Re: [PATCH V3] mm: Add sysfs interface to dump each node's zonelist information

From: Anshuman Khandual
Date: Wed Sep 07 2016 - 00:00:23 EST


On 09/07/2016 08:38 AM, Kees Cook wrote:
> On Tue, Sep 6, 2016 at 1:36 PM, Dave Hansen <dave.hansen@xxxxxxxxx> wrote:
>> On 09/06/2016 01:31 AM, Anshuman Khandual wrote:
>>> [NODE (0)]
>>> ZONELIST_FALLBACK
>>> (0) (node 0) (zone DMA c00000000140c000)
>>> (1) (node 1) (zone DMA c000000100000000)
>>> (2) (node 2) (zone DMA c000000200000000)
>>> (3) (node 3) (zone DMA c000000300000000)
>>> ZONELIST_NOFALLBACK
>>> (0) (node 0) (zone DMA c00000000140c000)
>>
>> Don't we have some prohibition on dumping out kernel addresses like this
>> so that attackers can't trivially defeat kernel layout randomization?
>
> Anything printing memory addresses should be using %pK (not %lx as done here).

Learned about the significance of %pK coupled with kptr_restrict
interface. Will change this. Thanks for pointing out.