From patchwork Wed Apr 21 16:19:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12216487 X-Patchwork-Delegate: paul@paul-moore.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0359CC43462 for ; Wed, 21 Apr 2021 16:21:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CDAAA6144D for ; Wed, 21 Apr 2021 16:21:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242415AbhDUQV4 (ORCPT ); Wed, 21 Apr 2021 12:21:56 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:2901 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242271AbhDUQVz (ORCPT ); Wed, 21 Apr 2021 12:21:55 -0400 Received: from fraeml714-chm.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4FQQdj1qVPz6yh4l; Thu, 22 Apr 2021 00:15:53 +0800 (CST) Received: from roberto-ThinkStation-P620.huawei.com (10.204.62.217) 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 15.1.2176.2; Wed, 21 Apr 2021 18:21:20 +0200 From: Roberto Sassu To: , , , CC: , , , , , Roberto Sassu Subject: [PATCH v2 6/6] evm: Support multiple LSMs providing an xattr Date: Wed, 21 Apr 2021 18:19:25 +0200 Message-ID: <20210421161925.968825-7-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210421161925.968825-1-roberto.sassu@huawei.com> References: <20210421161925.968825-1-roberto.sassu@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.204.62.217] X-ClientProxiedBy: lhreml754-chm.china.huawei.com (10.201.108.204) To fraeml714-chm.china.huawei.com (10.206.15.33) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Currently, evm_inode_init_security() processes a single LSM xattr from the array passed by security_inode_init_security(), and calculates the HMAC on it and other inode metadata. Given that initxattrs(), called by security_inode_init_security(), expects that this array is terminated when the xattr name is set to NULL, this patch reuses the same assumption for evm_inode_init_security() to scan all xattrs and to calculate the HMAC on all of them. Signed-off-by: Roberto Sassu --- security/integrity/evm/evm.h | 2 ++ security/integrity/evm/evm_crypto.c | 9 ++++++++- security/integrity/evm/evm_main.c | 15 +++++++++++---- 3 files changed, 21 insertions(+), 5 deletions(-) diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h index ae590f71ce7d..24eac42b9f32 100644 --- a/security/integrity/evm/evm.h +++ b/security/integrity/evm/evm.h @@ -49,6 +49,8 @@ struct evm_digest { char digest[IMA_MAX_DIGEST_SIZE]; } __packed; +int evm_protected_xattr(const char *req_xattr_name); + int evm_init_key(void); int __init evm_init_crypto(void); int evm_update_evmxattr(struct dentry *dentry, diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index b66264b53d5d..35c5eec0517d 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -358,6 +358,7 @@ int evm_init_hmac(struct inode *inode, const struct xattr *lsm_xattr, char *hmac_val) { struct shash_desc *desc; + const struct xattr *xattr; desc = init_desc(EVM_XATTR_HMAC, evm_hash_algo); if (IS_ERR(desc)) { @@ -365,7 +366,13 @@ int evm_init_hmac(struct inode *inode, const struct xattr *lsm_xattr, return PTR_ERR(desc); } - crypto_shash_update(desc, lsm_xattr->value, lsm_xattr->value_len); + for (xattr = lsm_xattr; xattr->name != NULL; xattr++) { + if (!evm_protected_xattr(xattr->name)) + continue; + + crypto_shash_update(desc, xattr->value, xattr->value_len); + } + hmac_add_misc(desc, inode, EVM_XATTR_HMAC, hmac_val); kfree(desc); return 0; diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 336a421e2e5a..c43e75cd37f3 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -261,7 +261,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, return evm_status; } -static int evm_protected_xattr(const char *req_xattr_name) +int evm_protected_xattr(const char *req_xattr_name) { int namelen; int found = 0; @@ -712,14 +712,21 @@ int evm_inode_init_security(struct inode *inode, struct inode *dir, struct xattr *xattrs, void *fs_data) { struct evm_xattr *xattr_data; + struct xattr *xattr; struct xattr *evm_xattr = lsm_find_xattr_slot(xattrs); - int rc; + int rc, evm_protected_xattrs = 0; if (!xattrs || !xattrs->name) return 0; - if (!(evm_initialized & EVM_INIT_HMAC) || - !evm_protected_xattr(xattrs->name)) + if (!(evm_initialized & EVM_INIT_HMAC)) + return -EOPNOTSUPP; + + for (xattr = xattrs; xattr->name != NULL; xattr++) + if (evm_protected_xattr(xattr->name)) + evm_protected_xattrs++; + + if (!evm_protected_xattrs) return -EOPNOTSUPP; xattr_data = kzalloc(sizeof(*xattr_data), GFP_NOFS);