Re: [PATCH] x86: Enable full randomization on i386 and X86_32.

From: Ingo Molnar
Date: Fri Mar 11 2016 - 03:53:57 EST

* Kees Cook <keescook@xxxxxxxxxxxx> wrote:

> On Thu, Mar 10, 2016 at 12:53 PM, Arjan van de Ven
> <arjan@xxxxxxxxxxxxxxx> wrote:
> >> Arjan, or other folks, can you remember why x86_32 disabled mmap
> >> randomization here? There doesn't seem to be a good reason for it that
> >> I see.
> >
> >
> > for unlimited stack it got really messy with threaded apps.
> Seems like it'd only cause problems for really really giant processes?
> (I think it's telling that the other 32-bit archs don't disable ASLR
> in this case...)

IIRC there was some sort of specific breakage with unlimited stack apps - I don't
remember the exact details.

> > anyway, I don't mind seeing if this will indeed work, with time running out
> > where 32 bit is going extinct... in a few years we just won't have enough
> > testing on this kind of change anymore.
> Sounds good. Ingo, can you pull this in and we can try it for -next?

Ok, we can certainly try. If there's breakage with old distros then we might need
to put this behind a legacy Kconfig switch.