From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2A27C4360C for ; Wed, 2 Oct 2019 21:53:55 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A763D20842 for ; Wed, 2 Oct 2019 21:53:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A763D20842 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46k8zP09JvzDqWs for ; Thu, 3 Oct 2019 07:53:53 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46k8tK0dLzzDqX0 for ; Thu, 3 Oct 2019 07:49:29 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) by bilbo.ozlabs.org (Postfix) with ESMTP id 46k8tF4Q1xz8swG for ; Thu, 3 Oct 2019 07:49:25 +1000 (AEST) Received: by ozlabs.org (Postfix) id 46k8tF32mHz9sPd; Thu, 3 Oct 2019 07:49:25 +1000 (AEST) Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=linux.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=zohar@linux.ibm.com; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 46k8tD2gPjz9sPL for ; Thu, 3 Oct 2019 07:49:24 +1000 (AEST) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x92LkkwN067898 for ; Wed, 2 Oct 2019 17:49:21 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2vd3pf0n05-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 02 Oct 2019 17:49:21 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 2 Oct 2019 22:49:14 +0100 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x92LnDE019792014 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 2 Oct 2019 21:49:13 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2BA8A4C044; Wed, 2 Oct 2019 21:49:13 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 339C64C040; Wed, 2 Oct 2019 21:49:11 +0000 (GMT) Received: from dhcp-9-31-103-196.watson.ibm.com (unknown [9.31.103.196]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 2 Oct 2019 21:49:11 +0000 (GMT) Subject: Re: [PATCH v6 3/9] powerpc: add support to initialize ima policy rules From: Mimi Zohar To: Nayna , Thiago Jung Bauermann , Nayna Jain Date: Wed, 02 Oct 2019 17:49:10 -0400 In-Reply-To: <84f057d0-6a0b-d486-0eb6-f1590f32e377@linux.vnet.ibm.com> References: <1569594360-7141-1-git-send-email-nayna@linux.ibm.com> <1569594360-7141-4-git-send-email-nayna@linux.ibm.com> <877e5pwa1b.fsf@morokweng.localdomain> <84f057d0-6a0b-d486-0eb6-f1590f32e377@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19100221-0016-0000-0000-000002B37556 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19100221-0017-0000-0000-000033147C3D Message-Id: <1570052950.4421.70.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-10-02_09:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=3 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910020172 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree@vger.kernel.org, linux-efi@vger.kernel.org, Ard Biesheuvel , Eric Ricther , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Claudio Carvalho , Matthew Garret , linuxppc-dev@ozlabs.org, Rob Herring , Paul Mackerras , Jeremy Kerr , Elaine Palmer , Oliver O'Halloran , linux-integrity@vger.kernel.org, George Wilson Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 2019-10-01 at 12:07 -0400, Nayna wrote: > > On 09/30/2019 09:04 PM, Thiago Jung Bauermann wrote: > > Hello, > > Hi, > > > > >> diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c > >> new file mode 100644 > >> index 000000000000..39401b67f19e > >> --- /dev/null > >> +++ b/arch/powerpc/kernel/ima_arch.c > >> @@ -0,0 +1,33 @@ > >> +// SPDX-License-Identifier: GPL-2.0 > >> +/* > >> + * Copyright (C) 2019 IBM Corporation > >> + * Author: Nayna Jain > >> + */ > >> + > >> +#include > >> +#include > >> + > >> +bool arch_ima_get_secureboot(void) > >> +{ > >> + return is_powerpc_os_secureboot_enabled(); > >> +} > >> + > >> +/* Defines IMA appraise rules for secureboot */ > >> +static const char *const arch_rules[] = { > >> + "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig", > >> +#if !IS_ENABLED(CONFIG_MODULE_SIG) > >> + "appraise func=MODULE_CHECK appraise_type=imasig|modsig", > >> +#endif > >> + NULL > >> +}; > >> + > >> +/* > >> + * Returns the relevant IMA arch policies based on the system secureboot state. > >> + */ > >> +const char *const *arch_get_ima_policy(void) > >> +{ > >> + if (is_powerpc_os_secureboot_enabled()) > >> + return arch_rules; > >> + > >> + return NULL; > >> +} > > If CONFIG_MODULE_SIG is enabled but module signatures aren't enforced, > > then IMA won't enforce module signature either. x86's > > arch_get_ima_policy() calls set_module_sig_enforced(). Doesn't the > > powerpc version need to do that as well? > > > > On the flip side, if module signatures are enforced by the module > > subsystem then IMA will verify the signature a second time since there's > > no sharing of signature verification results between the module > > subsystem and IMA (this was observed by Mimi). > > > > IMHO this is a minor issue, since module loading isn't a hot path and > > the duplicate work shouldn't impact anything. But it could be avoided by > > having a NULL entry in arch_rules, which arch_get_ima_policy() would > > dynamically update with the "appraise func=MODULE_CHECK" rule if > > is_module_sig_enforced() is true. > > Thanks Thiago for reviewing.  I am wondering that this will give two > meanings for NULL. Can we do something like below, there are possibly > two options ? > > 1. Set IMA_APPRAISED in the iint->flags if is_module_sig_enforced(). > > OR > > 2. Let ima_get_action() check for is_module_sig_enforced() when policy > is appraise and func is MODULE_CHECK. I'm a bit hesitant about mixing the module subsystem signature verification method with the IMA measure "template=ima-modsig" rules.  Does it actually work? We can at least limit verifying the same appended signature twice to when "module.sig_enforce" is specified on the boot command line, by changing "!IS_ENABLED(CONFIG_MODULE_SIG)" to test "CONFIG_MODULE_SIG_FORCE". Mimi