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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 B988BC43381 for ; Thu, 14 Mar 2019 22:31:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 80D5521019 for ; Thu, 14 Mar 2019 22:31:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727489AbfCNWbu (ORCPT ); Thu, 14 Mar 2019 18:31:50 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:51938 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726885AbfCNWbt (ORCPT ); Thu, 14 Mar 2019 18:31:49 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x2EMTY1o125615 for ; Thu, 14 Mar 2019 18:31:48 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2r7vv6yu2q-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 14 Mar 2019 18:31:47 -0400 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 14 Mar 2019 22:31:46 -0000 Received: from b06cxnps4075.portsmouth.uk.ibm.com (9.149.109.197) by e06smtp01.uk.ibm.com (192.168.101.131) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 14 Mar 2019 22:31:44 -0000 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 x2EMVhsP28246154 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 14 Mar 2019 22:31:43 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 56BA54C074; Thu, 14 Mar 2019 22:31:43 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 88CC84C07F; Thu, 14 Mar 2019 22:31:42 +0000 (GMT) Received: from localhost.localdomain (unknown [9.80.108.186]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 14 Mar 2019 22:31:42 +0000 (GMT) Subject: Re: [RFC] kexec: Allow kexec_file() with appropriate IMA policy when locked down From: Mimi Zohar To: Matthew Garrett Cc: linux-integrity , David Howells , Dmitry Kasatkin Date: Thu, 14 Mar 2019 18:31:31 -0400 In-Reply-To: References: <20190312195715.101995-1-matthewgarrett@google.com> <1552478316.24794.210.camel@linux.ibm.com> <1552512556.24794.229.camel@linux.ibm.com> <1552525698.24794.237.camel@linux.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: 19031422-4275-0000-0000-0000031B1CF0 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19031422-4276-0000-0000-0000382990CB Message-Id: <1552602691.8658.49.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-03-14_12:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=983 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1903140151 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Thu, 2019-03-14 at 14:08 -0700, Matthew Garrett wrote: > On Wed, Mar 13, 2019 at 6:08 PM Mimi Zohar wrote: > > The IMA hash and EVM hmac combination is fine for offline protection. > > It's used for mutable files. For immutable files, there must be > > either an IMA or EVM signature. > > Ok. Is the correct way to handle this to check that the file has a > signature, or to extend IMA policy to allow it to provide a > requirement that EVM verify a signature rather than an HMAC and have > the arch policy set that? I'm not sure what you mean by "check that the file has a signature". EVM and IMA are separate subsystems with a defined interface for interaction between them. evm_verifyxattr() isn't, but could be called by LSMs.  So evm_verifyxattr() would need to be extended to return the EVM xattr type.  The IMA policy could then require a specific evmxattr type.  Possible. Perhaps for now require IMA signatures and defer supporting EVM signatures? Mimi