Hi

Our company has a use case in which our domain is a tomcat process. In our code, we support a parallel protocol which uses In memory based jaas configuration - 

public class OurLoginConfiguration extends Configuration

In IBM JDK 7, we need to initiate using keytab which needs the system property javax.security.auth.useSubjectCredsOnly to be set to true for it to work. However Tomcat sets it in  

Inside SpnegoAuthenticator:-

 protected void initInternal() throws LifecycleException {
        super.initInternal();

        // Kerberos configuration file location
        String krb5Conf = System.getProperty(Constants.KRB5_CONF_PROPERTY);
        if (krb5Conf == null) {
            // System property not set, use the Tomcat default
            File krb5ConfFile = new File(Bootstrap.getCatalinaBase(),
                    Constants.DEFAULT_KRB5_CONF);
            System.setProperty(Constants.KRB5_CONF_PROPERTY,
                    krb5ConfFile.getAbsolutePath());
        }

        // JAAS configuration file location
        String jaasConf = System.getProperty(Constants.JAAS_CONF_PROPERTY);
        if (jaasConf == null) {
            // System property not set, use the Tomcat default
            File jaasConfFile = new File(Bootstrap.getCatalinaBase(),
                    Constants.DEFAULT_JAAS_CONF);
            System.setProperty(Constants.JAAS_CONF_PROPERTY,
                    jaasConfFile.getAbsolutePath());
        }
        
        // This property must be false for SPNEGO to work
        System.setProperty(Constants.USE_SUBJECT_CREDS_ONLY_PROPERTY, "false");
    }

as false in the last line which causes havoc in the code. A multithreaded startup causes a breakdown in further authentication for keytab based logging.


Now a little more investigation revealed that tomcat acts only as an acceptor. Now this property need not necessarily be set to false for it to work(in both IBM and SUN JDK). 

Source of claim - http://cr.openjdk.java.net/~weijun/special/krb5winguide-2/raw_files/new/kwin

Excerpt:-
 2. Direct JGSS:

      /* JGSS-API calls... */

       In this case, the JAAS config file's entry name MUST be the
       standard entry name (com.sun.security.jgss.krb5.initiate), and you
       must set -Djavax.security.auth.useSubjectCredsOnly=false on the
       Java command line. Read
       [26]http://java.sun.com/javase/6/docs/technotes/guides/security/jgs
       s/tutorials/BasicClientServer.html for details.
Which means only initiate based auth needs the system property.

This is also confirmed in IBM with a sample program.

PROPOSED FIX: COMMENT LAST LINE OF initInternal WHICH SETS THE SYSTEM PROPERTY IN THE FIRST PLACE AS FALSE.