From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:35402 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729120AbeJFAnl (ORCPT ); Fri, 5 Oct 2018 20:43:41 -0400 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w95HeBAR088040 for ; Fri, 5 Oct 2018 13:43:55 -0400 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0b-001b2d01.pphosted.com with ESMTP id 2mxcarrpn6-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 05 Oct 2018 13:43:55 -0400 Received: from localhost by e06smtp02.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 5 Oct 2018 18:43:53 +0100 From: Nayna Jain To: linux-integrity@vger.kernel.org Cc: zohar@linux.ibm.com, linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, jforbes@redhat.com, seth.forshee@canonical.com, kexec@lists.infradead.org, Eric Richter , Nayna Jain Subject: [PATCH v5 5/5] x86/ima: define arch_get_ima_policy() for x86 Date: Fri, 5 Oct 2018 23:10:15 +0530 In-Reply-To: <20181005174015.21939-1-nayna@linux.vnet.ibm.com> References: <20181005174015.21939-1-nayna@linux.vnet.ibm.com> Message-Id: <20181005174015.21939-6-nayna@linux.vnet.ibm.com> Sender: linux-integrity-owner@vger.kernel.org List-ID: From: Eric Richter On x86, there are two methods of verifying a kexec'ed kernel image signature being loaded via the kexec_file_load syscall - an architecture specific implementaton or a IMA KEXEC_KERNEL_CHECK appraisal rule. Neither of these methods verify the kexec'ed kernel image signature being loaded via the kexec_load syscall. Secure boot enabled systems require kexec images to be signed. Therefore, this patch loads an IMA KEXEC_KERNEL_CHECK policy rule on secure boot enabled systems not configured with CONFIG_KEXEC_VERIFY_SIG enabled. When IMA_APPRAISE_BOOTPARAM is configured, different IMA appraise modes (eg. fix, log) can be specified on the boot command line, allowing unsigned or invalidly signed kernel images to be kexec'ed. This patch permits enabling IMA_APPRAISE_BOOTPARAM or IMA_ARCH_POLICY, but not both. Signed-off-by: Eric Richter - Removed the policy KEXEC_ORIG_KERNEL_CHECK which was defined to disable the kexec_load syscall. - arch_get_ima_policy() uses arch_ima_get_secureboot() to get secureboot state Signed-off-by: Nayna Jain --- arch/x86/kernel/ima_arch.c | 18 ++++++++++++++++++ include/linux/ima.h | 4 ++++ security/integrity/ima/Kconfig | 10 +++++++++- 3 files changed, 31 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/ima_arch.c b/arch/x86/kernel/ima_arch.c index bb5a88d2b271..245976e49a55 100644 --- a/arch/x86/kernel/ima_arch.c +++ b/arch/x86/kernel/ima_arch.c @@ -15,3 +15,21 @@ bool arch_ima_get_secureboot(void) else return false; } + +/* arch rules for audit and user mode */ +static const char * const sb_arch_rules[] = { +#ifndef CONFIG_KEXEC_VERIFY_SIG + "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig", +#endif /* CONFIG_KEXEC_VERIFY_SIG */ + "measure func=KEXEC_KERNEL_CHECK", + NULL +}; + +#ifdef CONFIG_IMA_ARCH_POLICY +const char * const *arch_get_ima_policy(void) +{ + if (arch_ima_get_secureboot()) + return sb_arch_rules; + return NULL; +} +#endif diff --git a/include/linux/ima.h b/include/linux/ima.h index 350fa957f8a6..dabd3abdf671 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -39,10 +39,14 @@ static inline bool arch_ima_get_secureboot(void) } #endif +#if defined(CONFIG_X86) && defined(CONFIG_IMA_ARCH_POLICY) +extern const char * const *arch_get_ima_policy(void); +#else static inline const char * const *arch_get_ima_policy(void) { return NULL; } +#endif #else static inline int ima_bprm_check(struct linux_binprm *bprm) diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 13b446328dda..a18f8c6d13b5 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -157,6 +157,14 @@ config IMA_APPRAISE If unsure, say N. +config IMA_ARCH_POLICY + bool "Enable loading an IMA architecture specific policy" + depends on KEXEC_VERIFY_SIG || IMA_APPRAISE && INTEGRITY_ASYMMETRIC_KEYS + default n + help + This option enables loading an IMA architecture specific policy + based on run time secure boot flags. + config IMA_APPRAISE_BUILD_POLICY bool "IMA build time configured policy rules" depends on IMA_APPRAISE && INTEGRITY_ASYMMETRIC_KEYS @@ -217,7 +225,7 @@ config IMA_APPRAISE_REQUIRE_POLICY_SIGS config IMA_APPRAISE_BOOTPARAM bool "ima_appraise boot parameter" - depends on IMA_APPRAISE + depends on IMA_APPRAISE && !IMA_ARCH_POLICY default y help This option enables the different "ima_appraise=" modes -- 2.13.6