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From:   Roberto Sassu <roberto.sassu@huaweicloud.com>
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,
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        paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com,
        dhowells@redhat.com, jarkko@kernel.org,
        stephen.smalley.work@gmail.com, eparis@parisplace.org,
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Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-nfs@vger.kernel.org, linux-integrity@vger.kernel.org,
        linux-security-module@vger.kernel.org, keyrings@vger.kernel.org,
        selinux@vger.kernel.org, Roberto Sassu <roberto.sassu@huawei.com>,
        Stefan Berger <stefanb@linux.ibm.com>
Subject: [PATCH v2 18/25] security: Introduce inode_post_set_acl hook
Date:   Thu, 31 Aug 2023 12:41:29 +0200
Message-Id: <20230831104136.903180-19-roberto.sassu@huaweicloud.com>
In-Reply-To: <20230831104136.903180-1-roberto.sassu@huaweicloud.com>
References: <20230831104136.903180-1-roberto.sassu@huaweicloud.com>
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From: Roberto Sassu <roberto.sassu@huawei.com>

In preparation for moving IMA and EVM to the LSM infrastructure, introduce
the inode_post_set_acl hook.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
---
 fs/posix_acl.c                |  1 +
 include/linux/lsm_hook_defs.h |  2 ++
 include/linux/security.h      |  7 +++++++
 security/security.c           | 17 +++++++++++++++++
 4 files changed, 27 insertions(+)

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 7fa1b738bbab..3b7dbea5c3ff 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -1137,6 +1137,7 @@ int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 		error = -EIO;
 	if (!error) {
 		fsnotify_xattr(dentry);
+		security_inode_post_set_acl(dentry, acl_name, kacl);
 		evm_inode_post_set_acl(dentry, acl_name, kacl);
 	}
 
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 9ae573b83737..bba1fbd97207 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -157,6 +157,8 @@ LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry,
 	 const char *name)
 LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap,
 	 struct dentry *dentry, const char *acl_name, struct posix_acl *kacl)
+LSM_HOOK(void, LSM_RET_VOID, inode_post_set_acl, struct dentry *dentry,
+	 const char *acl_name, struct posix_acl *kacl)
 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,
diff --git a/include/linux/security.h b/include/linux/security.h
index 5f296761883f..556d019ebe5c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -367,6 +367,8 @@ int security_inode_setxattr(struct mnt_idmap *idmap,
 int security_inode_set_acl(struct mnt_idmap *idmap,
 			   struct dentry *dentry, const char *acl_name,
 			   struct posix_acl *kacl);
+void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name,
+				 struct posix_acl *kacl);
 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,
@@ -894,6 +896,11 @@ static inline int security_inode_set_acl(struct mnt_idmap *idmap,
 	return 0;
 }
 
+static inline void security_inode_post_set_acl(struct dentry *dentry,
+					       const char *acl_name,
+					       struct posix_acl *kacl)
+{ }
+
 static inline int security_inode_get_acl(struct mnt_idmap *idmap,
 					 struct dentry *dentry,
 					 const char *acl_name)
diff --git a/security/security.c b/security/security.c
index e5acb11f6ebd..4392fd878d58 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2260,6 +2260,23 @@ int security_inode_set_acl(struct mnt_idmap *idmap,
 	return evm_inode_set_acl(idmap, dentry, acl_name, kacl);
 }
 
+/**
+ * security_inode_post_set_acl() - Update inode security after set_acl()
+ * @dentry: file
+ * @acl_name: acl name
+ * @kacl: acl struct
+ *
+ * Update inode security field after successful set_acl operation on @dentry.
+ * The posix acls in @kacl are identified by @acl_name.
+ */
+void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name,
+				 struct posix_acl *kacl)
+{
+	if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
+		return;
+	call_void_hook(inode_post_set_acl, dentry, acl_name, kacl);
+}
+
 /**
  * security_inode_get_acl() - Check if reading posix acls is allowed
  * @idmap: idmap of the mount
-- 
2.34.1