From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757443AbZJ3UhY (ORCPT ); Fri, 30 Oct 2009 16:37:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757409AbZJ3UhX (ORCPT ); Fri, 30 Oct 2009 16:37:23 -0400 Received: from smtp-noauth7.primus.ca ([216.254.180.38]:56975 "EHLO mail-07.primus.ca" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756885AbZJ3UhW (ORCPT ); Fri, 30 Oct 2009 16:37:22 -0400 Date: Fri, 30 Oct 2009 16:37:15 -0400 From: Nick Bowler To: Pavel Machek Cc: "Eric W. Biederman" , Trond Myklebust , Jan Kara , "J. Bruce Fields" , "Serge E. Hallyn" , kernel list , linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, jamie@shareable.org Subject: Re: symlinks with permissions Message-ID: <20091030203715.GA28901@emergent.ellipticsemi.com> Mail-Followup-To: Pavel Machek , "Eric W. Biederman" , Trond Myklebust , Jan Kara , "J. Bruce Fields" , "Serge E. Hallyn" , kernel list , linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, jamie@shareable.org References: <1256579869.8576.7.camel@heimdal.trondhjem.org> <20091025093604.GA1501@ucw.cz> <20091028081653.GA18290@elf.ucw.cz> <20091028210323.GA4159@elf.ucw.cz> <20091029110344.GA1517@ucw.cz> <20091030183559.GF7008@elf.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091030183559.GF7008@elf.ucw.cz> Organization: Elliptic Technologies Inc. User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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/)