I am doing kerberos delegation. I noticed that GSSUtil.createSubject(context.getSrcName(), clientCred) returns a Subject without having credentials in it.
Prior to that i've done GSSCredential clientCred = context.getDelegCred(); which returns the credentials.
Edit: When I hit my service from one machine in same domain, it works, while if accessed from other machine in same domain, it doesn't.
Confused what additional settings are needed on AD ?
Any help is highly appreciated.
Following is my code:
public class KerberosTest {
public Subject loginImpl(byte[] kerberosTicket, String propertiesFileName) throws Exception {
System.setProperty("sun.security.krb5.debug", "true");
// // no effect // System.setProperty("javax.security.auth.useSubjectCredsOnly","false");
final Krb5LoginModule krb5LoginModule = new Krb5LoginModule();
Subject serviceUserSubject = new Subject();
final Map<String,String> optionMap = new HashMap<String,String>();
HashMap<String, String> shared = new HashMap<>();
optionMap.put("keyTab", "C:\\kerberos_files\\sapuser.keytab");
optionMap.put("principal", "HTTP/[email protected]"); // default realm
// optionMap.put("principal", "kerberosuser"); // default realm
optionMap.put("useFirstPass", "true");
optionMap.put("doNotPrompt", "true");
optionMap.put("refreshKrb5Config", "true");
optionMap.put("useTicketCache", "false");
optionMap.put("renewTGT", "false");
optionMap.put("useKeyTab", "true");
optionMap.put("storeKey", "true");
optionMap.put("isInitiator", "true");
optionMap.put("useSubjectCredsOnly", "false");
optionMap.put("debug", "true"); // switch on debug of the Java implementation
krb5LoginModule.initialize(serviceUserSubject, null, shared, optionMap);
// login using details mentioned inside keytab
boolean loginOk = krb5LoginModule.login();
System.out.println("Login success: " + loginOk);
// This API adds Kerberos Credentials to the the Subject's private credentials set
boolean commitOk = krb5LoginModule.commit();
}
System.out.println("Principal from subject: " + serviceUserSubject.getPrincipals()); // this must display name of user to which the keytab corresponds to
Subject clientSubject = getClientContext(serviceUserSubject, kerberosTicket);
System.out.println("Client Subject-> " + clientSubject);
System.out.println("Client principal-> "+clientSubject.getPrincipals().toArray()[0]);
return clientSubject;
}
// Completes the security context initialisation and returns the client name.
private Subject getClientContext(Subject subject, final byte[] kerberosTicket) throws PrivilegedActionException {
Subject clientSubject = Subject.doAs(subject, new KerberosValidateAction(kerberosTicket));
return clientSubject;
}
private class KerberosValidateAction implements PrivilegedExceptionAction<Subject> {
byte[] kerberosTicket;
public KerberosValidateAction(byte[] kerberosTicket) {
this.kerberosTicket = kerberosTicket;
}
@Override
public Subject run() throws Exception {
GSSManager gssManager = GSSManager.getInstance();
GSSContext context = gssManager.createContext((GSSCredential) null);
Oid kerberosOid = new Oid("1.2.840.113554.1.2.2");
// context.requestCredDeleg(true); // needed when we are demanding ticket from KDC. In our scenario, we are getting ticket from browser(client)
// Called by the context acceptor upon receiving a token from the peer. This is our context acceptor
// This method may return an output token which the application will need to send to the peer for further processing by its initSecContext call.
// We will only accept the incoming token from Peer (browser) and fwd it to third party system
while (!context.isEstablished()) {
byte[] nextToken = context.acceptSecContext(kerberosTicket, 0, kerberosTicket.length);
}
boolean established = context.isEstablished();
String user = context.getSrcName().toString();
String serviceAccnt = context.getTargName().toString();
//check if the credentials can be delegated
if (!context.getCredDelegState()) {
System.out.println("credentials can not be delegated!");
return null;
}
//get the delegated credentials from the calling peer...
GSSCredential clientCred = context.getDelegCred();
//Create a Subject out of the delegated credentials.
//With this Subject the application server can impersonate the client that sent the request.
Subject clientSubject = GSSUtil.createSubject(context.getSrcName(), clientCred);
return clientSubject; // ***this contains only principal name and not credentials !!
}
}