From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031254AbXDUOM0 (ORCPT ); Sat, 21 Apr 2007 10:12:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031253AbXDUOM0 (ORCPT ); Sat, 21 Apr 2007 10:12:26 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:60139 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031243AbXDUOMZ (ORCPT ); Sat, 21 Apr 2007 10:12:25 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Andrew Morton Cc: Miklos Szeredi , serue@us.ibm.com, viro@ftp.linux.org.uk, linuxram@us.ibm.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, containers@lists.osdl.org Subject: Re: [patch 7/8] allow unprivileged mounts References: <20070420102532.385211890@szeredi.hu> <20070420102652.075606533@szeredi.hu> <20070421005513.e230aa88.akpm@linux-foundation.org> Date: Sat, 21 Apr 2007 08:10:18 -0600 In-Reply-To: <20070421005513.e230aa88.akpm@linux-foundation.org> (Andrew Morton's message of "Sat, 21 Apr 2007 00:55:13 -0700") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton writes: > On Fri, 20 Apr 2007 12:25:39 +0200 Miklos Szeredi wrote: > >> Define a new fs flag FS_SAFE, which denotes, that unprivileged >> mounting of this filesystem may not constitute a security problem. >> >> Since most filesystems haven't been designed with unprivileged >> mounting in mind, a thorough audit is needed before setting this flag. > > Practically speaking, is there any realistic likelihood that any filesystem > apart from FUSE will ever use this? Also potentially some of the kernel virtual filesystems. /proc should be safe already. If you don't have any kind of backing store this problem gets easier. With unprivileged users allowed to create mounts the utility of kernel functionality exported as filesystems goes up quite a bit. We are not plan9 but this is the last bottleneck in allowing the everything is a filesystem paradigm from being really usable in linux. Eric