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From: Nick Bowler <nbowler@elliptictech.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	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 16:37:15 -0400	[thread overview]
Message-ID: <20091030203715.GA28901@emergent.ellipticsemi.com> (raw)
In-Reply-To: <20091030183559.GF7008@elf.ucw.cz>

On 19:35 Fri 30 Oct     , Pavel Machek wrote:
> > 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).

I've definitely written at least one script before that does something
along the lines of 'echo foo > /dev/fd/N'.  It's not one that I remember
anything else about, so perhaps its behaviour would be unaffected by
forbidding this if the particular file descriptor did not originally
have read-write permissions.  I have a hard time believing that amongst
millions of users, not one of them has a script that would be affected.

Frankly, I don't understand what is particularly surprising about the
fact that people can write to files with world write permissions.

-- 
Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)

  reply	other threads:[~2009-10-30 20:37 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
2009-10-30 20:37                             ` Nick Bowler [this message]
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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