linux-kernel - Re: [RFC v1] mm: SLAB freelist randomization

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Thu, 7 Apr 2016 19:31:52 -0700
From:	Kees Cook <keescook@...omium.org>
To:	Jesper Dangaard Brouer <brouer@...hat.com>
Cc:	Thomas Garnier <thgarnie@...gle.com>,
	Christoph Lameter <cl@...ux.com>,
	Pekka Enberg <penberg@...nel.org>,
	David Rientjes <rientjes@...gle.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Greg Thelen <gthelen@...gle.com>,
	"kernel-hardening@...ts.openwall.com" 
	<kernel-hardening@...ts.openwall.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux-MM <linux-mm@...ck.org>,
	Laura Abbott <labbott@...oraproject.org>
Subject: Re: [RFC v1] mm: SLAB freelist randomization

On Thu, Apr 7, 2016 at 2:14 PM, Jesper Dangaard Brouer
<brouer@...hat.com> wrote:
>
> On Wed, 6 Apr 2016 14:45:30 -0700 Kees Cook <keescook@...omium.org> wrote:
>
>> On Wed, Apr 6, 2016 at 12:35 PM, Thomas Garnier <thgarnie@...gle.com> wrote:
> [...]
>> > re-used on slab creation for performance.
>>
>> I'd like to see some benchmark results for this so the Kconfig can
>> include the performance characteristics. I recommend using hackbench
>> and kernel build times with a before/after comparison.
>>
>
> It looks like it only happens on init, right? (Thus must bench tools
> might not be the right choice).

Oh! Yes, you're right. I entirely missed that detail. :) 0-cost
randomization! Sounds good to me. :)

-Kees

>
> My slab tools for benchmarking the fastpath is here:
>  https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/mm/slab_bulk_test01.c
>
> And I also carry a version of Christoph's slab bench tool:
>  https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/mm/slab_test.c
>
> --
> Best regards,
>   Jesper Dangaard Brouer
>   MSc.CS, Principal Kernel Engineer at Red Hat
>   Author of http://www.iptv-analyzer.org
>   LinkedIn: http://www.linkedin.com/in/brouer



-- 
Kees Cook
Chrome OS & Brillo Security