Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934199AbdDEUTI (ORCPT ); Wed, 5 Apr 2017 16:19:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60110 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934086AbdDEUR0 (ORCPT ); Wed, 5 Apr 2017 16:17:26 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 9B2EBC04D2E9 Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=dhowells@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 9B2EBC04D2E9 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 18/24] acpi: Disable ACPI table override if the kernel is locked down From: David Howells To: linux-kernel@vger.kernel.org Cc: gnomes@lxorguk.ukuu.org.uk, linux-efi@vger.kernel.org, Linn Crosetto , matthew.garrett@nebula.com, gregkh@linuxfoundation.org, dhowells@redhat.com, linux-acpi@vger.kernel.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org Date: Wed, 05 Apr 2017 21:17:08 +0100 Message-ID: <149142342857.5101.10620312195465803812.stgit@warthog.procyon.org.uk> In-Reply-To: <149142326734.5101.4596394505987813763.stgit@warthog.procyon.org.uk> References: <149142326734.5101.4596394505987813763.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 [10.5.110.31]); Wed, 05 Apr 2017 20:17:11 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1174 Lines: 36 From: Linn Crosetto >From the kernel documentation (initrd_table_override.txt): If the ACPI_INITRD_TABLE_OVERRIDE compile option is true, it is possible to override nearly any ACPI table provided by the BIOS with an instrumented, modified one. When securelevel is set, the kernel should disallow any unauthenticated changes to kernel space. ACPI tables contain code invoked by the kernel, so do not allow ACPI tables to be overridden if the kernel is locked down. Signed-off-by: Linn Crosetto Signed-off-by: David Howells cc: linux-acpi@vger.kernel.org --- drivers/acpi/tables.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c index 2604189d6cd1..601096d0d849 100644 --- a/drivers/acpi/tables.c +++ b/drivers/acpi/tables.c @@ -542,6 +542,11 @@ void __init acpi_table_upgrade(void) if (table_nr == 0) return; + if (kernel_is_locked_down()) { + pr_notice("kernel is locked down, ignoring table override\n"); + return; + } + acpi_tables_addr = memblock_find_in_range(0, ACPI_TABLE_UPGRADE_MAX_PHYS, all_tables_size, PAGE_SIZE);