From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pekka J Enberg Subject: Re: [RFC/PATCH] revoke/frevoke system calls V2 Date: Fri, 28 Jul 2006 06:40:52 +0300 (EEST) Message-ID: References: <200607271930.k6RJUQ6s016546@laptop13.inf.utfsm.cl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: Petr Baudis , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, akpm@osdl.org, viro@zeniv.linux.org.uk, alan@lxorguk.ukuu.org.uk, tytso@mit.edu, tigran@veritas.com Return-path: Received: from courier.cs.helsinki.fi ([128.214.9.1]:6531 "EHLO mail.cs.helsinki.fi") by vger.kernel.org with ESMTP id S1751902AbWG1Dkx (ORCPT ); Thu, 27 Jul 2006 23:40:53 -0400 To: "Horst H. von Brand" In-Reply-To: <200607271930.k6RJUQ6s016546@laptop13.inf.utfsm.cl> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Thu, 27 Jul 2006, Horst H. von Brand wrote: > Doesn't that violate a POSIX guarantee that the lowest unused fd is > returned? If the leakage lasts "long enough", this gives an opportunity of > a nice DoS by using up fds... The fd is not unused, its revoked. To clarify, the potential DoS is inherit for revoke, but since only root or the file owner can revoke a file, I don't see that as a big problem in practice. The caller is expected to ensure that no one can reopen the file anyway. Pekka