kernel-hardening - Re: Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo

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Date: Sun, 18 Sep 2011 21:05:12 +0400
From: Vasiliy Kulikov <segoon@...nwall.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: kernel-hardening@...ts.openwall.com, Kees Cook <kees@...ntu.com>,
	Cyrill Gorcunov <gorcunov@...il.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	Christoph Lameter <cl@...ux-foundation.org>,
	Pekka Enberg <penberg@...nel.org>, Matt Mackall <mpm@...enic.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Dan Rosenberg <drosenberg@...curity.com>,
	Theodore Tso <tytso@....edu>, Alan Cox <alan@...ux.intel.com>,
	Jesper Juhl <jj@...osbits.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: Re: [RFC PATCH 2/2] mm: restrict access to
 /proc/slabinfo

Hi Andrew,

On Wed, Sep 14, 2011 at 12:27 -0700, Kees Cook wrote:
> On Sat, Sep 10, 2011 at 08:41:34PM +0400, Vasiliy Kulikov wrote:
> > Historically /proc/slabinfo has 0444 permissions and is accessible to
> > the world.  slabinfo contains rather private information related both to
> > the kernel and userspace tasks.  Depending on the situation, it might
> > reveal either private information per se or information useful to make
> > another targeted attack.  Some examples of what can be learned by
> > reading/watching for /proc/slabinfo entries:
> > ...
> > World readable slabinfo simplifies kernel developers' job of debugging
> > kernel bugs (e.g. memleaks), but I believe it does more harm than
> > benefits.  For most users 0444 slabinfo is an unreasonable attack vector.
> > 
> > Signed-off-by: Vasiliy Kulikov <segoon@...nwall.com>
> 
> Haven't had any mass complaints about the 0400 in Ubuntu (sorry Dave!), so
> I'm obviously for it.
> 
> Reviewed-by: Kees Cook <kees@...ntu.com>

Looks like the members of the previous slabinfo discussion don't object
against the patch now and it got two other Reviewed-by responses.  Can
you merge it as-is or should I probably convince someone else?

Thanks,

-- 
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments

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