Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Thu, 29 Jun 2017 11:56:47 -0600
From: Tycho Andersen <tycho@...ker.com>
To: Rik van Riel <riel@...hat.com>
Cc: Kees Cook <keescook@...omium.org>, Christoph Lameter <cl@...ux.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Laura Abbott <labbott@...hat.com>,
	Daniel Micay <danielmicay@...il.com>,
	Pekka Enberg <penberg@...nel.org>,
	David Rientjes <rientjes@...gle.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Ingo Molnar <mingo@...nel.org>,
	Josh Triplett <josh@...htriplett.org>,
	Andy Lutomirski <luto@...nel.org>,
	Nicolas Pitre <nicolas.pitre@...aro.org>, Tejun Heo <tj@...nel.org>,
	Daniel Mack <daniel@...que.org>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
	Helge Deller <deller@....de>, LKML <linux-kernel@...r.kernel.org>,
	Linux-MM <linux-mm@...ck.org>,
	"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>
Subject: Re: Re: [PATCH v2] mm: Add SLUB free list pointer
 obfuscation

On Thu, Jun 29, 2017 at 01:54:13PM -0400, Rik van Riel wrote:
> On Thu, 2017-06-29 at 10:47 -0700, Kees Cook wrote:
> > On Thu, Jun 29, 2017 at 10:05 AM, Christoph Lameter <cl@...ux.com>
> > wrote:
> > > On Sun, 25 Jun 2017, Kees Cook wrote:
> > > 
> > > > The difference gets lost in the noise, but if the above is
> > > > sensible,
> > > > it's 0.07% slower. ;)
> > > 
> > > Hmmm... These differences add up. Also in a repetative benchmark
> > > like that
> > > you do not see the impact that the additional cacheline use in the
> > > cpu
> > > cache has on larger workloads. Those may be pushed over the edge of
> > > l1 or
> > > l2 capacity at some point which then causes drastic regressions.
> > 
> > Even if that is true, it may be worth it to some people to have the
> > protection. Given that is significantly hampers a large class of heap
> > overflow attacks[1], I think it's an important change to have. I'm
> > not
> > suggesting this be on by default, it's cleanly behind
> > CONFIG-controlled macros, and is very limited in scope. If you can
> > Ack
> > it we can let system builders decide if they want to risk a possible
> > performance hit. I'm pretty sure most distros would like to have this
> > protection.
> 
> I could certainly see it being useful for all kinds of portable
> and network-connected systems where security is simply much
> more important than performance.

Indeed, I believe we would enable this in our kernels.

Cheers,

Tycho

Powered by blists - more mailing lists

Your e-mail address:

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.