Re: [PATCH] Make /proc/slabinfo 0400

Pekka Enberg
2011-03-04T22:14:59Z

On Sat, Mar 5, 2011 at 12:10 AM, Pekka Enberg <penberg@kernel.org> wrote:
> I can think of four things that will make things harder for the
> attacker (in the order of least theoretical performance impact):
>
>  (1) disable slub merging
>
>  (2) pin down random objects in the slab during setup (i.e. don't
> allow them to be allocated)
>
>  (3) randomize the initial freelist
>
>  (4) randomize padding between objects in a slab
>
> AFAICT, all of them will make brute force attacks using the kernel
> heap as an attack vector harder but won't prevent them.

There's also a fifth one:

(5) randomize slab page allocation order

which will make it harder to make sure you have full control over a
slab and figure out which allocation lands on it.

Pekka