From: Vasiliy Kulikov <segoon@openwall.com>
To: kernel-hardening@lists.openwall.com, Valdis.Kletnieks@vt.edu
Cc: David Rientjes <rientjes@google.com>,
Christoph Lameter <cl@gentwo.org>,
Pekka Enberg <penberg@kernel.org>, Matt Mackall <mpm@selenic.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Kees Cook <kees@ubuntu.com>,
Dave Hansen <dave@linux.vnet.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Alan Cox <alan@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [kernel-hardening] Re: [PATCH 2/2] mm: restrict access to /proc/meminfo
Date: Thu, 29 Sep 2011 21:25:31 +0400 [thread overview]
Message-ID: <20110929172531.GA19290@albatros> (raw)
In-Reply-To: <23921.1317315452@turing-police.cc.vt.edu>
On Thu, Sep 29, 2011 at 12:57 -0400, Valdis.Kletnieks@vt.edu wrote:
> But now he has to fly blind for the next 30 because the numbers will display
> exactly the same, and he can't correct for somebody else allocating one so he
> needs to only allocate 29...
You're still talking about "slabinfo", which is already restricted.
And meminfo can be still learned with the same race window (ala seq lock):
prepare_stuff();
fill_slabs(); // Here we know counters with KB granularity
while (number_is_not_ok()) {
prepare_stuff();
fill_slabs();
}
do_exploit();
Thanks,
--
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments
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next prev parent reply other threads:[~2011-09-29 17:26 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-27 17:54 [PATCH 1/2] mm: restrict access to slab files under procfs and sysfs Vasiliy Kulikov
2011-09-27 17:56 ` [PATCH 2/2] mm: restrict access to /proc/meminfo Vasiliy Kulikov
2011-09-27 18:27 ` David Rientjes
2011-09-27 19:14 ` Vasiliy Kulikov
2011-09-27 19:38 ` Vasiliy Kulikov
2011-09-27 20:03 ` Christoph Lameter
2011-09-27 20:33 ` David Rientjes
2011-09-27 20:47 ` Christoph Lameter
2011-09-28 20:31 ` Dave Hansen
2011-09-28 20:52 ` Alan Cox
2011-09-29 0:43 ` Valdis.Kletnieks
2011-09-29 14:11 ` Christoph Lameter
2011-09-29 16:18 ` Vasiliy Kulikov
2011-09-29 16:30 ` Dave Hansen
2011-09-29 16:43 ` [kernel-hardening] " Vasiliy Kulikov
2011-09-29 16:57 ` Valdis.Kletnieks
2011-09-29 17:25 ` Vasiliy Kulikov [this message]
2011-09-29 17:28 ` Vasiliy Kulikov
2011-09-28 21:46 ` Andrew Morton
2011-09-30 19:53 ` Vasiliy Kulikov
2011-09-30 20:03 ` Andrew Morton
2011-09-30 20:12 ` Vasiliy Kulikov
2011-09-30 20:15 ` Dave Hansen
2011-09-27 18:08 ` [PATCH 1/2] mm: restrict access to slab files under procfs and sysfs Christoph Lameter
2011-09-27 19:16 ` Vasiliy Kulikov
2011-09-27 19:35 ` Christoph Lameter
2011-09-27 18:21 ` David Rientjes
2011-09-27 20:00 ` Pekka Enberg
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