Re: fine grained security with SubjectTrackingMBeanServer example

Hi Luis-Miguel,

> When the JMX client calls mbsc.addNotificationListener() for the first time
> the connector server needs to register a listener on the MBeanServerDelegate
> MBean to listen for register/unregister MBean notifications. This call is made
> on behalf of the connector server (and not on behalf of the authenticated user)
> and thus no Subject will be available in the thread's context but the call will
> still go through the MBeanServerForwarder (i.e. your SubjectTrackingMBeanServer)
> and that's where your code throws a NullPointerException.

This is an implementation detail of the RI, and IMHO it is bad that it
behaves this way, breaking the least surprise rule.
If I am calling the remote MBeanServer *once* to add a listener, why
the forwarder gets called *twice* ?

> A solution to this problem might be having a special case for adding listeners
> to the MBeanServerDelegate MBean in your MBeanServerForwarder where a null
> Subject might be accepted.

This is even worse, because you cannot distinguish when a call is
really made without credentials, or it's an implementation artifact.
How can I distinguish when I should reject the call (because there are
no credentials) or let it through (because it's an implementation
artifact) ?
Furthermore, this solution makes code non-portable and heavily
dependent on the implementation used, which was the reason JMX was
standardized.

I consider this a bug of the RI. Your thoughts ?

Simon
-- 
http://bordet.blogspot.com

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