From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:34086 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727175AbeI0TuS (ORCPT ); Thu, 27 Sep 2018 15:50:18 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w8RDPDla069237 for ; Thu, 27 Sep 2018 09:31:59 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ms01f0exf-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 27 Sep 2018 09:31:59 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 27 Sep 2018 14:31:57 +0100 Subject: Re: [PATCH v4 6/6] x86/ima: define arch_get_ima_policy() for x86 From: Mimi Zohar To: Nayna Jain , linux-integrity@vger.kernel.org Cc: linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, jforbes@redhat.com, Eric Richter Date: Thu, 27 Sep 2018 09:31:42 -0400 In-Reply-To: <20180926122210.14642-7-nayna@linux.vnet.ibm.com> References: <20180926122210.14642-1-nayna@linux.vnet.ibm.com> <20180926122210.14642-7-nayna@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Message-Id: <1538055102.3459.112.camel@linux.ibm.com> Sender: linux-integrity-owner@vger.kernel.org List-ID: Hi Eric, Nayna, On Wed, 2018-09-26 at 17:52 +0530, Nayna Jain wrote: > From: Eric Richter > This patch implements an example arch-specific IMA policy for x86 to > enable measurement and appraisal of any kernel image loaded for kexec, > when CONFIG_KEXEC_VERIFY_SIG is not enabled. > > For systems with CONFIG_KEXEC_VERIFY_SIG enabled, only the measurement > rule is enabled, not the IMA-appraisal rule. The patch itself looks good, but this patch description explains "what" the patch is doing, not "why". Missing is the motivation for the patch. Mimi > > 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 | 8 ++++++++ > 3 files changed, 30 insertions(+) > > 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..97609a76aa14 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