/*
* @(#)ServicePermission.java 1.12 04/03/29
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.security.auth.kerberos;
import java.util.*;
import java.security.Permission;
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 protect Kerberos services and the
* credentials necessary to access those services. There is a one to
* one mapping of a service principal and the credentials necessary
* to access the service. Therefore granting access to a service
* principal implicitly grants access to the credential necessary to
* establish a security context with the service principal. This
* applies regardless of whether the credentials are in a cache
* or acquired via an exchange with the KDC. The credential can
* be either a ticket granting ticket, a service ticket or a secret
* key from a key table.
* <p>
* A ServicePermission contains a service principal name and
* a list of actions which specify the context the credential can be
* used within.
* <p>
* The service principal name is the canonical name of the
* <code>KereberosPrincipal</code> supplying the service, that is
* the KerberosPrincipal represents a Kerberos service
* principal. This name is treated in a case sensitive manner.
* An asterisk may appear by itself, to signify any service principal.
* <p>
* Granting this permission implies that the caller can use a cached
* credential (TGT, service ticket or secret key) within the context
* designated by the action. In the case of the TGT, granting this
* permission also implies that the TGT can be obtained by an
* Authentication Service exchange.
* <p>
* The possible actions are:
* <p>
* <pre>
* initiate - allow the caller to use the credential to
* initiate a security context with a service
* principal.
*
* accept - allow the caller to use the credential to
* accept security context as a particular
* principal.
* </pre>
*
* For example, to specify the permission to access to the TGT to
* initiate a security context the permission is constructed as follows:
* <p>
* <pre>
* ServicePermission("krbtgt/EXAMPLE.COM@EXAMPLE.COM", "initiate");
* </pre>
* <p>
* To obtain a service ticket to initiate a context with the "host"
* service the permission is constructed as follows:
* <pre>
* ServicePermission("host/foo.example.com@EXAMPLE.COM", "initiate");
* </pre>
* <p>
* For a Kerberized server the action is "accept". For example, the permission
* necessary to access and use the secret key of the Kerberized "host"
* service (telnet and the likes) would be constructed as follows:
* <p>
* <pre>
* ServicePermission("host/foo.example.com@EXAMPLE.COM", "accept");
* </pre>
*
* @since JDK1.4
*/
public final class ServicePermission extends Permission
implements java.io.Serializable {
private static final long serialVersionUID = -1227585031618624935L;
/**
* Initiate a security context to the specified service
*/
private final static int INITIATE = 0x1;
/**
* Accept a security context
*/
private final static int ACCEPT = 0x2;
/**
* All actions
*/
private final static int ALL = INITIATE|ACCEPT;
/**
* No actions.
*/
private final static int NONE = 0x0;
// the actions mask
private transient int mask;
/**
* the actions string.
*
* @serial
*/
private String actions; // Left null as long as possible, then
// created and re-used in the getAction function.
/**
* Create a new <code>ServicePermission</code>
* with the specified <code>servicePrincipal</code>
* and <code>action</code>.
*
* @param servicePrincipal the name of the service principal.
* An asterisk may appear by itself, to signify any service principal.
* <p>
* @param action the action string
*/
public ServicePermission(String servicePrincipal, String action) {
super(servicePrincipal);
init(servicePrincipal, getMask(action));
}
/**
* Initialize the ServicePermission object.
*/
private void init(String servicePrincipal, int mask) {
if (servicePrincipal == null)
throw new NullPointerException("service principal can't be null");
if ((mask & ALL) != mask)
throw new IllegalArgumentException("invalid actions mask");
this.mask = mask;
}
/**
* Checks if this Kerberos service permission object "implies" the
* specified permission.
* <P>
* If none of the above are true, <code>implies</code> 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 ServicePermission))
return false;
ServicePermission that = (ServicePermission) p;
return ((this.mask & that.mask) == that.mask) &&
impliesIgnoreMask(that);
}
boolean impliesIgnoreMask(ServicePermission p) {
return ((this.getName().equals("*")) ||
this.getName().equals(p.getName()));
}
/**
* Checks two ServicePermission objects for equality.
* <P>
* @param obj the object to test for equality with this object.
*
* @return true if <i>obj</i> is a ServicePermission, and has the
* same service principal, and actions as this
* ServicePermission object.
*/
public boolean equals(Object obj) {
if (obj == this)
return true;
if (! (obj instanceof ServicePermission))
return false;
ServicePermission that = (ServicePermission) obj;
return ((this.mask & that.mask) == that.mask) &&
this.getName().equals(that.getName());
}
/**
* Returns the hash code value for this object.
*
* @return a hash code value for this object.
*/
public int hashCode() {
return (getName().hashCode() ^ mask);
}
/**
* Returns the "canonical string representation" of the actions in the
* specified mask.
* Always returns present actions in the following order:
* initiate, accept.
*
* @param mask a specific integer action mask to translate into a string
* @return the canonical string representation of the actions
*/
private static String getActions(int mask)
{
StringBuilder sb = new StringBuilder();
boolean comma = false;
if ((mask & INITIATE) == INITIATE) {
if (comma) sb.append(',');
else comma = true;
sb.append("initiate");
}
if ((mask & ACCEPT) == ACCEPT) {
if (comma) sb.append(',');
else comma = true;
sb.append("accept");
}
return sb.toString();
}
/**
* Returns the canonical string representation of the actions.
* Always returns present actions in the following order:
* initiate, accept.
*/
public String getActions() {
if (actions == null)
actions = getActions(this.mask);
return actions;
}
/**
* Returns a PermissionCollection object for storing
* ServicePermission objects.
* <br>
* ServicePermission 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
* ServicePermissions.
*/
public PermissionCollection newPermissionCollection() {
return new KrbServicePermissionCollection();
}
/**
* Return the current action mask.
*
* @return the actions mask.
*/
int getMask() {
return mask;
}
/**
* Convert an action string to an integer actions mask.
*
* @param action the action string
* @return the action mask
*/
private static int getMask(String action) {
if (action == null) {
throw new NullPointerException("action can't be null");
}
if (action.equals("")) {
throw new IllegalArgumentException("action can't be empty");
}
int mask = NONE;
if (action == null) {
return mask;
}
char[] a = action.toCharArray();
int i = a.length - 1;
if (i < 0)
return mask;
while (i != -1) {
char c;
// skip whitespace
while ((i!=-1) && ((c = a[i]) == ' ' ||
c == '\r' ||
c == '\n' ||
c == '\f' ||
c == '\t'))
i--;
// check for the known strings
int matchlen;
if (i >= 7 && (a[i-7] == 'i' || a[i-7] == 'I') &&
(a[i-6] == 'n' || a[i-6] == 'N') &&
(a[i-5] == 'i' || a[i-5] == 'I') &&
(a[i-4] == 't' || a[i-4] == 'T') &&
(a[i-3] == 'i' || a[i-3] == 'I') &&
(a[i-2] == 'a' || a[i-2] == 'A') &&
(a[i-1] == 't' || a[i-1] == 'T') &&
(a[i] == 'e' || a[i] == 'E'))
{
matchlen = 8;
mask |= INITIATE;
} else if (i >= 5 && (a[i-5] == 'a' || a[i-5] == 'A') &&
(a[i-4] == 'c' || a[i-4] == 'C') &&
(a[i-3] == 'c' || a[i-3] == 'C') &&
(a[i-2] == 'e' || a[i-2] == 'E') &&
(a[i-1] == 'p' || a[i-1] == 'P') &&
(a[i] == 't' || a[i] == 'T'))
{
matchlen = 6;
mask |= ACCEPT;
} else {
// parse error
throw new IllegalArgumentException(
"invalid permission: " + action);
}
// make sure we didn't just match the tail of a word
// like "ackbarfaccept". Also, skip to the comma.
boolean seencomma = false;
while (i >= matchlen && !seencomma) {
switch(a[i-matchlen]) {
case ',':
seencomma = true;
/*FALLTHROUGH*/
case ' ': case '\r': case '\n':
case '\f': case '\t':
break;
default:
throw new IllegalArgumentException(
"invalid permission: " + action);
}
i--;
}
// point i at the location of the comma minus one (or -1).
i -= matchlen;
}
return mask;
}
/**
* WriteObject is called to save the state of the ServicePermission
* 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
{
// Write out the actions. The superclass takes care of the name
// call getActions to make sure actions field is initialized
if (actions == null)
getActions();
s.defaultWriteObject();
}
/**
* readObject is called to restore the state of the
* ServicePermission 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(),getMask(actions));
}
/*
public static void main(String args[]) throws Exception {
ServicePermission this_ =
new ServicePermission(args[0], "accept");
ServicePermission that_ =
new ServicePermission(args[1], "accept,initiate");
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");
KrbServicePermissionCollection nps =
new KrbServicePermissionCollection();
nps.add(this_);
nps.add(new ServicePermission("nfs/example.com@EXAMPLE.COM",
"accept"));
nps.add(new ServicePermission("host/example.com@EXAMPLE.COM",
"initiate"));
System.out.println("nps.implies(that) = " + nps.implies(that_));
System.out.println("-----\n");
Enumeration e = nps.elements();
while (e.hasMoreElements()) {
ServicePermission x =
(ServicePermission) e.nextElement();
System.out.println("nps.e = " + x);
}
}
*/
}
final class KrbServicePermissionCollection extends PermissionCollection
implements java.io.Serializable {
// Not serialized; see serialization section at end of class
private transient List perms;
public KrbServicePermissionCollection() {
perms = new ArrayList();
}
/**
* Check and see if this collection of permissions implies the permissions
* expressed in "permission".
*
* @param p 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 ServicePermission))
return false;
ServicePermission np = (ServicePermission) permission;
int desired = np.getMask();
int effective = 0;
int needed = desired;
synchronized (this) {
int len = perms.size();
// need to deal with the case where the needed permission has
// more than one action and the collection has individual permissions
// that sum up to the needed.
for (int i = 0; i < len; i++) {
ServicePermission x = (ServicePermission) perms.get(i);
//System.out.println(" trying "+x);
if (((needed & x.getMask()) != 0) && x.impliesIgnoreMask(np)) {
effective |= x.getMask();
if ((effective & desired) == desired)
return true;
needed = (desired ^ effective);
}
}
}
return false;
}
/**
* Adds a permission to the ServicePermissions. The key for
* the hash is the name.
*
* @param permission the Permission object to add.
*
* @exception IllegalArgumentException - if the permission is not a
* ServicePermission
*
* @exception SecurityException - if this PermissionCollection object
* has been marked readonly
*/
public void add(Permission permission) {
if (! (permission instanceof ServicePermission))
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 ServicePermission objects
* in the container.
*
* @return an enumeration of all the ServicePermission objects.
*/
public Enumeration elements() {
// Convert Iterator into Enumeration
synchronized (this) {
return Collections.enumeration(perms);
}
}
private static final long serialVersionUID = -4118834211490102011L;
// Need to maintain serialization interoperability with earlier releases,
// which had the serializable field:
// private Vector permissions;
/**
* @serialField permissions java.util.Vector
* A list of ServicePermission objects.
*/
private static final ObjectStreamField[] serialPersistentFields = {
new ObjectStreamField("permissions", Vector.class),
};
/**
* @serialData "permissions" field (a Vector containing the ServicePermissions).
*/
/*
* 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 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 ServicePermissions and saves them in the perms field.
*/
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 permissions = (Vector)gfields.get("permissions", null);
perms = new ArrayList(permissions.size());
perms.addAll(permissions);
}
}
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