From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932075Ab3A1QpE (ORCPT ); Mon, 28 Jan 2013 11:45:04 -0500 Received: from cavan.codon.org.uk ([93.93.128.6]:34032 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757333Ab3A1Qmv (ORCPT ); Mon, 28 Jan 2013 11:42:51 -0500 From: Matthew Garrett To: linux-kernel@vger.kernel.org Cc: linux-efi@vger.kernel.org, linux-security-module@vger.kernel.org, Josh Boyer Subject: [PATCH 03/15] Secure boot: Add a dummy kernel parameter that will switch on Secure Boot mode Date: Mon, 28 Jan 2013 11:42:27 -0500 Message-Id: <1359391359-25783-4-git-send-email-matthew.garrett@nebula.com> X-Mailer: git-send-email 1.8.0.2 In-Reply-To: <1359391359-25783-1-git-send-email-matthew.garrett@nebula.com> References: <1359391359-25783-1-git-send-email-matthew.garrett@nebula.com> X-SA-Do-Not-Run: Yes X-SA-Exim-Connect-IP: 2001:470:1f07:1371:6267:20ff:fec3:2318 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-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Josh Boyer This forcibly drops CAP_COMPROMISE_KERNEL from both cap_permitted and cap_bset in the init_cred struct, which everything else inherits from. This works on any machine and can be used to develop even if the box doesn't have UEFI. Signed-off-by: Josh Boyer --- Documentation/kernel-parameters.txt | 7 +++++++ kernel/cred.c | 17 +++++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 363e348..832b39b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2654,6 +2654,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Note: increases power consumption, thus should only be enabled if running jitter sensitive (HPC/RT) workloads. + secureboot_enable= + [KNL] Enables an emulated UEFI Secure Boot mode. This + locks down various aspects of the kernel guarded by the + CAP_COMPROMISE_KERNEL capability. This includes things + like /dev/mem, IO port access, and other areas. It can + be used on non-UEFI machines for testing purposes. + security= [SECURITY] Choose a security module to enable at boot. If this boot parameter is not specified, only the first security module asking for security registration will be diff --git a/kernel/cred.c b/kernel/cred.c index e0573a4..c3f4e3e 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -565,6 +565,23 @@ void __init cred_init(void) 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); } +void __init secureboot_enable() +{ + pr_info("Secure boot enabled\n"); + cap_lower((&init_cred)->cap_bset, CAP_COMPROMISE_KERNEL); + cap_lower((&init_cred)->cap_permitted, CAP_COMPROMISE_KERNEL); +} + +/* Dummy Secure Boot enable option to fake out UEFI SB=1 */ +static int __init secureboot_enable_opt(char *str) +{ + int sb_enable = !!simple_strtol(str, NULL, 0); + if (sb_enable) + secureboot_enable(); + return 1; +} +__setup("secureboot_enable=", secureboot_enable_opt); + /** * prepare_kernel_cred - Prepare a set of credentials for a kernel service * @daemon: A userspace daemon to be used as a reference -- 1.8.0.2