From mboxrd@z Thu Jan 1 00:00:00 1970 From: Edgar Toernig Subject: Re: [RFC/PATCH] revoke/frevoke system calls V2 Date: Wed, 9 Aug 2006 20:00:19 +0200 Message-ID: <20060809200019.0bd5eecd.froese@gmx.de> References: <20060805122936.GC5417@ucw.cz> <20060807101745.61f21826.froese@gmx.de> <84144f020608070251j2e14e909v8a18f62db85ff3d4@mail.gmail.com> <20060807224144.3bb64ac4.froese@gmx.de> <1155040157.5729.34.camel@localhost.localdomain> <20060809104155.48ad3c77.froese@gmx.de> <1155120128.5729.143.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Pekka Enberg , Pavel Machek , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, akpm@osdl.org, viro@zeniv.linux.org.uk, tytso@mit.edu, tigran@veritas.com Return-path: To: Alan Cox In-Reply-To: <1155120128.5729.143.camel@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Alan Cox wrote: > > Ar Mer, 2006-08-09 am 10:41 +0200, ysgrifennodd Edgar Toernig: > > > If I own the file I can make it a symlink to a pty/tty pair > > > I can revoke a pty/tty pair > > > > With the EIO/EOF behaviour that's not a problem - apps that deal > > with ttys have to expect that condition. > > Think about it a moment - I can symlink any file to a tty/pty pair so > any file I own you open might be a tty. Yes, OK. The EIO/EOF behaviour is fine. Even for regular files it's not something extraordinary. > > Hmm... which apps have an open fd on block devices? Usually a > > cdrecord, cd audio players, eject, .... And killing them is not OK? "fuser -km /dev/cdrom" already covers both cases, mounted somewhere and opened for special access. Sorry if I sound a little bit anal. IMO, a generic revoke is a pretty sharp sword which is given to ordinary users and I have a very uneasy feeling. They can dig in the innards of other people's processes - a clean headshot by root is something different ... Ciao, ET.