2.6.1.5 Authorization

Authorization works in the same way with both connectors. The authentication step produces a Java Subject, which is a collection of Principals. The security mechanisms in the Java platform allow permissions to be associated with each Principal. When a remote operation is performed, the required permissions must be present, usually because they are associated with one of the authenticated Principals in the policy file.

A simplified authorization scheme is supported by Java DMK. This scheme is also used in Sun's implementation of the J2SE platform, version 1.5. In the simplified scheme, Java permissions are not involved. This removes the need to create policy files and to set a security manager, which are relatively complicated. Instead, there are just two access levels, readonly and readwrite.

The readwrite level gives access to all MBean server operations. The only exceptions are the creation of m-lets and the addition of URLs to existing m-lets. Since these operations could allow arbitrary code to be loaded into the MBean server and run, they are forbidden even at the readwrite level. When there is a security manager, running arbitrary downloaded code is acceptable because it will have no permissions by default. But the simplified scheme is specifically intended for the case where there is no security manager.

The readonly level gives access only to operations that do not change the state of the MBean server, such as reading attributes or querying existing MBeans.

A text file defines the access levels for different principals. In this file, blank lines and lines beginning with # are ignored. Other lines must contain two blank-separated fields. The first is an authenticated principal name, and the second is readonly or readwrite.

The mechanism that checks authorization in this simplified scheme is intended for simple uses and for getting started. It is expected that users with strong security requirements will eventually graduate to using the full Java security model, with permissions, policy files, and a security manager.