From patchwork Thu May 5 12:31:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 12839504 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 B92D0C433F5 for ; Thu, 5 May 2022 12:32:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376684AbiEEMfn (ORCPT ); Thu, 5 May 2022 08:35:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376680AbiEEMfm (ORCPT ); Thu, 5 May 2022 08:35:42 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5DE1355228; Thu, 5 May 2022 05:32:03 -0700 (PDT) Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 245BxhJ6027909; Thu, 5 May 2022 12:32:00 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=qUXAepiDVmZx2bZLC9ayAdpC3X/oNkIf11N2exuWOCQ=; b=KLlxYG3UH65psfTxx3UT/YoE6x/E5UcqyWurY3dQKjdLfdq4bb4auKPE5ij0xZMeMsIf 1JB2S3o+BtBScGCM9LWM6jKC4CQjkSJL3LspY4zCUUlju4uiOuYh5KwDlShAPii6FJgW TwTly5nEcnVtr21xsobCaJO18V4PKkSO//udpXWfPw1rjp89DT661EjiqRH0vpGHlXZ6 PSVpxQ6rtSFpzVtxnTNI9CsVdMPZrlwsxihWowW71o7h6/UyvKibQz7Cs9Yq/Qf7DD5W mW6SQUyp5rMMg2d3/AkCqn8sPsSnx/fzMDbMw6/EoEqkYUAxZ03pDqoZF5MggX0wjIiT Og== Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3fve6rrnq4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 05 May 2022 12:31:59 +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 245CREdJ001521; Thu, 5 May 2022 12:31:57 GMT Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by ppma03ams.nl.ibm.com with ESMTP id 3ftp7fv1sw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 05 May 2022 12:31:57 +0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 245CVsFA47841578 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 5 May 2022 12:31:54 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 262684C059; Thu, 5 May 2022 12:31:54 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 34B044C04E; Thu, 5 May 2022 12:31:53 +0000 (GMT) Received: from li-f45666cc-3089-11b2-a85c-c57d1a57929f.ibm.com.com (unknown [9.65.81.94]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 5 May 2022 12:31:53 +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 v9 0/7] ima: support fs-verity digests and signatures Date: Thu, 5 May 2022 08:31:34 -0400 Message-Id: <20220505123141.1599622-1-zohar@linux.ibm.com> X-Mailer: git-send-email 2.27.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 7kNCAKdQCMdKPDlLV-V87FdgTInxbCpr X-Proofpoint-GUID: 7kNCAKdQCMdKPDlLV-V87FdgTInxbCpr X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-05_05,2022-05-05_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 impostorscore=0 malwarescore=0 clxscore=1015 mlxscore=0 priorityscore=1501 bulkscore=0 spamscore=0 phishscore=0 adultscore=0 mlxlogscore=999 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205050091 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 was discussed prior to fs-verity being upstreamed[1,2]. Including fs-verity file digests and signatures in the IMA measurement list need to be based on policy and be identifiable. To address being based on policy, a new policy rule option "digest_type=verity", applicable to both "measure" and "appraise" policy rules, is defined. To address being identifiable, a new template field 'd-ngv2' and two new template formats 'ima-ngv2' and 'ima-sigv2' are defined. d-ngv2: prefixes the digest type ("ima", "verity") to the digest algorithm and digest. ima-ngv2', ima-sigv2: templates with the new d-ngv2 field defined. In addition the signatures stored in 'security.ima' xattr need to be disambiguated. So instead of directly signing the fs-verity digest, the fs-verity digest is indirectly signed, by signing the hash of the new ima_file_id structure data (signature version 3) containing the fs-verity digest and other metadata. New policy rule option: appraise_type=sigv3: support for new IMA signature version 3 [1] https://events19.linuxfoundation.org/wp-content/uploads/2017/11/fs-verify_Mike-Halcrow_Eric-Biggers.pdf [2] Documentation/filesystems/fsverity.rst Changelog v9: - Based on Stefan Berger's review, fixed sprintf (again), updated comment replacing NULL with NUL, adding fuller comment explanation, and included his tags. Changelog v8: - Based on Eric Bigger's review, fixed the original 'd-ng' and the new DATA_FMT_DIGEST_WITH_TYPE_ALGO comments and documentation, moved the buffer measurement test to after fs-verity measurements, renamed appraise_type "sigv2" to "sigv3", require the new "digest_type=verity" policy option be specified prior to "appraise_type=sigv3", and updated the fs-verity documentation. Changelog v7: - Based on Stefan Berger's review, cleaned up code by defining an enum, removed unnecessary memcpy, fs-verity documentation suggestions. - Add comment in ima_get_verify_digest() with explanation for always returning the fs-verity digest. Changelog v6: - As suggested by Eric Bigger's, instead of defining a new field to differentiate between IMA and fs-verity signatures, prepend the digest type to the digest field. - Addressed Eric Bigger's comments: updated the patch description, corrected comment, squashed patches, fixed enumeration usage,and added assumption to fsverity_get_digest. - Removed the now unnecessary IMA_VERITY_DIGEST flag - Updated kernel-parameters.txt Changelog v5: - Define ima_max_digest_size struct, removing the locally defined versions. - Don't overload the 'digest_type=verity' to imply a verity signature, but extend the 'appraise_type' policy rule option to define 'sigv3'. 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 (7): ima: fix 'd-ng' comments and documentation ima: use IMA default hash algorithm for integrity violations fs-verity: define a function to return the integrity protected file digest ima: define a new template field named 'd-ngv2' and templates ima: permit fsverity's file digests in the IMA measurement list ima: support fs-verity file digest based version 3 signatures fsverity: update the documentation Documentation/ABI/testing/ima_policy | 45 ++++++- .../admin-guide/kernel-parameters.txt | 3 +- Documentation/filesystems/fsverity.rst | 35 ++++-- Documentation/security/IMA-templates.rst | 11 +- fs/verity/Kconfig | 1 + fs/verity/fsverity_private.h | 7 -- fs/verity/measure.c | 43 +++++++ include/linux/fsverity.h | 18 +++ security/integrity/digsig.c | 3 +- security/integrity/ima/ima_api.c | 47 +++++++- security/integrity/ima/ima_appraise.c | 114 +++++++++++++++++- security/integrity/ima/ima_main.c | 2 +- security/integrity/ima/ima_policy.c | 82 +++++++++++-- security/integrity/ima/ima_template.c | 4 + security/integrity/ima/ima_template_lib.c | 97 ++++++++++++--- security/integrity/ima/ima_template_lib.h | 4 + security/integrity/integrity.h | 27 ++++- 17 files changed, 481 insertions(+), 62 deletions(-)