From patchwork Wed Nov 16 21:48:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 9432841 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 820A360471 for ; Wed, 16 Nov 2016 21:49:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 71C9929168 for ; Wed, 16 Nov 2016 21:49:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 667CA2916D; Wed, 16 Nov 2016 21:49:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1D82029168 for ; Wed, 16 Nov 2016 21:49:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941171AbcKPVsz (ORCPT ); Wed, 16 Nov 2016 16:48:55 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43244 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S939765AbcKPVsx (ORCPT ); Wed, 16 Nov 2016 16:48:53 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8EBADC009DCE; Wed, 16 Nov 2016 21:48:52 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-116-110.phx2.redhat.com [10.3.116.110]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id uAGLmocf022950; Wed, 16 Nov 2016 16:48:51 -0500 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 13/16] asus-wmi: Restrict debugfs interface when the kernel is locked down From: David Howells To: keyrings@vger.kernel.org Cc: dhowells@redhat.com, matthew.garrett@nebula.com, linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 16 Nov 2016 21:48:50 +0000 Message-ID: <147933293066.19316.11104613433360959201.stgit@warthog.procyon.org.uk> In-Reply-To: <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk> References: <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Wed, 16 Nov 2016 21:48:52 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP 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 --- drivers/platform/x86/asus-wmi.c | 9 +++++++++ 1 file changed, 9 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c index ce6ca31a2d09..d860017f5240 100644 --- a/drivers/platform/x86/asus-wmi.c +++ b/drivers/platform/x86/asus-wmi.c @@ -1872,6 +1872,9 @@ static int show_dsts(struct seq_file *m, void *data) int err; u32 retval = -1; + if (kernel_is_locked_down()) + return -EPERM; + err = asus_wmi_get_devstate(asus, asus->debug.dev_id, &retval); if (err < 0) @@ -1888,6 +1891,9 @@ static int show_devs(struct seq_file *m, void *data) int err; u32 retval = -1; + if (kernel_is_locked_down()) + return -EPERM; + err = asus_wmi_set_devstate(asus->debug.dev_id, asus->debug.ctrl_param, &retval); @@ -1912,6 +1918,9 @@ static int show_call(struct seq_file *m, void *data) union acpi_object *obj; acpi_status status; + if (kernel_is_locked_down()) + return -EPERM; + status = wmi_evaluate_method(ASUS_WMI_MGMT_GUID, 1, asus->debug.method_id, &input, &output);