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

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Message-ID: <CAGXu5jK_sKa2dcVrwhXdp=ZA=ACEY6vmd-LDoy8KmMtCn_aDzw@mail.gmail.com>
Date:   Tue, 6 Sep 2016 20:08:18 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Dave Hansen <dave.hansen@...el.com>,
        Anshuman Khandual <khandual@...ux.vnet.ibm.com>
Cc:     Linux-MM <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH V3] mm: Add sysfs interface to dump each node's zonelist information

On Tue, Sep 6, 2016 at 1:36 PM, Dave Hansen <dave.hansen@...el.com> 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).

-Kees

-- 
Kees Cook
Nexus Security