From patchwork Thu Dec 14 17:08:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 13493458 Received: from frasgout13.his.huawei.com (frasgout13.his.huawei.com [14.137.139.46]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94D31196; Thu, 14 Dec 2023 09:14:09 -0800 (PST) Received: from mail.maildlp.com (unknown [172.18.186.51]) by frasgout13.his.huawei.com (SkyGuard) with ESMTP id 4SrdrN4zLHz9y7Zn; Fri, 15 Dec 2023 01:00:04 +0800 (CST) Received: from mail02.huawei.com (unknown [7.182.16.27]) by mail.maildlp.com (Postfix) with ESMTP id 175A214066B; Fri, 15 Dec 2023 01:13:58 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP2 (Coremail) with SMTP id GxC2BwAHuGFtN3tlDa2DAg--.53313S9; Thu, 14 Dec 2023 18:13:57 +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, shuah@kernel.org, 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, linux-kselftest@vger.kernel.org, Roberto Sassu , Stefan Berger Subject: [PATCH v8 17/24] security: Introduce inode_post_remove_acl hook Date: Thu, 14 Dec 2023 18:08:27 +0100 Message-Id: <20231214170834.3324559-18-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231214170834.3324559-1-roberto.sassu@huaweicloud.com> References: <20231214170834.3324559-1-roberto.sassu@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: GxC2BwAHuGFtN3tlDa2DAg--.53313S9 X-Coremail-Antispam: 1UD129KBjvJXoWxuryDCFW3JF48AF4rArWfAFb_yoWrCr1UpF s3K3Z8Ww4rXFy2gryktFWDuw1SvFWFgry7A3y2gw1IyFn2yr1jqFsxKFyjkry5ArW8KF1q qF1aqrsxC343Jr7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBIb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVWxJr0_GcWl84ACjcxK6I8E87Iv67AKxVW8JVWxJwA2z4x0Y4vEx4A2jsIEc7CjxVAF wI0_Cr1j6rxdM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7 xfMcIj6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Y z7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2 Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s02 6x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAKI48JMIIF0x vE2Ix0cI8IcVAFwI0_Gr0_Xr1lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4UJVW0owCI42IY 6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aV CY1x0267AKxVWxJr0_GcJvcSsGvfC2KfnxnUUI43ZEXa7IUbGXdUUUUUU== X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQALBF1jj5enwQAAsO 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 Acked-by: Casey Schaufler Reviewed-by: Mimi Zohar --- 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 5133dd88b5fb..bfb10a1e6a44 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 948aaddf0edd..7b753460f09d 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 5d25bbd18d66..a722d5db0a2c 100644 --- a/security/security.c +++ b/security/security.c @@ -2413,6 +2413,23 @@ 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 security after rm posix acls + * @idmap: idmap of the mount + * @dentry: file + * @acl_name: acl name + * + * Update inode security data after successfully removing posix acls 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