[FFmpeg-devel] [PATCH 2/6] lavc/avpacket: check NULL before using the pointer

[Michael Niedermayer]

On Fri, May 10, 2019 at 10:00:54PM +0200, Carl Eugen Hoyos wrote:
> Am Fr., 10. Mai 2019 um 18:13 Uhr schrieb Jun Zhao <mypopydev at gmail.com>:
> >
> > From: Jun Zhao <barryjzhao at tencent.com>
> >
> > Need to check NULL before using the pointer
> >
> > Signed-off-by: Jun Zhao <barryjzhao at tencent.com>
> > ---
> >  libavcodec/avpacket.c |    3 ++-
> >  1 files changed, 2 insertions(+), 1 deletions(-)
> >
> > diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
> > index 8f0603d..2b20067 100644
> > --- a/libavcodec/avpacket.c
> > +++ b/libavcodec/avpacket.c
> > @@ -522,11 +522,12 @@ fail:
> >
> >  int av_packet_unpack_dictionary(const uint8_t *data, int size, AVDictionary **dict)
> >  {
> > -    const uint8_t *end = data + size;
> > +    const uint8_t *end;
> >      int ret = 0;
> >
> >      if (!dict || !data || !size)
> >          return ret;
> > +    end = data + size;
> 
> Could somebody explain to me why this is necessary?

if data is NULL adding a non zero value to it would be undefined behavior
i think

thx

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

There will always be a question for which you do not know the correct answer.
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