From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755140AbdDMRoy (ORCPT ); Thu, 13 Apr 2017 13:44:54 -0400 Received: from mail.kernel.org ([198.145.29.136]:36314 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753005AbdDMRow (ORCPT ); Thu, 13 Apr 2017 13:44:52 -0400 MIME-Version: 1.0 In-Reply-To: References: <20170412230854.GA11963@fury> <20170413073228.GB1462@ozzy.nask.waw.pl> <0d4e6c4562fb4b85ad4c368ae73dbe06@ausx13mpc120.AMER.DELL.COM> <20170413170619.GF2064@fury> From: Andy Lutomirski Date: Thu, 13 Apr 2017 10:44:26 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: RFC: WMI Enhancements To: Mario.Limonciello@dell.com Cc: Darren Hart , Andrew Lutomirski , =?UTF-8?B?TWljaGHFgiBLxJlwaWXFhA==?= , "Rafael J. Wysocki" , Len Brown , =?UTF-8?Q?Pali_Roh=C3=A1r?= , Corentin Chary , Andy Shevchenko , "linux-kernel@vger.kernel.org" , platform-driver-x86@vger.kernel.org, "linux-pm@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 13, 2017 at 10:39 AM, wrote: >> -----Original Message----- >> From: Darren Hart [mailto:dvhart@infradead.org] >> Sent: Thursday, April 13, 2017 12:06 PM >> To: Limonciello, Mario >> Cc: luto@kernel.org; kernel@kempniu.pl; rjw@rjwysocki.net; >> len.brown@intel.com; pali.rohar@gmail.com; corentin.chary@gmail.com; >> andriy.shevchenko@linux.intel.com; linux-kernel@vger.kernel.org; platform- >> driver-x86@vger.kernel.org; linux-pm@vger.kernel.org >> Subject: Re: RFC: WMI Enhancements >> > Well the "most" interesting to me is the SMBIOS calling interface on the > regular Dell GUID (WMBA IIRC). That's what is used to manipulate keyboard > LED timeouts in dell-laptop (although through direct SMI today). > > It's also what is used for other SMBIOS calls like changing random BIOS settings > that shouldn't be generically exposed in sysfs but should be controlled by > manageability tools. > > Example: turning on/off legacy option ROM or changing legacy boot order. > IIUC we basically can't expose the SMI--based interface to this entry point to userspace because of its use of physical addressing. It is reasonably safe to expose the WMI version? (IOW should be expect that it doesn't enable kernel-mode or SMM code execution?) TBH, I've occasionally considered writing a driver to expose SMM code execution on systems with a known reliable exploit :)