/*
 * Copyright 2012 PD Inc / gitblit.com.
 *
 * Licensed 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 com.gitblit.utils;

import java.io.CharConversionException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.gitblit.GitBlit;
import com.gitblit.Keys;

/**
 * This is the support class for all container specific code.
 * 
 * @author jpyeron
 */
public class ContainerUtils
{
    private static Logger LOGGER = LoggerFactory.getLogger(ContainerUtils.class);

    /**
     * The support class for managing and evaluating the environment with
     * regards to CVE-2007-0405.
     * 
     * @see http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-0450
     * @author jpyeron
     */
    public static class CVE_2007_0450
    {
        /**
         * This method will test for know issues in certain containers where %2F
         * is blocked from use in URLs. It will emit a warning to the logger if
         * the configuration of Tomcat causes the URL processing to fail on %2F.
         */
        public static void test()
        {
            if (GitBlit.getBoolean(Keys.web.mountParameters, true)
                    && ((GitBlit.getChar(Keys.web.forwardSlashCharacter, '/')) == '/' || (GitBlit.getChar(
                            Keys.web.forwardSlashCharacter, '/')) == '\\'))
            {
                try
                {
                    if (GitBlit.isGO())
                        ;
                    else if (logCVE_2007_0450Tomcat())
                        ;
                    // else if (logCVE_2007_0450xxx());
                    else
                    {
                        LOGGER.info("Unknown container, cannot check for CVE-2007-0450 aplicability");
                    }
                }
                catch (Throwable t)
                {
                    LOGGER.warn("Failure in checking for CVE-2007-0450 aplicability", t);
                }
            }

        }

        /**
         * This method will test for know issues in certain versions of Tomcat,
         * JBOSS, glassfish, and other embedded uses of Tomcat where %2F is
         * blocked from use in certain URL s. It will emit a warning to the
         * logger if the configuration of Tomcat causes the URL processing to
         * fail on %2F.
         * 
         * @return true if it recognizes Tomcat, false if it does not recognize
         *         Tomcat
         */
        private static boolean logCVE_2007_0450Tomcat()
        {
            try
            {
                byte[] test = "http://server.domain:8080/context/servlet/param%2fparam".getBytes();

                // ByteChunk mb=new ByteChunk();
                Class<?> cByteChunk = Class.forName("org.apache.tomcat.util.buf.ByteChunk");
                Object mb = cByteChunk.newInstance();

                // mb.setBytes(test, 0, test.length);
                Method mByteChunck_setBytes = cByteChunk.getMethod("setBytes", byte[].class, int.class, int.class);
                mByteChunck_setBytes.invoke(mb, test, (int) 0, test.length);

                // UDecoder ud=new UDecoder();
                Class<?> cUDecoder = Class.forName("org.apache.tomcat.util.buf.UDecoder");
                Object ud = cUDecoder.newInstance();

                // ud.convert(mb,false);
                Method mUDecoder_convert = cUDecoder.getMethod("convert", cByteChunk, boolean.class);

                try
                {
                    mUDecoder_convert.invoke(ud, mb, false);
                }
                catch (InvocationTargetException e)
                {
                    if (e.getTargetException() != null && e.getTargetException() instanceof CharConversionException)
                    {
                        LOGGER.warn("You are using a Tomcat based system and the current settings regarding CVE-2007-0450 will prevent certain fetures from working. Please see http://gitblit.com/faq.html and http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-0450");
                        return true;
                    }
                    throw e;
                }
            }
            catch (Throwable t)
            {
                // The apache url decoder internals are different, this is not a
                // Tomcat matching the failure pattern for CVE-2007-0450
                if (t instanceof ClassNotFoundException || t instanceof NoSuchMethodException
                        || t instanceof IllegalArgumentException)
                    return false;
                LOGGER.debug("This is a tomcat, but the test operation failed somehow", t);
            }
            return true;
        }
    }

}