From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 0D1558D0039 for ; Wed, 16 Mar 2011 02:23:52 -0400 (EDT) Received: by gxk23 with SMTP id 23so707607gxk.14 for ; Tue, 15 Mar 2011 23:23:50 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1300244238.3128.420.camel@calx> References: <20110316022804.27676.qmail@science.horizon.com> <1300244238.3128.420.camel@calx> Date: Wed, 16 Mar 2011 08:23:50 +0200 Message-ID: Subject: Re: [PATCH 0/8] mm/slub: Add SLUB_RANDOMIZE support 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: Matt Mackall Cc: George Spelvin , penberg@cs.helsinki.fi, herbert@gondor.apana.org.au, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Christoph Lameter , Dan Rosenberg , Linus Torvalds Hi Matt, On Sun, 2011-03-13 at 20:20 -0400, George Spelvin wrote: >> As a followup to the "[PATCH] Make /proc/slabinfo 0400" thread, this >> is a patch series to randomize the order of object allocations within >> a page. =A0It can be extended to SLAB and SLOB if desired. =A0Mostly it'= s >> for benchmarking and discussion. On Wed, Mar 16, 2011 at 4:57 AM, Matt Mackall wrote: > I've spent a while thinking about this over the past few weeks, and I > really don't think it's productive to try to randomize the allocators. > It provides negligible defense and just makes life harder for kernel > hackers. If it's an optional feature and the impact on the code is low (as it seems to be), what's the downside? Combined with disabling SLUB's slab merging, randomization should definitely make it more difficult to have full control over a full slab. I don't know how much defense it will provide but I think randomization is definitely an option worth exploring. > (And you definitely can't randomize SLOB like this.) No, you can't but heap exploits like the one we discuss are slightly harder with SLOB anyway, no? 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