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From: Pavel Machek <pavel@ucw.cz>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: David Wagner <daw-news@cs.berkeley.edu>, linux-kernel@vger.kernel.org
Subject: Re: symlinks with permissions
Date: Fri, 30 Oct 2009 15:07:45 +0100	[thread overview]
Message-ID: <20091030140745.GC1481@ucw.cz> (raw)
In-Reply-To: <4AE91658.9090105@schaufler-ca.com>

Hi!


> > Perhaps take a look at Pavel's post describing the attack again?
> 
> Yeah, I did that. It still looks like the complaint is that
> /proc/8675309/fd/3 gives you the ability to gain RW access to
> an object for which you have RW access.
> 
> Look, with hard links and the various mount options available
> today you just can't count on setting the mode on a directory
> to completely protect the files that it references. Look carefully

Look again. I can count on paths if I can prevent mounts and
hardlinks. Mounts are irrelevant as they are root-only, and I was
checking for hardlinks.

> Now, ask me if I think that /proc/8675309/fd/3 is a good idea,
> and we'll have a different discussion, but from an old school

Cool, so we actually agree, and can drop this thread?
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

  parent reply	other threads:[~2009-10-30 14:07 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-25  6:29 symlinks with permissions Pavel Machek
2009-10-26 16:31 ` Jan Kara
2009-10-26 16:57   ` Serge E. Hallyn
2009-10-26 17:36     ` J. Bruce Fields
2009-10-26 17:46       ` Jan Kara
2009-10-26 17:57         ` Trond Myklebust
2009-10-25  9:36           ` Pavel Machek
2009-10-26 18:22             ` Trond Myklebust
2009-10-27  8:11               ` Pavel Machek
2009-10-27 10:27                 ` Jamie Lokier
2009-10-26 18:35             ` J. Bruce Fields
2009-10-28  4:15             ` Eric W. Biederman
2009-10-28  8:16               ` Pavel Machek
2009-10-28 11:25                 ` Eric W. Biederman
2009-10-28 21:03                   ` Pavel Machek
2009-10-29  2:20                     ` Eric W. Biederman
2009-10-29 11:03                       ` Pavel Machek
2009-10-29 16:23                         ` Eric W. Biederman
2009-10-30 18:35                           ` Pavel Machek
2009-10-30 20:37                             ` Nick Bowler
2009-10-30 23:03                             ` Eric W. Biederman
2009-10-31  2:30                               ` Jamie Lokier
2009-10-28 16:34                 ` Casey Schaufler
2009-10-28 19:44                   ` Jamie Lokier
2009-10-28 21:06                   ` Pavel Machek
2009-10-28 22:48                   ` David Wagner
2009-10-29  4:13                     ` Casey Schaufler
2009-10-29  7:53                       ` David Wagner
2009-10-30 14:07                       ` Pavel Machek [this message]
2009-10-31  4:09                         ` Casey Schaufler
2009-11-01  9:23                           ` David Wagner
2009-11-01 17:43                             ` Casey Schaufler
2009-11-01 20:39                               ` David Wagner
2009-11-01 22:05                                 ` Casey Schaufler
2009-10-26 18:02         ` J. Bruce Fields
2009-10-26 17:57       ` Serge E. Hallyn

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