Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758042AbZKXM2R (ORCPT ); Tue, 24 Nov 2009 07:28:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757695AbZKXM2Q (ORCPT ); Tue, 24 Nov 2009 07:28:16 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:34900 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757645AbZKXM2Q (ORCPT ); Tue, 24 Nov 2009 07:28:16 -0500 Date: Tue, 24 Nov 2009 13:09:06 +0100 From: Pavel Machek To: Miklos Szeredi Cc: Jeff Layton , jamie@shareable.org, ebiederm@xmission.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@ZenIV.linux.org.uk Subject: Re: [PATCH 0/3] vfs: plug some holes involving LAST_BIND symlinks and file bind mounts (try #5) Message-ID: <20091124120906.GA1700@ucw.cz> References: <1258998084-26797-1-git-send-email-jlayton@redhat.com> <20091123173616.75c3f600@tlielax.poochiereds.net> <20091123224948.GB5598@shareable.org> <20091123181545.05ad004d@tlielax.poochiereds.net> <20091123193426.55f1530a@tlielax.poochiereds.net> <20091124012027.GA14645@shareable.org> <20091124062621.744beddb@tlielax.poochiereds.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1408 Lines: 30 On Tue 2009-11-24 12:53:09, Miklos Szeredi wrote: > On Tue, 24 Nov 2009, Jeff Layton wrote: > > Since it's clear that these symlinks do need to have special semantics, > > perhaps the approach you suggest would be the best thing. I'll have to > > think about it a bit more. > > open() is not the only thing you need to think about. Anything that > checks read or write permission on the inode (truncate, utimes, > *xattr) would have to be changed to respect the open mode. > > See, this is not just about hacking the proc follow_symlink code to > check some lookup intent. It's about changing the permission checking > mechanism for theses beasts. And since the permission checking is > inode based, this is not at all trivial to do. > > I still believe leaving the current semantics and documenting them is > the best option. I believe that current semantics is ugly enough that 'documenting' it is not enough... and people want to port from other systems, too, not expecting nasty surprises like this... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- 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/