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Date: Tue, 13 Sep 2011 10:28:55 +0400
From: Vasiliy Kulikov <segoon@openwall.com>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: kernel-hardening@lists.openwall.com,
        Andrew Morton <akpm@linux-foundation.org>,
        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
Subject: Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo
Message-ID: <20110913062855.GA3221@albatros>
References: <20110910164001.GA2342@albatros>
 <20110910164134.GA2442@albatros>
 <20110912150630.GE25367@sun>
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On Mon, Sep 12, 2011 at 19:06 +0400, Cyrill Gorcunov 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:
> > 
> ...
> 
> Since this file is controversy point, probably its permissions might be
> configurable via setup option?

We could create DEBUG_PROC (of cource, defaults to =n) to keep current
relaxed procfs permissions, but I don't think a configure option is needed
for a thing which is trivially done via "chmod" in init scripts.

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