From patchwork Fri Nov 12 12:44:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12616715 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AB70C43219 for ; Fri, 12 Nov 2021 12:44:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0605061054 for ; Fri, 12 Nov 2021 12:44:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235157AbhKLMrn (ORCPT ); Fri, 12 Nov 2021 07:47:43 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:4086 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235086AbhKLMre (ORCPT ); Fri, 12 Nov 2021 07:47:34 -0500 Received: from fraeml714-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4HrJ9D1rK1z67bFK; Fri, 12 Nov 2021 20:41:04 +0800 (CST) Received: from roberto-ThinkStation-P620.huawei.com (10.204.63.22) by fraeml714-chm.china.huawei.com (10.206.15.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.15; Fri, 12 Nov 2021 13:44:40 +0100 From: Roberto Sassu To: , , , , , CC: , , , , , , Roberto Sassu Subject: [RFC][PATCH 1/5] fsverity: Introduce fsverity_get_file_digest() Date: Fri, 12 Nov 2021 13:44:07 +0100 Message-ID: <20211112124411.1948809-2-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211112124411.1948809-1-roberto.sassu@huawei.com> References: <20211112124411.1948809-1-roberto.sassu@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.204.63.22] X-ClientProxiedBy: lhreml753-chm.china.huawei.com (10.201.108.203) To fraeml714-chm.china.huawei.com (10.206.15.33) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Since the fsverity_info structure is defined internally in fsverity, expose the fsverity file digest through the new function fsverity_get_file_digest(). Given that an fsverity file is guaranteed to be immutable, also the retrieved file digest is stable and won't change. Signed-off-by: Roberto Sassu --- fs/verity/open.c | 24 ++++++++++++++++++++++++ include/linux/fsverity.h | 10 ++++++++++ 2 files changed, 34 insertions(+) diff --git a/fs/verity/open.c b/fs/verity/open.c index 92df87f5fa38..9127c77c6539 100644 --- a/fs/verity/open.c +++ b/fs/verity/open.c @@ -218,6 +218,30 @@ void fsverity_free_info(struct fsverity_info *vi) kmem_cache_free(fsverity_info_cachep, vi); } +/* + * Copy the file digest and associated algorithm taken from the passed + * fsverity_info structure to the locations supplied by the caller. + * + * Return: the digest size on success, a negative value on error + */ +ssize_t fsverity_get_file_digest(struct fsverity_info *info, u8 *buf, + size_t bufsize, enum hash_algo *algo) +{ + enum hash_algo a; + + a = match_string(hash_algo_name, HASH_ALGO__LAST, + info->tree_params.hash_alg->name); + if (a < 0) + return a; + + if (bufsize < hash_digest_size[a]) + return -ERANGE; + + *algo = a; + memcpy(buf, info->file_digest, hash_digest_size[*algo]); + return hash_digest_size[*algo]; +} + static bool validate_fsverity_descriptor(struct inode *inode, const struct fsverity_descriptor *desc, size_t desc_size) diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h index b568b3c7d095..877a7f609dd9 100644 --- a/include/linux/fsverity.h +++ b/include/linux/fsverity.h @@ -13,6 +13,7 @@ #include #include +#include /* Verity operations for filesystems */ struct fsverity_operations { @@ -137,6 +138,8 @@ int fsverity_ioctl_measure(struct file *filp, void __user *arg); int fsverity_file_open(struct inode *inode, struct file *filp); int fsverity_prepare_setattr(struct dentry *dentry, struct iattr *attr); void fsverity_cleanup_inode(struct inode *inode); +ssize_t fsverity_get_file_digest(struct fsverity_info *info, u8 *buf, + size_t bufsize, enum hash_algo *algo); /* read_metadata.c */ @@ -187,6 +190,13 @@ static inline void fsverity_cleanup_inode(struct inode *inode) { } +static inline ssize_t fsverity_get_file_digest(struct fsverity_info *info, + u8 *buf, size_t bufsize, + enum hash_algo *algo) +{ + return -EOPNOTSUPP; +} + /* read_metadata.c */ static inline int fsverity_ioctl_read_metadata(struct file *filp,