Using tapestry 4.0 with java 2 security enabled prevents the application from
starting on several application servers (solution proposed)
-----------------------------------------------------------------------------------------------------------------------------------------
Key: HIVEMIND-192
URL: http://issues.apache.org/jira/browse/HIVEMIND-192
Project: HiveMind
Issue Type: Bug
Affects Versions: 1.1
Environment: java version 1.4.1_07 , apache tomcat server, 5.0 IBM
Websphere server 5.0
Reporter: lionel gomez
problem: Using tapestry 4.0 with java 2 security enabled on several application
servers prevents the application from starting
Cause:
The SecurityManager do security checks for sensitive operation based on context
of the current execution thread and its execution stack. The
AccessControlContext obtains a stack of ProtectionDomains of all objects in the
execution stack and checks if all these ProtectionDomain have all the permision
required to perform the operation.
Tapestry/Hivemind uses javassist library to create enhaced pages and components
using bytecode manipulation and generates a ctClass object, then use
HivemindPool wich ends up in a call to ClassPool.toClass(CtClass).
Javassist uses reflection to make a call to ClassLoader.defineClass(String
name, byte[] b, int off, int len) wich generates an object with a default
ProtectionDomain. So pages and componentes will have the default
ProtectionDomain.
copied from java API:
This method assigns a default ProtectionDomain to the newly defined class. The
ProtectionDomain is effectively granted the same set of permissions returned
when Policy.getPolicy().getPermissions(new CodeSource(null, null)) is invoked.
When the AccessControlContext do the security checks on the ProtectionDomain of
these enhaced classes it fails to find the required permisions, because they
dont have any permision (or protectiondomain is null cant remember for sure any
way fails to find required permisions).
The solution is to instead use the method ClassLoader.defineClass(String name,
byte[] b, int off, int len, ProtectionDomain protectionDomain) this way we can
assign a ProtectionDomain that has the defined permisions in the policy.
So this is really a javassist problem not a Tapestry/Hivemind problem.
But fixing this in javassist is not easy. The ctClass class deal with bytecode
manipulation only, and the ProtectionDomain is a responsability of the
ClassLoader. Should javassist also take over the ClassLoader responsibility of
assigning ProtectionDomains and get the assigned permisions from policy. What
ProtectionDomain should a new set of bytecode have if made with makeClass() ?
Until javassist solves this in another realease and this realease is included
in another tapestry release, a solution is to modify the class HivemindPool. We
have used this and work fine. it works without modifying javassist.
Proposed Solution:
1. Modifyng the HivemindClassPool class to assign the ProtectionDomain of the
classloader or the HivemindClassPool to all the enhanced classes.
2. Rebuild the hivemind.jar
3. Modify the security policy file that grants the required permision for the
application. (start by granting all permisions to test and then replace with
the fine grained ones)
This makes all enhaced class to have a ProtectionDomain with permisions granted
on the policy file. Non enhaced classes will still have the fine grained
permisions specified in the policy file, but enhaced class will have the same
permision granted to the HivemindClassPool.
In file org.apache.hivemind.service.impl.HiveMindClassPool replace the
following :
public Class toClass(CtClass ctClass) throws CannotCompileException
{
return ctClass.toClass(_loader);
}
with the following:
It uses the other method of ClassLoader and pass the ProtectionDomain of the
HivemindClassPool.
public Class toClass(CtClass ctClass) throws CannotCompileException
{
return toClass(ctClass, _loader);
}
public Class toClass(CtClass ct, ClassLoader loader)
throws CannotCompileException
{
try {
byte[] b = ct.toBytecode();
Class cl = Class.forName("java.lang.ClassLoader");
java.lang.reflect.Method method =
cl.getDeclaredMethod("defineClass",
new Class[] { String.class, byte[].class,
int.class, int.class,
ProtectionDomain.class });
method.setAccessible(true);
Object[] args = new Object[] { ct.getName(), b, new Integer(0),
new Integer(b.length),
this.getClass().getProtectionDomain()};
Class clazz = (Class)method.invoke(loader, args);
method.setAccessible(false);
return clazz;
}
catch (RuntimeException e) {
throw e;
}
catch (java.lang.reflect.InvocationTargetException e) {
throw new CannotCompileException(e.getTargetException());
}
catch (Exception e) {
throw new CannotCompileException(e);
}
}
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira
