KEYS: Use keyring_alloc() to create special keyrings

Use keyring_alloc() to create special keyrings now that it has a permissions
parameter rather than using key_alloc() + key_instantiate_and_link().

Also document and export keyring_alloc() so that modules can use it too.

Signed-off-by: David Howells <dhowells@redhat.com>

Documentation/security/keys.txt

@@ -990,6 +990,23 @@ payload contents" for more information.
     reference pointer if successful.
 
 
+(*) A keyring can be created by:
+
+	struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
+				  const struct cred *cred,
+				  key_perm_t perm,
+				  unsigned long flags,
+				  struct key *dest);
+
+    This creates a keyring with the given attributes and returns it.  If dest
+    is not NULL, the new keyring will be linked into the keyring to which it
+    points.  No permission checks are made upon the destination keyring.
+
+    Error EDQUOT can be returned if the keyring would overload the quota (pass
+    KEY_ALLOC_NOT_IN_QUOTA in flags if the keyring shouldn't be accounted
+    towards the user's quota).  Error ENOMEM can also be returned.
+
+
 (*) To check the validity of a key, this function can be called:
 
 	int validate_key(struct key *key);

fs/cifs/cifsacl.c

@@ -537,19 +537,15 @@ init_cifs_idmap(void)
 	if (!cred)
 		return -ENOMEM;
 
-	keyring = key_alloc(&key_type_keyring, ".cifs_idmap", 0, 0, cred,
-			    (KEY_POS_ALL & ~KEY_POS_SETATTR) |
-			    KEY_USR_VIEW | KEY_USR_READ,
-			    KEY_ALLOC_NOT_IN_QUOTA);
+	keyring = keyring_alloc(".cifs_idmap", 0, 0, cred,
+				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
+				KEY_USR_VIEW | KEY_USR_READ,
+				KEY_ALLOC_NOT_IN_QUOTA, NULL);
 	if (IS_ERR(keyring)) {
 		ret = PTR_ERR(keyring);
 		goto failed_put_cred;
 	}
 
-	ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
-	if (ret < 0)
-		goto failed_put_key;
-
 	ret = register_key_type(&cifs_idmap_key_type);
 	if (ret < 0)
 		goto failed_put_key;

fs/nfs/idmap.c

@@ -192,19 +192,15 @@ static int nfs_idmap_init_keyring(void)
 	if (!cred)
 		return -ENOMEM;
 
-	keyring = key_alloc(&key_type_keyring, ".id_resolver", 0, 0, cred,
-			     (KEY_POS_ALL & ~KEY_POS_SETATTR) |
-			     KEY_USR_VIEW | KEY_USR_READ,
-			     KEY_ALLOC_NOT_IN_QUOTA);
+	keyring = keyring_alloc(".id_resolver", 0, 0, cred,
+				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
+				KEY_USR_VIEW | KEY_USR_READ,
+				KEY_ALLOC_NOT_IN_QUOTA, NULL);
 	if (IS_ERR(keyring)) {
 		ret = PTR_ERR(keyring);
 		goto failed_put_cred;
 	}
 
-	ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
-	if (ret < 0)
-		goto failed_put_key;
-
 	ret = register_key_type(&key_type_id_resolver);
 	if (ret < 0)
 		goto failed_put_key;

net/dns_resolver/dns_key.c

@@ -259,19 +259,15 @@ static int __init init_dns_resolver(void)
 	if (!cred)
 		return -ENOMEM;
 
-	keyring = key_alloc(&key_type_keyring, ".dns_resolver", 0, 0, cred,
-			    (KEY_POS_ALL & ~KEY_POS_SETATTR) |
-			    KEY_USR_VIEW | KEY_USR_READ,
-			    KEY_ALLOC_NOT_IN_QUOTA);
+	keyring = keyring_alloc(".dns_resolver", 0, 0, cred,
+				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
+				KEY_USR_VIEW | KEY_USR_READ,
+				KEY_ALLOC_NOT_IN_QUOTA, NULL);
 	if (IS_ERR(keyring)) {
 		ret = PTR_ERR(keyring);
 		goto failed_put_cred;
 	}
 
-	ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
-	if (ret < 0)
-		goto failed_put_key;
-
 	ret = register_key_type(&key_type_dns_resolver);
 	if (ret < 0)
 		goto failed_put_key;
@@ -303,3 +299,4 @@ static void __exit exit_dns_resolver(void)
 module_init(init_dns_resolver)
 module_exit(exit_dns_resolver)
 MODULE_LICENSE("GPL");
+

security/keys/keyring.c

@@ -275,6 +275,7 @@ struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
 
 	return keyring;
 }
+EXPORT_SYMBOL(keyring_alloc);
 
 /**
  * keyring_search_aux - Search a keyring tree for a key matching some criteria