From patchwork Thu Dec 2 21:55:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 12653525 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 A3E76C433F5 for ; Thu, 2 Dec 2021 21:55:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377183AbhLBV7S (ORCPT ); Thu, 2 Dec 2021 16:59:18 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:46308 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1377196AbhLBV7Q (ORCPT ); Thu, 2 Dec 2021 16:59:16 -0500 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 1B2LmFq0008337; Thu, 2 Dec 2021 21:55:51 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=PeO0/hc3erG3X51IVBgR1vS4QW4jYCIERfbZMYRZViw=; b=G760Z2+pDNHhLje9uO85fn9pJ2AaG9WKBARfIC168Pl9Jv6cx0/Bnxxse8dvrUAc6mEl jT0hYdYd6FJAIzOpE4UdWAupWbOohGEHe55ZbyGvsM3HYTBV+WyyxtJlRlYRMmCIh3dT heYOVtCcMeCnon3l6J9hNUXN4myuxEBI9iz6XoeXVMtQ1id84wDD0pUnEmpuhgWCOBns m5DL9kLJD9RTYhDmj/W+Cu+SaNGMpmuC5hJicT/eymMmzr1wi9EL14niz5waSm/zUdHZ +qqCP6maCwXHgbQKtE6IoeX/F5Q4SEg4Ok8SJf8AvWr1eyOZCB5aiuG6gqfzC8taOuEg oQ== 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 3cq6ccg68j-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 02 Dec 2021 21:55:51 +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 1B2LoM68008897; Thu, 2 Dec 2021 21:55:49 GMT Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by ppma06ams.nl.ibm.com with ESMTP id 3ckbxkrb72-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 02 Dec 2021 21:55:49 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 1B2Ltl0N26149130 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 2 Dec 2021 21:55:47 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0CE9152059; Thu, 2 Dec 2021 21:55:47 +0000 (GMT) Received: from li-f45666cc-3089-11b2-a85c-c57d1a57929f.ibm.com.com (unknown [9.65.72.23]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 56C915204E; Thu, 2 Dec 2021 21:55:46 +0000 (GMT) From: Mimi Zohar To: linux-integrity@vger.kernel.org Cc: Mimi Zohar , Eric Biggers , linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v1 5/5] fsverity: update the documentation Date: Thu, 2 Dec 2021 16:55:07 -0500 Message-Id: <20211202215507.298415-6-zohar@linux.ibm.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211202215507.298415-1-zohar@linux.ibm.com> References: <20211202215507.298415-1-zohar@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: c8JL2WTN8MOCgCK-YTxRD0r5SYXOvor8 X-Proofpoint-ORIG-GUID: c8JL2WTN8MOCgCK-YTxRD0r5SYXOvor8 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.790,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2021-12-02_14,2021-12-02_01,2021-12-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 lowpriorityscore=0 malwarescore=0 suspectscore=0 adultscore=0 spamscore=0 priorityscore=1501 mlxlogscore=999 impostorscore=0 clxscore=1015 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2110150000 definitions=main-2112020133 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..c71f6e365df5 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 (Integrity Measurement Architecture) supports fs-verity file +digests based signatures stored as security.ima xattrs, which are +identified by the signature type IMA_VERITY_DIGSIG. + 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?