From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id 1EE997F3F for ; Wed, 11 Sep 2013 09:22:52 -0500 (CDT) Message-ID: <52307CB6.3060506@sgi.com> Date: Wed, 11 Sep 2013 09:22:46 -0500 From: Mark Tinguely MIME-Version: 1.0 Subject: Re: [PATCH] xfs: change the immutable in xfs_open_by_handle References: <20130910184724.726933044@sgi.com> <20130911135502.GA21898@infradead.org> In-Reply-To: <20130911135502.GA21898@infradead.org> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Christoph Hellwig Cc: Greg Banks , xfs@oss.sgi.com On 09/11/13 08:55, Christoph Hellwig wrote: > On Tue, Sep 10, 2013 at 01:47:20PM -0500, Mark Tinguely wrote: >> This patch allows clients like DMF to modify an immutable file >> without changing the immutable capability on the file, which >> would expose the file to change. >> >> This patch is restricted to holders of the CAP_LINUX_IMMUTABLE, >> so no addition security risk has been introduced. > > The immutable flag means that the file can't be modified, and > CAP_LINUX_IMMUTABLE allows setting/removing that restriction, but not > ignoring it. > > So: NAK, this is a change in semantics and long-standing behaviour. > As you said, the CAP_LINUX_IMMUTABLE allows the holder of the capability to turn on/off the restriction. The holder of CAP_LINUX_IMMUTABLE could turn off immutability, modify it and then turn it back on, but during that window, others could modify it too which may be more undesirable than changing the behavior. --Mark. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs