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

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Date:	Mon, 19 Sep 2011 22:55:18 +0400
From:	Vasiliy Kulikov <segoon@...nwall.com>
To:	Pekka Enberg <penberg@...helsinki.fi>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	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>,
	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: [kernel-hardening] Re: [RFC PATCH 2/2] mm: restrict access to
 /proc/slabinfo

On Mon, Sep 19, 2011 at 21:46 +0300, Pekka Enberg wrote:
> On Mon, Sep 19, 2011 at 8:58 PM, Vasiliy Kulikov <segoon@...nwall.com> wrote:
> >> Isn't this
> >> much stronger protection especially if you combine that with /proc/slabinfo
> >> restriction?
> >
> > I don't see any reason to change allocators if we close slabinfo.
> 
> OK, so what about /proc/meminfo, sysfs, 'perf kmem', and other kernel interfaces
> through which you can get direct or indirect information about kernel memory
> allocations?

Oh, we also have perf...  Given these are separate interfaces, I think
slab oriented restriction makes more sense.

So, now we have:

/proc/slabinfo
/sys/kernel/slab
/proc/meminfo
'perf kmem' - not sure what specific files should be guarded


Is there another way to get directly or indirectly the information about
slabs?


Thanks,

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