8161129 Unsafe::getUnsafe should allow the platform class loader to access it

[Martin Buchholz]

Recent discussion here:

http://markmail.org/search/?q=core-libs-dev%20ConcurrentHashMap%20jdk.internal.misc.unsafe#query:core-libs-dev%20ConcurrentHashMap%20jdk.internal.misc.unsafe+page:1+mid:iviymmlotcuasv6t+state:results

There are too many places where reflective code can get its hands on a
jdk.internal.misc.Unsafe.  They can even call its toString method, but
(perhaps!) not the dangerous methods.

On Mon, Jul 18, 2016 at 10:29 AM, Remi Forax <forax at univ-mlv.fr> wrote:

> Hi Paul,
>
> ----- Mail original -----
> > De: "Paul Sandoz" <paul.sandoz at oracle.com>
> > À: "Core-Libs-Dev" <core-libs-dev at openjdk.java.net>
> > Envoyé: Lundi 18 Juillet 2016 18:06:44
> > Objet: 8161129 Unsafe::getUnsafe should allow the platform class loader
> to    access it
> >
> > Hi,
> >
> > Please review the patch below.
> >
>
> [...]
>
> > I also took the opportunity to hide the “theInternalUnsafe” field in the
> > sun.misc.Unsafe. That just avoids any futile attempts to obtain the
> field’s
> > value after which any reflective access on that value will fail.
>
> I see 3 good reasons to not do that,
> - as you said it is futile to try to get a reference to
> jdk.internal.misc.Unsafe because you will never be able to call a method on
> it.
> - the code you add contains a string that reference a field name which is
> erro prone when doing a refactoring
> - jdk.internal.misc.Unsafe is stored in static fields of a lot of exported
> classes, so why trying to 'protect' only sun.misc.Unsafe.
>
> >
> > Paul.
>
> Rémi
>
>
> > diff -r 4f5f82c457af
> src/jdk.unsupported/share/classes/sun/misc/Unsafe.java
> > --- a/src/jdk.unsupported/share/classes/sun/misc/Unsafe.java  Mon Jul 18
> > 13:13:52 2016 +0800
> > +++ b/src/jdk.unsupported/share/classes/sun/misc/Unsafe.java  Mon Jul 18
> > 17:50:20 2016 +0200
> > @@ -56,6 +56,7 @@
> >
> >      static {
> >          Reflection.registerMethodsToFilter(Unsafe.class, "getUnsafe");
> > +        Reflection.registerFieldsToFilter(Unsafe.class,
> > "theInternalUnsafe");
> >      }
> >
> >      private Unsafe() {}
> >
>