Both of test clips come from: SMPTE Recommended Practice -
> > VC-1 Decoder and Bitstream Conformance). And I think I got
> > a older VC-1 test clip in the case 1.
> >
> > Reviewed-by: Carl Eugen Hoyos <ceffmpeg at gmail.com>
> > Reviewed-by: Jerome Borsboom <jerome.borsboom at carpalis.nl>
> > Reviewed-by: Michael Niedermayer <michael at niedermayer.cc>
> > Signed-off-by: Jun Zhao <jun.zhao at intel.com>
> > Signed-off-by: Yan, FengX <fengx.yan at intel.com>
> > ---
> >  libavformat/vc1test.c |   12 ++++++++++--
> >  1 files changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/libavformat/vc1test.c b/libavformat/vc1test.c
> > index a801f4b..2427660 100644
> > --- a/libavformat/vc1test.c
> > +++ b/libavformat/vc1test.c
> > @@ -34,9 +34,14 @@
> >
> >  static int vc1t_probe(AVProbeData *p)
> >  {
> > +    int size;
> > +
> >      if (p->buf_size < 24)
> >          return 0;
> > -    if (p->buf[3] != 0xC5 || AV_RL32(&p->buf[4]) != 4 || AV_RL32(&p->buf[20]) != 0xC)
> > +
> > +    size = AV_RL32(&p->buf[4]);
> > +    if (p->buf[3] != 0xC5 || size < 4 || size+16 > p->buf_size ||
>
> size + 16 is undefined here as it can overflow the int range
>
And will check the int overflow issue.
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> If you drop bombs on a foreign country and kill a hundred thousand
> innocent people, expect your government to call the consequence
> "unprovoked inhuman terrorist attacks" and use it to justify dropping
> more bombs and killing more people. The technology changed, the idea is old.
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-- 
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Jun zhao/赵军
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