[FFmpeg-devel] [PATCH] check for failed extradata malloc in avidec

Reimar Döffinger Reimar.Doeffinger
Thu Jul 2 14:49:59 CEST 2009


On Wed, Jul 01, 2009 at 11:27:02PM +0200, Michael Niedermayer wrote:
> On Wed, Jul 01, 2009 at 08:16:56PM +0200, Reimar D?ffinger wrote:
> > Hello,
> > this fixes one of the files in issue1240.
> > Not sure if this is the best solution (the extradata size limit of 2^30 seems
> > rather extreme) but anyway...
> > Index: libavformat/avidec.c
> > ===================================================================
> > --- libavformat/avidec.c	(revision 19317)
> > +++ libavformat/avidec.c	(working copy)
> > @@ -478,6 +478,10 @@
> >                      if(size > 10*4 && size<(1<<30)){
> >                          st->codec->extradata_size= size - 10*4;
> >                          st->codec->extradata= av_malloc(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
> > +                        if (!st->codec->extradata) {
> > +                            st->codec->extradata_size= 0;
> > +                            return AVERROR(ENOMEM);
> > +                        }
> >                          get_buffer(pb, st->codec->extradata, st->codec->extradata_size);
> >                      }
> 
> hmm, id treat malloc failure like a too large extradata
> also a error message could be usefull for both

Well, here is it done that way, I don't like it too much.
And I think it creates the strange situation that on my small PC the
file now plays well thanks to the failing malloc, whereas on my normal
PC it would at least pointlessly try to read in the whole file (maybe
we should check how many bytes get_buffer actually read an resize the
extradata buffer?).
I also think the limit for extradata should be at most 1 << 27, that is
128MB and would already take 2 seconds to load from an average disk (and
it wouldn't fail on the average PC)...
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