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	/*
	* 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 javax.security.auth.kerberos;

	import java.util.*;
	import java.security.Permission;
	import java.security.BasicPermission;
	import java.security.PermissionCollection;
	import java.io.ObjectStreamField;
	import java.io.ObjectOutputStream;
	import java.io.ObjectInputStream;
	import java.io.IOException;

	/**
	* This class is used to restrict the usage of the Kerberos
	* delegation model, ie: forwardable and proxiable tickets.
	* <p>
	* The target name of this {@code Permission} specifies a pair of
	* kerberos service principals. The first is the subordinate service principal
	* being entrusted to use the TGT. The second service principal designates
	* the target service the subordinate service principal is to
	* interact with on behalf of the initiating KerberosPrincipal. This
	* latter service principal is specified to restrict the use of a
	* proxiable ticket.
	* <p>
	* For example, to specify the "host" service use of a forwardable TGT the
	* target permission is specified as follows:
	*
	* <pre>
	* DelegationPermission("\"host/foo.example.com@EXAMPLE.COM\" \"krbtgt/EXAMPLE.COM@EXAMPLE.COM\"");
	* </pre>
	* <p>
	* To give the "backup" service a proxiable nfs service ticket the target permission
	* might be specified:
	*
	* <pre>
	* DelegationPermission("\"backup/bar.example.com@EXAMPLE.COM\" \"nfs/home.EXAMPLE.COM@EXAMPLE.COM\"");
	* </pre>
	*
	* @since 1.4
	*/

	public final class DelegationPermission extends BasicPermission
	implements java.io.Serializable {

	private static final long serialVersionUID = 883133252142523922L;

	private transient String subordinate, service;

	/**
	* Create a new {@code DelegationPermission}
	* with the specified subordinate and target principals.
	*
	* <p>
	*
	* @param principals the name of the subordinate and target principals
	*
	* @throws NullPointerException if {@code principals} is {@code null}.
	* @throws IllegalArgumentException if {@code principals} is empty.
	*/
	public DelegationPermission(String principals) {
	super(principals);
	init(principals);
	}

	/**
	* Create a new {@code DelegationPermission}
	* with the specified subordinate and target principals.
	* <p>
	*
	* @param principals the name of the subordinate and target principals
	* <p>
	* @param actions should be null.
	*
	* @throws NullPointerException if {@code principals} is {@code null}.
	* @throws IllegalArgumentException if {@code principals} is empty.
	*/
	public DelegationPermission(String principals, String actions) {
	super(principals, actions);
	init(principals);
	}


	/**
	* Initialize the DelegationPermission object.
	*/
	private void init(String target) {

	StringTokenizer t = null;
	if (!target.startsWith("\"")) {
	throw new IllegalArgumentException
	("service principal [" + target +
	"] syntax invalid: " +
	"improperly quoted");
	} else {
	t = new StringTokenizer(target, "\"", false);
	subordinate = t.nextToken();
	if (t.countTokens() == 2) {
	t.nextToken(); // bypass whitespace
	service = t.nextToken();
	} else if (t.countTokens() > 0) {
	throw new IllegalArgumentException
	("service principal [" + t.nextToken() +
	"] syntax invalid: " +
	"improperly quoted");
	}
	}
	}

	/**
	* Checks if this Kerberos delegation permission object "implies" the
	* specified permission.
	* <P>
	* If none of the above are true, {@code implies} returns false.
	* @param p the permission to check against.
	*
	* @return true if the specified permission is implied by this object,
	* false if not.
	*/
	public boolean implies(Permission p) {
	if (!(p instanceof DelegationPermission))
	return false;

	DelegationPermission that = (DelegationPermission) p;
	if (this.subordinate.equals(that.subordinate) &&
	this.service.equals(that.service))
	return true;

	return false;
	}


	/**
	* Checks two DelegationPermission objects for equality.
	* <P>
	* @param obj the object to test for equality with this object.
	*
	* @return true if <i>obj</i> is a DelegationPermission, and
	* has the same subordinate and service principal as this.
	* DelegationPermission object.
	*/
	public boolean equals(Object obj) {
	if (obj == this)
	return true;

	if (! (obj instanceof DelegationPermission))
	return false;

	DelegationPermission that = (DelegationPermission) obj;
	return implies(that);
	}

	/**
	* Returns the hash code value for this object.
	*
	* @return a hash code value for this object.
	*/
	public int hashCode() {
	return getName().hashCode();
	}


	/**
	* Returns a PermissionCollection object for storing
	* DelegationPermission objects.
	* <br>
	* DelegationPermission objects must be stored in a manner that
	* allows them to be inserted into the collection in any order, but
	* that also enables the PermissionCollection implies method to
	* be implemented in an efficient (and consistent) manner.
	*
	* @return a new PermissionCollection object suitable for storing
	* DelegationPermissions.
	*/

	public PermissionCollection newPermissionCollection() {
	return new KrbDelegationPermissionCollection();
	}

	/**
	* WriteObject is called to save the state of the DelegationPermission
	* to a stream. The actions are serialized, and the superclass
	* takes care of the name.
	*/
	private synchronized void writeObject(java.io.ObjectOutputStream s)
	throws IOException
	{
	s.defaultWriteObject();
	}

	/**
	* readObject is called to restore the state of the
	* DelegationPermission from a stream.
	*/
	private synchronized void readObject(java.io.ObjectInputStream s)
	throws IOException, ClassNotFoundException
	{
	// Read in the action, then initialize the rest
	s.defaultReadObject();
	init(getName());
	}

	/*
	public static void main(String args[]) throws Exception {
	DelegationPermission this_ =
	new DelegationPermission(args[0]);
	DelegationPermission that_ =
	new DelegationPermission(args[1]);
	System.out.println("-----\n");
	System.out.println("this.implies(that) = " + this_.implies(that_));
	System.out.println("-----\n");
	System.out.println("this = "+this_);
	System.out.println("-----\n");
	System.out.println("that = "+that_);
	System.out.println("-----\n");

	KrbDelegationPermissionCollection nps =
	new KrbDelegationPermissionCollection();
	nps.add(this_);
	nps.add(new DelegationPermission("\"host/foo.example.com@EXAMPLE.COM\" \"CN=Gary Ellison/OU=JSN/O=SUNW/L=Palo Alto/ST=CA/C=US\""));
	try {
	nps.add(new DelegationPermission("host/foo.example.com@EXAMPLE.COM \"CN=Gary Ellison/OU=JSN/O=SUNW/L=Palo Alto/ST=CA/C=US\""));
	} catch (Exception e) {
	System.err.println(e);
	}

	System.out.println("nps.implies(that) = " + nps.implies(that_));
	System.out.println("-----\n");

	Enumeration e = nps.elements();

	while (e.hasMoreElements()) {
	DelegationPermission x =
	(DelegationPermission) e.nextElement();
	System.out.println("nps.e = " + x);
	}
	}
	*/
	}


	final class KrbDelegationPermissionCollection extends PermissionCollection
	implements java.io.Serializable {

	// Not serialized; see serialization section at end of class.
	private transient List<Permission> perms;

	public KrbDelegationPermissionCollection() {
	perms = new ArrayList<Permission>();
	}


	/**
	* Check and see if this collection of permissions implies the permissions
	* expressed in "permission".
	*
	* @param permission the Permission object to compare
	*
	* @return true if "permission" is a proper subset of a permission in
	* the collection, false if not.
	*/
	public boolean implies(Permission permission) {
	if (! (permission instanceof DelegationPermission))
	return false;

	synchronized (this) {
	for (Permission x : perms) {
	if (x.implies(permission))
	return true;
	}
	}
	return false;

	}

	/**
	* Adds a permission to the DelegationPermissions. The key for
	* the hash is the name.
	*
	* @param permission the Permission object to add.
	*
	* @exception IllegalArgumentException - if the permission is not a
	* DelegationPermission
	*
	* @exception SecurityException - if this PermissionCollection object
	* has been marked readonly
	*/
	public void add(Permission permission) {
	if (! (permission instanceof DelegationPermission))
	throw new IllegalArgumentException("invalid permission: "+
	permission);
	if (isReadOnly())
	throw new SecurityException("attempt to add a Permission to a readonly PermissionCollection");

	synchronized (this) {
	perms.add(0, permission);
	}
	}

	/**
	* Returns an enumeration of all the DelegationPermission objects
	* in the container.
	*
	* @return an enumeration of all the DelegationPermission objects.
	*/
	public Enumeration<Permission> elements() {
	// Convert Iterator into Enumeration
	synchronized (this) {
	return Collections.enumeration(perms);
	}
	}

	private static final long serialVersionUID = -3383936936589966948L;

	// Need to maintain serialization interoperability with earlier releases,
	// which had the serializable field:
	// private Vector permissions;
	/**
	* @serialField permissions java.util.Vector
	* A list of DelegationPermission objects.
	*/
	private static final ObjectStreamField[] serialPersistentFields = {
	new ObjectStreamField("permissions", Vector.class),
	};

	/**
	* @serialData "permissions" field (a Vector containing the DelegationPermissions).
	*/
	/*
	* Writes the contents of the perms field out as a Vector for
	* serialization compatibility with earlier releases.
	*/
	private void writeObject(ObjectOutputStream out) throws IOException {
	// Don't call out.defaultWriteObject()

	// Write out Vector
	Vector<Permission> permissions = new Vector<>(perms.size());

	synchronized (this) {
	permissions.addAll(perms);
	}

	ObjectOutputStream.PutField pfields = out.putFields();
	pfields.put("permissions", permissions);
	out.writeFields();
	}

	/*
	* Reads in a Vector of DelegationPermissions and saves them in the perms field.
	*/
	@SuppressWarnings("unchecked")
	private void readObject(ObjectInputStream in)
	throws IOException, ClassNotFoundException
	{
	// Don't call defaultReadObject()

	// Read in serialized fields
	ObjectInputStream.GetField gfields = in.readFields();

	// Get the one we want
	Vector<Permission> permissions =
	(Vector<Permission>)gfields.get("permissions", null);
	perms = new ArrayList<Permission>(permissions.size());
	perms.addAll(permissions);
	}
	}

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