From: Andreas Gruenbacher <agruen@suse.de>
Organization: SUSE Labs, Novell
To: Tetsuo Handa <from-lsm@i-love.sakura.ne.jp>
Subject: Re: [AppArmor 01/41] Pass struct vfsmount to the inode_create LSMhook
Date: Tue, 29 May 2007 19:07:29 +0200
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On Tuesday 29 May 2007 12:46, Tetsuo Handa wrote:
> But, from the pathname-based access control's point of view,
> bind mount interferes severely with pathname-based access control
> because it is impossible to determine which pathname was requested.

Wrong. It is very well possible to determine the path of a particular dentry 
(+ vfsmount) with bind mounts.

> Although both pathnames point to the same object, TOMOYO focuses on the
> PROCEDURE FOR REACHING AN OBJECT and being able to know the procedure is
> very important.

This doesn't make sense, either. With the following sequence of syscalls of 
processes A and B (both of them in the namespace root),

	A:				B:
	mkdir("/tmp/a")
	chdir("/tmp/a")
					rename("/tmp/a", "/tmp/b")
	creat("f")

the path being checked for the creat call must be "/tmp/b/f", even though 
process A never explicitly used "b". If that's not what TOMOYO is doing, then 
that's badly broken.

Andreas
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