Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758060AbYFCMLE (ORCPT ); Tue, 3 Jun 2008 08:11:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755560AbYFCMKx (ORCPT ); Tue, 3 Jun 2008 08:10:53 -0400 Received: from mail2.shareable.org ([80.68.89.115]:37382 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751094AbYFCMKw (ORCPT ); Tue, 3 Jun 2008 08:10:52 -0400 Date: Tue, 3 Jun 2008 13:10:15 +0100 From: Jamie Lokier To: Al Viro Cc: Michael Kerrisk , Miklos Szeredi , drepper@redhat.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-man@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] utimensat() non-conformances and fixes [v3] Message-ID: <20080603121015.GC28905@shareable.org> References: <48401E7E.9090304@gmail.com> <20080603112221.GW28946@ZenIV.linux.org.uk> <20080603113018.GA27955@shareable.org> <20080603114921.GX28946@ZenIV.linux.org.uk> <20080603120135.GA28905@shareable.org> <20080603120850.GZ28946@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080603120850.GZ28946@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1042 Lines: 27 Al Viro wrote: > On Tue, Jun 03, 2008 at 01:01:35PM +0100, Jamie Lokier wrote: > > > with a lot of things, starting with "why utimes(2) has weaker requirements > > > with NULL argument", but we are far too late to fix that. > > > > To be fair, having a writable file descriptor only lets you change the > > mtime to "now", and having a readable file descriptor only lets you > > change the atime to "now". > > > > Changing the times _in general_ can be seen as over-reaching those > > capabilities and arguably justifies more strict checks. > > Which is what all questions about writability apply only to NULL case > anyway... Oh! So if I have the file descriptor, I can just as well change the mtime by read a byte and write it back. Or even do a zero-length write, on some OSes. -- Jamie -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/