From patchwork Wed Jan 26 00:06:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 12724373 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90975C5DF62 for ; Wed, 26 Jan 2022 00:07:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235155AbiAZAH2 (ORCPT ); Tue, 25 Jan 2022 19:07:28 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:35354 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235166AbiAZAHY (ORCPT ); Tue, 25 Jan 2022 19:07:24 -0500 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 20PNgHVj026457; Wed, 26 Jan 2022 00:07:22 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=zROlUnGp7KwW/JRJDF1wWCeMVgCxWkXiPtbI6LaWmgA=; b=J86s2Md/Hr7go6qIbSwV+7RbychzpluXqIU+yP4bmdvUPkeGSVJuVocLODP36hnk5IYh +LlYb44tGjaYhx3qNVu8RohO0Frw3G9N7tsfdLecbCjeFgvJVqEmNSUBQqCVYasa555c 5nAd9K1+yVW/n2jm7Yx3dF8yeyRcLWDCLBWNRuU8JZGAQVfWrH9wyplGnOQ7QQc00Dla w3QmzskSg9HANIGdyTB1sc06Hmj72ce+DEcq/NCLEkGh0397DT/8tjhfYx48ZDMVhe8H YSunmyViQ8k6uJlq2SkVr9Ni8SzTlViOBDZEHSgG9DDcFSf+7RonzfBZzknLKLmz8PLt wg== Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 3dtu3u8e0p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 26 Jan 2022 00:07:22 +0000 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 20Q03ur7014076; Wed, 26 Jan 2022 00:07:20 GMT Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by ppma03ams.nl.ibm.com with ESMTP id 3dr9j9a7u8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 26 Jan 2022 00:07:19 +0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 20Q07GBQ20447568 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Jan 2022 00:07:16 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D1E704C040; Wed, 26 Jan 2022 00:07:16 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 01DCF4C059; Wed, 26 Jan 2022 00:07:16 +0000 (GMT) Received: from li-f45666cc-3089-11b2-a85c-c57d1a57929f.ibm.com.com (unknown [9.65.78.94]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 26 Jan 2022 00:07:15 +0000 (GMT) From: Mimi Zohar To: linux-integrity@vger.kernel.org Cc: Mimi Zohar , Eric Biggers , Stefan Berger , linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 8/8] fsverity: update the documentation Date: Tue, 25 Jan 2022 19:06:58 -0500 Message-Id: <20220126000658.138345-9-zohar@linux.ibm.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220126000658.138345-1-zohar@linux.ibm.com> References: <20220126000658.138345-1-zohar@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 8ATXkNbAEPxEWOFzGJZNBIPFAKkfpcOK X-Proofpoint-GUID: 8ATXkNbAEPxEWOFzGJZNBIPFAKkfpcOK X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2022-01-25_06,2022-01-25_02,2021-12-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 bulkscore=0 phishscore=0 spamscore=0 suspectscore=0 adultscore=0 lowpriorityscore=0 impostorscore=0 mlxlogscore=959 clxscore=1015 priorityscore=1501 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2201250145 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org Update the fsverity documentation related to IMA signature support. Signed-off-by: Mimi Zohar --- Documentation/filesystems/fsverity.rst | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst index 1d831e3cbcb3..7d8a574a0d3b 100644 --- a/Documentation/filesystems/fsverity.rst +++ b/Documentation/filesystems/fsverity.rst @@ -74,8 +74,12 @@ authenticating the files is up to userspace. However, to meet some users' needs, fs-verity optionally supports a simple signature verification mechanism where users can configure the kernel to require that all fs-verity files be signed by a key loaded into a keyring; see -`Built-in signature verification`_. Support for fs-verity file hashes -in IMA (Integrity Measurement Architecture) policies is also planned. +`Built-in signature verification`_. + +IMA supports including fs-verity file digests and signatures based +on the fs-verity file digests in the IMA (Integrity Measurement +Architecture) measurement list and verifying fs-verity based file +signatures stored as security.ima xattrs, based on policy. User API ======== @@ -653,13 +657,13 @@ weren't already directly answered in other parts of this document. hashed and what to do with those hashes, such as log them, authenticate them, or add them to a measurement list. - IMA is planned to support the fs-verity hashing mechanism as an - alternative to doing full file hashes, for people who want the - performance and security benefits of the Merkle tree based hash. - But it doesn't make sense to force all uses of fs-verity to be - through IMA. As a standalone filesystem feature, fs-verity - already meets many users' needs, and it's testable like other - filesystem features e.g. with xfstests. + IMA supports the fs-verity hashing mechanism as an alternative + to doing full file hashes, for people who want the performance + and security benefits of the Merkle tree based hash. But it + doesn't make sense to force all uses of fs-verity to be through + IMA. As a standalone filesystem feature, fs-verity already meets + many users' needs, and it's testable like other filesystem + features e.g. with xfstests. :Q: Isn't fs-verity useless because the attacker can just modify the hashes in the Merkle tree, which is stored on-disk?