From mboxrd@z Thu Jan 1 00:00:00 1970 Reply-To: kernel-hardening@lists.openwall.com Date: Wed, 14 Sep 2011 12:27:44 -0700 From: Kees Cook Message-ID: <20110914192744.GC4529@outflux.net> References: <20110910164001.GA2342@albatros> <20110910164134.GA2442@albatros> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110910164134.GA2442@albatros> Subject: [kernel-hardening] Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo To: Vasiliy Kulikov Cc: kernel-hardening@lists.openwall.com, Andrew Morton , Cyrill Gorcunov , Al Viro , Christoph Lameter , Pekka Enberg , Matt Mackall , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Hi Vasiliy, 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 Haven't had any mass complaints about the 0400 in Ubuntu (sorry Dave!), so I'm obviously for it. Reviewed-by: Kees Cook -Kees -- Kees Cook Ubuntu Security Team