From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264685AbUEaQIV (ORCPT ); Mon, 31 May 2004 12:08:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264683AbUEaQIV (ORCPT ); Mon, 31 May 2004 12:08:21 -0400 Received: from MAIL.13thfloor.at ([212.16.62.51]:21942 "EHLO mail.13thfloor.at") by vger.kernel.org with ESMTP id S264686AbUEaQIS (ORCPT ); Mon, 31 May 2004 12:08:18 -0400 Date: Mon, 31 May 2004 18:08:17 +0200 From: Herbert Poetzl To: Marcelo Tosatti Cc: linux-kernel@vger.kernel.org Subject: Re: file attributes (ext2/3) in 2.4.26 Message-ID: <20040531160816.GA16444@MAIL.13thfloor.at> Mail-Followup-To: Marcelo Tosatti , linux-kernel@vger.kernel.org References: <20040517185141.GA23102@MAIL.13thfloor.at> <20040520215909.GB21344@logos.cnet> <20040520224809.GA31445@MAIL.13thfloor.at> <20040531150537.GD20653@logos.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040531150537.GD20653@logos.cnet> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 31, 2004 at 12:05:37PM -0300, Marcelo Tosatti wrote: > On Fri, May 21, 2004 at 12:48:09AM +0200, Herbert Poetzl wrote: > > On Thu, May 20, 2004 at 06:59:09PM -0300, Marcelo Tosatti wrote: > > > On Mon, May 17, 2004 at 08:51:41PM +0200, Herbert Poetzl wrote: > > > > > > > > Hi Folks! > > > > > > > > is it intentional that the file attributes > > > > (those accessible with chattr -*) are modifyable > > > > even if a file has the 'i' immutable flag set, > > > > and the user is lacking CAP_IMMUTABLE (or all > > > > CAPs if you prefer that ;) > > > > > > > > # touch /tmp/x > > > > # chattr +iaA /tmp/x > > > > > > > > # lcap -z > > > > # chattr -i /tmp/x > > > > chattr: Operation not permitted while setting flags on /tmp/x > > > > > > > > # chattr -A /tmp/x > > > > # lsattr /tmp/x > > > > ----ia------- /tmp/x > > > > > > > > I'd consider this a bug, but it might be some > > > > strange posix/linux conformance issue too ... > > > > > > > > let me know if this _is_ a bug, if so, I'm > > > > willing to provide patches to fix it ... > > > > > > Hi Herbert, > > > > > > The chattr man page says > > > > > > A file with the `i' attribute cannot be modified: it cannot be deleted > > > or renamed, no link can be created to this file and no data can be > > > written to the file. Only the superuser or a process possessing the > > > CAP_LINUX_IMMUTABLE capability can set or clear this attribute. > > > > > > You still can modify other flags from the file, right? > > > > yep, that is what I consider unexpected behavior, but the > > man page doesn't say anything about other flags ... > > > > in the example above (which should be easy to verify) the > > 'A' (noatime) flag is cleared while 'i' is set and the > > user (root) has no capability at all ... > > > > the same is true for all other attribute flags for > > ext2/ext3, reiserfs and probably other fs implementing > > those attributes. > > Hi again Herbert, > > I suppose this is expected behaviour, a file with 'i' cannot > be modified, deleted or renamed and no link can be created to this > file and no data written to the file. Its valid to change the file > attributes. well, if the kernel development, at some point, decides to get rid of the suid stuff, and replace it by something CAP* based, then this will be fun, as it is then possible to modify the attributes of immutable files without CAP_IMMUTABLE ... > Not sure if any standard covers this, but it does not seem to be > a problem. okay, I have to handle this in linux-vserver anyway, so I just wanted to know if this was on purpose or accidentially ... > I suppose v2.6 behaves the same? yep, it does ... best, Herbert