From patchwork Fri Mar 18 18:21:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 12785756 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 87D26C433EF for ; Fri, 18 Mar 2022 18:22:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240102AbiCRSXk (ORCPT ); Fri, 18 Mar 2022 14:23:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238994AbiCRSXi (ORCPT ); Fri, 18 Mar 2022 14:23:38 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB7F730CD94; Fri, 18 Mar 2022 11:22:09 -0700 (PDT) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 22IHN3C7015386; Fri, 18 Mar 2022 18:22:06 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=conySYsg0ynx3rzah3UbXnChqXYMg2tQSfroH/ckxxg=; b=sO3Ls+5KgJetmOk9zC3Zw3PVuxOioXlX4nicOm2WjTjOqBeLri50mL2YeMqrwKDNoyx4 lYMOpCqn9QCtquQPkqgK7sfVXMU4rE2yDmuU4v/QKWQLIbY9/fj4jxoC9RZS2OVGsqr1 R7FM4eBMLjdzOfFH84qRIfVbMX16+vlhdUXfCsX+uLw3N7Y9xrWig2OGGsOCA84zpr2c Si7J3seDNBKaa68CohivbMK2N8aTd0ZEsrJuqFwkVw+qCA/fllnJ9mWSQX/hTfGCKEjG i1rOyj8CjKc343xe6QQIp6m0KqD7Xi2EZ3w3xodEMUkUsBFHsHRY7qz9dKNo/2sTYyaq Zg== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 3ev10dkhm1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 18 Mar 2022 18:22:06 +0000 Received: from m0098420.ppops.net (m0098420.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 22IIJqKG011473; Fri, 18 Mar 2022 18:22:05 GMT Received: from ppma06fra.de.ibm.com (48.49.7a9f.ip4.static.sl-reverse.com [159.122.73.72]) by mx0b-001b2d01.pphosted.com with ESMTP id 3ev10dkhkr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 18 Mar 2022 18:22:05 +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 22II4pwa014349; Fri, 18 Mar 2022 18:22:03 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 3erjshv1qx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 18 Mar 2022 18:22:03 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 22IIM0jK17563908 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 18 Mar 2022 18:22:00 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 154FFAE061; Fri, 18 Mar 2022 18:22:00 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0D7A1AE05A; Fri, 18 Mar 2022 18:21:59 +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 18:21:58 +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, Eric Biggers Subject: [PATCH v6 1/5] fs-verity: define a function to return the integrity protected file digest Date: Fri, 18 Mar 2022 14:21:47 -0400 Message-Id: <20220318182151.100847-2-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-ORIG-GUID: tI62bJJ4CaS6Y2cZVHoQQhGqwWuV9ALU X-Proofpoint-GUID: O41N78MGqdIsDvlpl58IXK1SGN5NLf6r 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 impostorscore=0 lowpriorityscore=0 mlxlogscore=999 suspectscore=0 phishscore=0 adultscore=0 spamscore=0 priorityscore=1501 clxscore=1015 bulkscore=0 malwarescore=0 mlxscore=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 Define a function named fsverity_get_digest() to return the verity file digest and the associated hash algorithm (enum hash_algo). This assumes that before calling fsverity_get_digest() the file must have been opened, which is true for the IMA measure/appraise on file open policy rule use case (func=FILE_CHECK). do_open() calls vfs_open() immediately prior to ima_file_check(). Acked-by: Eric Biggers Signed-off-by: Mimi Zohar --- fs/verity/Kconfig | 1 + fs/verity/fsverity_private.h | 7 ------ fs/verity/measure.c | 43 ++++++++++++++++++++++++++++++++++++ include/linux/fsverity.h | 18 +++++++++++++++ 4 files changed, 62 insertions(+), 7 deletions(-) diff --git a/fs/verity/Kconfig b/fs/verity/Kconfig index 24d1b54de807..54598cd80145 100644 --- a/fs/verity/Kconfig +++ b/fs/verity/Kconfig @@ -3,6 +3,7 @@ config FS_VERITY bool "FS Verity (read-only file-based authenticity protection)" select CRYPTO + select CRYPTO_HASH_INFO # SHA-256 is implied as it's intended to be the default hash algorithm. # To avoid bloat, other wanted algorithms must be selected explicitly. # Note that CRYPTO_SHA256 denotes the generic C implementation, but diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h index a7920434bae5..c6fb62e0ef1a 100644 --- a/fs/verity/fsverity_private.h +++ b/fs/verity/fsverity_private.h @@ -14,7 +14,6 @@ #define pr_fmt(fmt) "fs-verity: " fmt -#include #include #include @@ -26,12 +25,6 @@ struct ahash_request; */ #define FS_VERITY_MAX_LEVELS 8 -/* - * Largest digest size among all hash algorithms supported by fs-verity. - * Currently assumed to be <= size of fsverity_descriptor::root_hash. - */ -#define FS_VERITY_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE - /* A hash algorithm supported by fs-verity */ struct fsverity_hash_alg { struct crypto_ahash *tfm; /* hash tfm, allocated on demand */ diff --git a/fs/verity/measure.c b/fs/verity/measure.c index f0d7b30c62db..e99c00350c28 100644 --- a/fs/verity/measure.c +++ b/fs/verity/measure.c @@ -57,3 +57,46 @@ int fsverity_ioctl_measure(struct file *filp, void __user *_uarg) return 0; } EXPORT_SYMBOL_GPL(fsverity_ioctl_measure); + +/** + * fsverity_get_digest() - get a verity file's digest + * @inode: inode to get digest of + * @digest: (out) pointer to the digest + * @alg: (out) pointer to the hash algorithm enumeration + * + * Return the file hash algorithm and digest of an fsverity protected file. + * Assumption: before calling fsverity_get_digest(), the file must have been + * opened. + * + * Return: 0 on success, -errno on failure + */ +int fsverity_get_digest(struct inode *inode, + u8 digest[FS_VERITY_MAX_DIGEST_SIZE], + enum hash_algo *alg) +{ + const struct fsverity_info *vi; + const struct fsverity_hash_alg *hash_alg; + int i; + + vi = fsverity_get_info(inode); + if (!vi) + return -ENODATA; /* not a verity file */ + + hash_alg = vi->tree_params.hash_alg; + memset(digest, 0, FS_VERITY_MAX_DIGEST_SIZE); + + /* convert the verity hash algorithm name to a hash_algo_name enum */ + i = match_string(hash_algo_name, HASH_ALGO__LAST, hash_alg->name); + if (i < 0) + return -EINVAL; + *alg = i; + + if (WARN_ON_ONCE(hash_alg->digest_size != hash_digest_size[*alg])) + return -EINVAL; + memcpy(digest, vi->file_digest, hash_alg->digest_size); + + pr_debug("file digest %s:%*phN\n", hash_algo_name[*alg], + hash_digest_size[*alg], digest); + + return 0; +} diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h index b568b3c7d095..9a1b70cc7318 100644 --- a/include/linux/fsverity.h +++ b/include/linux/fsverity.h @@ -12,8 +12,16 @@ #define _LINUX_FSVERITY_H #include +#include +#include #include +/* + * Largest digest size among all hash algorithms supported by fs-verity. + * Currently assumed to be <= size of fsverity_descriptor::root_hash. + */ +#define FS_VERITY_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE + /* Verity operations for filesystems */ struct fsverity_operations { @@ -131,6 +139,9 @@ int fsverity_ioctl_enable(struct file *filp, const void __user *arg); /* measure.c */ int fsverity_ioctl_measure(struct file *filp, void __user *arg); +int fsverity_get_digest(struct inode *inode, + u8 digest[FS_VERITY_MAX_DIGEST_SIZE], + enum hash_algo *alg); /* open.c */ @@ -170,6 +181,13 @@ static inline int fsverity_ioctl_measure(struct file *filp, void __user *arg) return -EOPNOTSUPP; } +static inline int fsverity_get_digest(struct inode *inode, + u8 digest[FS_VERITY_MAX_DIGEST_SIZE], + enum hash_algo *alg) +{ + return -EOPNOTSUPP; +} + /* open.c */ static inline int fsverity_file_open(struct inode *inode, struct file *filp)