linux-kernel - Re: [PATCH] KERNEL: resource: Fix bug on leakage in /proc/iomem file

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Date:	Thu, 14 Apr 2016 03:39:05 -0400
From:	Emrah Demir <ed@...sec.com>
To:	Kees Cook <keescook@...omium.org>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Dan Rosenberg <dan.j.rosenberg@...il.com>,
	kernel-hardening@...ts.openwall.com, Dave Jones <davej@...hat.com>,
	keescook@...gle.com
Subject: Re: [PATCH] KERNEL: resource: Fix bug on leakage in /proc/iomem file

On 2016-04-14 00:27, Kees Cook wrote:
> On Wed, Apr 6, 2016 at 2:19 PM, Linus Torvalds
> <torvalds@...ux-foundation.org> wrote:
>> On Wed, Apr 6, 2016 at 10:54 AM, Linus Torvalds
>> <torvalds@...ux-foundation.org> wrote:
>>> 
>>> So I'd find a patch like the attached to be perfectly acceptable (in
>>> fact, we should have done this long ago).
>> 
>> I just committed it, let's see if some odd program uses the iomem
>> data. I doubt it, and I always enjoy improvements that remove more
>> lines of code than they add.
> 
> Hrm, it looks like at least Ubuntu's kernel security test suite
> expects to find these entries (when it verifies that STRICT_DEVMEM
> hasn't regressed). Also, the commit only removed the entries on x86.
> Most (all?) of the other architectures still have them. Could you
> revert this for now, and I'll cook up a %pK-based solution for -next?
> 

Actually, I have realized that this patch (Linus's patch) was for x86. I 
was planning to code the same for other architectures.
It seems your method is better. %pK will zero other values in 
/proc/iomem.

Perhaps Ubuntu patch might be a good option.