Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758656AbXIXMiZ (ORCPT ); Mon, 24 Sep 2007 08:38:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756123AbXIXMiR (ORCPT ); Mon, 24 Sep 2007 08:38:17 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:40217 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756102AbXIXMiQ (ORCPT ); Mon, 24 Sep 2007 08:38:16 -0400 Date: Mon, 24 Sep 2007 13:38:13 +0100 From: Christoph Hellwig To: Miklos Szeredi Cc: hch@infradead.org, trond.myklebust@fys.uio.no, adilger@clusterfs.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [patch 2/2] VFS: allow filesystem to override mknod capability checks Message-ID: <20070924123813.GB17409@infradead.org> Mail-Followup-To: Christoph Hellwig , Miklos Szeredi , trond.myklebust@fys.uio.no, adilger@clusterfs.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1224 Lines: 27 On Mon, Sep 24, 2007 at 02:25:54PM +0200, Miklos Szeredi wrote: > From: Miklos Szeredi > > Add a new super block flag, that results in the VFS not checking if > the current process has enough privileges to do an mknod(). > > If this flag is set, all mounts for this super block will have the > "nodev" flag implied. > > This is needed on filesystems, where an unprivileged user may be able > to create a device node, without causing security problems. > > One such example is "mountlo" a loopback mount utility implemented > with fuse and UML, which runs as an unprivileged userspace process. > In this case the user does in fact have the right to create device > nodes within the filesystem image, as long as the user has write > access to the image. Since the filesystem is mounted with "nodev", > adding device nodes is not a security concern. This one looks okay, but I'd prefer to not put it in until we actually have proper non-privilegued mounts. - 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/