Getting the caller subject from the thread


The Caller subject (or "received subject") contains the user authentication information used in the call for this request. This subject is returned after issuing the WSSubject.getCallerSubject API (API) to prevent replacing existing objects. The subject is marked read-only. This API can be used to get access to the WSCredential credential so that we can put or set data in the hashmap within the credential.

we need the following Java2 security permissions to runthis API: permission javax.security.auth.AuthPermission "wssecurity.getCallerSubject;".

If we use the Kerberos authentication mechanism, the KDC policy enables Kerberos delegation and the client has a forwardable Kerberos ticket, the subject has the client Kerberos tickets and the GSS delegate credential. Use APIs to access the Kerberos tickets and the GSS delegate credential.

Most data within the subject is not propagated downstream to another server. Only the credential token within the WSCredential credential is propagated downstream and a new caller subject is generated.

 

  1. Get the caller subject.

    caller_subject = com.ibm.websphere.security.auth.WSSubject.getCallerSubject();
    

  2. Access the WSCredential credential.

    caller_cred = caller_subject.getPublicCredentials(com.ibm.websphere
    .security.cred.WSCredential.class).iterator().next();
    

  3. Put or set data in the hashmap within the credential.

    String CALLERDATA = (String) caller_cred.get ("MYKEY");   System.out.println("My data from the Caller credential is:  " + CALLERDATA);
    

  4. Access the Kerberos tickets. For example:

            java.util.Set kerberosTickets = subject.getPrivateCredentials(KerberosTicket.class);
            if ( kerberosTickets.size() > 1) 
                System.out.println("Multiple Kerberos tickets found");
            Iterator credIter = kerberosTickets.iterator();
    

  5. Access the GSS credential. For example:

       GSSCredential gssCred = subject.getPrivateCredentials(GSSCredential.class).iterator().next();
    

 

Example

try { javax.security.auth.Subject caller_subject; com.ibm.websphere.security.cred.WSCredential caller_cred;
caller_subject = com.ibm.websphere.security.auth.WSSubject.getCallerSubject();
if (caller_subject != null) { caller_cred = caller_subject.getPublicCredentials
     (com.ibm.websphere.security.cred.WSCredential.class).iterator().next();
String CALLERDATA = (String) caller_cred.get ("MYKEY");
System.out.println("My data from the Caller credential is:  " + CALLERDATA); } }
catch (WSSecurityException e) { // log error } catch (Exception e) { // log error }

 

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