[FFmpeg-devel] [PATCH] *alloc(type)

[Michael Niedermayer]

On Sat, Nov 20, 2010 at 02:20:08PM +0100, Reimar D?ffinger wrote:
> On Sat, Nov 20, 2010 at 04:05:32PM +0300, Yuriy Kaminskiy wrote:
> > Reimar D?ffinger wrote:
> > > On Sat, Nov 20, 2010 at 04:37:30AM +0100, Michael Niedermayer wrote:
> > >> patchset below fixes the type used in malloc and co
> > >> The sense behind this patch is that feeding things that dont fit in unsigned
> > >> int into *alloc() can lead to successfull allocation of too small arrays which
> > >> is pretty bad.
> > >> There are probably more functions that should be changed like av_new_packet()
> > >> but i had to start somewhere and will look into the others too if noone else
> > >> does.
> > >> Note, i will apply this in a few days if there are no objections
> > > 
> > > This has some side-effects I do not like.
> > > For example, allocating more than 4 GB now becomes possible, even
> > > though such an allocation is almost certain to be a bug.
> > No. A bit more context:
> > === cut ===
> > void *av_malloc(unsigned int size)
> > {
> >     void *ptr = NULL;
> > #if CONFIG_MEMALIGN_HACK
> >     long diff;
> > #endif
> > 
> >     /* let's disallow possible ambiguous cases */
> >     if(size > (INT_MAX-16) )
> >         return NULL;
> 
> Ok, I'll change my suggestions to:
> How about using uint64_t always?

i dont know, it would slow down pure 32bit systems


> How about adding a
> #if SIZE_MAX < INT_MAX
> #error unsupported system (size_t < int)
> #endif

you could commit this and watch fate/roundup and if we hear something breaks
then we could go with uint64_t ...

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

In fact, the RIAA has been known to suggest that students drop out
of college or go to community college in order to be able to afford
settlements. -- The RIAA
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20101120/738dc67d/attachment.pgp>