Review request for 7198429: need checked categorization of caller-sensitive methods in the JDK

Mandy Chung mandy.chung at
Thu Mar 28 03:01:16 UTC 2013

Thanks for the review.  I forgot to mention that Chris contributed the 
initial patch (thanks).

On 3/27/2013 1:13 PM, Christian Thalinger wrote:
> On Mar 27, 2013, at 10:35 AM, Mandy Chung <mandy.chung at> wrote:
>> This is the JDK change for JEP 176: JEP 176: Mechanical Checking of Caller-Sensitive Methods [1].  Christian has posted the webrev for the hotspot VM change a couple weeks ago [2].
>> Webrev at:
> src/share/classes/java/lang/
> +    static void checkClassLoaderPermission(ClassLoader cl, Class<?> caller) {
> I think we should rename that method to:
> +    static void checkGetClassLoaderPermission(ClassLoader cl, Class<?> caller) {

I think checkClassLoaderPermission and needsClassLoaderPermissionCheck 
are just fine.  I'd like to keep it as it is not to make the method name 
too long.

> src/share/classes/java/lang/invoke/
> +        @sun.reflect.CallerSensitive
> +            Class<?> actual = sun.reflect.Reflection.getCallerClass();
> Why are we not using imports here?

imports are for convenience and ease of development.  For only one 
reference, I don't see any difference to import or not.

> src/share/classes/java/util/logging/
>               // 0: Reflection 1: Logger.demandLogger 2: Logger.getLogger 3: caller
>               final int SKIP_FRAMES = 3;
> Please remove these lines as well.

Removed.  Thanks for catching the leftover comment.
> src/share/native/sun/reflect/Reflection.c:
> Could you put back this comment:
> +     // Let's do at least some basic handshaking:
> +     const int depth = -1;
> It makes it clearer why it's -1.

I added this comment:
   32     // with the presence of @CallerSensitive annotation,
   33     // JVM_GetCallerClass asserts depth == -1 as the basic handshaking

> test/sun/reflect/
> Could you please don't use a shell script to copy the class file?

The shell test doesn't do a copy.  It compiles the source file in a 
separate directory that will be specified in -Xbootclasspath/a option in 
javac and java commands.

jtreg in the code-tool repo has added the bootclasspath support:

You can specify in the @run tag:
     @run main/bootclasspath opt class

This will be a better way to run a test on the bootclasspath.

> For example this test:
> does the same thing using a little Java program ClassFileInstaller:

This is a nice workaround to avoid shell tests.  It compiles the source 
file in $TESTCLASSES and copies the one in a different location (dest) 
that will be used in a @run main -Xbootclasspath/a:dest class.

I prefer to use the new jtreg bootclasspath support when it's released 
rather than adding yet another workaround to avoid shell tests.   We 
should replace many, if not all, existing shell tests that currently put 
classes in the bootclasspath with the jtreg bootclasspath support in one 
patch.  I keep the test as it is.


> -- Chris
>> While it touches many files, the fix is simple and straight-forward for review.
>> This fix annotates all methods that call Reflection.getCallerClass() method with @sun.reflect.CallerSensitive annotation so that it enables the VM to reliably enforce that methods looking up its immediate caller class are marked as caller-sensitive. The JVM will set a new caller-sensitive bit when resolving a MemberName and java.lang.invoke.MethodHandleNatives.isCallerSensitive is upgraded to query it directly.
>> The hand-maintained method list in MethodHandleNatives is removed.
>> A couple things to mention:
>> 1. I am working on a fix for 8007035 that proposes to deprecate SecurityManager.checkMemberAccess method as it requires the caller’s frame to be at a stack depth of four, which is fragile and difficult to enforce.
>> 2. NashornScriptEngineFactory.getAppClassLoader()
>> The change is to workaround the issue until 8009783 is resolved.
>> The current implementation walks the stack to find the classloader of the user context that NashornScriptEngine is running on which is fragile.  Also other script engine implementations may require similiar capability.  8009783 has been filed to revisit the scripting API to pass the user "context" to the script engine rather than relying the implementation to find it magically.
>> Thanks
>> Mandy
>> [1]
>> [2]

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