From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f198.google.com (mail-ig0-f198.google.com [209.85.213.198]) by kanga.kvack.org (Postfix) with ESMTP id 36BAC6B0005 for ; Fri, 15 Apr 2016 18:26:13 -0400 (EDT) Received: by mail-ig0-f198.google.com with SMTP id z8so48363316igl.3 for ; Fri, 15 Apr 2016 15:26:13 -0700 (PDT) Received: from smtprelay.hostedemail.com (smtprelay0055.hostedemail.com. [216.40.44.55]) by mx.google.com with ESMTPS id w16si11992630ioi.156.2016.04.15.15.26.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Apr 2016 15:26:12 -0700 (PDT) Message-ID: <1460759160.19090.50.camel@perches.com> Subject: Re: [PATCH] mm: SLAB freelist randomization From: Joe Perches 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" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: 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 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? -- 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/ . Don't email: email@kvack.org