Java example source code file (Krb5AcceptCredential.java)

This example Java source code file (Krb5AcceptCredential.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

accesscontrolcontext, credentials, destroyfailedexception, encryptionkey, gsscaller, gssexception, krb5acceptcredential, krb5credelement, krb5nameelement, oid, privilegedactionexception, privilegedexceptionaction, security, servicecreds, string

The Krb5AcceptCredential.java Java example source code

/*
 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.security.jgss.krb5;

import java.io.IOException;
import org.ietf.jgss.*;
import sun.security.jgss.GSSCaller;
import sun.security.jgss.spi.*;
import sun.security.krb5.*;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.security.AccessController;
import java.security.AccessControlContext;
import javax.security.auth.DestroyFailedException;

/**
 * Implements the krb5 acceptor credential element.
 *
 * @author Mayank Upadhyay
 * @since 1.4
 */
public class Krb5AcceptCredential
    implements Krb5CredElement {

    private final Krb5NameElement name;
    private final ServiceCreds screds;

    private Krb5AcceptCredential(Krb5NameElement name, ServiceCreds creds) {
        /*
         * Initialize this instance with the data from the acquired
         * KerberosKey. This class needs to be a KerberosKey too
         * hence we can't just store a reference.
         */

        this.name = name;
        this.screds = creds;
    }

    static Krb5AcceptCredential getInstance(final GSSCaller caller, Krb5NameElement name)
        throws GSSException {

        final String serverPrinc = (name == null? null:
            name.getKrb5PrincipalName().getName());
        final AccessControlContext acc = AccessController.getContext();

        ServiceCreds creds = null;
        try {
            creds = AccessController.doPrivileged(
                        new PrivilegedExceptionAction<ServiceCreds>() {
                public ServiceCreds run() throws Exception {
                    return Krb5Util.getServiceCreds(
                        caller == GSSCaller.CALLER_UNKNOWN ? GSSCaller.CALLER_ACCEPT: caller,
                        serverPrinc, acc);
                }});
        } catch (PrivilegedActionException e) {
            GSSException ge =
                new GSSException(GSSException.NO_CRED, -1,
                    "Attempt to obtain new ACCEPT credentials failed!");
            ge.initCause(e.getException());
            throw ge;
        }

        if (creds == null)
            throw new GSSException(GSSException.NO_CRED, -1,
                                   "Failed to find any Kerberos credentails");

        if (name == null) {
            String fullName = creds.getName();
            if (fullName != null) {
                name = Krb5NameElement.getInstance(fullName,
                                       Krb5MechFactory.NT_GSS_KRB5_PRINCIPAL);
            }
        }

        return new Krb5AcceptCredential(name, creds);
    }

    /**
     * Returns the principal name for this credential. The name
     * is in mechanism specific format.
     *
     * @return GSSNameSpi representing principal name of this credential
     * @exception GSSException may be thrown
     */
    public final GSSNameSpi getName() throws GSSException {
        return name;
    }

    /**
     * Returns the init lifetime remaining.
     *
     * @return the init lifetime remaining in seconds
     * @exception GSSException may be thrown
     */
    public int getInitLifetime() throws GSSException {
        return 0;
    }

    /**
     * Returns the accept lifetime remaining.
     *
     * @return the accept lifetime remaining in seconds
     * @exception GSSException may be thrown
     */
    public int getAcceptLifetime() throws GSSException {
        return GSSCredential.INDEFINITE_LIFETIME;
    }

    public boolean isInitiatorCredential() throws GSSException {
        return false;
    }

    public boolean isAcceptorCredential() throws GSSException {
        return true;
    }

    /**
     * Returns the oid representing the underlying credential
     * mechanism oid.
     *
     * @return the Oid for this credential mechanism
     * @exception GSSException may be thrown
     */
    public final Oid getMechanism() {
        return Krb5MechFactory.GSS_KRB5_MECH_OID;
    }

    public final java.security.Provider getProvider() {
        return Krb5MechFactory.PROVIDER;
    }

    public EncryptionKey[] getKrb5EncryptionKeys(PrincipalName princ) {
        return screds.getEKeys(princ);
    }

    /**
     * Called to invalidate this credential element.
     */
    public void dispose() throws GSSException {
        try {
            destroy();
        } catch (DestroyFailedException e) {
            GSSException gssException =
                new GSSException(GSSException.FAILURE, -1,
                 "Could not destroy credentials - " + e.getMessage());
            gssException.initCause(e);
        }
    }

    /**
     * Destroys the locally cached EncryptionKey value and then calls
     * destroy in the base class.
     */
    public void destroy() throws DestroyFailedException {
        screds.destroy();
    }

    /**
     * Impersonation is only available on the initiator side. The
     * service must starts as an initiator to get an initial TGT to complete
     * the S4U2self protocol.
     */
    @Override
    public GSSCredentialSpi impersonate(GSSNameSpi name) throws GSSException {
        Credentials cred = screds.getInitCred();
        if (cred != null) {
            return Krb5InitCredential.getInstance(this.name, cred)
                    .impersonate(name);
        } else {
            throw new GSSException(GSSException.FAILURE, -1,
                "Only an initiate credentials can impersonate");
        }
    }
}