diff --git a/lib/dns/include/dns/message.h b/lib/dns/include/dns/message.h
index 2b8c01973c..faab3e7802 100644
--- a/lib/dns/include/dns/message.h
+++ b/lib/dns/include/dns/message.h
@@ -944,11 +944,15 @@ dns_message_gettsig(dns_message_t *msg, dns_name_t **owner);
  * Requires:
  *
  *	'msg' is a valid message.
- *	'owner' is not NULL, and *owner is NULL.  Contains the owner on return.
+ *	'owner' is NULL or *owner is NULL.
  *
  * Returns:
  *
  *	The TSIG rdataset of 'msg', or NULL if there isn't one.
+ *
+ * Ensures:
+ *
+ * 	If 'owner' is not NULL, it will point to the owner name.
  */
 
 isc_result_t
@@ -1034,11 +1038,15 @@ dns_message_getsig0(dns_message_t *msg, dns_name_t **owner);
  * Requires:
  *
  *	'msg' is a valid message.
- *	'owner' is not NULL, and *owner is NULL.  Contains the owner on return.
+ *	'owner' is NULL or *owner is NULL.
  *
  * Returns:
  *
  *	The SIG(0) rdataset of 'msg', or NULL if there isn't one.
+ *
+ * Ensures:
+ *
+ * 	If 'owner' is not NULL, it will point to the owner name.
  */
 
 isc_result_t
diff --git a/lib/dns/message.c b/lib/dns/message.c
index 4185c6e963..e1fa1e68e0 100644
--- a/lib/dns/message.c
+++ b/lib/dns/message.c
@@ -2296,9 +2296,10 @@ dns_message_gettsig(dns_message_t *msg, dns_name_t **owner) {
 	 */
 
 	REQUIRE(DNS_MESSAGE_VALID(msg));
-	REQUIRE(owner != NULL && *owner == NULL);
+	REQUIRE(owner == NULL || *owner == NULL);
 
-	*owner = msg->tsigname;
+	if (owner != NULL)
+		*owner = msg->tsigname;
 	return (msg->tsig);
 }
 
@@ -2431,8 +2432,9 @@ dns_message_getsig0(dns_message_t *msg, dns_name_t **owner) {
 	 */
 
 	REQUIRE(DNS_MESSAGE_VALID(msg));
+	REQUIRE(owner == NULL || *owner == NULL);
 
-	if (msg->sig0 != NULL) {
+	if (msg->sig0 != NULL && owner != NULL) {
 		/* If dns_message_getsig0 is called on a rendered message
 		 * after the SIG(0) has been applied, we need to return the
 		 * root name, not NULL.
@@ -2441,12 +2443,8 @@ dns_message_getsig0(dns_message_t *msg, dns_name_t **owner) {
 			*owner = dns_rootname;
 		else
 			*owner = msg->sig0name;
-		return (msg->sig0);
-	}
-	else {
-		*owner = NULL;
-		return (NULL);
 	}
+	return (msg->sig0);
 }
 
 isc_result_t