Re: [cp-patches] Miscellaneous patches: RMI, AccessController, SharedLibHelper, Permissions

[Mark Wielaard]

Hi Andrew,

On Wed, 2005-02-16 at 18:47 +0000, Andrew Haley wrote:
> This is a batch of patches that I made while getting JOnAS to run on
> gcj.

Good stuff, very nice! Since I saw you already committed this to libgcj
I made sure to commit the parts that were relevant also to GNU Classpath
CVS:

2005-02-16  Andrew Haley  <address@hidden>

       * javax/security/auth/Subject.java (doAsPrivileged): If acc is
       null, create a new AccessControlContext.
       * java/security/SecureClassLoader.java (protectionDomainCache):
       new field.
       (defineClass): Create a new protection domain and add it to our
       cache.

       * java/rmi/server/UnicastRemoteObject.java (exportObject): Call
       addStub() to keep track of the stub we've exported.
       (unexportObject): Call deleteStub().
       * java/rmi/server/RemoteObject.java (stubs): New field.
       (addStub): New method.
       (deleteStub): New method.
       (toStub): Rewrite.

       * java/security/Permissions.java (PermissionsHash.implies):
       Iterate over the collection and invoke implies() on each
       element.

Two questions though.

- Could you look at the review of the PermissionsHash.implies patch
http://lists.gnu.org/archive/html/classpath-patches/2005-02/msg00039.html
It explains how you can prevent the FIXME by checking the readonly flag.

- Should java.rmi.server.RemoteObject.toStub() be synchronized since it
acesses the WeakHashMap field stubs?

Thanks,

Mark

Index: javax/security/auth/Subject.java
===================================================================
RCS file: /cvsroot/classpath/classpath/javax/security/auth/Subject.java,v
retrieving revision 1.2
diff -u -r1.2 Subject.java
--- javax/security/auth/Subject.java    22 Oct 2004 17:15:58 -0000      1.2
+++ javax/security/auth/Subject.java    17 Feb 2005 00:28:32 -0000
@@ -235,7 +235,7 @@
    */
   public static Object doAsPrivileged (final Subject subject,
                                        final PrivilegedExceptionAction action,
-                                       final AccessControlContext acc)
+                                      AccessControlContext acc)
     throws PrivilegedActionException
   {
     final SecurityManager sm = System.getSecurityManager();
@@ -243,6 +243,8 @@
       {
         sm.checkPermission (new AuthPermission ("doAsPrivileged"));
       }
+    if (acc == null)
+      acc = new AccessControlContext (new java.security.ProtectionDomain[0]);
     AccessControlContext context =
       new AccessControlContext (acc, new SubjectDomainCombiner (subject));
     return AccessController.doPrivileged (action, context);
Index: java/security/SecureClassLoader.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/security/SecureClassLoader.java,v
retrieving revision 1.11
diff -u -r1.11 SecureClassLoader.java
--- java/security/SecureClassLoader.java        3 Jun 2004 06:43:11 -0000       
1.11
+++ java/security/SecureClassLoader.java        17 Feb 2005 00:28:32 -0000
@@ -48,6 +48,8 @@
  */
 public class SecureClassLoader extends ClassLoader
 {
+  java.util.WeakHashMap protectionDomainCache = new java.util.WeakHashMap();
+
   protected SecureClassLoader(ClassLoader parent)
   {
     super(parent);
@@ -80,11 +82,29 @@
   protected final Class defineClass(String name, byte[] b, int off, int len,
                                    CodeSource cs)
   {
-    // FIXME: Need to cache ProtectionDomains according to 1.3 docs.
     if (cs != null)
       {
-       ProtectionDomain protectionDomain
-          = new ProtectionDomain(cs, getPermissions(cs), this, null);
+       ProtectionDomain protectionDomain;
+         
+       synchronized (protectionDomainCache)
+         {
+           protectionDomain = (ProtectionDomain)protectionDomainCache.get(cs);
+         }
+
+       if (protectionDomain == null)
+         {
+           protectionDomain 
+             = new ProtectionDomain(cs, getPermissions(cs), this, null);
+           synchronized (protectionDomainCache)
+             {
+               ProtectionDomain domain 
+                 = (ProtectionDomain)protectionDomainCache.get(cs);
+               if (domain == null)
+                 protectionDomainCache.put(cs, protectionDomain);
+               else
+                 protectionDomain = domain;
+             }
+         }
        return super.defineClass(name, b, off, len, protectionDomain);
       } 
     else
Index: java/security/Permissions.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/security/Permissions.java,v
retrieving revision 1.11
diff -u -r1.11 Permissions.java
--- java/security/Permissions.java      16 Feb 2005 11:18:38 -0000      1.11
+++ java/security/Permissions.java      17 Feb 2005 00:28:32 -0000
@@ -227,9 +227,18 @@
      * @param perm the permission to check
      * @return true if it is implied
      */
+    // FIXME: Should this method be synchronized?
     public boolean implies(Permission perm)
     {
-      return perms.get(perm) != null;
+      Enumeration elements = elements();
+      
+      while (elements.hasMoreElements())
+       {
+         Permission p = (Permission)elements.nextElement();
+         if (p.implies(perm))
+           return true;
+       }
+      return false;
     }
 
     /**
Index: java/rmi/server/UnicastRemoteObject.java
===================================================================
RCS file: 
/cvsroot/classpath/classpath/java/rmi/server/UnicastRemoteObject.java,v
retrieving revision 1.8
diff -u -r1.8 UnicastRemoteObject.java
--- java/rmi/server/UnicastRemoteObject.java    21 Oct 2004 20:14:51 -0000      
1.8
+++ java/rmi/server/UnicastRemoteObject.java    17 Feb 2005 00:28:32 -0000
@@ -98,7 +98,9 @@
       {
        sref = new UnicastServerRef(new ObjID (), port, ssf);
       }
-    return (sref.exportObject (obj)); 
+    Remote stub = sref.exportObject (obj); 
+    addStub(obj, stub);
+    return stub;
   }
 
   /**
@@ -116,12 +118,15 @@
   {
     if (obj instanceof RemoteObject)
       {
+       deleteStub(obj);
        UnicastServerRef sref = (UnicastServerRef)((RemoteObject)obj).getRef();
        return sref.unexportObject(obj, force);
       }
     else
-      //FIX ME
-      ;
+      {
+       //FIX ME
+       ;
+      }
     return true;
   }
 
Index: java/rmi/server/RemoteObject.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/rmi/server/RemoteObject.java,v
retrieving revision 1.6
diff -u -r1.6 RemoteObject.java
--- java/rmi/server/RemoteObject.java   18 Jan 2005 09:52:43 -0000      1.6
+++ java/rmi/server/RemoteObject.java   17 Feb 2005 00:28:32 -0000
@@ -45,6 +45,7 @@
 import java.rmi.NoSuchObjectException;
 import java.rmi.Remote;
 import java.rmi.UnmarshalException;
+import java.util.WeakHashMap;
 
 public abstract class RemoteObject
        implements Remote, Serializable {
@@ -53,6 +54,8 @@
 
 protected transient RemoteRef ref;
 
+private static final WeakHashMap stubs = new WeakHashMap();
+
 protected RemoteObject() {
        this(null);
 }
@@ -65,21 +68,24 @@
        return (ref);
 }
 
+synchronized static void addStub(Remote obj, Remote stub)
+{
+  stubs.put(obj, stub);
+}
+
+synchronized static void deleteStub(Remote obj)
+{
+  stubs.remove(obj);
+}
+
   public static Remote toStub(Remote obj) throws NoSuchObjectException 
   {
-    Class cls = obj.getClass();
-    String classname = cls.getName();
-    ClassLoader cl = cls.getClassLoader();
-    try 
-      {
-       Class scls = cl.loadClass(classname + "_Stub");
-       // JDK 1.2 stubs
-       Class[] stubprototype = new Class[] { RemoteRef.class };
-       Constructor con = scls.getConstructor(stubprototype);
-       return (Remote)(con.newInstance(new Object[]{obj}));
-      }
-    catch (Exception e) {}
-    throw new NoSuchObjectException(obj.getClass().getName());
+    Remote stub = (Remote)stubs.get(obj);
+
+    if (stub == null)
+      throw new NoSuchObjectException(obj.getClass().getName());
+
+    return stub;
   }
 
 public int hashCode() {

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