Chapter 17. Security - JBoss JBPM 3.1.3 userguide 英文版文档
Security features of jBPM are still in alpha stage. This chapter documents the pluggable authentication and authorization. And what parts of the framework are finished and what parts not yet.
On the framework part, we still need to define a set of permissions that are verified by the jbpm engine while a process is being executed. Currently you can check your own permissions, but there is not yet a jbpm default set of permissions.
Only one default authentication implementation is finished. Other authentication implementations are envisioned, but not yet implemented. Authorization is optional, and there is no authorization implementation yet. Also for authorization, there are a number of authorization implementations envisioned, but they are not yet worked out.
But for both authentication and authorization, the framework is there to plug in your own authentication and authorization mechanism.
Authentication is the process of knowing on who's behalf the code is running. In case of jBPM this information should be made available from the environment to jBPM. Cause jBPM is always executed in a specific environment like a webapp, an EJB, a swing application or some other environment, it is always the surrounding environment that should perform authentication.
In a few situations, jBPM needs to know who is running the code. E.g. to add authentication information in the process logs to know who did what and when. Another example is calculation of an actor based on the current authenticated actor.
In each situation where jBPM needs to know who is running the code, the central method org.jbpm.security.Authentication.getAuthenticatedActorId() is called. That method will delegate to an implementation of org.jbpm.security.authenticator.Authenticator. By specifying an implementation of the authenticator, you can configure how jBPM retrieves the currently authenticated actor from the environment.
The default authenticator is org.jbpm.security.authenticator.JbpmDefaultAutenticator. That implementation will maintain a ThreadLocal stack of authenticated actorId's. Authenticated blocks can be marked with the methods JbpmDefaultAutenticator.pushAuthenticatedActorId(String) and JbpmDefaultAutenticator.popAuthenticatedActorId(). Be sure to always put these demarcations in a try-finally block. For the push and pop methods of this authenticator implementation, there are convenience methods supplied on the base Authentication class. The reason that the JbpmDefaultAutenticator maintains a stack of actorIds instead of just one actorId is simple: it allows the jBPM code to distinct between code that is executed on behalf of the user and code that is executed on behalf of the jbpm engine.
See the javadocs for more information.
Authorization is validating if an authenticated user is allowed to perform a secured operation.
The jBPM engine and user code can verify if a user is allowed to perform a given operation with the API method org.jbpm.security.Authorization.checkPermission(Permission).
The Authrorization class will also delegate that call to a configurable implementation. The interface for pluggin in different authorization strategies is org.jbpm.security.authorizer.Authorizer.
In the package org.jbpm.security.authorizer there are some examples that show intentions of authorizer implementations. Most are not fully implemented and none of them are tested.
Also still todo is the definition of a set of jBPM permissions and the verification of those permissions by the jBPM engine. An example could be verifying that the current authenticated user has sufficient privileges to end a task by calling Authorization.checkPermission(new TaskPermission("end", Long.toString(id))) in the TaskInstance.end() method.