[FFmpeg-devel] [PATCH 4/5] avformat/icodec: Change order of operations to avoid NULL dereference

[Michael Niedermayer]

On Sat, Oct 17, 2020 at 07:52:02AM +1100, Peter Ross wrote:
> On Fri, Oct 16, 2020 at 07:35:29PM +0200, Michael Niedermayer wrote:
> > Fixes: SEGV on unknown address 0x000000000000
> > Fixes: 26379/clusterfuzz-testcase-minimized-ffmpeg_dem_ICO_fuzzer-5709011753893888
> > 
> > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > ---
> >  libavformat/icodec.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/libavformat/icodec.c b/libavformat/icodec.c
> > index b47fa98f80..c061f3ec42 100644
> > --- a/libavformat/icodec.c
> > +++ b/libavformat/icodec.c
> > @@ -156,12 +156,14 @@ static int read_packet(AVFormatContext *s, AVPacket *pkt)
> >      IcoDemuxContext *ico = s->priv_data;
> >      IcoImage *image;
> >      AVIOContext *pb = s->pb;
> > -    AVStream *st = s->streams[0];
> > +    AVStream *st;
> >      int ret;
> >  
> >      if (ico->current_image >= ico->nb_images)
> >          return AVERROR_EOF;
> >  
> > +    st = s->streams[0];
> > +
> >      image = &ico->images[ico->current_image];
> >  
> >      if ((ret = avio_seek(pb, image->offset, SEEK_SET)) < 0)
> > -- 
> > 2.17.1
> 
> looks good

will apply

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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