RFR: 8303809: Dispose context in SPNEGO NegotiatorImpl

[Daniel Jeliński]

On Wed, 8 Mar 2023 09:05:19 GMT, Alexey Bakhtin <abakhtin at openjdk.org> wrote:

> This patch fixes a possible native memory leak in case of a custom native GSS provider.
> The actual leak was reported in production.
> 
> sun/security/jgss, sun/security/krb5, sun/net/www/protocol/http jtreg tests are passed

I'm not familiar with this code and don't know how to execute it, but since you mentioned  native memory leak...

I'm assuming NativeGSSConext is the class that holds a reference to the native memory. The class has a cleaner that is supposed to release the memory. It was recently refactored in JDK-8284490, and I think this refactoring introduced the leak. See:
https://github.com/openjdk/jdk/blob/master/src/java.security.jgss/share/classes/sun/security/jgss/wrapper/NativeGSSContext.java#L374-L377
`cleanable.clean()` calls `stub.deleteContext(pContext)`, but `pContext` is already zero.
Before ffca23a5313855a6f9797ad6b342bb2e2cb1b49b `deleteContext` was called before setting `pContext` to zero.

In general, when fixing native memory leaks, please focus on fixing broken cleaners, rather than manually disposing the memory.

-------------

PR: https://git.openjdk.org/jdk/pull/12920