linux-kernel - Re: [AppArmor 00/44] AppArmor security module overview

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 27 Jun 2007 15:37:10 +0200
From:	Andreas Gruenbacher <agruen@...e.de>
To:	Kyle Moffett <mrmacman_g4@....com>
Cc:	John Johansen <jjohansen@...e.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Subject: Re: [AppArmor 00/44] AppArmor security module overview

On Wednesday 27 June 2007 12:58, Kyle Moffett wrote:
> I seem to recall you could actually end up racing and building a path
> to the file in those directories as "a/d/0/3" or some other path at
> which it never even remotely existed. I'd love to be wrong,

Cheer up, you recall wrong.

> but I can't help but see this problem in any reverse-pathname-generation
> proposal which gets the locking right.

Have a look at how __d_path() is implemented (with the fixes): It takes the 
dcache_lock, and the vfsmount_lock where necessary, and this ensures that the 
pathname can't change under it, neither because of a rename nor unlink nor 
remount. The pathname computed is *exactly* the name the file has at that 
specific point time.

A few more details about how pathnames work are explained in the tech doc at:
http://forge.novell.com/modules/xfcontent/downloads.php/apparmor/LKML_Submission-May_07

Andreas
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/