From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Matt Helsley <matthltc@us.ibm.com>
Cc: Pavel Emelyanov <xemul@parallels.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Glauber Costa <glommer@parallels.com>,
Andi Kleen <andi@firstfloor.org>, Tejun Heo <tj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/4] Checkpoint/Restore: Show in proc IDs of objects that can be shared between tasks
Date: Wed, 16 Nov 2011 10:19:23 +0400 [thread overview]
Message-ID: <20111116061923.GB15492@moon> (raw)
In-Reply-To: <20111116054427.GA14827@count0.beaverton.ibm.com>
On Tue, Nov 15, 2011 at 09:44:27PM -0800, Matt Helsley wrote:
...
> >
> > The object address is XOR-ed with a "random" value of the same size and then
> > shown in proc. Providing this poison is not leaked into the userspace then
> > ID seem to be safe.
>
> Really? There's no way to quickly derive the random number from known
> allocation patterns and thereby break the obfuscation scheme?
> To start we can note that the low N bits are directly exposed in the ID
> of anything that requires 2^N-byte alignment.
>
> I think it's really a question of whether the high order bits can be derived.
>
Good point. I suppose we might use 2 random numbers here, one for xor and
second to shuffle bits.
> And of course the random number only needs to be derived once per boot
> before it reveals the address of everything with an ID.
Cyrill
next prev parent reply other threads:[~2011-11-16 6:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-15 11:35 [PATCH 0/4] Checkpoint/Restore: Show in proc IDs of objects that can be shared between tasks Pavel Emelyanov
2011-11-15 11:36 ` [PATCH 1/4] Routine for generating an safe ID for kernel pointer Pavel Emelyanov
2011-11-15 11:38 ` Pekka Enberg
2011-11-15 11:44 ` Pavel Emelyanov
2011-11-15 11:51 ` Pekka Enberg
2011-11-15 15:13 ` Eric Dumazet
2011-11-15 15:20 ` Tejun Heo
2011-11-15 11:36 ` [PATCH 2/4] proc: Show namespaces IDs in /proc/pid/ns/* files Pavel Emelyanov
2011-11-15 11:37 ` [PATCH 3/4] proc: Show open file ID in /proc/pid/fdinfo/* Pavel Emelyanov
2011-11-16 5:44 ` [PATCH 0/4] Checkpoint/Restore: Show in proc IDs of objects that can be shared between tasks Matt Helsley
2011-11-16 6:19 ` Cyrill Gorcunov [this message]
2011-11-16 8:25 ` Pavel Emelyanov
2011-11-18 23:25 ` Matt Helsley
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