Re: 2.6.23-rc3-mm1 - memory layout change? - lost support for MAP_32BIT? - mono crashes

[Arjan van de Ven <arjan@infradead.org>]

On Fri, 24 Aug 2007 02:09:59 +0200 (CEST)
Jiri Kosina <jkosina@suse.cz> wrote:

> (some more CCs added)
> 
> On Thu, 23 Aug 2007, Andrew Morton wrote:
> 
> > It is quite unobvious to me that the whole pie-randomization thing
> > is worth merging.  Why shouldn't we just drop the lot?
> 
> Hi Andrew,
> 
> well, whenever it comes to address space layout randomization, there 
> usually follows a huge debate whether it is needed or not, some
> people think it's useful and powerful security protection against
> 0day attacks, other people think that it's just fighting the bugs in
> userspace software in a wrong way.

randomizing PIE's is as a whole worth getting right and in mainline.
That means that ONLY the PIE text should be randomized, not that mmap
should break ;)

Randomizing address space is very widely recognized as being part of a
whole set of things (and there's a lot of discussion about what that
whole set should be, each vendor will say their solution should be part
of that and that all others suck) that you need to do to make it a LOT
harder to get a general purpose exploit working. (It's not fool proof;
it's more comparable than a 4 tumble number lock than it is to a iris
scan; yet even a tumble number lock makes it harder to break into your
gym locker)
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