From patchwork Fri Feb 11 21:43:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 12743930 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 7A5F5C43217 for ; Fri, 11 Feb 2022 21:43:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353822AbiBKVnk (ORCPT ); Fri, 11 Feb 2022 16:43:40 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:55498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353821AbiBKVnj (ORCPT ); Fri, 11 Feb 2022 16:43:39 -0500 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3BF0C71; Fri, 11 Feb 2022 13:43:36 -0800 (PST) Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 21BJwbHv026909; Fri, 11 Feb 2022 21:43:35 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=pDKMI1eUkL84S5jAyct8e/8DIEtDBZme95zZJ3pvjmU=; b=jwC7RCHOtFfv5qpMEbJyNsC1DUfLGKvecJDa5LABsZobwid/7+9JT+TF3M/vcpGWCV8f vSA2YMc6tctF83BwC/Il1v27ROlZkI53pom+BpWU0xfWkR487N7qeWGXGsGM0O5pXnWz /iITMjP1+cglwcCUt+yloYfVYP7PckQpMaApCvt+gj6P8RbbP5TBiQrojO7NsTHKRb91 GfAmXbQDtKZfR/r/uOMq88YQVQL3mVhwW1AFSL+n6rzOJzGhiOHKKjn+rrQ2MlJIn2Qf QsXml1yWGQIfXwozsfwaHyQ1DTjuhE5Qe3RJvvxbdj7r73xAntHanNNxf8ywudWmLuOI 5w== Received: from ppma02fra.de.ibm.com (47.49.7a9f.ip4.static.sl-reverse.com [159.122.73.71]) by mx0a-001b2d01.pphosted.com with ESMTP id 3e5xe9hnwk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 11 Feb 2022 21:43:35 +0000 Received: from pps.filterd (ppma02fra.de.ibm.com [127.0.0.1]) by ppma02fra.de.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 21BLWMlR016653; Fri, 11 Feb 2022 21:43:32 GMT Received: from b06avi18626390.portsmouth.uk.ibm.com (b06avi18626390.portsmouth.uk.ibm.com [9.149.26.192]) by ppma02fra.de.ibm.com with ESMTP id 3e1gvaaj23-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 11 Feb 2022 21:43:32 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 21BLXFVY39190844 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 11 Feb 2022 21:33:15 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 184445204E; Fri, 11 Feb 2022 21:43:28 +0000 (GMT) Received: from li-f45666cc-3089-11b2-a85c-c57d1a57929f.ibm.com.com (unknown [9.65.69.128]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 4493852054; Fri, 11 Feb 2022 21:43:27 +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 v5 5/8] ima: permit fsverity's file digests in the IMA measurement list Date: Fri, 11 Feb 2022 16:43:07 -0500 Message-Id: <20220211214310.119257-6-zohar@linux.ibm.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220211214310.119257-1-zohar@linux.ibm.com> References: <20220211214310.119257-1-zohar@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: ce9OqL54LlkBVzNA_JxJhSOoUPW_y3NI X-Proofpoint-ORIG-GUID: ce9OqL54LlkBVzNA_JxJhSOoUPW_y3NI 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=2022-02-11_05,2022-02-11_01,2021-12-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 malwarescore=0 spamscore=0 mlxscore=0 adultscore=0 phishscore=0 lowpriorityscore=0 suspectscore=0 bulkscore=0 impostorscore=0 priorityscore=1501 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2202110108 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org Permit fsverity's file digest (a hash of struct fsverity_digest) to be included in the 'd-ng' field of the IMA measurement list, based on the new measurement policy rule 'digest_type=verity' option. To differentiate between an unsigned regular IMA file hash and an unsigned fsverity's file digest stored in the 'd-ng' field of the measurement list, it is recommended to include the 'd-type' template field. The following policy rule requires fsverity file digests and specifies the new 'ima-ngv2' template, which contains the new 'd-type' field. The policy rule may be constrained, for example based on a fsuuid or LSM label. measure func=FILE_CHECK digest_type=verity template=ima-ngv2 Signed-off-by: Mimi Zohar --- Documentation/ABI/testing/ima_policy | 10 ++++++ Documentation/security/IMA-templates.rst | 7 ++++ security/integrity/ima/ima_api.c | 39 +++++++++++++++++++++-- security/integrity/ima/ima_policy.c | 38 +++++++++++++++++++++- security/integrity/ima/ima_template_lib.c | 9 +++++- security/integrity/integrity.h | 4 ++- 6 files changed, 102 insertions(+), 5 deletions(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 839fab811b18..ff3c906738cb 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -51,6 +51,9 @@ Description: appraise_flag:= [check_blacklist] Currently, blacklist check is only for files signed with appended signature. + digest_type:= verity + Require fs-verity's file digest instead of the + regular IMA file hash. keyrings:= list of keyrings (eg, .builtin_trusted_keys|.ima). Only valid when action is "measure" and func is KEY_CHECK. @@ -149,3 +152,10 @@ Description: security.ima xattr of a file: appraise func=SETXATTR_CHECK appraise_algos=sha256,sha384,sha512 + + Example of 'measure' rule requiring fs-verity's digests on a + particular filesystem with indication of type of digest in + the measurement list. + + measure func=FILE_CHECK digest_type=verity \ + fsuuid=... template=ima-ngv2 diff --git a/Documentation/security/IMA-templates.rst b/Documentation/security/IMA-templates.rst index 1a91d92950a7..1e3fe986764e 100644 --- a/Documentation/security/IMA-templates.rst +++ b/Documentation/security/IMA-templates.rst @@ -69,6 +69,8 @@ descriptors by adding their identifier to the format string algorithm (field format: [:]digest, where the digest prefix is shown only if the hash algorithm is not SHA1 or MD5); - 'd-modsig': the digest of the event without the appended modsig; + - 'd-type': differentiate between fs-verity's Merkle tree based file hash + from a regular IMA file hash measurement. - 'n-ng': the name of the event, without size limitations; - 'sig': the file signature, or the EVM portable signature if the file signature is not found; @@ -106,3 +108,8 @@ currently the following methods are supported: the ``ima_template=`` parameter; - register a new template descriptor with custom format through the kernel command line parameter ``ima_template_fmt=``. + + +References +========== +[1] Documentation/filesystems/fsverity.rst diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index c6805af46211..68c93a1cb876 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "ima.h" @@ -200,6 +201,23 @@ int ima_get_action(struct user_namespace *mnt_userns, struct inode *inode, allowed_algos); } +static int ima_get_verity_digest(struct integrity_iint_cache *iint, + struct ima_max_digest_data *hash) +{ + u8 verity_digest[FS_VERITY_MAX_DIGEST_SIZE]; + enum hash_algo verity_alg; + int ret; + + ret = fsverity_get_digest(iint->inode, verity_digest, &verity_alg); + if (ret) + return ret; + if (hash->hdr.algo != verity_alg) + return -EINVAL; + hash->hdr.length = hash_digest_size[verity_alg]; + memcpy(hash->hdr.digest, verity_digest, hash->hdr.length); + return 0; +} + /* * ima_collect_measurement - collect file measurement * @@ -242,14 +260,31 @@ int ima_collect_measurement(struct integrity_iint_cache *iint, */ i_version = inode_query_iversion(inode); hash.hdr.algo = algo; + hash.hdr.length = hash_digest_size[algo]; /* Initialize hash digest to 0's in case of failure */ memset(&hash.digest, 0, sizeof(hash.digest)); - if (buf) + if (buf) { result = ima_calc_buffer_hash(buf, size, &hash.hdr); - else + } else if (iint->flags & IMA_VERITY_REQUIRED) { + result = ima_get_verity_digest(iint, &hash); + switch (result) { + case 0: + iint->flags |= IMA_VERITY_DIGEST; + break; + case -ENODATA: + audit_cause = "no-verity-digest"; + result = -EINVAL; + break; + case -EINVAL: + default: + audit_cause = "invalid-verity-digest"; + break; + } + } else { result = ima_calc_file_hash(file, &hash.hdr); + } if (result && result != -EBADF && result != -EINVAL) goto out; diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index a0f3775cbd82..28aca1f9633b 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -1024,6 +1024,7 @@ enum policy_opt { Opt_fowner_gt, Opt_fgroup_gt, Opt_uid_lt, Opt_euid_lt, Opt_gid_lt, Opt_egid_lt, Opt_fowner_lt, Opt_fgroup_lt, + Opt_digest_type, Opt_appraise_type, Opt_appraise_flag, Opt_appraise_algos, Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings, Opt_label, Opt_err @@ -1066,6 +1067,7 @@ static const match_table_t policy_tokens = { {Opt_egid_lt, "egid<%s"}, {Opt_fowner_lt, "fowner<%s"}, {Opt_fgroup_lt, "fgroup<%s"}, + {Opt_digest_type, "digest_type=%s"}, {Opt_appraise_type, "appraise_type=%s"}, {Opt_appraise_flag, "appraise_flag=%s"}, {Opt_appraise_algos, "appraise_algos=%s"}, @@ -1173,6 +1175,21 @@ static void check_template_modsig(const struct ima_template_desc *template) #undef MSG } +/* + * Make sure the policy rule and template format are in sync. + */ +static void check_template_field(const struct ima_template_desc *template, + const char *field, const char *msg) +{ + int i; + + for (i = 0; i < template->num_fields; i++) + if (!strcmp(template->fields[i]->field_id, field)) + return; + + pr_notice_once("%s", msg); +} + static bool ima_validate_rule(struct ima_rule_entry *entry) { /* Ensure that the action is set and is compatible with the flags */ @@ -1215,7 +1232,8 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) IMA_INMASK | IMA_EUID | IMA_PCR | IMA_FSNAME | IMA_GID | IMA_EGID | IMA_FGROUP | IMA_DIGSIG_REQUIRED | - IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS)) + IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS | + IMA_VERITY_REQUIRED)) return false; break; @@ -1708,6 +1726,13 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) LSM_SUBJ_TYPE, AUDIT_SUBJ_TYPE); break; + case Opt_digest_type: + ima_log_string(ab, "digest_type", args[0].from); + if ((strcmp(args[0].from, "verity")) == 0) + entry->flags |= IMA_VERITY_REQUIRED; + else + result = -EINVAL; + break; case Opt_appraise_type: ima_log_string(ab, "appraise_type", args[0].from); if ((strcmp(args[0].from, "imasig")) == 0) @@ -1798,6 +1823,15 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) check_template_modsig(template_desc); } + /* d-type template field recommended for unsigned fs-verity digests */ + if (!result && entry->action == MEASURE && + entry->flags & IMA_VERITY_REQUIRED) { + template_desc = entry->template ? entry->template : + ima_template_desc_current(); + check_template_field(template_desc, "d-type", + "verity rules should include d-type"); + } + audit_log_format(ab, "res=%d", !result); audit_log_end(ab); return result; @@ -2155,6 +2189,8 @@ int ima_policy_show(struct seq_file *m, void *v) else seq_puts(m, "appraise_type=imasig "); } + if (entry->flags & IMA_VERITY_REQUIRED) + seq_puts(m, "digest_type=verity "); if (entry->flags & IMA_CHECK_BLACKLIST) seq_puts(m, "appraise_flag=check_blacklist "); if (entry->flags & IMA_PERMIT_DIRECTIO) diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c index a213579e825e..d370fca04de4 100644 --- a/security/integrity/ima/ima_template_lib.c +++ b/security/integrity/ima/ima_template_lib.c @@ -389,7 +389,14 @@ int ima_eventdigest_ng_init(struct ima_event_data *event_data, int ima_eventdigest_type_init(struct ima_event_data *event_data, struct ima_field_data *field_data) { - static const char * const digest_type[] = {"ima"}; + static const char * const digest_type[] = {"ima", "verity"}; + + if (event_data->iint->flags & IMA_VERITY_DIGEST) { + return ima_write_template_field_data(digest_type[1], + strlen(digest_type[1]), + DATA_FMT_STRING, + field_data); + } return ima_write_template_field_data(digest_type[0], strlen(digest_type[0]), diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index daf49894fd7d..39a999877013 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -32,7 +32,7 @@ #define IMA_HASHED 0x00000200 /* iint policy rule cache flags */ -#define IMA_NONACTION_FLAGS 0xff000000 +#define IMA_NONACTION_FLAGS 0xff800000 #define IMA_DIGSIG_REQUIRED 0x01000000 #define IMA_PERMIT_DIRECTIO 0x02000000 #define IMA_NEW_FILE 0x04000000 @@ -40,6 +40,8 @@ #define IMA_FAIL_UNVERIFIABLE_SIGS 0x10000000 #define IMA_MODSIG_ALLOWED 0x20000000 #define IMA_CHECK_BLACKLIST 0x40000000 +#define IMA_VERITY_REQUIRED 0x80000000 +#define IMA_VERITY_DIGEST 0x00800000 #define IMA_DO_MASK (IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \ IMA_HASH | IMA_APPRAISE_SUBMASK)