From patchwork Sun Jan 9 18:55:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 12707923 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 8C397C433F5 for ; Sun, 9 Jan 2022 18:55:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236617AbiAISzh (ORCPT ); Sun, 9 Jan 2022 13:55:37 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:9550 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236598AbiAISzd (ORCPT ); Sun, 9 Jan 2022 13:55:33 -0500 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 209EMD0A003517; Sun, 9 Jan 2022 18:55:32 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=YYTonSNfXP8UHbpZWJGG6JVeUUqrszhUrcdnmhXYxbg=; b=F4zu5FloDNwge4LYgn/7lRYCiw93blNEdPx28Wb50nO/M7X/h37dqiSw/QGKnLK+V0Jq hCPoxoytLff1uhmFNzywMPTD6fiaCsKjhZ1qBWguAv5W0LZHbToeCRlzkgMDjdhq3wnk l1fIuBj2StT/vKROjuEunDnZfKivbK5tIPIxesPC6DLhzYlSf9ghE7NTXh49ev20hzlF ft/N03VpGSIVzQdZfm1fQ8Ggw0DndWG3hbYFoz+52UKCvXyUhozODoHECYScgvPFFVnj yavvgyq1SCeGe3+mvgXrU4r2ZVW3Ua1j8u/mlAnALdfcORu7w9ijzVhE9EQDjOHk/LjA Hw== Received: from ppma04ams.nl.ibm.com (63.31.33a9.ip4.static.sl-reverse.com [169.51.49.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 3dfmpmb6n9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 09 Jan 2022 18:55:31 +0000 Received: from pps.filterd (ppma04ams.nl.ibm.com [127.0.0.1]) by ppma04ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 209IrmxL023334; Sun, 9 Jan 2022 18:55:29 GMT Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by ppma04ams.nl.ibm.com with ESMTP id 3df288ekhx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 09 Jan 2022 18:55:29 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 209ItR9037552602 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 9 Jan 2022 18:55:27 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DF3F0A4040; Sun, 9 Jan 2022 18:55:26 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 02E77A404D; Sun, 9 Jan 2022 18:55:26 +0000 (GMT) Received: from li-f45666cc-3089-11b2-a85c-c57d1a57929f.ibm.com.com (unknown [9.65.69.17]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Sun, 9 Jan 2022 18:55:25 +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 v2 2/6] fs-verity: define a function to return the integrity protected file digest Date: Sun, 9 Jan 2022 13:55:13 -0500 Message-Id: <20220109185517.312280-3-zohar@linux.ibm.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220109185517.312280-1-zohar@linux.ibm.com> References: <20220109185517.312280-1-zohar@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: zvlrYw4PV7PbguiQvlTHQMnO33zIFWlo X-Proofpoint-ORIG-GUID: zvlrYw4PV7PbguiQvlTHQMnO33zIFWlo 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=2022-01-09_07,2022-01-07_01,2021-12-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 lowpriorityscore=0 adultscore=0 priorityscore=1501 phishscore=0 malwarescore=0 bulkscore=0 clxscore=1015 impostorscore=0 mlxscore=0 spamscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2110150000 definitions=main-2201090135 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). Signed-off-by: Mimi Zohar Acked-by: Eric Biggers --- fs/verity/Kconfig | 1 + fs/verity/fsverity_private.h | 7 ------- fs/verity/measure.c | 40 ++++++++++++++++++++++++++++++++++++ include/linux/fsverity.h | 18 ++++++++++++++++ 4 files changed, 59 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..52906b2e5811 100644 --- a/fs/verity/measure.c +++ b/fs/verity/measure.c @@ -57,3 +57,43 @@ 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. + * + * 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); + *alg = HASH_ALGO__LAST; + + /* convert hash algorithm to hash_algo_name */ + i = match_string(hash_algo_name, HASH_ALGO__LAST, hash_alg->name); + if (i < 0) + return -EINVAL; + *alg = i; + + 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)