From patchwork Wed Nov 23 09:52:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 13053371 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 391A6C4332F for ; Wed, 23 Nov 2022 10:02:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236756AbiKWKCx (ORCPT ); Wed, 23 Nov 2022 05:02:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236016AbiKWKB3 (ORCPT ); Wed, 23 Nov 2022 05:01:29 -0500 Received: from frasgout13.his.huawei.com (frasgout13.his.huawei.com [14.137.139.46]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06D0E45A25; Wed, 23 Nov 2022 01:53:38 -0800 (PST) Received: from mail02.huawei.com (unknown [172.18.147.227]) by frasgout13.his.huawei.com (SkyGuard) with ESMTP id 4NHGVX3Wfsz9xFGw; Wed, 23 Nov 2022 17:46:44 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP1 (Coremail) with SMTP id LxC2BwAH829J7X1jzDqKAA--.13162S7; Wed, 23 Nov 2022 10:53:09 +0100 (CET) From: Roberto Sassu To: mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com, 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: ocfs2-devel@oss.oracle.com, reiserfs-devel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-kernel@vger.kernel.org, keescook@chromium.org, nicolas.bouchinet@clip-os.org, Roberto Sassu Subject: [PATCH v5 5/6] evm: Align evm_inode_init_security() definition with LSM infrastructure Date: Wed, 23 Nov 2022 10:52:01 +0100 Message-Id: <20221123095202.599252-6-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221123095202.599252-1-roberto.sassu@huaweicloud.com> References: <20221123095202.599252-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: LxC2BwAH829J7X1jzDqKAA--.13162S7 X-Coremail-Antispam: 1UD129KBjvJXoW3Jw1UGF15uF43Zr43CFW3Jrb_yoW7GrW3pF 43Ka4UCr1rJFyUWry0yF48u3WSgFWrGr4UKrZ3G34jyFnrtr1xtryFyr15ury5X3y8GF1v qw42vr1rWwn0y3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPlb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv6xkF7I0E 14v26r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrV C2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE 7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCY1x0262 kKe7AKxVW8ZVWrXwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s02 6c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GF v_WrylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvE c7CjxVAFwI0_Gr1j6F4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aV AFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZF pf9x07jIPfQUUUUU= X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAgAFBF1jj4HGaQAAsc 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, in preparation for moving IMA and EVM to that infrastructure. Keep the existing behavior of including in the HMAC calculation only the xattr the first LSM provides. Changing the evm_inode_init_security() definition requires passing only the xattr array allocated by security_inode_init_security(), instead of the first LSM xattr and the place where the EVM xattr should be filled. In lieu of passing the EVM xattr, EVM must position itself after the last filled xattr (by checking the xattr name), since only the beginning of the xattr array is given. Currently, the LSM infrastructure makes sure that there is space for the EVM xattr in the xattr array. If EVM is moved to the LSM infrastructure, it will use the xattr reservation mechanism to achieve the same, as the other LSMs. 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(). Don't change the return value in the inline function evm_inode_init_security() in include/linux/evm.h, as the function will be removed if EVM is moved to the LSM infrastructure. Signed-off-by: Roberto Sassu --- include/linux/evm.h | 12 ++++++------ security/integrity/evm/evm_main.c | 20 +++++++++++++------- security/security.c | 5 ++--- 3 files changed, 21 insertions(+), 16 deletions(-) diff --git a/include/linux/evm.h b/include/linux/evm.h index aa63e0b3c0a2..3bb2ae9fe098 100644 --- a/include/linux/evm.h +++ b/include/linux/evm.h @@ -35,9 +35,9 @@ extern int evm_inode_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry, const char *xattr_name); extern void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name); -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); 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, @@ -108,9 +108,9 @@ static inline void evm_inode_post_removexattr(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) { return 0; } diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 23d484e05e6f..0a312cafb7de 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -845,23 +845,29 @@ 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) { struct evm_xattr *xattr_data; + struct xattr *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; + + for (xattr = xattrs; xattr->value != NULL; xattr++) + ; + + evm_xattr = xattr; 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 26aaa5850867..d256bd223ef4 100644 --- a/security/security.c +++ b/security/security.c @@ -1184,9 +1184,8 @@ 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); + if (ret && ret != -EOPNOTSUPP) goto out; ret = initxattrs(inode, new_xattrs, fs_data); out: