Logout.java

package servlets;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.log4j.Logger;

import utils.ShepherdLogManager;
import utils.Validate;

/**
 * Control class for the logout operation
 * <br/><br/>
 * This file is part of the Security Shepherd Project.
 * 
 * The Security Shepherd project is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.<br/>
 * 
 * The Security Shepherd project is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.<br/>
 * 
 * You should have received a copy of the GNU General Public License
 * along with the Security Shepherd project.  If not, see <http://www.gnu.org/licenses/>. 
 * @author Mark Denihan
 *
 */
public class Logout extends HttpServlet
{
	private static final long serialVersionUID = 1L;
	private static org.apache.log4j.Logger log = Logger.getLogger(Logout.class);
	
	/**
	 * Initiated in index.jsp. Invalidates session and Security Shepherd tokens are removed. The user is logged out.
	 * @param csrfToken 
	 */
	public void doGet (HttpServletRequest request, HttpServletResponse response) 
	throws ServletException, IOException
	{
		//Setting IpAddress To Log and taking header for original IP if forwarded from proxy
		ShepherdLogManager.setRequestIp(request.getRemoteAddr(), request.getHeader("X-Forwarded-For"));
		log.debug("**** servlets.Logout ***");
		HttpSession ses = request.getSession(true);
		if(Validate.validateSession(ses))
		{
			ShepherdLogManager.setRequestIp(request.getRemoteAddr(), request.getHeader("X-Forwarded-For"), ses.getAttribute("userName").toString());
			log.debug("Current User: " + ses.getAttribute("userName").toString());
			Cookie tokenCookie = Validate.getToken(request.getCookies());
			Object tokenParmeter = request.getParameter("csrfToken");
			if(Validate.validateTokens(tokenCookie, tokenParmeter))
			{
				//Remove Everything
				ses.removeAttribute("userStamp");
				ses.removeAttribute("userName");
				ses.removeAttribute("userRole");
				//Invalid Session on server
				ses.invalidate();
				ses = request.getSession(true);
				//Remove cookie
				Cookie emptyCookie = new Cookie("token", "");
				response.addCookie(emptyCookie);
				emptyCookie = new Cookie("JSESSIONID3", "");
				response.addCookie(emptyCookie);
				log.debug("User Logged Out");
				response.sendRedirect("login.jsp");
			}
			else
			{
				log.error("CSRF Attack Detected");
				response.sendRedirect("index.jsp");
			}
		}
		else
		{
			log.error("Logout Function Called with no valid session");
			response.sendRedirect("login.jsp");
		}
		log.debug("*** END Logout ***");
	}
}