From patchwork Thu Dec 2 21:55:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 12653517 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 74877C433EF for ; Thu, 2 Dec 2021 21:55:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377128AbhLBV7H (ORCPT ); Thu, 2 Dec 2021 16:59:07 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:39228 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243133AbhLBV7G (ORCPT ); Thu, 2 Dec 2021 16:59:06 -0500 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 1B2Jr1AH029117; Thu, 2 Dec 2021 21:55:41 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=+DeRp858qnInW1elOnLNsw4/TGKd2BJwXQzP9ThUne8=; b=Z4AQH6Bmg4Udr9aXP6K4DvTHCdz8HxO1aTaweEXZHyPPQ/7KK3sr3qmy41/LFmq2i1F4 C4zf3X5nYp401+PnmJtwm6DsZKI/rrDW4JFNneaVQDDaqrDq7VT9SK34gCFHdl2Rw54r 6VUCVLdgYz002IQ5Go4QVy6NznhSR6/Z2+/SnCzVGdKYT0FoX+WAAgCMX62mFKKJ9KfP xhXZdNXUxp0tqXV0Yc15tq851o+XFYrGoBd42Jd3FTD+DErYKQT0iU/6upWk7nL8me2l NJbYX1i3eS2UfgD36Zwt+Oqb5w5ViKP4YURjCWDdzF7WxIDU4cnbmWPNrjowEQ5rEnMy tQ== Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0a-001b2d01.pphosted.com with ESMTP id 3cq4pajjkq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 02 Dec 2021 21:55:41 +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 1B2LoEsV008840; Thu, 2 Dec 2021 21:55:39 GMT Received: from b06avi18626390.portsmouth.uk.ibm.com (b06avi18626390.portsmouth.uk.ibm.com [9.149.26.192]) by ppma06ams.nl.ibm.com with ESMTP id 3ckbxkrb6g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 02 Dec 2021 21:55:39 +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 1B2Lm6sW20775222 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 2 Dec 2021 21:48:06 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 055F852052; Thu, 2 Dec 2021 21:55:37 +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 4F03F52050; Thu, 2 Dec 2021 21:55:36 +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 1/5] fs-verity: define a function to return the integrity protected file digest Date: Thu, 2 Dec 2021 16:55:03 -0500 Message-Id: <20211202215507.298415-2-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: 3uCrgem_OIuA4nxWYeCB44FaaiVWJ_i4 X-Proofpoint-ORIG-GUID: 3uCrgem_OIuA4nxWYeCB44FaaiVWJ_i4 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 malwarescore=0 clxscore=1015 adultscore=0 lowpriorityscore=0 impostorscore=0 bulkscore=0 mlxlogscore=999 suspectscore=0 spamscore=0 priorityscore=1501 mlxscore=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 Define a function named fsverity_collect_digest() to return the verity file digest and the associated hash algorithm (enum hash_algo). Signed-off-by: Mimi Zohar --- Changelog v1: - Renamed new function to fsverity_collect_digest(), based on discussion with Eric Biggers and Lakshmi. - Addressed Eric's suggestions: updated kernel doc variable and function description, removed unnecessary include file. fs/verity/Kconfig | 1 + fs/verity/fsverity_private.h | 7 ------ fs/verity/measure.c | 49 ++++++++++++++++++++++++++++++++++++ include/linux/fsverity.h | 18 +++++++++++++ 4 files changed, 68 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..64fbfbd408d4 100644 --- a/fs/verity/measure.c +++ b/fs/verity/measure.c @@ -57,3 +57,52 @@ int fsverity_ioctl_measure(struct file *filp, void __user *_uarg) return 0; } EXPORT_SYMBOL_GPL(fsverity_ioctl_measure); + +/** + * fsverity_collect_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. + * + * Return: 0 on success, -errno on failure + */ +int fsverity_collect_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); + *alg = HASH_ALGO__LAST; + + /* convert hash algorithm to hash_algo_name */ + for (i = 0; i < HASH_ALGO__LAST; i++) { + pr_debug("name %s hash_algo_name[%d] %s\n", + hash_alg->name, i, hash_algo_name[i]); + + if (!strcmp(hash_alg->name, hash_algo_name[i])) { + *alg = i; + break; + } + } + + /* Shouldn't happen */ + if (*alg == HASH_ALGO__LAST) + 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..2755e8bd80e5 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_collect_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_collect_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)