Class ServicePermission

All Implemented Interfaces:
Serializable, Guard

public final class ServicePermission
extends Permission
implements Serializable
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.

Granting this permission also implies creating KerberosPrincipal or GSSName without providing a Kerberos realm, as long as the permission's service principal is in this realm.

The possible actions are:

    initiate -              allow the caller to use the credential to
                            initiate a security context with a service

    accept -                allow the caller to use the credential to
                            accept security context as a particular
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/", "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/", "accept");
See Also:
Serialized Form
  • Constructor Details

    • ServicePermission

      public ServicePermission​(String servicePrincipal, String action)
      Create a new ServicePermission with the specified servicePrincipal and action.
      servicePrincipal - the name of the service principal. An asterisk may appear by itself, to signify any service principal.
      action - the action string
  • Method Details

    • implies

      public boolean implies​(Permission p)
      Checks if this Kerberos service permission object "implies" the specified permission.

      More specifically, this method returns true if all of the following are true (and returns false if any of them are not):

      • p is an instanceof ServicePermission,
      • p's actions are a proper subset of this ServicePermission's actions,
      • p's name is equal to this ServicePermission's name or this ServicePermission's name is "*".
      Specified by:
      implies in class Permission
      p - the permission to check against.
      true if the specified permission is implied by this object, false if not.
    • equals

      public boolean equals​(Object obj)
      Checks two ServicePermission objects for equality.
      Specified by:
      equals in class Permission
      obj - the object to test for equality with this object.
      true if obj is a ServicePermission, and has the same service principal, and actions as this ServicePermission object.
      See Also:
      Object.hashCode(), HashMap
    • hashCode

      public int hashCode()
      Returns the hash code value for this object.
      Specified by:
      hashCode in class Permission
      a hash code value for this object.
      See Also:
      Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)
    • getActions

      public String getActions()
      Returns the canonical string representation of the actions. Always returns present actions in the following order: initiate, accept.
      Specified by:
      getActions in class Permission
      the actions of this Permission.
    • newPermissionCollection

      public PermissionCollection newPermissionCollection()
      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.
      newPermissionCollection in class Permission
      a new PermissionCollection object suitable for storing ServicePermissions.