From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752966AbdJSOwR (ORCPT ); Thu, 19 Oct 2017 10:52:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34730 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752909AbdJSOwO (ORCPT ); Thu, 19 Oct 2017 10:52:14 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C7944820FE Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=dhowells@redhat.com Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 13/27] asus-wmi: Restrict debugfs interface when the kernel is locked down From: David Howells To: linux-security-module@vger.kernel.org Cc: gnomes@lxorguk.ukuu.org.uk, linux-efi@vger.kernel.org, matthew.garrett@nebula.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, jforbes@redhat.com Date: Thu, 19 Oct 2017 15:52:11 +0100 Message-ID: <150842473184.7923.9538070958624850416.stgit@warthog.procyon.org.uk> In-Reply-To: <150842463163.7923.11081723749106843698.stgit@warthog.procyon.org.uk> References: <150842463163.7923.11081723749106843698.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Thu, 19 Oct 2017 14:52:14 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Matthew Garrett We have no way of validating what all of the Asus WMI methods do on a given machine - and there's a risk that some will allow hardware state to be manipulated in such a way that arbitrary code can be executed in the kernel, circumventing module loading restrictions. Prevent that if the kernel is locked down. Signed-off-by: Matthew Garrett Signed-off-by: David Howells cc: acpi4asus-user@lists.sourceforge.net cc: platform-driver-x86@vger.kernel.org --- drivers/platform/x86/asus-wmi.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c index 48e1541dc8d4..ef5587469337 100644 --- a/drivers/platform/x86/asus-wmi.c +++ b/drivers/platform/x86/asus-wmi.c @@ -1905,6 +1905,9 @@ static int show_dsts(struct seq_file *m, void *data) int err; u32 retval = -1; + if (kernel_is_locked_down("Asus WMI")) + return -EPERM; + err = asus_wmi_get_devstate(asus, asus->debug.dev_id, &retval); if (err < 0) @@ -1921,6 +1924,9 @@ static int show_devs(struct seq_file *m, void *data) int err; u32 retval = -1; + if (kernel_is_locked_down("Asus WMI")) + return -EPERM; + err = asus_wmi_set_devstate(asus->debug.dev_id, asus->debug.ctrl_param, &retval); @@ -1945,6 +1951,9 @@ static int show_call(struct seq_file *m, void *data) union acpi_object *obj; acpi_status status; + if (kernel_is_locked_down("Asus WMI")) + return -EPERM; + status = wmi_evaluate_method(ASUS_WMI_MGMT_GUID, 0, asus->debug.method_id, &input, &output);