RFR [9]: 8177036: Class.checkMemberAccess throws NPE when calling Class methods via JNI

[David Holmes]

As I'm discussing in the RFR for

"8177136: Caller sensitive methods Logger.getLogger, 
Logger.getAnonymousLogger, and System.getLogger should throw 
IllegalCallerException if there is no caller on the stack."

I am quite concerned by this, seemingly sudden, problem that we have a 
whole bunch of methods that now rely on there being a Java caller on the 
stack and as a result if called from JNI they fail! It's fine for the 
internal methods that depend on a caller to throw exceptions, but the 
public APIs should have defined semantics about how they depend on any 
kind of "caller context" and not just suddenly make the call illegal by 
throwing an IllegalCallerException as in 8177136!

Cheers,
David

On 21/03/2017 4:06 AM, Mandy Chung wrote:
>
>> On Mar 20, 2017, at 5:15 AM, Daniel Fuchs <daniel.fuchs at oracle.com> wrote:
>>
>> Hi Peter,
>>
>> On 20/03/2017 12:01, Peter Levart wrote:
>>> Perhaps the best way to rectify those problems in one place would be for
>>> Reflection.getCallerClass() to return a special internal class in its
>>> own package, such as:
>>>
>>> jdk.internal.solitary.NoCaller
>>>
>>> ...when there is no caller. This would work correctly for class loader
>>> checks and would only allow invoking public exported members by core
>>> reflection if invoked with no caller...
>>
>> I believe this might be dangerous as it would probably hide bugs
>> in places where 'null' results in NPE being thrown in today's
>> implementation.
>>
>> Allowing the code to succeed is not always the right thing to
>> do, and I don't believe it can be fixed in one place.
>> It's probably better to let the caller of Reflection.getCallerClass()
>> decide what to do when null is returned, even if this means
>> we might have to analyze all places where @CallerSensitive is
>> used.
>>
>
> Exactly.  We ought to examine all @CS methods and determine if it handles the no caller case properly and as intended.  I file a JBS issue to track this:
>
> https://bugs.openjdk.java.net/browse/JDK-8177155
>
> FYI.  Several options were discussed what StackWalker::getCallerClass should return and captured in [1].
>
> Mandy
> [1] https://bugs.openjdk.java.net/browse/JDK-8140450?focusedCommentId=13867764&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13867764
>