From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752636AbcDOW0O (ORCPT ); Fri, 15 Apr 2016 18:26:14 -0400 Received: from smtprelay0035.hostedemail.com ([216.40.44.35]:41682 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752560AbcDOW0N (ORCPT ); Fri, 15 Apr 2016 18:26:13 -0400 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,joe@perches.com,:::::::::::::::::::::::,RULES_HIT:41:355:379:541:599:800:960:965:966:973:988:989:1260:1277:1311:1313:1314:1345:1359:1373:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2196:2198:2199:2200:2393:2553:2559:2562:2731:2828:2894:3138:3139:3140:3141:3142:3353:3622:3865:3866:3867:3871:4250:4321:4385:4390:4395:5007:9010:10004:10400:10848:10967:11026:11232:11473:11658:11914:12296:12438:12517:12519:12740:13069:13311:13357:13439:14181:14659:14721:21080:30054:30090:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:1,LUA_SUMMARY:none X-HE-Tag: tank72_18c3a2ff5b305 X-Filterd-Recvd-Size: 2773 Message-ID: <1460759160.19090.50.camel@perches.com> Subject: Re: [PATCH] mm: SLAB freelist randomization From: Joe Perches To: Andrew Morton , Thomas Garnier Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Kees Cook , gthelen@google.com, labbott@fedoraproject.org, kernel-hardening@lists.openwall.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Date: Fri, 15 Apr 2016 15:26:00 -0700 In-Reply-To: <20160415150026.65abbdd5b2ef741cd070c769@linux-foundation.org> References: <1460741159-51752-1-git-send-email-thgarnie@google.com> <20160415150026.65abbdd5b2ef741cd070c769@linux-foundation.org> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.18.5.2-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2016-04-15 at 15:00 -0700, Andrew Morton wrote: > On Fri, 15 Apr 2016 10:25:59 -0700 Thomas Garnier wrote: > > Provide an optional config (CONFIG_FREELIST_RANDOM) to randomize the > > SLAB freelist. The list is randomized during initialization of a new set > > of pages. The order on different freelist sizes is pre-computed at boot > > for performance. This security feature reduces the predictability of the > > kernel SLAB allocator against heap overflows rendering attacks much less > > stable. trivia: > > @@ -1229,6 +1229,61 @@ static void __init set_up_node(struct kmem_cache *cachep, int index) [] > > + */ > > +static freelist_idx_t master_list_2[2]; > > +static freelist_idx_t master_list_4[4]; > > +static freelist_idx_t master_list_8[8]; > > +static freelist_idx_t master_list_16[16]; > > +static freelist_idx_t master_list_32[32]; > > +static freelist_idx_t master_list_64[64]; > > +static freelist_idx_t master_list_128[128]; > > +static freelist_idx_t master_list_256[256]; > > +static struct m_list { > > + size_t count; > > + freelist_idx_t *list; > > +} master_lists[] = { > > + { ARRAY_SIZE(master_list_2), master_list_2 }, > > + { ARRAY_SIZE(master_list_4), master_list_4 }, > > + { ARRAY_SIZE(master_list_8), master_list_8 }, > > + { ARRAY_SIZE(master_list_16), master_list_16 }, > > + { ARRAY_SIZE(master_list_32), master_list_32 }, > > + { ARRAY_SIZE(master_list_64), master_list_64 }, > > + { ARRAY_SIZE(master_list_128), master_list_128 }, > > + { ARRAY_SIZE(master_list_256), master_list_256 }, > > +}; static const struct m_list?