From: Ingo Molnar <mingo@elte.hu>
To: Andi Kleen <ak@suse.de>
Cc: torvalds@osdl.org, akpm@osdl.org, discuss@x86-64.org,
linux-kernel@vger.kernel.org,
Chuck Ebbert <76306.1226@compuserve.com>
Subject: Re: [PATCH for 2.6.18-rc2] [2/8] i386/x86-64: Don't randomize stack top when no randomization personality is set
Date: Sun, 16 Jul 2006 23:11:27 +0200 [thread overview]
Message-ID: <20060716211126.GA2880@elte.hu> (raw)
In-Reply-To: <200607162314.07764.ak@suse.de>
* Andi Kleen <ak@suse.de> wrote:
> On Sunday 16 July 2006 22:47, Ingo Molnar wrote:
> > * Andi Kleen <ak@suse.de> wrote:
> > > unsigned long arch_align_stack(unsigned long sp)
> > > {
> > > - if (randomize_va_space)
> > > + if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
> > > sp -= get_random_int() % 8192;
> > > return sp & ~0xf;
> >
> > i'm not opposing this patch at all, but didnt the performance problems
> > go away when the 0xf was changed to 0x7f?
>
> Yes, but i sent the patch before that other patch was available.
excuses, excuses ;)
> I guess it's a separate issue anyways - this patch is just concerned
> about disabling randomization consistently. Performance optimization
> can be done in another one.
yeah. There's one security issue: the 'dont randomize' flag must be
cleared when we cross a protection domain. When for example suid-ing in
exec().
Ingo
next prev parent reply other threads:[~2006-07-16 21:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-16 12:22 [PATCH for 2.6.18-rc2] [2/8] i386/x86-64: Don't randomize stack top when no randomization personality is set Andi Kleen
2006-07-16 20:47 ` Ingo Molnar
2006-07-16 21:14 ` Andi Kleen
2006-07-16 21:11 ` Ingo Molnar [this message]
2006-07-16 21:27 ` Andi Kleen
2006-07-16 21:33 ` [discuss] Re: [PATCH for 2.6.18-rc2] [2/8] i386/x86-64: Don't randomize stack top when no randomization personality is set II Andi Kleen
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