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", then "X-Real-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                 $index3 = strtoupper ( 'X-Real-IP' );
  25         } else {
  26                 // Subject to spoofing with headers like X_Forwarded_For
  27                 $set = $_SERVER;
  28                 $index = 'HTTP_X_FORWARDED_FOR';
  29                 $index2 = 'CLIENT-IP';
  30                 $index3 = 'HTTP_X_REAL_IP';
  31         }
  32
  33         #Try a couple of headers
  34         if( isset( $set[$index] ) ) {
  35                 return $set[$index];
  36         } elseif( isset( $set[$index2] ) ) {
  37                 return $set[$index2];
  38         } elseif( isset( $set[$index3] ) ) {
  39                 return $set[$index3];
  40         } else {
  41                 return null;
  42         }
  43 }
  44
  45 /**
  46  * Returns the browser/OS data from the request header
  47  * Note: headers are spoofable
  48  *
  49  * @deprecated in 1.18; use $wgRequest->getHeader( 'User-Agent' ) instead.
  50  * @return string
  51  */
  52 function wfGetAgent() {
  53         wfDeprecated( __FUNCTION__ );
  54         if( function_exists( 'apache_request_headers' ) ) {
  55                 // More reliable than $_SERVER due to case and -/_ folding
  56                 $set = array();
  57                 foreach ( apache_request_headers() as $tempName => $tempValue ) {
  58                         $set[ strtoupper( $tempName ) ] = $tempValue;
  59                 }
  60                 $index = strtoupper ( 'User-Agent' );
  61         } else {
  62                 // Subject to spoofing with headers like X_Forwarded_For
  63                 $set = $_SERVER;
  64                 $index = 'HTTP_USER_AGENT';
  65         }
  66         if( isset( $set[$index] ) ) {
  67                 return $set[$index];
  68         } else {
  69                 return '';
  70         }
  71 }
  72
  73 /**
  74  * Work out the IP address based on various globals
  75  * For trusted proxies, use the XFF client IP (first of the chain)
  76  * @return string
  77  */
  78 function wfGetIP() {
  79         global $wgUsePrivateIPs, $wgCommandLineMode;
  80         static $ip = false;
  81
  82         # Return cached result
  83         if ( !empty( $ip ) ) {
  84                 return $ip;
  85         }
  86
  87         /* collect the originating ips */
  88         # Client connecting to this webserver
  89         if ( isset( $_SERVER['REMOTE_ADDR'] ) ) {
  90                 $ip = IP::canonicalize( $_SERVER['REMOTE_ADDR'] );
  91         } elseif( $wgCommandLineMode ) {
  92                 $ip = '127.0.0.1';
  93         }
  94
  95         # Append XFF
  96         $forwardedFor = wfGetForwardedFor();
  97         if ( $forwardedFor !== null ) {
  98                 $ipchain = array_map( 'trim', explode( ',', $forwardedFor ) );
  99                 $ipchain = array_reverse( $ipchain );
 100                 if ( $ip ) {
 101                         array_unshift( $ipchain, $ip );
 102                 }
 103
 104                 # Step through XFF list and find the last address in the list which is a trusted server
 105                 # Set $ip to the IP address given by that trusted server, unless the address is not sensible (e.g. private)
 106                 foreach ( $ipchain as $i => $curIP ) {
 107                         $curIP = IP::canonicalize( $curIP );
 108                         if ( wfIsTrustedProxy( $curIP ) ) {
 109                                 if ( isset( $ipchain[$i + 1] ) ) {
 110                                         if( $wgUsePrivateIPs || IP::isPublic( $ipchain[$i + 1 ] ) ) {
 111                                                 $ip = $ipchain[$i + 1];
 112                                         }
 113                                 }
 114                         } else {
 115                                 break;
 116                         }
 117                 }
 118         }
 119
 120         # Allow extensions to improve our guess
 121         wfRunHooks( 'GetIP', array( &$ip ) );
 122
 123         if( !$ip ) {
 124                 throw new MWException( "Unable to determine IP" );
 125         }
 126
 127         wfDebug( "IP: $ip\n" );
 128         return $ip;
 129 }
 130
 131 /**
 132  * Checks if an IP is a trusted proxy providor
 133  * Useful to tell if X-Fowarded-For data is possibly bogus
 134  * Squid cache servers for the site and AOL are whitelisted
 135  * @param $ip String
 136  * @return bool
 137  */
 138 function wfIsTrustedProxy( $ip ) {
 139         global $wgSquidServers, $wgSquidServersNoPurge;
 140
 141         $trusted = in_array( $ip, $wgSquidServers ) ||
 142                 in_array( $ip, $wgSquidServersNoPurge );
 143         wfRunHooks( 'IsTrustedProxy', array( &$ip, &$trusted ) );
 144         return $trusted;
 145 }
 146
 147 /**
 148  * Forks processes to scan the originating IP for an open proxy server
 149  * MemCached can be used to skip IPs that have already been scanned
 150  */
 151 function wfProxyCheck() {
 152         global $wgBlockOpenProxies, $wgProxyPorts, $wgProxyScriptPath;
 153         global $wgMemc, $wgProxyMemcExpiry;
 154         global $wgProxyKey;
 155
 156         if ( !$wgBlockOpenProxies ) {
 157                 return;
 158         }
 159
 160         $ip = wfGetIP();
 161
 162         # Get MemCached key
 163         $mcKey = wfMemcKey( 'proxy', 'ip', $ip );
 164         $mcValue = $wgMemc->get( $mcKey );
 165         $skip = (bool)$mcValue;
 166
 167         # Fork the processes
 168         if ( !$skip ) {
 169                 $title = SpecialPage::getTitleFor( 'Blockme' );
 170                 $iphash = md5( $ip . $wgProxyKey );
 171                 $url = $title->getFullURL( 'ip='.$iphash );
 172
 173                 foreach ( $wgProxyPorts as $port ) {
 174                         $params = implode( ' ', array(
 175                                                 escapeshellarg( $wgProxyScriptPath ),
 176                                                 escapeshellarg( $ip ),
 177                                                 escapeshellarg( $port ),
 178                                                 escapeshellarg( $url )
 179                                                 ));
 180                         exec( "php $params >" . wfGetNull() . " 2>&1 &" );
 181                 }
 182                 # Set MemCached key
 183                 $wgMemc->set( $mcKey, 1, $wgProxyMemcExpiry );
 184         }
 185 }