wpa_supplicant: Support Multi-AP backhaul STA onboarding with WPS

The Wi-Fi Alliance Multi-AP Specification v1.0 allows onboarding of a
backhaul STA through WPS. To enable this, the backhaul STA needs to add
a Multi-AP IE to the WFA vendor extension element in the WSC M1 message
that indicates it supports the Multi-AP backhaul STA role. The Registrar
(if it support Multi-AP onboarding) will respond to that with a WSC M8
message that also contains the Multi-AP IE, and that contains the
credentials for the backhaul SSID (which may be different from the SSID
on which WPS is performed).

Introduce a new parameter to wpas_wps_start_pbc() and allow it to be
set via control interface's new multi_ap=1 parameter of WPS_PBC call.
multi_ap_backhaul_sta is set to 1 in the automatically created SSID.
Thus, if the AP does not support Multi-AP, association will fail and
WPS will be terminated.

Only wps_pbc is supported.

This commit adds the multi_ap argument only to the control socket
interface, not to the D-Bus interface.

Since WPS associates with the fronthaul BSS instead of the backhaul BSS,
we should not drop association if the AP announces fronthaul-only BSS.
Still, we should only do that in the specific case of WPS. Therefore,
add a check to multi_ap_process_assoc_resp() to allow association with a
fronthaul-only BSS if and only if key_mgmt contains WPS.

Signed-off-by: Davina Lu <ylu@quantenna.com>
Signed-off-by: Igor Mitsyanko <igor.mitsyanko.os@quantenna.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Cc: Marianna Carrera <marianna.carrera.so@quantenna.com>

src/eap_peer/eap_wsc.c

@@ -255,6 +255,9 @@ static void * eap_wsc_init(struct eap_sm *sm)
 		cfg.new_ap_settings = &new_ap_settings;
 	}
 
+	if (os_strstr(phase1, "multi_ap=1"))
+		cfg.multi_ap_backhaul_sta = 1;
+
 	data->wps = wps_init(&cfg);
 	if (data->wps == NULL) {
 		os_free(data);

src/wps/wps.c

@@ -145,6 +145,8 @@ struct wps_data * wps_init(const struct wps_config *cfg)
 		data->peer_pubkey_hash_set = 1;
 	}
 
+	data->multi_ap_backhaul_sta = cfg->multi_ap_backhaul_sta;
+
 	return data;
 }
 

src/wps/wps.h

@@ -187,6 +187,12 @@ struct wps_config {
 	 * peer_pubkey_hash - Peer public key hash or %NULL if not known
 	 */
 	const u8 *peer_pubkey_hash;
+
+	/**
+	 * multi_ap_backhaul_sta - Whether this is a Multi-AP backhaul STA
+	 * enrollee
+	 */
+	int multi_ap_backhaul_sta;
 };
 
 struct wps_data * wps_init(const struct wps_config *cfg);

src/wps/wps_enrollee.c

@@ -105,6 +105,7 @@ static struct wpabuf * wps_build_m1(struct wps_data *wps)
 {
 	struct wpabuf *msg;
 	u16 config_methods;
+	u8 multi_ap_backhaul_sta = 0;
 
 	if (random_get_bytes(wps->nonce_e, WPS_NONCE_LEN) < 0)
 		return NULL;
@@ -134,6 +135,9 @@ static struct wpabuf * wps_build_m1(struct wps_data *wps)
 				    WPS_CONFIG_PHY_PUSHBUTTON);
 	}
 
+	if (wps->multi_ap_backhaul_sta)
+		multi_ap_backhaul_sta = MULTI_AP_BACKHAUL_STA;
+
 	if (wps_build_version(msg) ||
 	    wps_build_msg_type(msg, WPS_M1) ||
 	    wps_build_uuid_e(msg, wps->uuid_e) ||
@@ -152,7 +156,7 @@ static struct wpabuf * wps_build_m1(struct wps_data *wps)
 	    wps_build_dev_password_id(msg, wps->dev_pw_id) ||
 	    wps_build_config_error(msg, WPS_CFG_NO_ERROR) ||
 	    wps_build_os_version(&wps->wps->dev, msg) ||
-	    wps_build_wfa_ext(msg, 0, NULL, 0, 0) ||
+	    wps_build_wfa_ext(msg, 0, NULL, 0, multi_ap_backhaul_sta) ||
 	    wps_build_vendor_ext_m1(&wps->wps->dev, msg)) {
 		wpabuf_free(msg);
 		return NULL;

src/wps/wps_i.h

@@ -125,6 +125,8 @@ struct wps_data {
 	int pbc_in_m1;
 
 	struct wps_nfc_pw_token *nfc_pw_token;
+
+	int multi_ap_backhaul_sta;
 };
 
 

wpa_supplicant/ctrl_iface.c

@@ -1168,8 +1168,11 @@ static int wpa_supplicant_ctrl_iface_wps_pbc(struct wpa_supplicant *wpa_s,
 #ifdef CONFIG_AP
 	u8 *_p2p_dev_addr = NULL;
 #endif /* CONFIG_AP */
+	char *pos;
+	int multi_ap = 0;
 
-	if (cmd == NULL || os_strcmp(cmd, "any") == 0) {
+	if (!cmd || os_strcmp(cmd, "any") == 0 ||
+	    os_strncmp(cmd, "any ", 4) == 0) {
 		_bssid = NULL;
 #ifdef CONFIG_P2P
 	} else if (os_strncmp(cmd, "p2p_dev_addr=", 13) == 0) {
@@ -1181,18 +1184,29 @@ static int wpa_supplicant_ctrl_iface_wps_pbc(struct wpa_supplicant *wpa_s,
 		}
 		_p2p_dev_addr = p2p_dev_addr;
 #endif /* CONFIG_P2P */
+	} else if (os_strncmp(cmd, "multi_ap=", 9) == 0) {
+		_bssid = NULL;
+		multi_ap = atoi(cmd + 9);
 	} else if (hwaddr_aton(cmd, bssid)) {
 		wpa_printf(MSG_DEBUG, "CTRL_IFACE WPS_PBC: invalid BSSID '%s'",
 			   cmd);
 		return -1;
 	}
 
+	if (cmd) {
+		pos = os_strstr(cmd, " multi_ap=");
+		if (pos) {
+			pos += 10;
+			multi_ap = atoi(pos);
+		}
+	}
+
 #ifdef CONFIG_AP
 	if (wpa_s->ap_iface)
 		return wpa_supplicant_ap_wps_pbc(wpa_s, _bssid, _p2p_dev_addr);
 #endif /* CONFIG_AP */
 
-	return wpas_wps_start_pbc(wpa_s, _bssid, 0);
+	return wpas_wps_start_pbc(wpa_s, _bssid, 0, multi_ap);
 }
 
 

wpa_supplicant/dbus/dbus_new_handlers_wps.c

@@ -293,7 +293,7 @@ DBusMessage * wpas_dbus_handler_wps_start(DBusMessage *message,
 					message, "invalid PIN");
 		}
 	} else {
-		ret = wpas_wps_start_pbc(wpa_s, params.bssid, 0);
+		ret = wpas_wps_start_pbc(wpa_s, params.bssid, 0, 0);
 	}
 
 	if (ret < 0) {

wpa_supplicant/dbus/dbus_old_handlers_wps.c

@@ -37,9 +37,9 @@ DBusMessage * wpas_dbus_iface_wps_pbc(DBusMessage *message,
 		return wpas_dbus_new_invalid_opts_error(message, NULL);
 
 	if (os_strcmp(arg_bssid, "any") == 0)
-		ret = wpas_wps_start_pbc(wpa_s, NULL, 0);
+		ret = wpas_wps_start_pbc(wpa_s, NULL, 0, 0);
 	else if (!hwaddr_aton(arg_bssid, bssid))
-		ret = wpas_wps_start_pbc(wpa_s, bssid, 0);
+		ret = wpas_wps_start_pbc(wpa_s, bssid, 0, 0);
 	else {
 		return wpas_dbus_new_invalid_opts_error(message,
 							"Invalid BSSID");

wpa_supplicant/events.c

@@ -2305,6 +2305,13 @@ static void multi_ap_process_assoc_resp(struct wpa_supplicant *wpa_s,
 	}
 
 	if (!(map_sub_elem[2] & MULTI_AP_BACKHAUL_BSS)) {
+		if ((map_sub_elem[2] & MULTI_AP_FRONTHAUL_BSS) &&
+		    wpa_s->current_ssid->key_mgmt & WPA_KEY_MGMT_WPS) {
+			wpa_printf(MSG_INFO,
+				   "WPS active, accepting fronthaul-only BSS");
+			/* Don't set 4addr mode in this case, so just return */
+			return;
+		}
 		wpa_printf(MSG_INFO, "AP doesn't support backhaul BSS");
 		goto fail;
 	}
@@ -4829,7 +4836,7 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 		break;
 	case EVENT_WPS_BUTTON_PUSHED:
 #ifdef CONFIG_WPS
-		wpas_wps_start_pbc(wpa_s, NULL, 0);
+		wpas_wps_start_pbc(wpa_s, NULL, 0, 0);
 #endif /* CONFIG_WPS */
 		break;
 	case EVENT_AVOID_FREQUENCIES:

wpa_supplicant/p2p_supplicant.c

@@ -1656,7 +1656,7 @@ static void wpas_start_wps_enrollee(struct wpa_supplicant *wpa_s,
 	wpa_supplicant_ap_deinit(wpa_s);
 	wpas_copy_go_neg_results(wpa_s, res);
 	if (res->wps_method == WPS_PBC) {
-		wpas_wps_start_pbc(wpa_s, res->peer_interface_addr, 1);
+		wpas_wps_start_pbc(wpa_s, res->peer_interface_addr, 1, 0);
 #ifdef CONFIG_WPS_NFC
 	} else if (res->wps_method == WPS_NFC) {
 		wpas_wps_start_nfc(wpa_s, res->peer_device_addr,

wpa_supplicant/wps_supplicant.c

@@ -1137,9 +1137,10 @@ static void wpas_wps_reassoc(struct wpa_supplicant *wpa_s,
 
 
 int wpas_wps_start_pbc(struct wpa_supplicant *wpa_s, const u8 *bssid,
-		       int p2p_group)
+		       int p2p_group, int multi_ap_backhaul_sta)
 {
 	struct wpa_ssid *ssid;
+	char phase1[32];
 
 #ifdef CONFIG_AP
 	if (wpa_s->ap_iface) {
@@ -1177,10 +1178,14 @@ int wpas_wps_start_pbc(struct wpa_supplicant *wpa_s, const u8 *bssid,
 		}
 	}
 #endif /* CONFIG_P2P */
-	if (wpa_config_set(ssid, "phase1", "\"pbc=1\"", 0) < 0)
+	os_snprintf(phase1, sizeof(phase1), "pbc=1%s",
+		    multi_ap_backhaul_sta ? " multi_ap=1" : "");
+	if (wpa_config_set_quoted(ssid, "phase1", phase1) < 0)
 		return -1;
 	if (wpa_s->wps_fragment_size)
 		ssid->eap.fragment_size = wpa_s->wps_fragment_size;
+	if (multi_ap_backhaul_sta)
+		ssid->multi_ap_backhaul_sta = 1;
 	wpa_supplicant_wps_event(wpa_s, WPS_EV_PBC_ACTIVE, NULL);
 	eloop_register_timeout(WPS_PBC_WALK_TIME, 0, wpas_wps_timeout,
 			       wpa_s, NULL);

wpa_supplicant/wps_supplicant.h

@@ -30,7 +30,7 @@ void wpas_wps_deinit(struct wpa_supplicant *wpa_s);
 int wpas_wps_eapol_cb(struct wpa_supplicant *wpa_s);
 enum wps_request_type wpas_wps_get_req_type(struct wpa_ssid *ssid);
 int wpas_wps_start_pbc(struct wpa_supplicant *wpa_s, const u8 *bssid,
-		       int p2p_group);
+		       int p2p_group, int multi_ap_backhaul_sta);
 int wpas_wps_start_pin(struct wpa_supplicant *wpa_s, const u8 *bssid,
 		       const char *pin, int p2p_group, u16 dev_pw_id);
 void wpas_wps_pbc_overlap(struct wpa_supplicant *wpa_s);