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From: Pavel Machek <pavel@ucw.cz>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>,
	Jan Kara <jack@suse.cz>, "J. Bruce Fields" <bfields@fieldses.org>,
	"Serge E. Hallyn" <serue@us.ibm.com>,
	kernel list <linux-kernel@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
	jamie@shareable.org
Subject: Re: symlinks with permissions
Date: Fri, 30 Oct 2009 19:35:59 +0100	[thread overview]
Message-ID: <20091030183559.GF7008@elf.ucw.cz> (raw)
In-Reply-To: <m1d4466uel.fsf@fess.ebiederm.org>

Hi!

> > Basically, that follow link should behave as dup(), not as open().
> 
> There are reasons why an open is an open here.  I don't remember the
> details but I found the archive of that conversation once.  Maybe it was
> just technical limitations of the time.

That would be really really useful to bring 

> >> I certainly am not interested in debugging or maintaining the stacking
> >> inode code that would be necessary to close this theoretical corner
> >> case.  There are much more real bugs that need attention.
> >
> > But if we can get trivial 10-liner, that should be acceptable, right?
> 
> How many linux shell scripts and other applications that use /dev/fd/N
> or /proc/self/fd/N will you be breaking?

Zero. (Well unless someone is exploiting it in wild).

> Closing a theoretical security hole at the expense of breaking real
> applications is a show stopper.

I don't plan to remove /proc/*/fd; but I would like it to behave like
dup().

(I still hope some security team does work for me :-).
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

  reply	other threads:[~2009-10-30 18:35 UTC|newest]

Thread overview: 27+ 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 [this message]
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
2009-10-26 18:02         ` J. Bruce Fields
2009-10-26 17:57       ` Serge E. Hallyn

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