Re: [kernel-hardening] Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo

[Pekka Enberg]

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 <dave@xxxxxxxxxxxxxxxxxx> 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?

                         Pekka
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