Re: Patch 4/6 randomize the stack pointer

[Arjan van de Ven]

On Thu, 2005-01-27 at 20:32 +0000, Christoph Hellwig wrote:
> > The patch below replaces the existing 8Kb randomisation of the userspace
> > stack pointer (which is currently only done for Hyperthreaded P-IVs) with a
> > more general randomisation over a 64Kb range. 64Kb is not a lot, but it's a
> > start and once the dust settles we can increase this value to a more
> > agressive value.
> 
> Why are we doing this for x86 only, btw? 
> 
> > +unsigned long arch_align_stack(unsigned long sp)
> > +{
> > +	if (randomize_va_space)
> > +		sp -= ((get_random_int() % 4096) << 4);
> > +	return sp & ~0xf;
> > +}
> 
> this looks like it'd work nicely on all architectures.

the problem is that the <<4 is the minimum x86 stack pointer alignment.
That value differs per architecture afaics.....


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/