From patchwork Fri Oct 27 08:35:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 13438292 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 AC9E0C25B72 for ; Fri, 27 Oct 2023 08:42:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235210AbjJ0ImX (ORCPT ); Fri, 27 Oct 2023 04:42:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345623AbjJ0Ily (ORCPT ); Fri, 27 Oct 2023 04:41:54 -0400 Received: from frasgout13.his.huawei.com (frasgout13.his.huawei.com [14.137.139.46]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD1E61A5; Fri, 27 Oct 2023 01:41:10 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.228]) by frasgout13.his.huawei.com (SkyGuard) with ESMTP id 4SGwll2cdwz9yKWr; Fri, 27 Oct 2023 16:28:03 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP1 (Coremail) with SMTP id LxC2BwCX8JGqdjtlDvIBAw--.29710S19; Fri, 27 Oct 2023 09:40:42 +0100 (CET) From: Roberto Sassu To: viro@zeniv.linux.org.uk, brauner@kernel.org, chuck.lever@oracle.com, jlayton@kernel.org, neilb@suse.de, kolga@netapp.com, Dai.Ngo@oracle.com, tom@talpey.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, zohar@linux.ibm.com, dmitry.kasatkin@gmail.com, dhowells@redhat.com, jarkko@kernel.org, stephen.smalley.work@gmail.com, eparis@parisplace.org, casey@schaufler-ca.com, mic@digikod.net Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, selinux@vger.kernel.org, Roberto Sassu , Stefan Berger Subject: [PATCH v4 17/23] security: Introduce inode_post_remove_acl hook Date: Fri, 27 Oct 2023 10:35:52 +0200 Message-Id: <20231027083558.484911-18-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231027083558.484911-1-roberto.sassu@huaweicloud.com> References: <20231027083558.484911-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: LxC2BwCX8JGqdjtlDvIBAw--.29710S19 X-Coremail-Antispam: 1UD129KBjvJXoWxuryDCFW3JF48AF4rArWfAFb_yoWrAr1DpF sxK3Z8Ww4rXFy2gry8tFWDuw1IvFWFgry7A3y2gw4IyFn2yr12qFsxCFyjkry5ArW8KF1q qF1aqrsxC343Jr7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBqb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv6xkF7I0E 14v26F4UJVW0owAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I 80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCj c4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxAIw28Icx kI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2Iq xVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0EwIxGrwCI42 IY6xIIjxv20xvE14v26r4j6ryUMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UMIIF 0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87 Iv6xkF7I0E14v26r4UJVWxJrUvcSsGvfC2KfnxnUUI43ZEXa7IU13l1DUUUUU== X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQADBF1jj5WUaQAAsf X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Roberto Sassu In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_remove_acl hook. At inode_remove_acl hook, EVM verifies the file's existing HMAC value. At inode_post_remove_acl, EVM re-calculates the file's HMAC with the passed POSIX ACL removed and other file metadata. Other LSMs could similarly take some action after successful POSIX ACL removal. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu Reviewed-by: Stefan Berger --- fs/posix_acl.c | 1 + include/linux/lsm_hook_defs.h | 2 ++ include/linux/security.h | 8 ++++++++ security/security.c | 17 +++++++++++++++++ 4 files changed, 28 insertions(+) diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 58e3c1e2fbbc..e3fbe1a9f3f5 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -1246,6 +1246,7 @@ int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry, error = -EIO; if (!error) { fsnotify_xattr(dentry); + security_inode_post_remove_acl(idmap, dentry, acl_name); evm_inode_post_remove_acl(idmap, dentry, acl_name); } diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 42962ce8301a..8ff172ba5681 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -163,6 +163,8 @@ LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name) LSM_HOOK(int, 0, inode_remove_acl, struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name) +LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, struct mnt_idmap *idmap, + struct dentry *dentry, const char *acl_name) LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry) LSM_HOOK(int, 0, inode_killpriv, struct mnt_idmap *idmap, struct dentry *dentry) diff --git a/include/linux/security.h b/include/linux/security.h index 278b97f688dc..d8e359d651d2 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -378,6 +378,9 @@ int security_inode_get_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name); int security_inode_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name); +void security_inode_post_remove_acl(struct mnt_idmap *idmap, + struct dentry *dentry, + const char *acl_name); void security_inode_post_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags); int security_inode_getxattr(struct dentry *dentry, const char *name); @@ -934,6 +937,11 @@ static inline int security_inode_remove_acl(struct mnt_idmap *idmap, return 0; } +static inline void security_inode_post_remove_acl(struct mnt_idmap *idmap, + struct dentry *dentry, + const char *acl_name) +{ } + static inline void security_inode_post_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { } diff --git a/security/security.c b/security/security.c index 622c24cbfbb6..6ca8fdd1f037 100644 --- a/security/security.c +++ b/security/security.c @@ -2406,6 +2406,23 @@ int security_inode_remove_acl(struct mnt_idmap *idmap, return evm_inode_remove_acl(idmap, dentry, acl_name); } +/** + * security_inode_post_remove_acl() - Update inode sec after remove_acl op + * @idmap: idmap of the mount + * @dentry: file + * @acl_name: acl name + * + * Update inode security field after successful remove_acl operation on @dentry + * in @idmap. The posix acls are identified by @acl_name. + */ +void security_inode_post_remove_acl(struct mnt_idmap *idmap, + struct dentry *dentry, const char *acl_name) +{ + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) + return; + call_void_hook(inode_post_remove_acl, idmap, dentry, acl_name); +} + /** * security_inode_post_setxattr() - Update the inode after a setxattr operation * @dentry: file