+
+ public static String getGssToken(Subject subject, String service, String server) {
+ if (subject.getPrivateCredentials(KerberosTicket.class).isEmpty())
+ throw new IllegalArgumentException("Subject " + subject + " is not GSS authenticated.");
+ return Subject.doAs(subject, (PrivilegedAction<String>) () -> {
+ // !! different format than Kerberos
+ String serverPrinc = service + "@" + server;
+ GSSContext context = null;
+ String tokenStr = null;
+
+ try {
+ // Get service's principal name
+ GSSManager manager = GSSManager.getInstance();
+ // GSSName serverName = manager.createName(serverPrinc,
+ // GSSName.NT_HOSTBASED_SERVICE, KERBEROS_OID);
+ GSSName serverName = manager.createName(serverPrinc, GSSName.NT_HOSTBASED_SERVICE);
+
+ // Get the context for authentication
+ context = manager.createContext(serverName, KERBEROS_OID, null, GSSContext.DEFAULT_LIFETIME);
+ // context.requestMutualAuth(true); // Request mutual authentication
+ // context.requestConf(true); // Request confidentiality
+ context.requestCredDeleg(true);
+
+ byte[] token = new byte[0];
+
+ // token is ignored on the first call
+ token = context.initSecContext(token, 0, token.length);
+
+ // Send a token to the server if one was generated by
+ // initSecContext
+ if (token != null) {
+ tokenStr = Base64.getEncoder().encodeToString(token);
+ // complete=true;
+ }
+ return tokenStr;
+
+ } catch (GSSException e) {
+ throw new IllegalStateException("Cannot authenticate to " + serverPrinc, e);
+ }
+ });
+ }