/*
    * Copyright (c) 2002-2022, City of Paris
    * All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    *
    *  1. Redistributions of source code must retain the above copyright notice
   *     and the following disclaimer.
   *
   *  2. Redistributions in binary form must reproduce the above copyright notice
   *     and the following disclaimer in the documentation and/or other materials
   *     provided with the distribution.
   *
   *  3. Neither the name of 'Mairie de Paris' nor 'Lutece' nor the names of its
   *     contributors may be used to endorse or promote products derived from
   *     this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   * License 1.0
   */
  package fr.paris.lutece.util.http;
  
  import java.util.Enumeration;
  
  import javax.servlet.http.HttpServletRequest;
  
  import org.apache.commons.lang3.BooleanUtils;
  import org.apache.commons.lang3.StringUtils;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.springframework.util.AntPathMatcher;
  
  import fr.paris.lutece.portal.service.util.AppPathService;
  import fr.paris.lutece.portal.service.util.AppPropertiesService;
  import fr.paris.lutece.portal.web.LocalVariables;
  import fr.paris.lutece.util.string.StringUtil;
  
  /**
   * Security utils
   *
   */
  public final class SecurityUtil
  {
      private static final String LOGGER_NAME = "lutece.security.http";
      private static final String CONSTANT_HTTP_HEADER_X_FORWARDED_FOR = "X-Forwarded-For";
      private static final String PATTERN_IP_ADDRESS = "^([0-9]{1,3}\\.){3}[0-9]{1,3}$";
      private static final String CONSTANT_COMMA = ",";
      private static final String [ ] XXE_TERMS = {
              "!DOCTYPE", "!ELEMENT", "!ENTITY"
      };
      private static final String [ ] PATH_MANIPULATION = {
              "..", "/", "\\"
      };
  
      public static final String PROPERTY_REDIRECT_URL_SAFE_PATTERNS = "lutece.security.redirectUrlSafePatterns";
      public static final Logger _log = LogManager.getLogger( LOGGER_NAME );
  
      /**
       * Private Constructor
       */
      private SecurityUtil( )
      {
      }
  
      /**
       * Scan request parameters to see if there no malicious code.
       *
       * @param request
       *            The HTTP request
       * @return true if all parameters don't contains any special characters
       */
      public static boolean containsCleanParameters( HttpServletRequest request )
      {
          return containsCleanParameters( request, null );
      }
  
      /**
       * Scan request parameters to see if there no malicious code.
       *
       * @param request
       *            The HTTP request
       * @param strXssCharacters
       *            a String wich contain a list of Xss characters to check in strValue
       * @return true if all parameters don't contains any special characters
       */
      public static boolean containsCleanParameters( HttpServletRequest request, String strXssCharacters )
     {
         String key;
         String [ ] values;
         Enumeration<String> e = request.getParameterNames( );
 
         while ( e.hasMoreElements( ) )
         {
             key = e.nextElement( );
             values = request.getParameterValues( key );
 
             int length = values.length;
 
             for ( int i = 0; i < length; i++ )
             {
                 if ( SecurityUtil.containsXssCharacters( request, values [i], strXssCharacters ) || SecurityUtil.containsXssCharacters( request, key, strXssCharacters )  )
                 {
                     _log.warn( "SECURITY WARNING : INVALID REQUEST PARAMETERS {}", ( ) -> dumpRequest( request ) );
 
                     return false;
                 }
             }
         }
 
         return true;
     }
 
     /**
      * Checks if a String contains characters that could be used for a cross-site scripting attack.
      *
      * @param request
      *            The HTTP request
      * @param strString
      *            a character String
      * @return true if the String contains illegal characters
      */
     public static boolean containsXssCharacters( HttpServletRequest request, String strString )
     {
         return containsXssCharacters( request, strString, null );
     }
 
     /**
      * Checks if a String contains characters that could be used for a cross-site scripting attack.
      *
      * @param request
      *            The HTTP request
      * @param strValue
      *            a character String
      * @param strXssCharacters
      *            a String wich contain a list of Xss characters to check in strValue
      * @return true if the String contains illegal characters
      */
     public static boolean containsXssCharacters( HttpServletRequest request, String strValue, String strXssCharacters )
     {
         boolean bContains = ( strXssCharacters == null ) ? StringUtil.containsXssCharacters( strValue )
                 : StringUtil.containsXssCharacters( strValue, strXssCharacters );
 
         if ( bContains )
         {
             _log.warn( "SECURITY WARNING : XSS CHARACTERS DETECTED {}", ( ) -> dumpRequest( request ) );
         }
 
         return bContains;
     }
 
     /**
      * Check if the value contains terms used for XML External Entity Injection
      * 
      * @param strValue
      *            The value
      * @return true if
      */
     public static boolean containsXmlExternalEntityInjectionTerms( String strValue )
     {
         for ( String strTerm : XXE_TERMS )
         {
             if ( StringUtils.indexOfIgnoreCase( strValue, strTerm ) >= 0 )
             {
                 _log.warn( "SECURITY WARNING : XXE TERMS DETECTED : {}", ( ) -> dumpRequest( LocalVariables.getRequest( ) ) );
                 return true;
             }
         }
         return false;
     }
 
     /**
      * Check if the value contains characters used for Path Manipulation
      * 
      * @param request
      *            The Http request
      * @param strValue
      *            The value
      * @return true if
      */
     public static boolean containsPathManipulationChars( HttpServletRequest request, String strValue )
     {
         for ( String strTerm : PATH_MANIPULATION )
         {
             if ( strValue.contains( strTerm ) )
             {
                 _log.warn( "SECURITY WARNING : PATH_MANIPULATION DETECTED : {}", ( ) -> dumpRequest( request ) );
                 return true;
             }
         }
         return false;
     }
 
     /**
      * Dump all request info
      * 
      * @param request
      *            The HTTP request
      * @return A report containing all request info
      */
     public static String dumpRequest( HttpServletRequest request )
     {
         StringBuilder sbDump = new StringBuilder( "\r\n Request Dump : \r\n" );
         if ( request != null )
         {
             dumpTitle( sbDump, "Request variables" );
             dumpVariables( sbDump, request );
             dumpTitle( sbDump, "Request parameters" );
             dumpParameters( sbDump, request );
             dumpTitle( sbDump, "Request headers" );
             dumpHeaders( sbDump, request );
         }
         else
         {
             sbDump.append( "no request provided." );
         }
 
         return sbDump.toString( );
     }
 
     /**
      * Get the IP of the user from a request. If the user is behind an apache server, return the ip of the user instead of the ip of the server.
      * 
      * @param request
      *            The request
      * @return The IP of the user that made the request
      */
     public static String getRealIp( HttpServletRequest request )
     {
         String strIPAddress = request.getHeader( CONSTANT_HTTP_HEADER_X_FORWARDED_FOR );
 
         if ( strIPAddress != null )
         {
             while ( !strIPAddress.matches( PATTERN_IP_ADDRESS ) && strIPAddress.contains( CONSTANT_COMMA ) )
             {
                 String strIpForwarded = strIPAddress.substring( 0, strIPAddress.indexOf( CONSTANT_COMMA ) );
                 strIPAddress = strIPAddress.substring( strIPAddress.indexOf( CONSTANT_COMMA ) ).replaceFirst( CONSTANT_COMMA, StringUtils.EMPTY ).trim( );
 
                 if ( ( strIpForwarded != null ) && strIpForwarded.matches( PATTERN_IP_ADDRESS ) )
                 {
                     strIPAddress = strIpForwarded;
                 }
             }
 
             if ( !strIPAddress.matches( PATTERN_IP_ADDRESS ) )
             {
                 strIPAddress = request.getRemoteAddr( );
             }
         }
         else
         {
             strIPAddress = request.getRemoteAddr( );
         }
 
         return strIPAddress;
     }
 
     /**
      * Validate a forward URL to avoid open redirect with url safe patterns found in properties
      * 
      * @see SecurityUtil#isInternalRedirectUrlSafe(java.lang.String, javax.servlet.http.HttpServletRequest, java.lang.String)
      * 
      * @param strUrl
      * @param request
      * @return true if valid
      */
     public static boolean isInternalRedirectUrlSafe( String strUrl, HttpServletRequest request )
     {
         String strAntPathMatcherPatternsValues = AppPropertiesService.getProperty( SecurityUtil.PROPERTY_REDIRECT_URL_SAFE_PATTERNS );
 
         return isInternalRedirectUrlSafe( strUrl, request, strAntPathMatcherPatternsValues );
     }
 
     /**
      * Validate an internal redirect URL to avoid internal open redirect. (Use this function only if the use of internal url redirect keys is not possible. For
      * external url redirection control, use the plugin plugin-verifybackurl)
      * 
      * the url should : - not be blank (null or empty string or spaces) - not start with "http://" or "https://" or "//" OR match the base URL or any URL in the
      * pattern list
      * 
      * example with a base url "https://lutece.fr/ : - valid : myapp/jsp/site/Portal.jsp , Another.jsp , https://lutece.fr/myapp/jsp/site/Portal.jsp - invalid :
      * http://anothersite.com , https://anothersite.com , //anothersite.com , file://my.txt , ...
      * 
      * 
      * @param strUrl
      *            the Url to validate
      * @param request
      *            the current request (containing the baseUrl)
      * @param strAntPathMatcherPatterns
      *            a comma separated list of AntPathMatcher patterns, as "https://**.lutece.com"" target="alexandria_uri">http://**.lutece.com,https://**.lutece.com"
      * @return true if valid
      */
     public static boolean isInternalRedirectUrlSafe( String strUrl, HttpServletRequest request, String strAntPathMatcherPatterns )
     {
 
         if ( StringUtils.isBlank( strUrl ) )
         {
             return true; // this is not a valid redirect Url, but it is not unsafe
         }
 
         // filter schemes
         boolean [ ] conditions = new boolean [ ] {
                 !strUrl.startsWith( "//" ), !strUrl.startsWith( "http:" ), !strUrl.startsWith( "https:" ), !strUrl.contains( "://" ),
                 !strUrl.startsWith( "javascript:" )
         };
 
         if ( BooleanUtils.and( conditions ) )
         {
             return true; // should be a relative path
         }
 
         // compare with current baseUrl
         if ( strUrl.startsWith( AppPathService.getBaseUrl( request ) ) )
         {
             return true;
         }
 
         // compare with allowed url patterns
         if ( !StringUtils.isBlank( strAntPathMatcherPatterns ) )
         {
             AntPathMatcher pathMatcher = new AntPathMatcher( );
 
             String [ ] strAntPathMatcherPatternsTab = strAntPathMatcherPatterns.split( CONSTANT_COMMA );
             for ( String pattern : strAntPathMatcherPatternsTab )
             {
                 if ( pattern != null && pathMatcher.match( pattern, strUrl ) )
                 {
                     return true;
                 }
             }
         }
 
         // the Url does not match the allowed patterns
         _log.warn( "SECURITY WARNING : OPEN_REDIRECT DETECTED : {}", ( ) -> dumpRequest( request ) );
 
         return false;
 
     }
 
     /**
      * Identify user data saved in log files to prevent Log Forging attacks
      * 
      * @param strUserInputData
      *            User Input Data
      * @return The User Data to log
      */
     public static String logForgingProtect( String strUserInputData )
     {
         int nCharCount = strUserInputData.length( );
         int nLineCount = StringUtils.countMatches( strUserInputData, "\n" );
         String strPrefixedLines = strUserInputData.replace( "\n", "\n** " );
         return "\n** USER INPUT DATA : BEGIN (" + nLineCount + " lines and " + nCharCount + " chars) ** \n" + strPrefixedLines + "\n** USER INPUT DATA : END\n";
     }
 
     /**
      * Write a title into the dump stringbuffer
      * 
      * @param sbDump
      *            The dump stringbuffer
      * @param strTitle
      *            The title
      */
     private static void dumpTitle( StringBuilder sbDump, String strTitle )
     {
         sbDump.append( "** " );
         sbDump.append( strTitle );
         sbDump.append( "  **\r\n" );
     }
 
     /**
      * Write request variables into the dump stringbuffer
      * 
      * @param sb
      *            The dump stringbuffer
      * @param request
      *            The HTTP request
      */
     private static void dumpVariables( StringBuilder sb, HttpServletRequest request )
     {
         dumpVariable( sb, "AUTH_TYPE", request.getAuthType( ) );
         dumpVariable( sb, "REQUEST_METHOD", request.getMethod( ) );
         dumpVariable( sb, "PATH_INFO", request.getPathInfo( ) );
         dumpVariable( sb, "PATH_TRANSLATED", request.getPathTranslated( ) );
         dumpVariable( sb, "QUERY_STRING", request.getQueryString( ) );
         dumpVariable( sb, "REQUEST_URI", request.getRequestURI( ) );
         dumpVariable( sb, "SCRIPT_NAME", request.getServletPath( ) );
         dumpVariable( sb, "LOCAL_ADDR", request.getLocalAddr( ) );
         dumpVariable( sb, "SERVER_PROTOCOL", request.getProtocol( ) );
         dumpVariable( sb, "REMOTE_ADDR", request.getRemoteAddr( ) );
         dumpVariable( sb, "REMOTE_HOST", request.getRemoteHost( ) );
         dumpVariable( sb, "HTTPS", request.getScheme( ) );
         dumpVariable( sb, "SERVER_NAME", request.getServerName( ) );
         dumpVariable( sb, "SERVER_PORT", String.valueOf( request.getServerPort( ) ) );
     }
 
     /**
      * Write request headers infos into the dump stringbuffer
      * 
      * @param sb
      *            The dump stringbuffer
      * @param request
      *            The HTTP request
      */
     private static void dumpHeaders( StringBuilder sb, HttpServletRequest request )
     {
         Enumeration<String> values;
         String key;
         Enumeration<String> headers = request.getHeaderNames( );
 
         while ( headers.hasMoreElements( ) )
         {
             key = headers.nextElement( );
             values = request.getHeaders( key );
 
             while ( values.hasMoreElements( ) )
             {
                 dumpVariable( sb, key, values.nextElement( ) );
             }
         }
     }
 
     /**
      * Write request parameters infos into the dump stringbuffer
      * 
      * @param sb
      *            The dump stringbuffer
      * @param request
      *            The HTTP request
      */
     private static void dumpParameters( StringBuilder sb, HttpServletRequest request )
     {
         String key;
         String [ ] values;
 
         Enumeration<String> e = request.getParameterNames( );
 
         while ( e.hasMoreElements( ) )
         {
             key = e.nextElement( );
             values = request.getParameterValues( key );
 
             int length = values.length;
 
             for ( int i = 0; i < length; i++ )
             {
                 dumpVariable( sb, key, values [i] );
             }
         }
     }
 
     /**
      * Write name / value infos into the dump stringbuffer
      * 
      * @param sb
      *            The dump string buffer
      * @param strName
      *            The info name
      * @param strValue
      *            The info value
      */
     private static void dumpVariable( StringBuilder sb, String strName, String strValue )
     {
         sb.append( strName );
         sb.append( " : \"" );
         sb.append( strValue );
         sb.append( "\"\r\n" );
     }
 }