[FFmpeg-devel] Security issues?

[Michael Niedermayer]

On Wed, Sep 23, 2009 at 05:02:49PM +0200, Reimar D?ffinger wrote:
> On Wed, Sep 23, 2009 at 03:22:02PM +0200, Michael Niedermayer wrote:
> > On Wed, Sep 23, 2009 at 03:15:06PM +0200, Reimar D?ffinger wrote:
> > > On Wed, Sep 23, 2009 at 02:57:31PM +0200, Michael Niedermayer wrote:
> > > > > Index: libavcodec/vorbis_dec.c
> > > > > ===================================================================
> > > > > --- libavcodec/vorbis_dec.c     (revision 19987)
> > > > > +++ libavcodec/vorbis_dec.c     (working copy)
> > > > > @@ -162,6 +162,13 @@
> > > > >  #define BARK(x) \
> > > > >      (13.1f*atan(0.00074f*(x))+2.24f*atan(1.85e-8f*(x)*(x))+1e-4f*(x))
> > > > >  
> > > > > +
> > > > > +#define VALIDATE_INDEX(ctx, idx, limit, onerror) \
> > > > 
> > > > > +    if (idx >= limit) {\
> > > > 
> > > > the check should be an argument to the macro
> > > > 
> > > > 
> > > > > +        av_log(ctx, AV_LOG_ERROR, "Index value %d out of range (0 - %d) for "#idx "\n", idx, limit);\
> > > 
> > > Uh, and what should be the message then? If you change the check, this
> > > message no longer makes sense, 
> > 
> > the message could be an argument too
> 
> The message and the arguments then. And IMO then you don't really save
> much.
> For what guess, there are maybe 10 places where this macro can be
> used unchanged and a few where you'd have to add a if (... != -1),
> and I just think a macro for this special case alone would be justified
> and making it more generic just re-adds some of the bloat it is supposed
> to avoid...

blah ...

#define MACRO(dst, cond, bits, err)\
unsigned int tmp= get_bits(bits);\
if(!(cond)){\
    av_log( #dst " fails the condition " #cond "\n");\
    return err
}


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Thouse who are best at talking, realize last or never when they are wrong.
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