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From: "J. Bruce Fields" <bfields@fieldses.org>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Jan Engelhardt <jengelh@computergmbh.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: NFS4 authentification / fsuid
Date: Thu, 30 Aug 2007 17:44:31 -0400	[thread overview]
Message-ID: <20070830214431.GF10808@fieldses.org> (raw)
In-Reply-To: <1188486240.6755.51.camel@heimdal.trondhjem.org>

On Thu, Aug 30, 2007 at 11:04:00AM -0400, Trond Myklebust wrote:
> With CIFS or other password based protocols (including RPCSEC_GSS)

Well, rpcsec_gss isn't inherently password based, and you can
authenticate in some way that doesn't actually give away your password
(or other long-lived credential).

> What I'm saying is that the superuser can pretty much do whatever it
> takes to grab either your kerberos password (e.g. install a keyboard
> listener), a stored credential (read the contents of your kerberos
> on-disk credential cache), or s/he can access the cached contents of the
> file by hunting through /dev/kmem.
> 
> IOW: There is no such thing as security on a root-compromised machine.

And in theory a kernel could provide *some* guarantees against root,
right?  (Is there some reason a unix-like kernel must provide such
things as /dev/kmem?)

--b.

  reply	other threads:[~2007-08-30 21:44 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-08-30 14:12 NFS4 authentification / fsuid Jan Engelhardt
2007-08-30 14:29 ` Trond Myklebust
2007-08-30 14:32   ` Trond Myklebust
2007-08-30 14:42     ` Jan Engelhardt
2007-08-30 15:04       ` Trond Myklebust
2007-08-30 21:44         ` J. Bruce Fields [this message]
2007-09-06  8:14           ` Satyam Sharma
2007-09-06  8:29             ` Satyam Sharma
2007-09-06 15:11               ` J. Bruce Fields
2007-09-06 23:21                 ` Trond Myklebust
2007-09-06 23:32                   ` Trond Myklebust
2007-09-07 15:34                     ` J. Bruce Fields
2007-09-18 23:27                       ` Satyam Sharma
2007-09-18 23:12                 ` Satyam Sharma
2007-09-06 15:06             ` J. Bruce Fields
2007-09-06 23:30               ` Kyle Moffett
2007-09-06 23:35                 ` Trond Myklebust
2007-09-07  0:56                   ` Kyle Moffett
2007-09-07  5:14                     ` Trond Myklebust
2007-09-07  5:47                       ` Kyle Moffett
2007-09-07  6:37                         ` Bernd Eckenfels
2007-09-18 23:48                         ` Satyam Sharma
2007-09-18 23:44                     ` Satyam Sharma
2007-09-19  5:16                       ` Kyle Moffett
2007-09-19 12:16                         ` Satyam Sharma
2007-09-19 13:49                           ` Kyle Moffett
2007-09-19 14:12                             ` Satyam Sharma
2007-09-19 15:01                               ` J. Bruce Fields
2007-09-20  7:03                                 ` Satyam Sharma
2007-09-19 16:38                         ` Valdis.Kletnieks
2007-09-20  7:15                           ` Satyam Sharma
2007-08-30 15:12       ` J. Bruce Fields

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