/*

 * Copyright 2000-2006 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.security.jgss;

import com.sun.security.auth.callback.TextCallbackHandler;

import javax.security.auth.Subject;

import javax.security.auth.kerberos.KerberosPrincipal;

import javax.security.auth.kerberos.KerberosTicket;

import javax.security.auth.kerberos.KerberosKey;

import org.ietf.jgss.*;

import sun.security.jgss.spi.GSSNameSpi;

import sun.security.jgss.spi.GSSCredentialSpi;

import sun.security.action.GetPropertyAction;

import sun.security.jgss.krb5.Krb5NameElement;

import sun.security.jgss.spnego.SpNegoCredElement;

import java.util.Set;

import java.util.HashSet;

import java.util.Vector;

import java.util.Iterator;

import java.security.AccessController;

import java.security.AccessControlContext;

import java.security.PrivilegedExceptionAction;

import java.security.PrivilegedActionException;

import javax.security.auth.callback.CallbackHandler;

import javax.security.auth.login.LoginContext;

import javax.security.auth.login.LoginException;

import sun.security.action.GetBooleanAction;

/**

 * The GSSUtilImplementation that knows how to work with the internals of

 * the GSS-API.

 */

public class GSSUtil {

    public static final Oid GSS_KRB5_MECH_OID =

                GSSUtil.createOid("1.2.840.113554.1.2.2");

    public static final Oid GSS_KRB5_MECH_OID2 =

                GSSUtil.createOid("1.3.5.1.5.2");

    public static final Oid GSS_SPNEGO_MECH_OID =

                GSSUtil.createOid("1.3.6.1.5.5.2");

    public static final Oid NT_GSS_KRB5_PRINCIPAL =

                GSSUtil.createOid("1.2.840.113554.1.2.2.1");

    public static final Oid NT_HOSTBASED_SERVICE2 =

                GSSUtil.createOid("1.2.840.113554.1.2.1.4");

    private static final String DEFAULT_HANDLER =

            "auth.login.defaultCallbackHandler";

    public static final int CALLER_UNKNOWN         = -1;

    public static final int CALLER_INITIATE        = 1;

    public static final int CALLER_ACCEPT          = 2;

    public static final int CALLER_SSL_CLIENT      = 3;

    public static final int CALLER_SSL_SERVER      = 4;

    public static final int CALLER_HTTP_NEGOTIATE  = 5;

    static final boolean DEBUG;

    static {

        DEBUG = (AccessController.doPrivileged

                        (new GetBooleanAction("sun.security.jgss.debug"))).

                                booleanValue();

    }

    static void debug(String message) {

        if (DEBUG) {

            assert(message != null);

            System.out.println(message);

        }

    }

    // NOTE: this method is only for creating Oid objects with

    // known to be valid <code>oidStr</code> given it ignores

    // the GSSException

    public static Oid createOid(String oidStr) {

        try {

            return new Oid(oidStr);

        } catch (GSSException e) {

            debug("Ignored invalid OID: " + oidStr);

            return null;

        }

    }

    public static boolean isSpNegoMech(Oid oid) {

        return (GSS_SPNEGO_MECH_OID.equals(oid));

    }

    public static boolean isKerberosMech(Oid oid) {

        return (GSS_KRB5_MECH_OID.equals(oid) ||

                GSS_KRB5_MECH_OID2.equals(oid));

    }

    public static String getMechStr(Oid oid) {

        if (isSpNegoMech(oid)) {

            return "SPNEGO";

        } else if (isKerberosMech(oid)) {

            return "Kerberos V5";

        } else {

            return oid.toString();

        }

    }

    /**

     * Note: The current impl only works with Sun's impl of

     * GSSName and GSSCredential since it depends on package

     * private APIs.

     */

    public static Subject getSubject(GSSName name,

                                     GSSCredential creds) {

        HashSet<Object> privCredentials = null;

        HashSet<Object> pubCredentials = new HashSet<Object>(); // empty Set

        Set<GSSCredentialSpi> gssCredentials = null;

        Set<KerberosPrincipal> krb5Principals =

                                new HashSet<KerberosPrincipal>();

        if (name instanceof GSSNameImpl) {

            try {

                GSSNameSpi ne = ((GSSNameImpl) name).getElement

                    (GSS_KRB5_MECH_OID);

                String krbName = ne.toString();

                if (ne instanceof Krb5NameElement) {

                    krbName =

                        ((Krb5NameElement) ne).getKrb5PrincipalName().getName();

                }

                KerberosPrincipal krbPrinc = new KerberosPrincipal(krbName);

                krb5Principals.add(krbPrinc);

            } catch (GSSException ge) {

                debug("Skipped name " + name + " due to " + ge);

            }

        }

        if (creds instanceof GSSCredentialImpl) {

            gssCredentials = ((GSSCredentialImpl) creds).getElements();

            privCredentials = new HashSet<Object>(gssCredentials.size());

            populateCredentials(privCredentials, gssCredentials);

        } else {

            privCredentials = new HashSet<Object>(); // empty Set

        }

        debug("Created Subject with the following");

        debug("principals=" + krb5Principals);

        debug("public creds=" + pubCredentials);

        debug("private creds=" + privCredentials);

        return new Subject(false, krb5Principals, pubCredentials,

                           privCredentials);

    }

    /**

     * Populates the set credentials with elements from gssCredentials. At

     * the same time, it converts any subclasses of KerberosTicket

     * into KerberosTicket instances and any subclasses of KerberosKey into

     * KerberosKey instances. (It is not desirable to expose the customer

     * to sun.security.jgss.krb5.Krb5InitCredential which extends

     * KerberosTicket and sun.security.jgss.krb5.Kbr5AcceptCredential which

     * extends KerberosKey.)

     */

    private static void populateCredentials(Set<Object> credentials,

                                            Set<?> gssCredentials) {

        Object cred;

        Iterator<?> elements = gssCredentials.iterator();

        while (elements.hasNext()) {

            cred = elements.next();

            // Retrieve the internal cred out of SpNegoCredElement

            if (cred instanceof SpNegoCredElement) {

                cred = ((SpNegoCredElement) cred).getInternalCred();

            }

            if (cred instanceof KerberosTicket) {

                if (!cred.getClass().getName().equals

                    ("javax.security.auth.kerberos.KerberosTicket")) {

                    KerberosTicket tempTkt = (KerberosTicket) cred;

                    cred = new KerberosTicket(tempTkt.getEncoded(),

                                              tempTkt.getClient(),

                                              tempTkt.getServer(),

                                              tempTkt.getSessionKey().getEncoded(),

                                              tempTkt.getSessionKeyType(),

                                              tempTkt.getFlags(),

                                              tempTkt.getAuthTime(),

                                              tempTkt.getStartTime(),

                                              tempTkt.getEndTime(),

                                              tempTkt.getRenewTill(),

                                              tempTkt.getClientAddresses());

                }

                credentials.add(cred);

            } else if (cred instanceof KerberosKey) {

                if (!cred.getClass().getName().equals

                    ("javax.security.auth.kerberos.KerberosKey")) {

                    KerberosKey tempKey = (KerberosKey) cred;

                    cred = new KerberosKey(tempKey.getPrincipal(),

                                           tempKey.getEncoded(),

                                           tempKey.getKeyType(),

                                           tempKey.getVersionNumber());

                }

                credentials.add(cred);

            } else {

                // Ignore non-KerberosTicket and non-KerberosKey elements

                debug("Skipped cred element: " + cred);

            }

        }

    }

    /**

     * Authenticate using the login module from the specified

     * configuration entry.

     *

     * @param caller the caller of JAAS Login

     * @param mech the mech to be used

     * @return the authenticated subject

     */

    public static Subject login(int caller, Oid mech) throws LoginException {

        CallbackHandler cb = null;

        if (caller == GSSUtil.CALLER_HTTP_NEGOTIATE) {

            cb = new sun.net.www.protocol.http.NegotiateCallbackHandler();

        } else {

            String defaultHandler =

                    java.security.Security.getProperty(DEFAULT_HANDLER);

            // get the default callback handler

            if ((defaultHandler != null) && (defaultHandler.length() != 0)) {

                cb = null;

            } else {

                cb = new TextCallbackHandler();

            }

        }

        // New instance of LoginConfigImpl must be created for each login,

        // since the entry name is not passed as the first argument, but

        // generated with caller and mech inside LoginConfigImpl

        LoginContext lc = new LoginContext("", null, cb,

                new LoginConfigImpl(caller, mech));

        lc.login();

        return lc.getSubject();

    }

    /**

     * Determines if the application doesn't mind if the mechanism obtains

     * the required credentials from outside of the current Subject. Our

     * Kerberos v5 mechanism would do a JAAS login on behalf of the

     * application if this were the case.

     *

     * The application indicates this by explicitly setting the system

     * property javax.security.auth.useSubjectCredsOnly to false.

     */

    public static boolean useSubjectCredsOnly(int caller) {

        // HTTP/SPNEGO doesn't use the standard JAAS framework. Instead, it

        // uses the java.net.Authenticator style, therefore always return

        // false here.

        if (caller == CALLER_HTTP_NEGOTIATE) {

            return false;

        }

        /*

         * Don't use GetBooleanAction because the default value in the JRE

         * (when this is unset) has to treated as true.

         */

        String propValue = AccessController.doPrivileged(

                new GetPropertyAction("javax.security.auth.useSubjectCredsOnly",

                "true"));

        /*

         * This property has to be explicitly set to "false". Invalid

         * values should be ignored and the default "true" assumed.

         */

        return (!propValue.equalsIgnoreCase("false"));

    }

    /**

     * Determines the SPNEGO interoperability mode with Microsoft;

     * by default it is set to true.

     *

     * To disable it, the application indicates this by explicitly setting

     * the system property sun.security.spnego.interop to false.

     */

    public static boolean useMSInterop() {

        /*

         * Don't use GetBooleanAction because the default value in the JRE

         * (when this is unset) has to treated as true.

         */

        String propValue = AccessController.doPrivileged(

                new GetPropertyAction("sun.security.spnego.msinterop",

                "true"));

        /*

         * This property has to be explicitly set to "false". Invalid

         * values should be ignored and the default "true" assumed.

         */

        return (!propValue.equalsIgnoreCase("false"));

    }

    /**

     * Searches the private credentials of current Subject with the

     * specified criteria and returns the matching GSSCredentialSpi

     * object out of Sun's impl of GSSCredential. Returns null if

     * no Subject present or a Vector which contains 0 or more

     * matching GSSCredentialSpi objects.

     */

    public static Vector searchSubject(final GSSNameSpi name,

                                       final Oid mech,

                                       final boolean initiate,

                                       final Class credCls) {

        debug("Search Subject for " + getMechStr(mech) +

              (initiate? " INIT" : " ACCEPT") + " cred (" +

              (name == null? "<<DEF>>" : name.toString()) + ", " +

              credCls.getName() + ")");

        final AccessControlContext acc = AccessController.getContext();

        try {

            Vector creds =

                AccessController.doPrivileged

                (new PrivilegedExceptionAction<Vector>() {

                    public Vector run() throws Exception {

                        Subject accSubj = Subject.getSubject(acc);

                        Vector<GSSCredentialSpi> result = null;

                        if (accSubj != null) {

                            result = new Vector<GSSCredentialSpi>();

                            Iterator<GSSCredentialImpl> iterator =

                                accSubj.getPrivateCredentials

                                (GSSCredentialImpl.class).iterator();

                            while (iterator.hasNext()) {

                                GSSCredentialImpl cred = iterator.next();

                                debug("...Found cred" + cred);

                                try {

                                    GSSCredentialSpi ce =

                                        cred.getElement(mech, initiate);

                                    debug("......Found element: " + ce);

                                    if (ce.getClass().equals(credCls) &&

                                        (name == null ||

                                         name.equals((Object) ce.getName()))) {

                                        result.add(ce);

                                    } else {

                                        debug("......Discard element");

                                    }

                                } catch (GSSException ge) {

                                    debug("...Discard cred (" + ge + ")");

                                }

                            }

                        } else debug("No Subject");

                        return result;

                    }

                });

            return creds;

        } catch (PrivilegedActionException pae) {

            debug("Unexpected exception when searching Subject:");

            if (DEBUG) pae.printStackTrace();

            return null;

        }

    }

}