includes/ProxyTools.php

   1 <?php
   2 /**
   3  * Functions for dealing with proxies
   4  *
   5  * @file
   6  */
   7
   8 /**
   9  * Extracts the XFF string from the request header
  10  * Checks first for "X-Forwarded-For", then "Client-ip"
  11  * Note: headers are spoofable
  12  * @return string
  13  */
  14 function wfGetForwardedFor() {
  15         $apacheHeaders = function_exists( 'apache_request_headers' ) ? apache_request_headers() : null;
  16         if( is_array( $apacheHeaders ) ) {
  17                 // More reliable than $_SERVER due to case and -/_ folding
  18                 $set = array();
  19                 foreach ( $apacheHeaders as $tempName => $tempValue ) {
  20                         $set[ strtoupper( $tempName ) ] = $tempValue;
  21                 }
  22                 $index = strtoupper ( 'X-Forwarded-For' );
  23                 $index2 = strtoupper ( 'Client-ip' );
  24         } else {
  25                 // Subject to spoofing with headers like X_Forwarded_For
  26                 $set = $_SERVER;
  27                 $index = 'HTTP_X_FORWARDED_FOR';
  28                 $index2 = 'CLIENT-IP';
  29         }
  30
  31         #Try a couple of headers
  32         if( isset( $set[$index] ) ) {
  33                 return $set[$index];
  34         } else if( isset( $set[$index2] ) ) {
  35                 return $set[$index2];
  36         } else {
  37                 return null;
  38         }
  39 }
  40
  41 /**
  42  * Returns the browser/OS data from the request header
  43  * Note: headers are spoofable
  44  * @return string
  45  */
  46 function wfGetAgent() {
  47         if( function_exists( 'apache_request_headers' ) ) {
  48                 // More reliable than $_SERVER due to case and -/_ folding
  49                 $set = array();
  50                 foreach ( apache_request_headers() as $tempName => $tempValue ) {
  51                         $set[ strtoupper( $tempName ) ] = $tempValue;
  52                 }
  53                 $index = strtoupper ( 'User-Agent' );
  54         } else {
  55                 // Subject to spoofing with headers like X_Forwarded_For
  56                 $set = $_SERVER;
  57                 $index = 'HTTP_USER_AGENT';
  58         }
  59         if( isset( $set[$index] ) ) {
  60                 return $set[$index];
  61         } else {
  62                 return '';
  63         }
  64 }
  65
  66 /**
  67  * Work out the IP address based on various globals
  68  * For trusted proxies, use the XFF client IP (first of the chain)
  69  * @return string
  70  */
  71 function wfGetIP() {
  72         global $wgUsePrivateIPs, $wgCommandLineMode;
  73         static $ip = false;
  74
  75         # Return cached result
  76         if ( !empty( $ip ) ) {
  77                 return $ip;
  78         }
  79
  80         $ipchain = array();
  81
  82         /* collect the originating ips */
  83         # Client connecting to this webserver
  84         if ( isset( $_SERVER['REMOTE_ADDR'] ) ) {
  85                 $ip = IP::canonicalize( $_SERVER['REMOTE_ADDR'] );
  86         } elseif( $wgCommandLineMode ) {
  87                 $ip = '127.0.0.1';
  88         }
  89         if( $ip ) {
  90                 $ipchain[] = $ip;
  91         }
  92
  93         # Append XFF on to $ipchain
  94         $forwardedFor = wfGetForwardedFor();
  95         if ( isset( $forwardedFor ) ) {
  96                 $xff = array_map( 'trim', explode( ',', $forwardedFor ) );
  97                 $xff = array_reverse( $xff );
  98                 $ipchain = array_merge( $ipchain, $xff );
  99         }
 100
 101         # Step through XFF list and find the last address in the list which is a trusted server
 102         # Set $ip to the IP address given by that trusted server, unless the address is not sensible (e.g. private)
 103         foreach ( $ipchain as $i => $curIP ) {
 104                 $curIP = IP::canonicalize( $curIP );
 105                 if ( wfIsTrustedProxy( $curIP ) ) {
 106                         if ( isset( $ipchain[$i + 1] ) ) {
 107                                 if( $wgUsePrivateIPs || IP::isPublic( $ipchain[$i + 1 ] ) ) {
 108                                         $ip = $ipchain[$i + 1];
 109                                 }
 110                         }
 111                 } else {
 112                         break;
 113                 }
 114         }
 115
 116         # Allow extensions to improve our guess
 117         wfRunHooks( 'GetIP', array( &$ip ) );
 118
 119         if( !$ip ) {
 120                 throw new MWException( "Unable to determine IP" );
 121         }
 122
 123         wfDebug( "IP: $ip\n" );
 124         return $ip;
 125 }
 126
 127 /**
 128  * Checks if an IP is a trusted proxy providor
 129  * Useful to tell if X-Fowarded-For data is possibly bogus
 130  * Squid cache servers for the site and AOL are whitelisted
 131  * @param $ip String
 132  * @return bool
 133  */
 134 function wfIsTrustedProxy( $ip ) {
 135         global $wgSquidServers, $wgSquidServersNoPurge;
 136
 137         $trusted = in_array( $ip, $wgSquidServers ) ||
 138                 in_array( $ip, $wgSquidServersNoPurge );
 139         wfRunHooks( 'IsTrustedProxy', array( &$ip, &$trusted ) );
 140         return $trusted;
 141 }
 142
 143 /**
 144  * Forks processes to scan the originating IP for an open proxy server
 145  * MemCached can be used to skip IPs that have already been scanned
 146  */
 147 function wfProxyCheck() {
 148         global $wgBlockOpenProxies, $wgProxyPorts, $wgProxyScriptPath;
 149         global $wgMemc, $wgProxyMemcExpiry;
 150         global $wgProxyKey;
 151
 152         if ( !$wgBlockOpenProxies ) {
 153                 return;
 154         }
 155
 156         $ip = wfGetIP();
 157
 158         # Get MemCached key
 159         $mcKey = wfMemcKey( 'proxy', 'ip', $ip );
 160         $mcValue = $wgMemc->get( $mcKey );
 161         $skip = (bool)$mcValue;
 162
 163         # Fork the processes
 164         if ( !$skip ) {
 165                 $title = SpecialPage::getTitleFor( 'Blockme' );
 166                 $iphash = md5( $ip . $wgProxyKey );
 167                 $url = $title->getFullURL( 'ip='.$iphash );
 168
 169                 foreach ( $wgProxyPorts as $port ) {
 170                         $params = implode( ' ', array(
 171                                                 escapeshellarg( $wgProxyScriptPath ),
 172                                                 escapeshellarg( $ip ),
 173                                                 escapeshellarg( $port ),
 174                                                 escapeshellarg( $url )
 175                                                 ));
 176                         exec( "php $params >" . wfGetNull() . " 2>&1 &" );
 177                 }
 178                 # Set MemCached key
 179                 $wgMemc->set( $mcKey, 1, $wgProxyMemcExpiry );
 180         }
 181 }
 182
 183 /**
 184  * Check if an IP address is in the local proxy list
 185  * @return bool
 186  */
 187 function wfIsLocallyBlockedProxy( $ip ) {
 188         global $wgProxyList;
 189
 190         if ( !$wgProxyList ) {
 191                 return false;
 192         }
 193         wfProfileIn( __METHOD__ );
 194
 195         if ( !is_array( $wgProxyList ) ) {
 196                 # Load from the specified file
 197                 $wgProxyList = array_map( 'trim', file( $wgProxyList ) );
 198         }
 199
 200         if ( !is_array( $wgProxyList ) ) {
 201                 $ret = false;
 202         } elseif ( array_search( $ip, $wgProxyList ) !== false ) {
 203                 $ret = true;
 204         } elseif ( array_key_exists( $ip, $wgProxyList ) ) {
 205                 # Old-style flipped proxy list
 206                 $ret = true;
 207         } else {
 208                 $ret = false;
 209         }
 210         wfProfileOut( __METHOD__ );
 211         return $ret;
 212 }
 213