WPS: Copy UUID from the first interface

Instead of generating a different UUID for each interface, use the
same UUID that was either configured of generated for the first
interface. This avoids potential issues with PBC session overlap
detection should multiple interfaces end up running a PBC scan
at the same time which may happen at least in some P2P use cases.

wpa_supplicant/wps_supplicant.c

@@ -1101,12 +1101,23 @@ int wpas_wps_init(struct wpa_supplicant *wpa_s)
 	wps->dev.os_version = WPA_GET_BE32(wpa_s->conf->os_version);
 	wps->dev.rf_bands = WPS_RF_24GHZ | WPS_RF_50GHZ; /* TODO: config */
 	os_memcpy(wps->dev.mac_addr, wpa_s->own_addr, ETH_ALEN);
+	wpa_printf(MSG_DEBUG, "WPS: Set UUID for interface %s", wpa_s->ifname);
 	if (is_nil_uuid(wpa_s->conf->uuid)) {
-		uuid_gen_mac_addr(wpa_s->own_addr, wps->uuid);
-		wpa_hexdump(MSG_DEBUG, "WPS: UUID based on MAC address",
-			    wps->uuid, WPS_UUID_LEN);
-	} else
+		if (wpa_s->global->ifaces && wpa_s->global->ifaces != wpa_s) {
+			os_memcpy(wps->uuid, wpa_s->global->ifaces->wps->uuid,
+				  WPS_UUID_LEN);
+			wpa_hexdump(MSG_DEBUG, "WPS: UUID from the first "
+				    "interface", wps->uuid, WPS_UUID_LEN);
+		} else {
+			uuid_gen_mac_addr(wpa_s->own_addr, wps->uuid);
+			wpa_hexdump(MSG_DEBUG, "WPS: UUID based on MAC "
+				    "address", wps->uuid, WPS_UUID_LEN);
+		}
+	} else {
 		os_memcpy(wps->uuid, wpa_s->conf->uuid, WPS_UUID_LEN);
+		wpa_hexdump(MSG_DEBUG, "WPS: UUID based on configuration",
+			    wps->uuid, WPS_UUID_LEN);
+	}
 
 	wps->auth_types = WPS_AUTH_WPA2PSK | WPS_AUTH_WPAPSK;
 	wps->encr_types = WPS_ENCR_AES | WPS_ENCR_TKIP;