From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757390Ab2IDP54 (ORCPT ); Tue, 4 Sep 2012 11:57:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63747 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757269Ab2IDPzl (ORCPT ); Tue, 4 Sep 2012 11:55:41 -0400 From: Matthew Garrett To: linux-kernel@vger.kernel.org Cc: linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, Matthew Garrett Subject: [PATCH 04/11] ACPI: Limit access to custom_method Date: Tue, 4 Sep 2012 11:55:10 -0400 Message-Id: <1346774117-2277-5-git-send-email-mjg@redhat.com> In-Reply-To: <1346774117-2277-1-git-send-email-mjg@redhat.com> References: <1346774117-2277-1-git-send-email-mjg@redhat.com> X-SA-Do-Not-Run: Yes X-SA-Exim-Connect-IP: 66.187.233.206 X-SA-Exim-Mail-From: mjg@redhat.com X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It must be impossible for even root to get code executed in kernel context under a secure boot environment. custom_method effectively allows arbitrary access to system memory, so it needs to have a capability check here. Signed-off-by: Matthew Garrett --- drivers/acpi/custom_method.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c index 5d42c24..3e78014 100644 --- a/drivers/acpi/custom_method.c +++ b/drivers/acpi/custom_method.c @@ -29,6 +29,9 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf, struct acpi_table_header table; acpi_status status; + if (!capable(CAP_SECURE_FIRMWARE)) + return -EPERM; + if (!(*ppos)) { /* parse the table header to get the table length */ if (count <= sizeof(struct acpi_table_header)) -- 1.7.11.4