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
                            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/[email protected]", "initiate");
 

To obtain a service ticket to initiate a context with the "host" service the permission is constructed as follows:

     ServicePermission("host/[email protected]", "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/[email protected]", "accept");