From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cyrill Gorcunov <gorcunov@gmail.com>
Subject: Re: [patch 2/2] fs, proc: Introduce the /proc/<pid>/map_files/
 directory v6
Date: Wed, 31 Aug 2011 14:12:26 +0400
Message-ID: <20110831101226.GB25465@sun>
References: <20110831075814.003575573@openvz.org>
 <20110831080229.100652529@openvz.org>
 <20110831090612.GA3253@albatros>
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Cc: containers@lists.osdl.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, Nathan Lynch <ntl@pobox.com>,
	Oren Laadan <orenl@cs.columbia.edu>,
	Daniel Lezcano <dlezcano@fr.ibm.com>,
	Glauber Costa <glommer@parallels.com>,
	James Bottomley <jbottomley@parallels.com>,
	Tejun Heo <tj@kernel.org>,
	"Kirill A. Shutemov" <kirill@shutemov.name>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Al Viro <viro@ZenIV.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Pavel Emelyanov <xemul@parallels.com>
To: Vasiliy Kulikov <segoon@openwall.com>
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On Wed, Aug 31, 2011 at 01:06:12PM +0400, Vasiliy Kulikov wrote:
> Hi,
> 
> On Wed, Aug 31, 2011 at 11:58 +0400, Cyrill Gorcunov wrote:
> > From: Pavel Emelyanov <xemul@parallels.com>
> > 
> > This one behaves similarly to the /proc/<pid>/fd/ one - it contains symlinks
> > one for each mapping with file, the name of a symlink is "vma->vm_start-vma->vm_end",
> > the target is the file. Opening a symlink results in a file that point exactly
> > to the same inode as them vma's one.
> 
> I'm late noting it before the RFCv6 :)  Besides checking
> ptrace_may_access() on ->lookup and ->readdir you also should define
> ->stat, otherwise you can bypass ptrace checks if there is a
> corresponding dentry in the cache.  The same issue existed in fd* handlers:
> 
> http://www.openwall.com/lists/kernel-hardening/2011/08/29/1
> 

Yeah, good point, thanks Vasiliy.

	Cyrill