eCryptfs: added support for the encrypted key type

The function ecryptfs_keyring_auth_tok_for_sig() has been modified in order
to search keys of both 'user' and 'encrypted' types.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Acked-by: Gianluca Ramunno <ramunno@polito.it>
Acked-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index bb8ec5d..b36c557 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -29,6 +29,7 @@
 #define ECRYPTFS_KERNEL_H
 
 #include <keys/user-type.h>
+#include <keys/encrypted-type.h>
 #include <linux/fs.h>
 #include <linux/fs_stack.h>
 #include <linux/namei.h>
@@ -78,11 +79,47 @@
 	} param;
 };
 
+#if defined(CONFIG_ENCRYPTED_KEYS) || defined(CONFIG_ENCRYPTED_KEYS_MODULE)
+static inline struct ecryptfs_auth_tok *
+ecryptfs_get_encrypted_key_payload_data(struct key *key)
+{
+	if (key->type == &key_type_encrypted)
+		return (struct ecryptfs_auth_tok *)
+			(&((struct encrypted_key_payload *)key->payload.data)->payload_data);
+	else
+		return NULL;
+}
+
+static inline struct key *ecryptfs_get_encrypted_key(char *sig)
+{
+	return request_key(&key_type_encrypted, sig, NULL);
+}
+
+#else
+static inline struct ecryptfs_auth_tok *
+ecryptfs_get_encrypted_key_payload_data(struct key *key)
+{
+	return NULL;
+}
+
+static inline struct key *ecryptfs_get_encrypted_key(char *sig)
+{
+	return ERR_PTR(-ENOKEY);
+}
+
+#endif /* CONFIG_ENCRYPTED_KEYS */
+
 static inline struct ecryptfs_auth_tok *
 ecryptfs_get_key_payload_data(struct key *key)
 {
-	return (struct ecryptfs_auth_tok *)
-		(((struct user_key_payload*)key->payload.data)->data);
+	struct ecryptfs_auth_tok *auth_tok;
+
+	auth_tok = ecryptfs_get_encrypted_key_payload_data(key);
+	if (!auth_tok)
+		return (struct ecryptfs_auth_tok *)
+			(((struct user_key_payload *)key->payload.data)->data);
+	else
+		return auth_tok;
 }
 
 #define ECRYPTFS_MAX_KEYSET_SIZE 1024