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From: Eric Lammerts <eric@lammerts.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Marc Ballarin <Ballarin.Marc@gmx.de>, Greg KH <greg@kroah.com>,
	albert@users.sourceforge.net,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: dynamic /dev security hole?
Date: Mon, 9 Aug 2004 12:47:15 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.58.0408091238080.8693@vivaldi.madbase.net> (raw)
In-Reply-To: <1092065586.14144.31.camel@localhost.localdomain>


I guess I'm missing something here...

On Mon, 9 Aug 2004, Alan Cox wrote:
> User closes device
> I have linked copy (not open)
> Device unloaded

At this point, udev (with the chown/chmod patch) would chown your
linked copy (before unlinking the original device node), right?

> I open the linked copy

So this wouldn't work.

> This makes new device load for me.
>
>
> I'm just trying to point out that the order of operations matters here
> because the old nodes must all be dead before the new device. Its even
> worse for less dynamic numbering.

The only problem I can think of is a race when a new device appears
with the same major/minor before udev gets a chance to do its stuff,
eg.

1) User closes device
2) I have linked copy (not open)
3) Device unloaded
4) New device appears
5) I open the linked copy
6) Udev chowns/chmods old device node (triggered by 3)) --> too late

Eric

  reply	other threads:[~2004-08-09 16:47 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-08-08 12:47 dynamic /dev security hole? Albert Cahalan
2004-08-08 15:58 ` Marc Ballarin
2004-08-08 15:04   ` Albert Cahalan
2004-08-08 20:42     ` Greg KH
2004-08-08 16:21   ` Greg KH
2004-08-08 21:43     ` Marc Ballarin
2004-08-08 22:07     ` Marc Ballarin
2004-08-09  4:40       ` Eric Lammerts
2004-08-09 13:30         ` Michael Buesch
2004-08-09 13:19           ` Albert Cahalan
2004-08-09 16:54             ` Michael Buesch
2004-08-09 17:04               ` Eric Lammerts
2004-08-09 17:14                 ` Michael Buesch
2004-08-10  0:21                   ` Greg KH
2004-08-11 17:12             ` [RFC, PATCH] sys_revoke(), just a try. (was: Re: dynamic /dev security hole?) Michael Buesch
2004-08-12 16:49               ` Michael Buesch
2004-08-12 19:51                 ` Alan Cox
2004-08-12 19:39                   ` Albert Cahalan
2004-08-13 12:39                   ` Michael Buesch
2004-08-09 14:49         ` dynamic /dev security hole? Alan Cox
2004-08-09 16:17           ` Eric Lammerts
2004-08-09 15:33             ` Alan Cox
2004-08-09 16:47               ` Eric Lammerts [this message]
2004-08-09 17:54                 ` Alan Cox
2004-08-10  0:21       ` Greg KH

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