WPS: Reject invalid credential more cleanly

If WPS Registrar tries to provision a WPA/WPA2-Personal network without
including a valid Network Key, the network block cannot be used to
connect to the network. Reject such credential without adding the
network block. This makes wpa_supplicant send WSC_NACK as a response to
the invalid Credential and stop the provisioning process immediately
rather than only after trying unsuccessfully to connect to the network.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>

src/wps/wps_enrollee.c

@@ -665,6 +665,7 @@ static int wps_process_cred_e(struct wps_data *wps, const u8 *cred,
 {
 	struct wps_parse_attr attr;
 	struct wpabuf msg;
+	int ret = 0;
 
 	wpa_printf(MSG_DEBUG, "WPS: Received Credential");
 	os_memset(&wps->cred, 0, sizeof(wps->cred));
@@ -714,12 +715,12 @@ static int wps_process_cred_e(struct wps_data *wps, const u8 *cred,
 	if (wps->wps->cred_cb) {
 		wps->cred.cred_attr = cred - 4;
 		wps->cred.cred_attr_len = cred_len + 4;
-		wps->wps->cred_cb(wps->wps->cb_ctx, &wps->cred);
+		ret = wps->wps->cred_cb(wps->wps->cb_ctx, &wps->cred);
 		wps->cred.cred_attr = NULL;
 		wps->cred.cred_attr_len = 0;
 	}
 
-	return 0;
+	return ret;
 }
 
 

wpa_supplicant/wps_supplicant.c

@@ -256,6 +256,15 @@ static int wpa_supplicant_wps_cred(void *ctx,
 		return 0;
 	}
 
+	if (auth_type == WPS_AUTH_WPAPSK || auth_type == WPS_AUTH_WPA2PSK) {
+		if (cred->key_len < 8 || cred->key_len > 2 * PMK_LEN) {
+			wpa_printf(MSG_ERROR, "WPS: Reject PSK credential with "
+				   "invalid Network Key length %lu",
+				   (unsigned long) cred->key_len);
+			return -1;
+		}
+	}
+
 	if (ssid && (ssid->key_mgmt & WPA_KEY_MGMT_WPS)) {
 		wpa_printf(MSG_DEBUG, "WPS: Replace WPS network block based "
 			   "on the received credential");