From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755719Ab2ITOld (ORCPT ); Thu, 20 Sep 2012 10:41:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:21622 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755635Ab2ITOla (ORCPT ); Thu, 20 Sep 2012 10:41:30 -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 V2 04/10] ACPI: Limit access to custom_method Date: Thu, 20 Sep 2012 10:40:59 -0400 Message-Id: <1348152065-31353-5-git-send-email-mjg@redhat.com> In-Reply-To: <1348152065-31353-1-git-send-email-mjg@redhat.com> References: <1348152065-31353-1-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..247d58b 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_COMPROMISE_KERNEL)) + return -EPERM; + if (!(*ppos)) { /* parse the table header to get the table length */ if (count <= sizeof(struct acpi_table_header)) -- 1.7.11.4