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From: Thomas Garnier <thgarnie@google.com>
To: Yves-Alexis Perez <corsac@debian.org>
Cc: kernel-hardening@lists.openwall.com,
	Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	David Rientjes <rientjes@google.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Greg Thelen <gthelen@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>,
	Laura Abbott <labbott@fedoraproject.org>
Subject: Re: [kernel-hardening] Re: [RFC v1] mm: SLAB freelist randomization
Date: Thu, 7 Apr 2016 09:35:46 -0700	[thread overview]
Message-ID: <CAJcbSZFx4rT6fXKvOF-wgHTSZBgqfQGw0qn=JqwAygNHDVUvNQ@mail.gmail.com> (raw)
In-Reply-To: <1460045867.2818.67.camel@debian.org>

That's a use after free. The randomization of the freelist should not
have much effect on that. I was going to quote this exploit that is
applicable to SLAB as well:
https://jon.oberheide.org/blog/2010/09/10/linux-kernel-can-slub-overflow

Regards.
Thomas

On Thu, Apr 7, 2016 at 9:17 AM, Yves-Alexis Perez <corsac@debian.org> wrote:
> On mer., 2016-04-06 at 14:45 -0700, Kees Cook wrote:
>> > This security feature reduces the predictability of
>> > the kernel slab allocator against heap overflows.
>>
>> I would add "... rendering attacks much less stable." And if you can
>> find a specific example exploit that is foiled by this, I would refer
>> to it.
>
> One good example might (or might not) be the keyring issue from earlier this
> year (CVE-2016-0728):
>
> http://perception-point.io/2016/01/14/analysis-and-exploitation-of-a-linux-ker
> nel-vulnerability-cve-2016-0728/
>
> Regards,
> --
> Yves-Alexis
>

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  reply	other threads:[~2016-04-07 16:35 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-06 19:35 Thomas Garnier
2016-04-06 20:54 ` [kernel-hardening] " Greg KH
2016-04-06 21:03   ` Thomas Garnier
2016-04-06 21:45 ` Kees Cook
2016-04-07 15:28   ` Thomas Garnier
2016-04-07 16:17   ` [kernel-hardening] " Yves-Alexis Perez
2016-04-07 16:35     ` Thomas Garnier [this message]
2016-04-07 21:14   ` Jesper Dangaard Brouer
2016-04-08  2:31     ` Kees Cook

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