From patchwork Mon Mar 18 21:32:28 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 228816 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id EE2F22C00AE for ; Tue, 19 Mar 2013 08:35:24 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932908Ab3CRVeY (ORCPT ); Mon, 18 Mar 2013 17:34:24 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:35942 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933365Ab3CRVc6 (ORCPT ); Mon, 18 Mar 2013 17:32:58 -0400 Received: from [2001:470:1f07:1371:e0f4:3a1:9c35:d688] (helo=x230.mview.int.nebula.com) by cavan.codon.org.uk with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.72) (envelope-from ) id 1UHhft-0006Ez-D3; Mon, 18 Mar 2013 21:32:57 +0000 From: Matthew Garrett To: linux-kernel@vger.kernel.org Cc: linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, Matthew Garrett Subject: [PATCH 07/12] ACPI: Limit access to custom_method Date: Mon, 18 Mar 2013 17:32:28 -0400 Message-Id: <1363642353-30749-7-git-send-email-matthew.garrett@nebula.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1363642353-30749-1-git-send-email-matthew.garrett@nebula.com> References: <1363642353-30749-1-git-send-email-matthew.garrett@nebula.com> X-SA-Do-Not-Run: Yes X-SA-Exim-Connect-IP: 2001:470:1f07:1371:e0f4:3a1:9c35:d688 X-SA-Exim-Mail-From: matthew.garrett@nebula.com X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@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 12b62f2..edf0710 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))