mka: Detect duplicate MAC addresses during key server election

In the unlikely event the local KaY and the elected peer have the same
actor priority as well as the same MAC address, log a warning message
and do not elect a key server. Resolution is for network administrator
to reconfigure MAC address.

Signed-off-by: Michael Siedzik <msiedzik@extremenetworks.com>

src/pae/ieee802_1x_kay.c

@@ -2093,6 +2093,7 @@ ieee802_1x_kay_elect_key_server(struct ieee802_1x_mka_participant *participant)
 	struct ieee802_1x_kay_peer *key_server = NULL;
 	struct ieee802_1x_kay *kay = participant->kay;
 	Boolean i_is_key_server;
+	int priority_comparison;
 
 	if (participant->is_obliged_key_server) {
 		participant->new_sak = TRUE;
@@ -2123,8 +2124,14 @@ ieee802_1x_kay_elect_key_server(struct ieee802_1x_mka_participant *participant)
 
 		tmp.key_server_priority = kay->actor_priority;
 		os_memcpy(&tmp.sci, &kay->actor_sci, sizeof(tmp.sci));
-		if (compare_priorities(&tmp, key_server) < 0)
+		priority_comparison = compare_priorities(&tmp, key_server);
+		if (priority_comparison < 0) {
 			i_is_key_server = TRUE;
+		} else if (priority_comparison == 0) {
+			wpa_printf(MSG_WARNING,
+				   "KaY: Cannot elect key server between me and peer, duplicate MAC detected");
+			key_server = NULL;
+		}
 	} else if (participant->can_be_key_server) {
 		i_is_key_server = TRUE;
 	}