From patchwork Wed Mar 29 13:04:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 13192384 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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C376AC77B6D for ; Wed, 29 Mar 2023 13:05:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230119AbjC2NFy (ORCPT ); Wed, 29 Mar 2023 09:05:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230118AbjC2NFi (ORCPT ); Wed, 29 Mar 2023 09:05:38 -0400 Received: from frasgout12.his.huawei.com (frasgout12.his.huawei.com [14.137.139.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5F8E4EF5; Wed, 29 Mar 2023 06:05:32 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.227]) by frasgout12.his.huawei.com (SkyGuard) with ESMTP id 4PmmkL3Qj3z9xGX2; Wed, 29 Mar 2023 20:55:38 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP1 (Coremail) with SMTP id LxC2BwCXFABgNyRk2AzcAQ--.1625S5; Wed, 29 Mar 2023 14:05:09 +0100 (CET) From: Roberto Sassu To: zohar@linux.ibm.com, dmitry.kasatkin@gmail.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, stephen.smalley.work@gmail.com, eparis@parisplace.org, casey@schaufler-ca.com Cc: reiserfs-devel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, bpf@vger.kernel.org, kpsingh@kernel.org, keescook@chromium.org, nicolas.bouchinet@clip-os.org, Roberto Sassu Subject: [PATCH v9 3/4] evm: Align evm_inode_init_security() definition with LSM infrastructure Date: Wed, 29 Mar 2023 15:04:14 +0200 Message-Id: <20230329130415.2312521-4-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230329130415.2312521-1-roberto.sassu@huaweicloud.com> References: <20230329130415.2312521-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: LxC2BwCXFABgNyRk2AzcAQ--.1625S5 X-Coremail-Antispam: 1UD129KBjvJXoWxXF43tw4xZrW8tFyUWw1UGFg_yoWrKw48pa nxt3WUCr1rJFyUWryFyF47u3WSgFWrGr4UtrZ3G34jyFnrtr1xtFWSyr15uFyrWrW8GrnY qw42vr1rWwn8t3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPqb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUWw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVWUCVW8JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2 WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkE bVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7 AKxVW8ZVWrXwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02 F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_Wr ylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUCVW8JwCI42IY6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI 0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x 07jzE__UUUUU= X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAgALBF1jj4dSLAAAsF X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org From: Roberto Sassu Change the evm_inode_init_security() definition to align with the LSM infrastructure. Keep the existing behavior of including in the HMAC calculation only the first xattr provided by LSMs. Changing the evm_inode_init_security() definition requires passing the xattr array allocated by security_inode_init_security(), and the number of xattrs filled by previously invoked LSMs. Use the newly introduced lsm_find_xattr_slot() to position EVM correctly in the xattrs array, like a regular LSM, and to increment the number of filled slots. For now, the LSM infrastructure allocates enough xattrs slots to store the EVM xattr, without using the reservation mechanism. Finally, make evm_inode_init_security() return value compatible with the inode_init_security hook conventions, i.e. return -EOPNOTSUPP if it is not setting an xattr. EVM is a bit tricky, because xattrs is both an input and an output. If it was just output, EVM should have returned zero if xattrs is NULL. But, since xattrs is also input, EVM is unable to do its calculations, so return -EOPNOTSUPP and handle this error in security_inode_init_security(). Signed-off-by: Roberto Sassu --- include/linux/evm.h | 14 ++++++++------ security/integrity/evm/evm_main.c | 18 +++++++++++------- security/security.c | 6 +++--- 3 files changed, 22 insertions(+), 16 deletions(-) diff --git a/include/linux/evm.h b/include/linux/evm.h index 7dc1ee74169..3c0e8591b69 100644 --- a/include/linux/evm.h +++ b/include/linux/evm.h @@ -56,9 +56,10 @@ static inline void evm_inode_post_set_acl(struct dentry *dentry, { return evm_inode_post_setxattr(dentry, acl_name, NULL, 0); } -extern int evm_inode_init_security(struct inode *inode, - const struct xattr *xattr_array, - struct xattr *evm); +extern int evm_inode_init_security(struct inode *inode, struct inode *dir, + const struct qstr *qstr, + struct xattr *xattrs, + int *num_filled_xattrs); extern bool evm_revalidate_status(const char *xattr_name); extern int evm_protected_xattr_if_enabled(const char *req_xattr_name); extern int evm_read_protected_xattrs(struct dentry *dentry, u8 *buffer, @@ -157,9 +158,10 @@ static inline void evm_inode_post_set_acl(struct dentry *dentry, return; } -static inline int evm_inode_init_security(struct inode *inode, - const struct xattr *xattr_array, - struct xattr *evm) +static inline int evm_inode_init_security(struct inode *inode, struct inode *dir, + const struct qstr *qstr, + struct xattr *xattrs, + int *num_filled_xattrs) { return 0; } diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index cf24c525558..9e75759150c 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include @@ -864,23 +865,26 @@ void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) /* * evm_inode_init_security - initializes security.evm HMAC value */ -int evm_inode_init_security(struct inode *inode, - const struct xattr *lsm_xattr, - struct xattr *evm_xattr) +int evm_inode_init_security(struct inode *inode, struct inode *dir, + const struct qstr *qstr, struct xattr *xattrs, + int *num_filled_xattrs) { struct evm_xattr *xattr_data; + struct xattr *evm_xattr; int rc; - if (!(evm_initialized & EVM_INIT_HMAC) || - !evm_protected_xattr(lsm_xattr->name)) - return 0; + if (!(evm_initialized & EVM_INIT_HMAC) || !xattrs || + !evm_protected_xattr(xattrs->name)) + return -EOPNOTSUPP; + + evm_xattr = lsm_find_xattr_slot(xattrs, num_filled_xattrs); xattr_data = kzalloc(sizeof(*xattr_data), GFP_NOFS); if (!xattr_data) return -ENOMEM; xattr_data->data.type = EVM_XATTR_HMAC; - rc = evm_init_hmac(inode, lsm_xattr, xattr_data->digest); + rc = evm_init_hmac(inode, xattrs, xattr_data->digest); if (rc < 0) goto out; diff --git a/security/security.c b/security/security.c index be33d643a81..22ab4fb7ebf 100644 --- a/security/security.c +++ b/security/security.c @@ -1674,9 +1674,9 @@ int security_inode_init_security(struct inode *inode, struct inode *dir, if (!num_filled_xattrs) goto out; - ret = evm_inode_init_security(inode, new_xattrs, - new_xattrs + num_filled_xattrs); - if (ret) + ret = evm_inode_init_security(inode, dir, qstr, new_xattrs, + &num_filled_xattrs); + if (ret && ret != -EOPNOTSUPP) goto out; ret = initxattrs(inode, new_xattrs, fs_data); out: