[FFmpeg-devel] [PATCH 1/4] Fix invalid pointer deferences when parsing index in flv demuxer.

[Laurent Aimar]

On Sat, Sep 24, 2011 at 06:04:48PM +0200, Laurent Aimar wrote:
> On Sat, Sep 24, 2011 at 05:36:51PM +0200, Michael Niedermayer wrote:
> > On Sat, Sep 24, 2011 at 04:16:38PM +0200, fenrir at elivagar.org wrote:
> > > From: Laurent Aimar <fenrir at videolan.org>
> > > 
> > > ---
> > >  libavformat/flvdec.c |    4 ++--
> > >  1 files changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
> > > index 569d734..e32829d 100644
> > > --- a/libavformat/flvdec.c
> > > +++ b/libavformat/flvdec.c
> > > @@ -196,8 +196,8 @@ static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, AVStream
> > >          }
> > >      }
> > >  
> > > -    if (timeslen == fileposlen)
> > > -         for(i = 0; i < arraylen; i++)
> > > +    if (!ret && timeslen == fileposlen)
> > > +         for(i = 0; i < fileposlen; i++)
> > >               av_add_index_entry(vstream, filepositions[i], times[i]*1000, 0, 0, AVINDEX_KEYFRAME);
> > 
> > This bug is libav.org specific
> > And your fix is wrong, theres an integer overflow further up that causes
> > the allocated array size to be too small.
>  It might be a good think to add an av_calloc() that would take care
> of the overflow check, no? It seems it's a common enough pattern.

I have attached a patch adding av_calloc().

-- 
fenrir

-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-Add-av_calloc-helper.patch
Type: text/x-diff
Size: 1559 bytes
Desc: not available
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20110924/af5a9443/attachment.bin>