WPS: Add a test mechanism for adding an extra credential into M8

This can be used to build a test version of ER that adds an extra
Credential attribute into M8.

src/wps/wps_registrar.c

@@ -1354,6 +1354,30 @@ int wps_build_cred(struct wps_data *wps, struct wpabuf *msg)
 	}
 
 use_provided:
+#ifdef CONFIG_WPS_TESTING_EXTRA_CRED
+	cred = wpabuf_alloc(200);
+	if (cred) {
+		struct wps_credential dummy;
+		wpa_printf(MSG_DEBUG, "WPS: Add dummy credential");
+		os_memset(&dummy, 0, sizeof(dummy));
+		os_memcpy(dummy.ssid, "dummy", 5);
+		dummy.ssid_len = 5;
+		dummy.auth_type = WPS_AUTH_WPA2PSK;
+		dummy.encr_type = WPS_ENCR_AES;
+		os_memcpy(dummy.key, "dummy psk", 9);
+		dummy.key_len = 9;
+		os_memcpy(dummy.mac_addr, wps->mac_addr_e, ETH_ALEN);
+		wps_build_credential(cred, &dummy);
+		wpa_hexdump_buf(MSG_DEBUG, "WPS: Dummy Credential", cred);
+
+		wpabuf_put_be16(msg, ATTR_CRED);
+		wpabuf_put_be16(msg, wpabuf_len(cred));
+		wpabuf_put_buf(msg, cred);
+
+		wpabuf_free(cred);
+	}
+#endif /* CONFIG_WPS_TESTING_EXTRA_CRED */
+
 	cred = wpabuf_alloc(200);
 	if (cred == NULL)
 		return -1;