From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id 514F69000BD for ; Mon, 19 Sep 2011 14:03:44 -0400 (EDT) Received: from d03relay03.boulder.ibm.com (d03relay03.boulder.ibm.com [9.17.195.228]) by e37.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id p8JI0KhC027004 for ; Mon, 19 Sep 2011 12:00:20 -0600 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay03.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p8JI3Nol179946 for ; Mon, 19 Sep 2011 12:03:28 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p8JI2voI018043 for ; Mon, 19 Sep 2011 12:02:58 -0600 Subject: Re: [kernel-hardening] Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo From: Dave Hansen In-Reply-To: References: <20110910164134.GA2442@albatros> <20110914192744.GC4529@outflux.net> <20110918170512.GA2351@albatros> <20110919144657.GA5928@albatros> <20110919155718.GB16272@albatros> <20110919161837.GA2232@albatros> <20110919173539.GA3751@albatros> Content-Type: text/plain; charset="UTF-8" Date: Mon, 19 Sep 2011 11:03:15 -0700 Message-ID: <1316455395.16137.160.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: Vasiliy Kulikov , 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 Mon, 2011-09-19 at 20:51 +0300, Pekka Enberg wrote: > How is the attacker able to identify that we kmalloc()'d from ecryptfs or > VFS based on non-root /proc/slabinfo when the slab allocator itself does > not have that sort of information if you mix up the allocations? Isn't this > much stronger protection especially if you combine that with /proc/slabinfo > restriction? Mixing it up just adds noise. It makes the attack somewhat more difficult, but it still leaves open the possibility that the attacker can filter out the noise somehow. -- Dave -- 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