From: Andrew Haley <aph@redhat.com>
To: java@gcc.gnu.org
Subject: Re: problem with class accessiblity check in invoke (natMethod.cc)
Date: Wed, 23 Dec 2009 10:47:00 -0000 [thread overview]
Message-ID: <4B31F521.1010404@redhat.com> (raw)
In-Reply-To: <aaec99390912230238s2fa25e4buac3bfbab679e8d92@mail.gmail.com>
On 12/23/2009 10:38 AM, Erik Groeneveld wrote:
> We recently upgraded from libgcj7 to libgcj9. This broke our code. We
> found out that in natMethod.cc in invoke() there is an additional
> check for class accessibility. It starts out with:
>
> // Check accessibility, if required.
> if (! this->isAccessible())
> {
> if (! (Modifier::isPublic (meth->accflags)))
> {
> Class *caller = _Jv_StackTrace::GetCallingClass (&Method::class$);
> if (! _Jv_CheckAccess(caller, declaringClass, meth->accflags))
> throw new IllegalAccessException;
> }
>
> and then continues here (this part is new):
>
> else
> // Method is public, check to see if class is accessible.
> {
> jint flags = (declaringClass->accflags
> & (Modifier::PUBLIC
> | Modifier::PROTECTED
> | Modifier::PRIVATE));
> if (flags == 0) // i.e. class is package private
> {
> Class *caller = _Jv_StackTrace::GetCallingClass (&Method::class$);
> if (! _Jv_ClassNameSamePackage (caller->name,
> declaringClass->name))
> throw new IllegalAccessException;
> }
> }
> }
>
> The added code prevents legal calls to fail. For example, it is no
> longer possible to call invoke on the ´hasNext´ method on the iterator
> from AbstractList. The method AbstractList.iterator() returns an
> anonymous innerclass object which according to the C code above is not
> accessible since it is package private. There are two problems here:
>
> 1. The systems segfaults on the caller->name because there is no calling class.
How can there be no calling class?
> 2. We believe class accessibility is not relevant here: there is no
> reason why a Method object with public access should not be invokable,
> or is there?
>
> We found the following modification log, which is why we address
> Andrew Haley directly as well as the list:
>
> 2007-04-16 Andrew Haley <aph@redhat.com>
>
> * java/lang/reflect/natMethod.cc (Method::invoke): In invoke also
> check that the method's declaring class is accessible.
>
> Can you or anybody else explain why this was considered to be necessary?
Yes, but can you send a test case before we go any further? Then at least
we'll all know what you're talking about.
Andrew.
next prev parent reply other threads:[~2009-12-23 10:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-23 10:38 Erik Groeneveld
2009-12-23 10:47 ` Andrew Haley [this message]
2009-12-23 13:34 ` Erik Groeneveld
2009-12-23 15:09 ` Bryce McKinlay
2009-12-23 16:39 ` Erik Groeneveld
[not found] ` <C62FFC62-326C-49A1-893F-3181BC4C3DCD@cq2.nl>
2009-12-23 16:44 ` Bryce McKinlay
2009-12-23 18:09 ` Erik Groeneveld
2009-12-23 18:45 ` Andrew Haley
2009-12-23 20:57 ` Erik Groeneveld
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