From: Dan Rosenberg <drosenberg@vsecurity.com>
To: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Dave Hansen <dave@linux.vnet.ibm.com>,
Theodore Tso <tytso@mit.edu>,
cl@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] Make /proc/slabinfo 0400
Date: Fri, 04 Mar 2011 16:44:02 -0500 [thread overview]
Message-ID: <1299275042.2071.1422.camel@dan> (raw)
In-Reply-To: <AANLkTina+O77BFV+7mO9fX2aJimpO0ov_MKwxGtMwqG+@mail.gmail.com>
On Fri, 2011-03-04 at 23:30 +0200, Pekka Enberg wrote:
> Right. So you fill a slab with objects A that you want to overflow
> (struct shmid_kernel in the example exploit) then free one of them,
> allocate object B, smash it (and the next object), and find the
> smashed object A.
>
> But doesn't that make the whole /slab/procinfo discussion moot? You
> can always use brute force to allocate N objects (where N is larger
> than max objects in a slab) and then just free nth object that's most
> likely to land on the slab you have full control over (as explained by
> Matt).
>
> Pekka
This is a good point, and one that I've come to accept as a result of
having this conversation. Consider the patch dropped, unless there are
other reasons I've missed. I still think it's worth brainstorming
techniques for hardening the kernel heap in ways that don't create
performance impact, but I admit that the presence or absence of this
debugging information isn't a crucial factor in successful exploitation.
Thanks,
Dan
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next prev parent reply other threads:[~2011-03-04 21:44 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-03 17:50 [PATCH] Make /proc/slabinfo 0400 Dan Rosenberg
2011-03-03 18:17 ` Dave Hansen
2011-03-03 18:29 ` Dan Rosenberg
2011-03-03 20:58 ` Matt Mackall
2011-03-03 21:16 ` Dan Rosenberg
2011-03-03 21:44 ` Matt Mackall
2011-03-03 22:30 ` Dan Rosenberg
2011-03-03 23:08 ` Matt Mackall
2011-03-04 0:32 ` Dave Hansen
2011-03-04 0:50 ` Theodore Tso
2011-03-04 6:52 ` Pekka Enberg
2011-03-04 17:36 ` Dave Hansen
2011-03-04 17:48 ` Linus Torvalds
2011-03-04 18:14 ` Matt Mackall
2011-03-04 20:02 ` Pekka Enberg
2011-03-04 20:31 ` Matt Mackall
2011-03-04 20:42 ` Dan Rosenberg
2011-03-04 20:56 ` Pekka Enberg
2011-03-04 21:08 ` Dan Rosenberg
2011-03-04 21:30 ` Pekka Enberg
2011-03-04 21:44 ` Dan Rosenberg [this message]
2011-03-04 22:10 ` Pekka Enberg
2011-03-04 22:14 ` Pekka Enberg
2011-03-04 23:02 ` Matt Mackall
2011-03-05 16:25 ` Ted Ts'o
2011-03-06 13:19 ` Alan Cox
2011-03-07 14:56 ` Dan Rosenberg
2011-03-07 16:02 ` Matt Mackall
2011-03-04 20:37 ` Dan Rosenberg
2011-03-04 20:58 ` Pekka Enberg
2011-03-04 21:10 ` Dan Rosenberg
2011-03-06 0:42 ` Jesper Juhl
2011-03-06 0:57 ` Dan Rosenberg
2011-03-06 1:09 ` Matt Mackall
2011-03-06 1:15 ` Jesper Juhl
2011-03-07 16:40 ` Christoph Lameter
2011-03-04 21:12 ` Matt Mackall
2011-03-04 11:58 ` Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2011-03-07 14:19 [PATCH] Make /proc/slabinfo 040 George Spelvin
2011-03-07 17:49 ` [PATCH] Make /proc/slabinfo 0400 George Spelvin
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