From patchwork Tue Feb 8 01:41:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 12738047 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 2505DC35272 for ; Tue, 8 Feb 2022 01:48:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343507AbiBHBsL (ORCPT ); Mon, 7 Feb 2022 20:48:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344851AbiBHBmW (ORCPT ); Mon, 7 Feb 2022 20:42:22 -0500 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5FA95C061355; Mon, 7 Feb 2022 17:42:21 -0800 (PST) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 217MZBR3010102; Tue, 8 Feb 2022 01:42:19 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : mime-version; s=pp1; bh=UNUur/hBWvqFbCPOd/NO7v0L0HXsVxHb5kP1rmwZ78I=; b=FC5+b6Yg+hB7IS0MJtqKFStj1ANHUixlyf5/N0SCLdYIP9Z2nivXWkxXV5gcN39Bsn9c cPQSA1AfKj6irNGuaX4zot06MnARp8u6MxsTJp1qUuYQCkCD5UIsNZ3AS1JgATfVMtc1 5PYLhYfqY/X7ZLZqHbB8THCY0qR8JU2WtbOr4tkEj/61TgMAcbO5Wz8cTsOQD6qbq4Od +Yu8PO1mTrL7AC7dumfNxYZtzYqRX8Z/+QFuwqfZ4kyBnRDCxvzS29dlIS9jf30oPogj k2n19aorhPRAD17c+d8RMeBqtupKwSwc/nv2x7jaAWlaZO/O8kLCv23JbupW7IuDEGKz Mw== Received: from ppma06fra.de.ibm.com (48.49.7a9f.ip4.static.sl-reverse.com [159.122.73.72]) by mx0a-001b2d01.pphosted.com with ESMTP id 3e22qf4n4s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 08 Feb 2022 01:42:19 +0000 Received: from pps.filterd (ppma06fra.de.ibm.com [127.0.0.1]) by ppma06fra.de.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 2181WqOr025785; Tue, 8 Feb 2022 01:42:17 GMT Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by ppma06fra.de.ibm.com with ESMTP id 3e1ggj0pqs-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 08 Feb 2022 01:42:16 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 2181gDB339584252 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 8 Feb 2022 01:42:13 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 55EB9A4057; Tue, 8 Feb 2022 01:42:13 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6B102A4053; Tue, 8 Feb 2022 01:42:12 +0000 (GMT) Received: from li-f45666cc-3089-11b2-a85c-c57d1a57929f.ibm.com.com (unknown [9.65.90.153]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 8 Feb 2022 01:42:12 +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 v4 0/8] ima: support fs-verity digests and signatures Date: Mon, 7 Feb 2022 20:41:32 -0500 Message-Id: <20220208014140.483447-1-zohar@linux.ibm.com> X-Mailer: git-send-email 2.27.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: tiZgD6NcCqFjkfNAaXxdhQJyE1d3TVam X-Proofpoint-GUID: tiZgD6NcCqFjkfNAaXxdhQJyE1d3TVam X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 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=2022-02-07_07,2022-02-07_02,2021-12-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 mlxscore=0 adultscore=0 malwarescore=0 clxscore=1015 suspectscore=0 bulkscore=0 lowpriorityscore=0 impostorscore=0 priorityscore=1501 spamscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2202080006 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org Support for including fs-verity file digests and signatures in the IMA measurement list as well as verifying the fs-verity file digest based signatures, both based on IMA policy rules, was discussed prior to fs-verity being upstreamed[1,2]. Support for including fs-verity file digests in the 'd-ng' template field is based on a new policy rule option named 'digest_type=verity'. A new template field named 'd-type' as well as a new template named 'ima-ngv2' are defined to differentiate between the regular IMA file hashes from the fs-verity file digests (tree-hash based file hashes) stored in the 'd-ng' template field. Support for verifying fs-verity based file signatures stored in the 'security.ima' xattr is similarly based on the policy rule option 'digest_type=verity'. To differentiate IMA from fs-verity file signatures a new xattr_type named IMA_VERITY_DIGSIG is defined. Signature version 3, which is a hash of the ima_file_id struct, disambiguates the signatures stored as 'security.ima' xattr. fs-verity only supports the new signature format (version 3). To prevent abuse of the different signature formats, policy rules must be limited to a specific signature version. [1] https://events19.linuxfoundation.org/wp-content/uploads/2017/11/fs-verify_Mike-Halcrow_Eric-Biggers.pdf [2] Documentation/filesystems/fsverity.rst Changelog v4: - Based on Eric Bigger's signature verification concerns of replacing the contents of a file with the ima_file_id struct hash, require per policy rule signature versions. - Addressed Eric Bigger's other comments. - Added new audit messages "causes". - Updated patch descriptions. Changelog v3: - Addressed Eric Bigger's comments: included Ack, incremented the signature format version, the crypto issues are generic and will be addressed by him separately. - Addressed Vitaly Chikunov's comments: hard coded maximum digest size rather than using a flexible array, removed unnecessary assignment, and fixed comment to match variable name. - Defined new "ima_max_digest_size" struct to avoid wrapping the "ima_digest_data" struct inside a function local structure or having to dynamically allocate it with enough memory for the specific hash algo size. Changelog v2: - Addressed Eric Bigger's comments: sign the hash of fsverity's digest and the digest's metadata, use match_string, use preferred function name fsverity_get_digest(), support including unsigned fs-verity's digests in the IMA measurement list. - Remove signatures requirement for including fs-verity's file digests in the 'd-ng' field of the measurement list. Changelog v1: - Updated both fsverity and IMA documentation. - Addressed both Eric Bigger's and Lakshmi's comments. Mimi Zohar (8): ima: rename IMA_ACTION_FLAGS to IMA_NONACTION_FLAGS ima: define ima_max_digest_data struct without a flexible array variable fs-verity: define a function to return the integrity protected file digest ima: define a new template field 'd-type' and a new template 'ima-ngv2' ima: permit fsverity's file digests in the IMA measurement list ima: define signature version 3 ima: support fs-verity file digest based version 3 signatures fsverity: update the documentation Documentation/ABI/testing/ima_policy | 22 +++++ Documentation/filesystems/fsverity.rst | 22 +++-- Documentation/security/IMA-templates.rst | 11 ++- fs/verity/Kconfig | 1 + fs/verity/fsverity_private.h | 7 -- fs/verity/measure.c | 41 ++++++++ include/linux/fsverity.h | 18 ++++ security/integrity/digsig.c | 3 +- security/integrity/ima/ima_api.c | 59 ++++++++--- security/integrity/ima/ima_appraise.c | 113 +++++++++++++++++++++- security/integrity/ima/ima_init.c | 10 +- security/integrity/ima/ima_main.c | 2 +- security/integrity/ima/ima_policy.c | 45 ++++++++- security/integrity/ima/ima_template.c | 3 + security/integrity/ima/ima_template_lib.c | 23 ++++- security/integrity/ima/ima_template_lib.h | 2 + security/integrity/integrity.h | 53 +++++++++- 17 files changed, 385 insertions(+), 50 deletions(-)