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From: Christopher Lameter <cl@linux.com>
To: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Pekka Enberg <penberg@kernel.org>,
	David Rientjes <rientjes@google.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Daniel Micay <danielmicay@gmail.com>,
	Vitaly Nikolenko <vnik@duasynt.com>,
	Silvio Cesare <silvio.cesare@gmail.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] slub: Relocate freelist pointer to middle of object
Date: Sun, 8 Mar 2020 19:21:09 +0000 (UTC)	[thread overview]
Message-ID: <alpine.DEB.2.21.2003081919290.14266@www.lameter.com> (raw)
In-Reply-To: <202003051624.AAAC9AECC@keescook>

On Thu, 5 Mar 2020, Kees Cook wrote:

> Instead of having the freelist pointer at the very beginning of an
> allocation (offset 0) or at the very end of an allocation (effectively
> offset -sizeof(void *) from the next allocation), move it away from
> the edges of the allocation and into the middle. This provides some
> protection against small-sized neighboring overflows (or underflows),
> for which the freelist pointer is commonly the target. (Large or well
> controlled overwrites are much more likely to attack live object contents,
> instead of attempting freelist corruption.)

Sounds good. You could even randomize the position to avoid attacks on via
the freelist pointer.

Acked-by: Christoph Lameter <cl@linux.com>

  reply	other threads:[~2020-03-08 19:21 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-06  0:26 Kees Cook
2020-03-08 19:21 ` Christopher Lameter [this message]
2020-03-11 14:48   ` David Laight
2020-03-11 17:37     ` Kees Cook
2020-03-11 17:44     ` Kees Cook
2020-03-15 14:11       ` Christopher Lameter

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