From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 581EA9000BD for ; Mon, 19 Sep 2011 10:30:52 -0400 (EDT) Received: by gxk2 with SMTP id 2so768123gxk.14 for ; Mon, 19 Sep 2011 07:30:50 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110918170512.GA2351@albatros> References: <20110910164001.GA2342@albatros> <20110910164134.GA2442@albatros> <20110914192744.GC4529@outflux.net> <20110918170512.GA2351@albatros> Date: Mon, 19 Sep 2011 17:30:49 +0300 Message-ID: Subject: Re: [kernel-hardening] Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo From: Pekka Enberg Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Vasiliy Kulikov 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 > 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. =A0slabinfo contains rather private information related bot= h to >> > the kernel and userspace tasks. =A0Depending on the situation, it migh= t >> > reveal either private information per se or information useful to make >> > another targeted attack. =A0Some 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. =A0For most users 0444 slabinfo is an unreasonable attack ve= ctor. >> > >> > Signed-off-by: Vasiliy Kulikov On Sun, Sep 18, 2011 at 8:05 PM, Vasiliy Kulikov wrot= e: >> Haven't had any mass complaints about the 0400 in Ubuntu (sorry Dave!), = so >> I'm obviously for it. >> >> Reviewed-by: Kees Cook > > Looks like the members of the previous slabinfo discussion don't object > against the patch now and it got two other Reviewed-by responses. =A0Can > you merge it as-is or should I probably convince someone else? We discussed this in March (google for 'Make /proc/slabinfo 0400') and concluded that it's not worth it doesn't really protect from anything and causes harm to developers. Pekka -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org