Tomcat example source code file (SecurityUtil.java)

This example Tomcat source code file (SecurityUtil.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

class, class, http, httpservletrequest, ioexception, method, method, object, object, privilegedexceptionaction, reflection, request, response, security, servlet, servlet, servletexception, string, string, subject

The Tomcat SecurityUtil.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.catalina.security;


import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.security.Principal;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.HashMap;

import javax.security.auth.Subject;
import javax.servlet.Filter;
import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.UnavailableException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.catalina.Globals;
import org.apache.catalina.util.StringManager;
/**
 * This utility class associates a <code>Subject to the current 
 * <code>AccessControlContext. When a SecurityManager is
 * used, * the container will always associate the called thread with an 
 * AccessControlContext * containing only the principal of the requested
 * Servlet/Filter.
 *
 * This class uses reflection to invoke the invoke methods.
 *
 * @author Jean-Francois Arcand
 */

public final class SecurityUtil{
    
    private final static int INIT= 0;
    private final static int SERVICE = 1;
    private final static int DOFILTER = 1;
    private final static int DESTROY = 2;
    
    private final static String INIT_METHOD = "init";
    private final static String DOFILTER_METHOD = "doFilter";
    private final static String SERVICE_METHOD = "service";
    private final static String DESTROY_METHOD = "destroy";
   
    /**
     * Cache every object for which we are creating method on it.
     */
    private static HashMap objectCache = new HashMap();
        
    private static org.apache.juli.logging.Log log=
        org.apache.juli.logging.LogFactory.getLog( SecurityUtil.class );
    
    private static String PACKAGE = "org.apache.catalina.security";
    
    private static boolean packageDefinitionEnabled =  
         (System.getProperty("package.definition") == null && 
           System.getProperty("package.access")  == null) ? false : true;
    
    /**
     * The string resources for this package.
     */
    private static final StringManager sm =
        StringManager.getManager(PACKAGE);    
    
    
    /**
     * Perform work as a particular </code>Subject. Here the work
     * will be granted to a <code>null subject. 
     *
     * @param methodName the method to apply the security restriction
     * @param targetObject the <code>Servlet on which the method will
     * be called.
     */
    public static void doAsPrivilege(final String methodName, 
                                     final Servlet targetObject) throws java.lang.Exception{
         doAsPrivilege(methodName, targetObject, null, null, null);                                
    }

    
    /**
     * Perform work as a particular </code>Subject. Here the work
     * will be granted to a <code>null subject. 
     *
     * @param methodName the method to apply the security restriction
     * @param targetObject the <code>Servlet on which the method will
     * be called.
     * @param targetType <code>Class array used to instanciate a i
     * <code>Method object.
     * @param targetArguments <code>Object array contains the runtime 
     * parameters instance.
     */
    public static void doAsPrivilege(final String methodName, 
                                     final Servlet targetObject, 
                                     final Class[] targetType,
                                     final Object[] targetArguments) 
        throws java.lang.Exception{    

         doAsPrivilege(methodName, 
                       targetObject, 
                       targetType, 
                       targetArguments, 
                       null);                                
    }
    
    
    /**
     * Perform work as a particular </code>Subject. Here the work
     * will be granted to a <code>null subject. 
     *
     * @param methodName the method to apply the security restriction
     * @param targetObject the <code>Servlet on which the method will
     * be called.
     * @param targetType <code>Class array used to instanciate a 
     * <code>Method object.
     * @param targetArguments <code>Object array contains the 
     * runtime parameters instance.
     * @param principal the <code>Principal to which the security 
     * privilege apply..
     */    
    public static void doAsPrivilege(final String methodName, 
                                     final Servlet targetObject, 
                                     final Class[] targetType,
                                     final Object[] targetArguments,
                                     Principal principal) 
        throws java.lang.Exception{

        Method method = null;
        Method[] methodsCache = null;
        if(objectCache.containsKey(targetObject)){
            methodsCache = (Method[])objectCache.get(targetObject);
            method = findMethod(methodsCache, methodName);
            if (method == null){
                method = createMethodAndCacheIt(methodsCache,
                                                methodName,
                                                targetObject,
                                                targetType);
            }
        } else {
            method = createMethodAndCacheIt(methodsCache,
                                            methodName,
                                            targetObject,
                                            targetType);                     
        }

        execute(method, targetObject, targetArguments, principal);
    }
 
    
    /**
     * Perform work as a particular </code>Subject. Here the work
     * will be granted to a <code>null subject. 
     *
     * @param methodName the method to apply the security restriction
     * @param targetObject the <code>Filter on which the method will 
     * be called.
     */    
    public static void doAsPrivilege(final String methodName, 
                                     final Filter targetObject) 
        throws java.lang.Exception{

         doAsPrivilege(methodName, targetObject, null, null);                                
    }
 
    
    /**
     * Perform work as a particular </code>Subject. Here the work
     * will be granted to a <code>null subject. 
     *
     * @param methodName the method to apply the security restriction
     * @param targetObject the <code>Filter on which the method will 
     * be called.
     * @param targetType <code>Class array used to instanciate a
     * <code>Method object.
     * @param targetArguments <code>Object array contains the 
     * runtime parameters instance.
     */    
    public static void doAsPrivilege(final String methodName, 
                                     final Filter targetObject, 
                                     final Class[] targetType,
                                     final Object[] targetArguments) 
        throws java.lang.Exception{
        Method method = null;

        Method[] methodsCache = null;
        if(objectCache.containsKey(targetObject)){
            methodsCache = (Method[])objectCache.get(targetObject);
            method = findMethod(methodsCache, methodName);
            if (method == null){
                method = createMethodAndCacheIt(methodsCache,
                                                methodName,
                                                targetObject,
                                                targetType);
            }
        } else {
            method = createMethodAndCacheIt(methodsCache,
                                            methodName,
                                            targetObject,
                                            targetType);                     
        }

        execute(method, targetObject, targetArguments, null);
    }
    
    
    /**
     * Perform work as a particular </code>Subject. Here the work
     * will be granted to a <code>null subject. 
     *
     * @param methodName the method to apply the security restriction
     * @param targetObject the <code>Servlet on which the method will
     * be called.
     * @param targetArguments <code>Object array contains the 
     * runtime parameters instance.
     * @param principal the <code>Principal to which the security 
     * privilege applies
     */    
    private static void execute(final Method method,
                                final Object targetObject, 
                                final Object[] targetArguments,
                                Principal principal) 
        throws java.lang.Exception{
       
        try{   
            Subject subject = null;
            PrivilegedExceptionAction pea = new PrivilegedExceptionAction(){
                    public Object run() throws Exception{
                       method.invoke(targetObject, targetArguments);
                       return null;
                    }
            };

            // The first argument is always the request object
            if (targetArguments != null 
                    && targetArguments[0] instanceof HttpServletRequest){
                HttpServletRequest request = 
                    (HttpServletRequest)targetArguments[0];

                boolean hasSubject = false;
                HttpSession session = request.getSession(false);
                if (session != null){
                    subject = 
                        (Subject)session.getAttribute(Globals.SUBJECT_ATTR);
                    hasSubject = (subject != null);
                }

                if (subject == null){
                    subject = new Subject();
                    
                    if (principal != null){
                        subject.getPrincipals().add(principal);
                    }
                }

                if (session != null && !hasSubject) {
                    session.setAttribute(Globals.SUBJECT_ATTR, subject);
                }
            }

            Subject.doAsPrivileged(subject, pea, null);       
       } catch( PrivilegedActionException pe) {
            Throwable e = ((InvocationTargetException)pe.getException())
                                .getTargetException();
            
            if (log.isDebugEnabled()){
                log.debug(sm.getString("SecurityUtil.doAsPrivilege"), e); 
            }
            
            if (e instanceof UnavailableException)
                throw (UnavailableException) e;
            else if (e instanceof ServletException)
                throw (ServletException) e;
            else if (e instanceof IOException)
                throw (IOException) e;
            else if (e instanceof RuntimeException)
                throw (RuntimeException) e;
            else
                throw new ServletException(e.getMessage(), e);
        }  
    }
    
    
    /**
     * Find a method stored within the cache.
     * @param methodsCache the cache used to store method instance
     * @param methodName the method to apply the security restriction
     * @return the method instance, null if not yet created.
     */
    private static Method findMethod(Method[] methodsCache,
                                     String methodName){
        if (methodName.equalsIgnoreCase(INIT_METHOD) 
                && methodsCache[INIT] != null){
            return methodsCache[INIT];
        } else if (methodName.equalsIgnoreCase(DESTROY_METHOD) 
                && methodsCache[DESTROY] != null){
            return methodsCache[DESTROY];            
        } else if (methodName.equalsIgnoreCase(SERVICE_METHOD) 
                && methodsCache[SERVICE] != null){
            return methodsCache[SERVICE];
        } else if (methodName.equalsIgnoreCase(DOFILTER_METHOD) 
                && methodsCache[DOFILTER] != null){
            return methodsCache[DOFILTER];          
        } 
        return null;
    }
    
    
    /**
     * Create the method and cache it for further re-use.
     * @param methodsCache the cache used to store method instance
     * @param methodName the method to apply the security restriction
     * @param targetObject the <code>Servlet on which the method will
     * be called.
     * @param targetType <code>Class array used to instanciate a 
     * <code>Method object.
     * @return the method instance.
     */
    private static Method createMethodAndCacheIt(Method[] methodsCache,
                                                 String methodName,
                                                 Object targetObject,
                                                 Class[] targetType) 
            throws Exception{
        
        if ( methodsCache == null){
            methodsCache = new Method[3];
        }               
                
        Method method = 
            targetObject.getClass().getMethod(methodName, targetType); 

        if (methodName.equalsIgnoreCase(INIT_METHOD)){
            methodsCache[INIT] = method;
        } else if (methodName.equalsIgnoreCase(DESTROY_METHOD)){
            methodsCache[DESTROY] = method;
        } else if (methodName.equalsIgnoreCase(SERVICE_METHOD)){
            methodsCache[SERVICE] = method;
        } else if (methodName.equalsIgnoreCase(DOFILTER_METHOD)){
            methodsCache[DOFILTER] = method;
        } 
         
        objectCache.put(targetObject, methodsCache );
                                           
        return method;
    }

    
    /**
     * Remove the object from the cache.
     *
     * @param cachedObject The object to remove
     */
    public static void remove(Object cachedObject){
        objectCache.remove(cachedObject);
    }
    
    
    /**
     * Return the <code>SecurityManager only if Security is enabled AND
     * package protection mechanism is enabled.
     */
    public static boolean isPackageProtectionEnabled(){
        if (packageDefinitionEnabled && Globals.IS_SECURITY_ENABLED){
            return true;
        }
        return false;
    }
    
    
}