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Date: Mon, 19 Sep 2011 21:21:15 +0300
From: Pekka Enberg <>
To: Dave Hansen <>
Cc: Vasiliy Kulikov <>, Andrew Morton <>,, Kees Cook <>, 
	Cyrill Gorcunov <>, Al Viro <>, 
	Christoph Lameter <>, Matt Mackall <>,,, Dan Rosenberg <>, Theodore Tso <>, 
	Alan Cox <>, Jesper Juhl <>, 
	Linus Torvalds <>
Subject: Re: Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo

On Mon, 2011-09-19 at 20:51 +0300, Pekka Enberg wrote:
>> How is the attacker able to identify that we kmalloc()'d from ecryptfs or
>> VFS based on non-root /proc/slabinfo when the slab allocator itself does
>> not have that sort of information if you mix up the allocations? Isn't this
>> much stronger protection especially if you combine that with /proc/slabinfo
>> restriction?

On Mon, Sep 19, 2011 at 9:03 PM, Dave Hansen <> wrote:
> Mixing it up just adds noise.  It makes the attack somewhat more
> difficult, but it still leaves open the possibility that the attacker
> can filter out the noise somehow.

So that would mean the attacker has somewhat fine-grained control over
kernel memory allocations, no? Can they use /proc/meminfo to deduce
the same kind of information? Should we close that down too?


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