linux-kernel - Re: [RFC][PATCH] Randomize kernel base address on boot

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Message-ID: <20110527172004.GZ19633@outflux.net>
Date:	Fri, 27 May 2011 10:20:04 -0700
From:	Kees Cook <kees.cook@...onical.com>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Dan Rosenberg <drosenberg@...curity.com>,
	Ingo Molnar <mingo@...e.hu>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>, Tony Luck <tony.luck@...il.com>,
	linux-kernel@...r.kernel.org, davej@...hat.com,
	davem@...emloft.net, eranian@...gle.com, adobriyan@...il.com,
	penberg@...nel.org, Arjan van de Ven <arjan@...radead.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Valdis.Kletnieks@...edu, pageexec@...email.hu
Subject: Re: [RFC][PATCH] Randomize kernel base address on boot

On Fri, May 27, 2011 at 10:13:54AM -0700, H. Peter Anvin wrote:
> On 05/27/2011 10:10 AM, Dan Rosenberg wrote:
> > 
> > Just to play devil's advocate, how is it easier for a local attacker to
> > figure out where kernel internals are if it's been relinked vs.
> > randomized at load time, assuming we follow through on fixing the info
> > leaks?
> > 
> 
> You can read the on-disk kernel file and find out.

If we're still operating under the assumption of "defend against non-root",
distros can trivially make the on-disk kernels 0400.

-Kees

-- 
Kees Cook
Ubuntu Security Team
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