From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262488AbVAPMEm (ORCPT ); Sun, 16 Jan 2005 07:04:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262489AbVAPMEl (ORCPT ); Sun, 16 Jan 2005 07:04:41 -0500 Received: from verein.lst.de ([213.95.11.210]:56029 "EHLO mail.lst.de") by vger.kernel.org with ESMTP id S262488AbVAPMEi (ORCPT ); Sun, 16 Jan 2005 07:04:38 -0500 Date: Sun, 16 Jan 2005 13:04:36 +0100 From: Christoph Hellwig To: Thomas Viehmann Cc: linux-kernel@vger.kernel.org Subject: Re: permissions of /proc/tty/driver Message-ID: <20050116120436.GA13906@lst.de> References: <41E80535.1060309@beamnet.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <41E80535.1060309@beamnet.de> User-Agent: Mutt/1.3.28i X-Spam-Score: -4.901 () BAYES_00 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 14, 2005 at 06:45:25PM +0100, Thomas Viehmann wrote: > Hi. > > This may not be stritly on topic, but I couln't figure out a better > place to ask: > > During the packaging of an application, I have the following problem: > I would like to run a daemon as non-root. The daemon likes to > (continually) check /proc/tty/driver/usbserial to see whether or not > interesting USB devices are connected. The permissions of this actual > file is (on a kernel compiled from Debian's kernel-source-2.6.10) 0444, > so this isn't a problem. However, the parent directory /proc/tty/driver > is 0500. I'm not sure whether this is related to Debian DSAs 358 or 423 > (where /proc/tty/driver/serial is mentioned as leaking sensitive > information), to me the contents of usbserial look innocent enough. > Do you have any hints on what might be a good solution? The permissions on the directory look indeed too strict to me. It might be better to just use strict permissions on /proc/tty/driver/serial indeed. Counter-question: What information is available in /proc/tty/driver/usbserial but not in sysfs?