From mboxrd@z Thu Jan  1 00:00:00 1970
Reply-To: kernel-hardening@lists.openwall.com
Sender: Vasiliy Kulikov <segooon@gmail.com>
Date: Sun, 18 Sep 2011 21:05:12 +0400
From: Vasiliy Kulikov <segoon@openwall.com>
Message-ID: <20110918170512.GA2351@albatros>
References: <20110910164001.GA2342@albatros>
 <20110910164134.GA2442@albatros>
 <20110914192744.GC4529@outflux.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20110914192744.GC4529@outflux.net>
Subject: Re: [kernel-hardening] Re: [RFC PATCH 2/2] mm: restrict access to
 /proc/slabinfo
To: Andrew Morton <akpm@linux-foundation.org>
Cc: kernel-hardening@lists.openwall.com, Kees Cook <kees@ubuntu.com>, Cyrill Gorcunov <gorcunov@gmail.com>, Al Viro <viro@zeniv.linux.org.uk>, Christoph Lameter <cl@linux-foundation.org>, Pekka Enberg <penberg@kernel.org>, Matt Mackall <mpm@selenic.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dan Rosenberg <drosenberg@vsecurity.com>, Theodore Tso <tytso@mit.edu>, Alan Cox <alan@linux.intel.com>, Jesper Juhl <jj@chaosbits.net>, Linus Torvalds <torvalds@linux-foundation.org>
List-ID: <kernel-hardening.lists.openwall.com>

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@openwall.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@ubuntu.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