From patchwork Fri Mar 18 18:21:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 12785759 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 63488C433F5 for ; Fri, 18 Mar 2022 18:22:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240098AbiCRSXn (ORCPT ); Fri, 18 Mar 2022 14:23:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240094AbiCRSXj (ORCPT ); Fri, 18 Mar 2022 14:23:39 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1C76430CDAE; Fri, 18 Mar 2022 11:22:12 -0700 (PDT) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 22IHN266023400; Fri, 18 Mar 2022 18:22:10 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=y0TAq5uOzk+Jle3ny7B++D4HVgPEgEWaFU3XPVXJg8U=; b=XyUhszYWI904V5MNyMw78ui1qXiT27dzvslnCSEIPTpj3kS44h1dKSHkkBMXBB781I6F wuBtCS/YxSKNXsH0u9mnBIc5hGmZ45YR0M4D2LBj8kWxepaPh16qeIo/b4nb7RLmFKdd ViqZvn1EZA6MJ9gBer0Urtz+FaJqF/+YY5x+Z/FqU2Zon7FM17DhvjDOrPbDXD+p1eX0 rXX/cvBfO40+7xiaZG68XTofdU6N70fqBmWmvBsTTI5p0KkPVUoF9euXpNA+V4e1rA+g H70GdghOF5ZKSmrqOyTH6Z3MnEsAxEM9wYyiCEWR/PuwBZc6XpINczlvSscTs3njffwI Ew== Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0b-001b2d01.pphosted.com with ESMTP id 3euy5wx0ef-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 18 Mar 2022 18:22:09 +0000 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 22II4pdZ028153; Fri, 18 Mar 2022 18:22:08 GMT Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by ppma06ams.nl.ibm.com with ESMTP id 3euc6r5juh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 18 Mar 2022 18:22:08 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 22IIM4Ki43909402 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 18 Mar 2022 18:22:04 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A843EAE05F; Fri, 18 Mar 2022 18:22:04 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CBEE6AE05A; Fri, 18 Mar 2022 18:22:03 +0000 (GMT) Received: from li-f45666cc-3089-11b2-a85c-c57d1a57929f.ibm.com.com (unknown [9.65.75.142]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 18 Mar 2022 18:22:03 +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 v6 5/5] fsverity: update the documentation Date: Fri, 18 Mar 2022 14:21:51 -0400 Message-Id: <20220318182151.100847-6-zohar@linux.ibm.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220318182151.100847-1-zohar@linux.ibm.com> References: <20220318182151.100847-1-zohar@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 9Hmc_71JoqzadQh3KMJNdCTdUIuKBryl X-Proofpoint-ORIG-GUID: 9Hmc_71JoqzadQh3KMJNdCTdUIuKBryl X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-18_13,2022-03-15_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 clxscore=1015 impostorscore=0 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 mlxlogscore=897 lowpriorityscore=0 priorityscore=1501 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2203180095 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..28a47488848e 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 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?