[PATCH v2] MKA: Do not enable MACsec transmission if there is any risk of a duplicate SCI

[Greg Goblirsch]

It is obvious that restarting wpa_supplicant could result in a live peer and a potential peer having the same SCI.

9.4.2 Member identification and message numbers
  The KaY will not enable MACsec transmission if there is any risk of a duplicate SCI 

Signed-off-by: Greg Goblirsch <gregg at thinklogical.com>

@@ -466,6 +466,25 @@ ieee802_1x_kay_get_peer_sci(struct ieee802_1x_mka_participant *participant,
 }
 
 
+/**
+ * ieee802_1x_kay_get_live_peer_sci
+ */
+static struct ieee802_1x_kay_peer *
+ieee802_1x_kay_get_live_peer_sci(struct ieee802_1x_mka_participant *participant,
+                           const struct ieee802_1x_mka_sci *sci)
+{
+       struct ieee802_1x_kay_peer *peer;
+
+       dl_list_for_each(peer, &participant->live_peers,
+                        struct ieee802_1x_kay_peer, list) {
+               if (sci_equal(&peer->sci, sci))
+                       return peer;
+       }
+
+       return NULL;
+}
+
+
 static void ieee802_1x_kay_use_data_key(struct data_key *pkey);
 
 /**
@@ -683,6 +702,13 @@ ieee802_1x_kay_move_live_peer(struct ieee802_1x_mka_participant *participant,
        if (!peer)
                return NULL;
 
+       if (ieee802_1x_kay_get_live_peer_sci(participant,
+                       &participant->current_peer_sci)) {
+               wpa_printf(MSG_WARNING,
+                       "KaY: live peer and potential peer have the same SCI");
+               return NULL;
+       }
+
        rxsc = ieee802_1x_kay_init_receive_sc(&participant->current_peer_sci);
        if (!rxsc)
                return NULL;