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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

WARNING: multiple messages have this Message-ID (diff)
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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  reply	other threads:[~2011-09-29 17:25 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-27 17:54 [kernel-hardening] [PATCH 1/2] mm: restrict access to slab files under procfs and sysfs Vasiliy Kulikov
2011-09-27 17:54 ` Vasiliy Kulikov
2011-09-27 17:54 ` Vasiliy Kulikov
2011-09-27 17:56 ` [kernel-hardening] [PATCH 2/2] mm: restrict access to /proc/meminfo Vasiliy Kulikov
2011-09-27 17:56   ` Vasiliy Kulikov
2011-09-27 17:56   ` Vasiliy Kulikov
2011-09-27 18:27   ` [kernel-hardening] " David Rientjes
2011-09-27 18:27     ` David Rientjes
2011-09-27 18:27     ` David Rientjes
2011-09-27 19:14     ` [kernel-hardening] " Vasiliy Kulikov
2011-09-27 19:14       ` Vasiliy Kulikov
2011-09-27 19:14       ` Vasiliy Kulikov
2011-09-27 19:38   ` [kernel-hardening] " Vasiliy Kulikov
2011-09-27 19:38     ` Vasiliy Kulikov
2011-09-27 19:38     ` Vasiliy Kulikov
2011-09-27 20:03     ` [kernel-hardening] " Christoph Lameter
2011-09-27 20:03       ` Christoph Lameter
2011-09-27 20:03       ` Christoph Lameter
2011-09-27 20:33       ` [kernel-hardening] " David Rientjes
2011-09-27 20:33         ` David Rientjes
2011-09-27 20:33         ` David Rientjes
2011-09-27 20:47         ` [kernel-hardening] " Christoph Lameter
2011-09-27 20:47           ` Christoph Lameter
2011-09-27 20:47           ` Christoph Lameter
2011-09-28 20:31           ` [kernel-hardening] " Dave Hansen
2011-09-28 20:31             ` Dave Hansen
2011-09-28 20:31             ` Dave Hansen
2011-09-28 20:52             ` [kernel-hardening] " Alan Cox
2011-09-28 20:52               ` Alan Cox
2011-09-28 20:52               ` Alan Cox
2011-09-29  0:43             ` [kernel-hardening] " Valdis.Kletnieks
2011-09-29  0:43               ` Valdis.Kletnieks
2011-09-29 14:11               ` [kernel-hardening] " Christoph Lameter
2011-09-29 14:11                 ` Christoph Lameter
2011-09-29 14:11                 ` Christoph Lameter
2011-09-29 16:18         ` [kernel-hardening] " Vasiliy Kulikov
2011-09-29 16:18           ` Vasiliy Kulikov
2011-09-29 16:18           ` Vasiliy Kulikov
2011-09-29 16:30           ` [kernel-hardening] " Dave Hansen
2011-09-29 16:30             ` Dave Hansen
2011-09-29 16:30             ` Dave Hansen
2011-09-29 16:43             ` [kernel-hardening] " Vasiliy Kulikov
2011-09-29 16:43               ` Vasiliy Kulikov
2011-09-29 16:57           ` Valdis.Kletnieks
2011-09-29 16:57             ` Valdis.Kletnieks
2011-09-29 17:25             ` Vasiliy Kulikov [this message]
2011-09-29 17:25               ` [kernel-hardening] " Vasiliy Kulikov
2011-09-29 17:28           ` Vasiliy Kulikov
2011-09-29 17:28             ` Vasiliy Kulikov
2011-09-29 17:28             ` Vasiliy Kulikov
2011-09-28 21:46     ` [kernel-hardening] " Andrew Morton
2011-09-28 21:46       ` Andrew Morton
2011-09-28 21:46       ` Andrew Morton
2011-09-30 19:53       ` [kernel-hardening] " Vasiliy Kulikov
2011-09-30 19:53         ` Vasiliy Kulikov
2011-09-30 19:53         ` Vasiliy Kulikov
2011-09-30 20:03         ` [kernel-hardening] " Andrew Morton
2011-09-30 20:03           ` Andrew Morton
2011-09-30 20:03           ` Andrew Morton
2011-09-30 20:12           ` [kernel-hardening] " Vasiliy Kulikov
2011-09-30 20:12             ` Vasiliy Kulikov
2011-09-30 20:12             ` Vasiliy Kulikov
2011-09-30 20:15           ` [kernel-hardening] " Dave Hansen
2011-09-30 20:15             ` Dave Hansen
2011-09-30 20:15             ` Dave Hansen
2011-09-27 18:08 ` [kernel-hardening] Re: [PATCH 1/2] mm: restrict access to slab files under procfs and sysfs Christoph Lameter
2011-09-27 18:08   ` Christoph Lameter
2011-09-27 18:08   ` Christoph Lameter
2011-09-27 19:16   ` [kernel-hardening] " Vasiliy Kulikov
2011-09-27 19:16     ` Vasiliy Kulikov
2011-09-27 19:16     ` Vasiliy Kulikov
2011-09-27 19:35     ` [kernel-hardening] " Christoph Lameter
2011-09-27 19:35       ` Christoph Lameter
2011-09-27 19:35       ` Christoph Lameter
2011-09-27 18:21 ` [kernel-hardening] " David Rientjes
2011-09-27 18:21   ` David Rientjes
2011-09-27 18:21   ` David Rientjes
2011-09-27 20:00   ` [kernel-hardening] " Pekka Enberg
2011-09-27 20:00     ` Pekka Enberg
2011-09-27 20:00     ` Pekka Enberg

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