RFR: 6983726: remove Proxy from MethodHandleProxies.asInterfaceInstance SAM conversion [v6]

[Jorn Vernee]

On Thu, 6 Apr 2023 15:57:33 GMT, Johannes Kuhn <jkuhn at openjdk.org> wrote:

>> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Whitespace, cleanup, rename benchmarks to be informative
>
> src/java.base/share/classes/java/lang/invoke/MethodHandleProxies.java line 284:
> 
>> 282:                     return type.getDeclaredAnnotation(WrapperInstance.class);
>> 283:                 }
>> 284:             }) : type.getDeclaredAnnotation(WrapperInstance.class);
> 
> This may introduce a security vulnerability:
> 
> 
> @AnnotationTest.ClassHolder(sun.misc.Unsafe.class)
> public class AnnotationTest {
>     
>     @Target(ElementType.TYPE)
>     @Retention(RetentionPolicy.RUNTIME)
>     @interface ClassHolder {
>         Class<?> value();
>     }
>     public static void main(String[] args) throws PrivilegedActionException {
>         MethodHandleProxies.isWrapperInstance(new AnnotationTest());
>         System.out.println(AnnotationTest.class.getDeclaredAnnotation(ClassHolder.class).value());
>     }
> }
> 
> 
> Don't parse annotations in a privileged context.

I'm not sure how the example shows that this is a security vulnerability? It still works fine without the call to `isWrapperInstance` (even if you switch to using jdk.internal.misc.Unsafe.class, although that also requires `--add-exports` when compiling)

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PR Review Comment: https://git.openjdk.org/jdk/pull/13197#discussion_r1160005209