From mboxrd@z Thu Jan 1 00:00:00 1970 Reply-To: kernel-hardening@lists.openwall.com Sender: Vasiliy Kulikov Date: Mon, 19 Sep 2011 22:55:18 +0400 From: Vasiliy Kulikov Message-ID: <20110919185518.GA5563@albatros> References: <20110919144657.GA5928@albatros> <20110919155718.GB16272@albatros> <20110919161837.GA2232@albatros> <20110919173539.GA3751@albatros> <20110919175856.GA4282@albatros> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [kernel-hardening] Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo To: Pekka Enberg Cc: Andrew Morton , kernel-hardening@lists.openwall.com, Kees Cook , Cyrill Gorcunov , Al Viro , Christoph Lameter , Matt Mackall , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dan Rosenberg , Theodore Tso , Alan Cox , Jesper Juhl , Linus Torvalds List-ID: On Mon, Sep 19, 2011 at 21:46 +0300, Pekka Enberg wrote: > On Mon, Sep 19, 2011 at 8:58 PM, Vasiliy Kulikov 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