Ignore duplicated SSID element when parsing

Some APs have managed to add two SSID elements into Beacon frames and
that used to result in picking the last one which had incorrect data in
the known examples of this misbehavior. Pick the first one to get the
correct SSID.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/common/ieee802_11_common.c

@@ -365,6 +365,11 @@ ParseRes ieee802_11_parse_elems(const u8 *start, size_t len,
 					   elen);
 				break;
 			}
+			if (elems->ssid) {
+				wpa_printf(MSG_MSGDUMP,
+					   "Ignored duplicated SSID element");
+				break;
+			}
 			elems->ssid = pos;
 			elems->ssid_len = elen;
 			break;