From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262196AbTDUVSq (ORCPT ); Mon, 21 Apr 2003 17:18:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262228AbTDUVSq (ORCPT ); Mon, 21 Apr 2003 17:18:46 -0400 Received: from cerebus.wirex.com ([65.102.14.138]:55794 "EHLO figure1.int.wirex.com") by vger.kernel.org with ESMTP id S262196AbTDUVSp (ORCPT ); Mon, 21 Apr 2003 17:18:45 -0400 Date: Mon, 21 Apr 2003 14:26:24 -0700 From: Chris Wright To: Junfeng Yang Cc: linux-kernel@vger.kernel.org Subject: Re: [CHECKER] Help Needed! Message-ID: <20030421142624.B11886@figure1.int.wirex.com> Mail-Followup-To: Junfeng Yang , linux-kernel@vger.kernel.org References: <20030327091058.A22868@figure1.int.wirex.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from yjf@stanford.edu on Mon, Apr 21, 2003 at 12:49:13AM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Junfeng Yang (yjf@stanford.edu) wrote: > > It seems to us that create_dev can only be called at boot time (the > "__init" attribute), so devfs_name must be an untainted kernel pointer. > The warning on line 437 isn't a real error. Yes. > However, this pointer is finally passed into strncpy_from_user through the > call chain [ sys_symlink (devfs_name, name) --> getname (oldname) --> > do_getname(filename, _) --> strncpy_from_user (_, filename, _)]. Is it > okay to call *_from_user functions with the second arguements untainted? > What will access_ok(VERIFY_READ, src, 1) return? This checks against the current addr_limit which depends on the context. KERNEL_DS lets this check succeed. thanks, -chris -- Linux Security Modules http://lsm.immunix.org http://lsm.bkbits.net