From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263937AbTDHEy3 (for ); Tue, 8 Apr 2003 00:54:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263942AbTDHEy2 (for ); Tue, 8 Apr 2003 00:54:28 -0400 Received: from almesberger.net ([63.105.73.239]:42503 "EHLO host.almesberger.net") by vger.kernel.org with ESMTP id S263937AbTDHEy2 (for ); Tue, 8 Apr 2003 00:54:28 -0400 Date: Tue, 8 Apr 2003 02:06:00 -0300 From: Werner Almesberger To: Clayton Weaver Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] new syscall: flink Message-ID: <20030408020600.E19288@almesberger.net> References: <20030407165009.13596.qmail@email.com> <20030407154303.C19288@almesberger.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030407154303.C19288@almesberger.net>; from wa@almesberger.net on Mon, Apr 07, 2003 at 03:43:03PM -0300 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I wrote: > Example: I write some kind of RAID mounted at /world, that contains > my disk under /world/disk, and some Flash storage under /world/flash. > I protect /world/flash against writes by other people. If a > read-only FD could be turned into something writeable, some malicious > creature could "wear out" my Flash by writing to it a lot of times. Just to clarify: the file in question would be inaccessible for the abuser, and the read-only fd would have to be handed out by some access mediator. Obviously, if the abuser obtains a read-only fd directly by opening a file, the hypothetical flink couldn't be used for privilege escalation. - Werner -- _________________________________________________________________________ / Werner Almesberger, Buenos Aires, Argentina wa@almesberger.net / /_http://www.almesberger.net/____________________________________________/