package org.owasp.webgoat.lessons;

import java.util.ArrayList;
import java.util.List;
import javax.servlet.http.Cookie;
import org.apache.ecs.Element;
import org.apache.ecs.ElementContainer;
import org.apache.ecs.StringElement;
import org.apache.ecs.html.B;
import org.apache.ecs.html.H1;
import org.apache.ecs.html.Input;
import org.apache.ecs.html.P;
import org.apache.ecs.html.TD;
import org.apache.ecs.html.TH;
import org.apache.ecs.html.TR;
import org.apache.ecs.html.Table;
import org.owasp.webgoat.session.*;


/**
 *  Copyright (c) 2002 Free Software Foundation developed under the custody of the Open Web
 *  Application Security Project (http://www.owasp.org) This software package org.owasp.webgoat.is published by OWASP
 *  under the GPL. You should read and accept the LICENSE before you use, modify and/or redistribute
 *  this software.
 *
 * @author     Jeff Williams <a href="http://www.aspectsecurity.com">Aspect Security</a>
 * @created    October 28, 2003
 */
public class WeakAuthenticationCookie extends LessonAdapter
{
	/**
	 *  Description of the Field
	 */
	protected final static String AUTHCOOKIE = "AuthCookie";
	/**
	 *  Description of the Field
	 */
	protected final static String LOGOUT = "WACLogout";
	/**
	 *  Description of the Field
	 */
	protected final static String PASSWORD = "Password";
	/**
	 *  Description of the Field
	 */
	protected final static String USERNAME = "Username";


	/**
	 *  Description of the Method
	 *
	 * @param  s              Description of the Parameter
	 * @return                Description of the Return Value
	 * @exception  Exception  Description of the Exception
	 */
	protected String checkCookie( WebSession s ) throws Exception
	{
		String cookie = getCookie( s );

		if ( cookie != null )
		{
			if ( cookie.equals( encode( "webgoat12345" ) ) )
			{
				return ( "webgoat" );
			}

			if ( cookie.equals( encode( "aspect12345" ) ) )
			{
				return ( "aspect" );
			}

			if ( cookie.equals( encode( "alice12345" ) ) )
			{
				makeSuccess( s );
				return ( "alice" );
			}
			else
			{
				s.setMessage( "Invalid cookie" );
				s.eatCookies();
			}
		}

		return ( null );
	}

	/**
	 *  Description of the Method
	 *
	 * @param  s              Description of the Parameter
	 * @return                Description of the Return Value
	 * @exception  Exception  Description of the Exception
	 */
	protected String checkParams( WebSession s ) throws Exception
	{
		String username = s.getParser().getStringParameter( USERNAME, "" );
		String password = s.getParser().getStringParameter( PASSWORD, "" );

		if ( ( username.length() > 0 ) && ( password.length() > 0 ) )
		{
			String loginID = "";
			
			if ( username.equals( "webgoat" ) && password.equals( "webgoat" ) )
			{
				loginID = encode( "webgoat12345" );
			}
			else if ( username.equals( "aspect" ) && password.equals( "aspect" ) )
			{
				loginID = encode( "aspect12345" );
			}
			
			if ( loginID != "" )
			{
				Cookie newCookie = new Cookie( AUTHCOOKIE, loginID );
				s.setMessage( "Your identity has been remembered" );
				s.getResponse().addCookie( newCookie );

				return ( username );
			}				
			else
			{
				s.setMessage( "Invalid username and password entered." );
			}
		}

		return ( null );
	}


	/**
	 *  Description of the Method
	 *
	 * @param  s  Description of the Parameter
	 * @return    Description of the Return Value
	 */
	protected Element createContent( WebSession s )
	{
		boolean logout = s.getParser().getBooleanParameter( LOGOUT, false );

		if ( logout )
		{
			s.setMessage( "Goodbye!  Your password has been forgotten" );
			s.eatCookies();

			return ( makeLogin( s ) );
		}

		try
		{
			String user = checkCookie( s );

			if ( ( user != null ) && ( user.length() > 0 ) )
			{
				return ( makeUser( s, user, "COOKIE" ) );
			}

			user = checkParams( s );

			if ( ( user != null ) && ( user.length() > 0 ) )
			{
				return ( makeUser( s, user, "PARAMETERS" ) );
			}
		}
		catch ( Exception e )
		{
			s.setMessage( "Error generating " + this.getClass().getName() );
			e.printStackTrace();
		}

		return ( makeLogin( s ) );
	}


	/**
	 *  Description of the Method
	 *
	 * @param  value  Description of the Parameter
	 * @return        Description of the Return Value
	 */
	private String encode( String value )
	{
		//<START_OMIT_SOURCE>
		StringBuffer encoded = new StringBuffer();

		for ( int i = 0; i < value.length(); i++ )
		{
			encoded.append( String.valueOf( (char) ( value.charAt( i ) + 1 ) ) );
		}

		return encoded.reverse().toString();
		//<END_OMIT_SOURCE>
	}


	/**
	 *  Gets the category attribute of the WeakAuthenticationCookie object
	 *
	 * @return    The category value
	 */
	protected Category getDefaultCategory()
	{
		return AbstractLesson.A3;
	}


	/**
	 *  Gets the cookie attribute of the CookieScreen object
	 *
	 * @param  s  Description of the Parameter
	 * @return    The cookie value
	 */
	protected String getCookie( WebSession s )
	{
		Cookie[] cookies = s.getRequest().getCookies();

		for ( int i = 0; i < cookies.length; i++ )
		{
			if ( cookies[i].getName().equalsIgnoreCase( AUTHCOOKIE ) )
			{
				return ( cookies[i].getValue() );
			}
		}

		return ( null );
	}


	/**
	 *  Gets the hints attribute of the CookieScreen object
	 *
	 * @return    The hints value
	 */
	protected List getHints()
	{
		List hints = new ArrayList();
		hints.add( "The server skips authentication if you send the right cookie." );
		hints.add( "Is the AuthCookie value guessable knowing the username and password?" );
		hints.add( "Add 'AuthCookie=********;' to the Cookie: header using <A href=\"http://www.owasp.org/development/webscarab\">WebScarab</A>." );

		return hints;
	}


	/**
	 *  Gets the instructions attribute of the WeakAuthenticationCookie object
	 *
	 * @return    The instructions value
	 */
	public String getInstructions(WebSession s)
	{
		String instructions = "Login using the webgoat/webgoat account to see what happens. You may also try aspect/aspect. When you understand the authentication cookie, try changing your identity to alice.";

		return ( instructions );
	}




	private final static Integer DEFAULT_RANKING = new Integer(90);

	protected Integer getDefaultRanking()
	{
		return DEFAULT_RANKING;
	}

	/**
	 *  Gets the title attribute of the CookieScreen object
	 *
	 * @return    The title value
	 */
	public String getTitle()
	{
		return ( "How to Spoof an Authentication Cookie" );
	}


	/**
	 *  Description of the Method
	 *
	 * @param  s  Description of the Parameter
	 * @return    Description of the Return Value
	 */
	protected Element makeLogin( WebSession s )
	{
		ElementContainer ec = new ElementContainer();

		ec.addElement( new H1().addElement( "Sign In " ));
		Table t = new Table().setCellSpacing( 0 ).setCellPadding( 2 ).setBorder( 0 ).setWidth("90%").setAlign("center");

		if ( s.isColor() )
		{
			t.setBorder( 1 );
		}
		
		TR tr = new TR();
		tr.addElement( new TH().addElement("Please sign in to your account.  See the OWASP admin if you do not have an account.")
				.setColSpan(2).setAlign("left"));
		t.addElement( tr );

		tr = new TR();
		tr.addElement( new TD().addElement("*Required Fields").setWidth("30%"));
		t.addElement( tr );
		
		tr = new TR();
		tr.addElement( new TD().addElement("&nbsp;").setColSpan(2));
		t.addElement( tr );
		
		TR row1 = new TR();
		TR row2 = new TR();
		row1.addElement( new TD( new B( new StringElement( "*User Name: " ) ) ));
		row2.addElement( new TD( new B(new StringElement( "*Password: " ) ) ));

		Input input1 = new Input( Input.TEXT, USERNAME, "" );
		Input input2 = new Input( Input.PASSWORD, PASSWORD, "" );
		row1.addElement( new TD( input1 ) );
		row2.addElement( new TD( input2 ) );
		t.addElement( row1 );
		t.addElement( row2 );

		Element b = ECSFactory.makeButton( "Login" );
		t.addElement( new TR( new TD( b ) ) );
		ec.addElement( t );

		return ( ec );
	}


	/**
	 *  Description of the Method
	 *
	 * @param  s              Description of the Parameter
	 * @param  user           Description of the Parameter
	 * @param  method         Description of the Parameter
	 * @return                Description of the Return Value
	 * @exception  Exception  Description of the Exception
	 */
	protected Element makeUser( WebSession s, String user, String method ) throws Exception
	{
		ElementContainer ec = new ElementContainer();
		ec.addElement( new P().addElement( "Welcome, " + user ) );
		ec.addElement( new P().addElement( "You have been authenticated with " + method ) );
		ec.addElement( new P().addElement( ECSFactory.makeLink( "Logout", LOGOUT, true ) ) );
		ec.addElement( new P().addElement( ECSFactory.makeLink( "Refresh", "", "" ) ) );

		return ( ec );
	}
}