linux-kernel - Re: [RFC] fs, proc: Introduce the /proc/<pid>/map

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Message-ID: <4E566093.8080707@parallels.com>
Date:	Thu, 25 Aug 2011 18:47:47 +0400
From:	Pavel Emelyanov <xemul@...allels.com>
To:	Andi Kleen <andi@...stfloor.org>
CC:	Zan Lynx <zlynx@....org>, Cyrill Gorcunov <gorcunov@...il.com>,
	Nathan Lynch <ntl@...ox.com>,
	Oren Laadan <orenl@...columbia.edu>,
	Daniel Lezcano <dlezcano@...ibm.com>,
	Tejun Heo <tj@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Glauber Costa <glommer@...allels.com>,
	"containers@...ts.osdl.org" <containers@...ts.osdl.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Serge Hallyn <serge.hallyn@...onical.com>,
	LINUXFS-ML <linux-fsdevel@...r.kernel.org>,
	James Bottomley <jbottomley@...allels.com>
Subject: Re: [RFC] fs, proc: Introduce the /proc/<pid>/map_files/ directory
 v2

On 08/25/2011 06:04 PM, Andi Kleen wrote:
> On Thu, Aug 25, 2011 at 10:42:44AM +0400, Pavel Emelyanov wrote:
>> On 08/24/2011 09:36 PM, Andi Kleen wrote:
>>> Pavel Emelyanov <xemul@...allels.com> writes:
>>>>
>>>> No and this is the trick - when you readlink it - it give you trash, but
>>>> when you open one - you get exactly the same file as the map points to.
>>>
>>> Isn't that a minor security hole?
>>>
>>> For example if I pass a file descriptor into a chroot process for
>>> reading, and with this interface you can open it for writing too.
>>> I could see this causing problems.
>>
>> How does it differ from the /proc/pid/fd links?
> 
> Those cannot be opened I thought.

Neither can be these links then - I use the same access checks in my code.

> -Andi
> 

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