> From: andreas [mailto:anpa0...@telia.com]
> Subject: Re: Tomcat 6.0.20, JDK1.6.0_14 and security manager
> 
> But I wonder what this means in terms of security?

Konstantin's suggestion should not be a problem.  Note that code in Tomcat's 
lib directory is given all permissions (by default), but only bootstrap.jar and 
commons-daemon.jar from Tomcat's bin directory also enjoy the same privilege.

Here's the new code in 6u14:

        private Cleaner() {
            /* Set context class loader to null in order to avoid
             * keeping a strong reference to an application classloader.
             */
            this.setContextClassLoader(null);
        }

The reason the AccessControlException is thrown is because of the following in
http://java.sun.com/javase/6/docs/technotes/guides/security/permissions.html

"whenever a resource access is attempted, all code traversed by the execution 
thread up to that point must have permission for that resource access"

Despite the fact that code from rt.jar is given all permissions, code that 
calls methods in rt.jar is not unless explicitly granted by the security 
policy.  The setContextClassLoader(null) call has to be in the constructor 
rather than the Cleaner's run() method since this subclass of Thread doesn't 
actually execute until the JVM is shut down; wiping out the reference to any 
existing classloader copied from the caller's current Thread must occur early 
to allow GC to clean out webapps that have been undeployed.

Looks like Sun simply forgot to document this security incompatibility 
introduced in 6u14.

- Chuck


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