Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030292AbVKITIm (ORCPT ); Wed, 9 Nov 2005 14:08:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030291AbVKITIl (ORCPT ); Wed, 9 Nov 2005 14:08:41 -0500 Received: from e36.co.us.ibm.com ([32.97.110.154]:1686 "EHLO e36.co.us.ibm.com") by vger.kernel.org with ESMTP id S1030292AbVKITIl (ORCPT ); Wed, 9 Nov 2005 14:08:41 -0500 Subject: Re: [PATCH 2/18] cleanups and bug fix in do_loopback() From: Ram Pai To: Miklos Szeredi Cc: Al Viro , torvalds@osdl.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org In-Reply-To: References: <1131439567.5400.221.camel@localhost> Content-Type: text/plain Organization: IBM Message-Id: <1131563299.5400.392.camel@localhost> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Wed, 09 Nov 2005 11:08:19 -0800 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1457 Lines: 37 On Tue, 2005-11-08 at 01:28, Miklos Szeredi wrote: > > > I see no other reason for wanting to prevent binds from detached > > > mounts or other namespaces. It has been discussed that it would be a > > > good _controlled_ way to send/receive mounts from other namespace > > > without adding any complexity. > > > > AFAICT, the ability to bind across namespaces defeats the private-ness > > property of per-process-namespaces. > > No. The privateness is guaranteed by proc_check_root(), which is > similar, but not the same as check_mnt(), and wich restrict _access_ > to other namespaces. > check_mnt() restricts operations on other namespaces if you _already_ > have access to said namespace. For example via a file descriptor sent > between two processes in different namespaces. Yes there is some contradiction of some sorts on this. private-ness means that the namespace must _not_ be accesible to processes in other namespace. But 'file descriptor sent between two processes in different namespaces' seems to break that guarantee. > > Also with ptrace() you can still access other process's namespace, so > proc_check_root() is also too strict (or ptrace() too lax). same here. RP > > Miklos - 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/