On 30/11/2020 8:04 pm, [email protected] wrote:
----- Mail original -----
De: "David Holmes" <[email protected]>
À: "Remi Forax" <[email protected]>, "core-libs-dev"
<[email protected]>
Envoyé: Lundi 30 Novembre 2020 08:57:37
Objet: Re: Why having the wrong InnerClasses attribute is an issue for the VM ?
On 30/11/2020 5:08 pm, Remi Forax wrote:
I've forgotten a cast in an invokedynamic, hence a call to wrongTargetType,
but in order to create the error message, MethodType.toString(), getSimpleName()
is called and it fails because getDeclaringClass() verifies the InnerClasses
attribute.
For me InnerClasses was just an attribute for javac not something the VM should
take care of,
it seems that the VM strongly verifies this attribute and i wonder what is the
reason behind that ?
From the VM code - InstanceKlass::compute_enclosing_class:
// Throws an exception if outer klass has not declared k as an inner
klass
// We need evidence that each klass knows about the other, or else
// the system could allow a spoof of an inner class to gain access
rights.
Reflection::check_for_inner_class(outer_klass, this,
*inner_is_member, CHECK_NULL);
I don't understand how to spoof the InnerClasses attribute to gain access given
that the access rights are not based on the InnerClasses attribute.
Good point.
That aside though, how do you answer the is_top_level_class question if
the enclosed and enclosing classes disagree about the relationship?
David
-----
David
Rémi
regards,
Rémi
Exception in thread "main" java.lang.IncompatibleClassChangeError:
fr.umlv.transmogrif.ImplMap and
fr.umlv.transmogrif.ImplMap$Row/0x0000000801007400 disagree on InnerClasses
attribute
at java.base/java.lang.Class.getDeclaringClass0(Native Method)
at java.base/java.lang.Class.isTopLevelClass(Class.java:1970)
at java.base/java.lang.Class.getSimpleBinaryName(Class.java:1955)
at java.base/java.lang.Class.getSimpleName0(Class.java:1835)
at java.base/java.lang.Class.getSimpleName(Class.java:1826)
at java.base/java.lang.Class.getSimpleName0(Class.java:1833)
at java.base/java.lang.Class.getSimpleName(Class.java:1826)
at java.base/java.lang.invoke.MethodType.toString(MethodType.java:895)
at java.base/java.lang.String.valueOf(String.java:3365)
at java.base/java.lang.StringBuilder.append(StringBuilder.java:169)
at
java.base/java.lang.invoke.MethodHandle.standardString(MethodHandle.java:1611)
at
java.base/java.lang.invoke.MethodHandle.toString(MethodHandle.java:1608)
at java.base/java.lang.String.valueOf(String.java:3365)
at
java.base/java.lang.invoke.CallSite.wrongTargetType(CallSite.java:203)
at java.base/java.lang.invoke.CallSite.makeSite(CallSite.java:333)
at
java.base/java.lang.invoke.MethodHandleNatives.linkCallSiteImpl(MethodHandleNatives.java:280)
at
java.base/java.lang.invoke.MethodHandleNatives.linkCallSite(MethodHandleNatives.java:270)
at
fr.umlv.transmogrif.ImplMap/0x0000000801003c00.<init>(ImplMap.java:21)
at fr.umlv.transmogrif.Main.main(Main.java:7)
