java/7 : javax/security/auth/kerberos/ServicePermission.java

ServicePermission
KrbServicePermissionCollection
https://openjdk.java.net/
GPLv2 + Classpath Exception
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * particular file as subject to the "Classpath" exception as provided
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * accompanied this code).
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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.

A ServicePermission contains a service principal name and
a list of actions which specify the context the credential can be
used within.
 The service principal name is the canonical name of the KerberosPrincipal 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. 

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.

The possible actions are:
   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.

For example, to specify the permission to access to the TGT to
initiate a security context the permission is constructed as follows:
    ServicePermission("krbtgt/EXAMPLE.COM@EXAMPLE.COM", "initiate");


To obtain a service ticket to initiate a context with the "host"
service the permission is constructed as follows:
    ServicePermission("host/foo.example.com@EXAMPLE.COM", "initiate");


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:
    ServicePermission("host/foo.example.com@EXAMPLE.COM", "accept");

Since: 1.4/**
 * 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 KerberosPrincipal} 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:
 *
 * <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:
 *
 * <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:
 *
 * <pre>
 *     ServicePermission("host/foo.example.com@EXAMPLE.COM", "accept");
 * </pre>
 *
 * @since 1.4
 */

public final class ServicePermission extends Permission
    implements java.io.Serializable {

    private static final long serialVersionUID = -1227585031618624935L;

    Initiate a security context to the specified service
/**
     * Initiate a security context to the specified service
     */
    private final static int INITIATE   = 0x1;

    Accept a security context
/**
     * Accept a security context
     */
    private final static int ACCEPT     = 0x2;

    All actions
/**
     * All actions
     */
    private final static int ALL        = INITIATE|ACCEPT;

    No actions.
/**
     * No actions.
     */
    private final static int NONE    = 0x0;

    // the actions mask
    private transient int mask;

    the actions string.
@serial /**
     * 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 ServicePermission with the specified servicePrincipal and action. 
Params: servicePrincipal – the name of the service principal.
An asterisk may appear by itself, to signify any service principal.
action – the action string/**
     * Create a new {@code ServicePermission}
     * with the specified {@code servicePrincipal}
     * and {@code action}.
     *
     * @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) {
        // Note: servicePrincipal can be "@REALM" which means any principal in
        // this realm implies it. action can be "-" which means any
        // action implies it.
        super(servicePrincipal);
        init(servicePrincipal, getMask(action));
    }


    Initialize the ServicePermission object.
/**
     * 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.
 If none of the above are true, implies returns false. 
Params: p – the permission to check against.
Returns: true if the specified permission is implied by this object,
false if not./**
     * Checks if this Kerberos service 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 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()) ||
                (p.getName().startsWith("@") &&
                        this.getName().endsWith(p.getName())));
    }

    Checks two ServicePermission objects for equality.

Params: obj – the object to test for equality with this object.
Returns: true if obj is a ServicePermission, and has the
 same service principal, and actions as this
ServicePermission object./**
     * 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.
Returns: a hash code value for this object./**
     * 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.
Params: mask – a specific integer action mask to translate into a string
Returns: the canonical string representation of the actions/**
     * 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.
/**
     * 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.


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.
Returns: a new PermissionCollection object suitable for storing
ServicePermissions./**
     * 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.
Returns: the actions mask./**
     * Return the current action mask.
     *
     * @return the actions mask.
     */

    int getMask() {
        return mask;
    }

    Convert an action string to an integer actions mask.
Note: if action is "-", action will be NONE, which means any
action implies it.
Params: action – the action string.
Returns: the action mask/**
     * Convert an action string to an integer actions mask.
     *
     * Note: if action is "-", action will be NONE, which means any
     * action implies it.
     *
     * @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;

        char[] a = action.toCharArray();

        if (a.length == 1 && a[0] == '-') {
            return mask;
        }

        int i = a.length - 1;

        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.
/**
     * 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 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.
/**
     * readObject is called to restore the state of the
     * ServicePermission from a stream.
     */
    private 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<Permission> perms;

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

    Check and see if this collection of permissions implies the permissions
expressed in "permission".
Params: p – the Permission object to compare
Returns: true if "permission" is a proper subset of a permission in
the collection, false if not./**
     * 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();

        if (desired == 0) {
            for (Permission p: perms) {
                ServicePermission sp = (ServicePermission)p;
                if (sp.impliesIgnoreMask(np)) {
                    return true;
                }
            }
            return false;
        }

        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.
Params: permission – the Permission object to add.
Throws: IllegalArgumentException – - if the permission is not a
                                      ServicePermission
SecurityException – - if this PermissionCollection object
                               has been marked readonly/**
     * 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.
Returns: an enumeration of all the ServicePermission objects./**
     * Returns an enumeration of all the ServicePermission objects
     * in the container.
     *
     * @return an enumeration of all the ServicePermission objects.
     */

    public Enumeration<Permission> 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./**
     * @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)./**
     * @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<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 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<Permission> permissions =
                (Vector<Permission>)gfields.get("permissions", null);
        perms = new ArrayList<Permission>(permissions.size());
        perms.addAll(permissions);
    }
}
Params:	p – the permission to check against.
Returns:	true if the specified permission is implied by this object, false if not.
Params:	obj – the object to test for equality with this object.
Returns:	true if obj is a ServicePermission, and has the same service principal, and actions as this ServicePermission object.
Params:	mask – a specific integer action mask to translate into a string
Returns:	the canonical string representation of the actions
Params:	p – the Permission object to compare
Returns:	true if "permission" is a proper subset of a permission in the collection, false if not.
Params:	permission – the Permission object to add.
Throws:	IllegalArgumentException – - if the permission is not a ServicePermission SecurityException – - if this PermissionCollection object has been marked readonly
/

java/ 7/ javax/security/auth/kerberos/ServicePermission.java
