From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Bowler Subject: Re: symlinks with permissions Date: Fri, 30 Oct 2009 16:37:15 -0400 Message-ID: <20091030203715.GA28901@emergent.ellipticsemi.com> 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 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 To: Pavel Machek Return-path: Content-Disposition: inline In-Reply-To: <20091030183559.GF7008@elf.ucw.cz> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.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/)