From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: David Wagner <daw-usenet@taverner.cs.berkeley.edu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC/PATCH] revoke/frevoke system calls V2
Date: Tue, 08 Aug 2006 13:13:20 +0100 [thread overview]
Message-ID: <1155039200.5729.18.camel@localhost.localdomain> (raw)
In-Reply-To: <eb8g8b$837$1@taverner.cs.berkeley.edu>
Ar Llu, 2006-08-07 am 22:52 +0000, ysgrifennodd David Wagner:
> I'm still trying to understand the semantics of this proposed
> frevoke() implementation. Can an attacker use this to forcibly
> close some other processes' file descriptor? Suppose the target
No.
> process has fd 0 open and the attacker revokes the file corresponding
> to fd 0; what is the state of fd 0 in the target process? Is it
> closed? If the target process then open()s another file, does it
No its revoked. Just like a tty hangup
> get bound to fd 0? (Recall that open() always binds to the lowest
> unused fd.) If the answers are "yes", then the security consequences
> seem very scary.
Of course it doesn't. The BSD folk who added revoke were security people
not idiots.
Alan
next prev parent reply other threads:[~2006-08-08 11:53 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-27 14:25 [RFC/PATCH] revoke/frevoke system calls V2 Pekka J Enberg
2006-07-27 15:07 ` Alan Cox
2006-07-27 15:33 ` Pekka Enberg
2006-07-27 16:09 ` Alan Cox
2006-07-27 16:01 ` Pekka J Enberg
2006-07-27 16:30 ` Alan Cox
2006-07-27 17:07 ` Pekka J Enberg
2006-07-27 18:27 ` Pekka Enberg
2006-07-27 16:41 ` Ulrich Drepper
2006-07-27 17:05 ` Pekka J Enberg
2006-07-27 17:13 ` Ulrich Drepper
2006-07-27 17:33 ` H. Peter Anvin
2006-07-27 17:44 ` Ulrich Drepper
2006-07-27 18:00 ` H. Peter Anvin
2006-07-27 17:33 ` Alan Cox
2006-07-27 17:33 ` O_CAREFUL flag to disable open() side effects H. Peter Anvin
2006-07-27 17:43 ` Russell King
2006-07-27 17:50 ` Ulrich Drepper
2006-07-27 18:05 ` Alan Cox
2006-07-27 18:03 ` H. Peter Anvin
2006-07-27 18:14 ` Joshua Hudson
2006-08-05 21:05 ` [RFC/PATCH] revoke/frevoke system calls V2 Pavel Machek
2006-07-27 18:06 ` Petr Baudis
2006-07-27 18:10 ` Pekka Enberg
2006-07-27 19:30 ` Horst H. von Brand
2006-07-28 3:40 ` Pekka J Enberg
2006-07-27 18:34 ` Alan Cox
2006-08-05 12:29 ` Pavel Machek
2006-08-07 5:42 ` Pekka J Enberg
2006-08-07 8:17 ` Edgar Toernig
2006-08-07 9:51 ` Pekka Enberg
2006-08-07 20:41 ` Edgar Toernig
2006-08-07 22:24 ` Chase Venters
2006-08-08 12:15 ` Alan Cox
2006-08-09 8:41 ` Edgar Toernig
2006-08-09 10:39 ` Alan Cox
2006-08-09 18:00 ` Edgar Toernig
2006-08-09 18:36 ` Alan Cox
2006-08-09 19:13 ` Pekka Enberg
2006-08-09 20:08 ` Edgar Toernig
2006-08-09 21:29 ` Edgar Toernig
2006-08-11 7:52 ` Helge Hafting
2006-08-07 22:52 ` David Wagner
2006-08-07 22:56 ` Daniel Jacobowitz
2006-08-07 23:12 ` Chase Venters
2006-08-08 12:16 ` Pekka Enberg
2006-08-08 16:02 ` Kari Hurtta
2006-08-08 21:54 ` Theodore Tso
2006-08-09 6:32 ` Pekka Enberg
2006-08-08 12:13 ` Alan Cox [this message]
2006-08-08 12:29 ` Alan Cox
2006-08-08 12:31 ` Pekka Enberg
2006-08-08 12:57 ` Pavel Machek
2006-08-08 14:14 ` Alan Cox
2006-08-08 13:57 ` Pavel Machek
2006-08-09 8:41 ` Edgar Toernig
2006-08-09 10:42 ` Alan Cox
2006-08-09 18:00 ` Edgar Toernig
2006-08-09 18:35 ` Alan Cox
2006-08-09 19:14 ` Pekka Enberg
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