RFR 8220513: Wrapper Key may get deleted when closing sessions in SunPKCS11 crypto provider

[Martin Balao]

Hi Valerie,

On 3/19/19 7:17 PM, Valerie Peng wrote:
> 
> How about another potential problem - wrapper key may never get deleted?
> If we don't have a good solution to addressing it, at least add a
> comment about it?
> Rest looks fine.
> 

Thanks for your feedback.

The Wrapper Key was never meant to be destroyed. However, it's a good
idea and we should do it, in addition to fixing this bug.

Here it's my proposal for getting rid of the Wrapper Key when it's no
longer needed:

Webrev 01:

 * http://cr.openjdk.java.net/~mbalao/webrevs/8220513/8220513.webrev.01/

Please note that a few changes were required in SessionKeyRef objects
lifetime. SessionKeyRef objects will live as long as their corresponding
P11Key object lives -a similar scheme was implemented in the original
patch-. This allows us to decrement Wrapper Key references -and
eventually destroy it- while P11Key objects which don't have a native
key created are deleted. In other words, objects that have wrapped
native key information but don't have a native key alive can also
decrement the Wrapper Key reference counter when deleted.

Testing:

 * No regressions found in sun/security/pkcs11.

 * I've verified with the debugger all the new execution flows,
including the deletion of a Wrapper Key. It would be a bit difficult to
assert this from an automated test though.

Kind regards,
Martin.-