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  * Note: headers are spoofable
  11  * @return string
  12  */
  13 function wfGetForwardedFor() {
  14         $apacheHeaders = function_exists( 'apache_request_headers' ) ? apache_request_headers() : null;
  15         if( is_array( $apacheHeaders ) ) {
  16                 // More reliable than $_SERVER due to case and -/_ folding
  17                 $set = array();
  18                 foreach ( $apacheHeaders as $tempName => $tempValue ) {
  19                         $set[ strtoupper( $tempName ) ] = $tempValue;
  20                 }
  21                 $index = strtoupper ( 'X-Forwarded-For' );
  22         } else {
  23                 // Subject to spoofing with headers like X_Forwarded_For
  24                 $set = $_SERVER;
  25                 $index = 'HTTP_X_FORWARDED_FOR';
  26         }
  27
  28         #Try to see if XFF is set
  29         if( isset( $set[$index] ) ) {
  30                 return $set[$index];
  31         } else {
  32                 return null;
  33         }
  34 }
  35
  36 /**
  37  * Returns the browser/OS data from the request header
  38  * Note: headers are spoofable
  39  *
  40  * @deprecated in 1.18; use $wgRequest->getHeader( 'User-Agent' ) instead.
  41  * @return string
  42  */
  43 function wfGetAgent() {
  44         wfDeprecated( __FUNCTION__ );
  45         if( function_exists( 'apache_request_headers' ) ) {
  46                 // More reliable than $_SERVER due to case and -/_ folding
  47                 $set = array();
  48                 foreach ( apache_request_headers() as $tempName => $tempValue ) {
  49                         $set[ strtoupper( $tempName ) ] = $tempValue;
  50                 }
  51                 $index = strtoupper ( 'User-Agent' );
  52         } else {
  53                 // Subject to spoofing with headers like X_Forwarded_For
  54                 $set = $_SERVER;
  55                 $index = 'HTTP_USER_AGENT';
  56         }
  57         if( isset( $set[$index] ) ) {
  58                 return $set[$index];
  59         } else {
  60                 return '';
  61         }
  62 }
  63
  64 /**
  65  * Work out the IP address based on various globals
  66  * For trusted proxies, use the XFF client IP (first of the chain)
  67  * @param $reset boolean Used to reset the internal static variable
  68  * tracking the IP address. Set to anything non empty to reset it, for
  69  * example: wfGetIP( 'reset' ); (default: false).
  70  * @return string
  71  */
  72 function wfGetIP( $reset = false ) {
  73         global $wgUsePrivateIPs, $wgCommandLineMode;
  74         static $ip = false;
  75
  76         if( $reset ) {
  77                 $ip = false;
  78         }
  79
  80         # Return cached result
  81         if ( !empty( $ip ) ) {
  82                 return $ip;
  83         }
  84
  85         /* collect the originating ips */
  86         # Client connecting to this webserver
  87         if ( isset( $_SERVER['REMOTE_ADDR'] ) ) {
  88                 $ip = IP::canonicalize( $_SERVER['REMOTE_ADDR'] );
  89         } elseif( $wgCommandLineMode ) {
  90                 $ip = '127.0.0.1';
  91         }
  92
  93         # Append XFF
  94         $forwardedFor = wfGetForwardedFor();
  95         if ( $forwardedFor !== null ) {
  96                 $ipchain = array_map( 'trim', explode( ',', $forwardedFor ) );
  97                 $ipchain = array_reverse( $ipchain );
  98                 if ( $ip ) {
  99                         array_unshift( $ipchain, $ip );
 100                 }
 101
 102                 # Step through XFF list and find the last address in the list which is a trusted server
 103                 # Set $ip to the IP address given by that trusted server, unless the address is not sensible (e.g. private)
 104                 foreach ( $ipchain as $i => $curIP ) {
 105                         $curIP = IP::canonicalize( $curIP );
 106                         if ( wfIsTrustedProxy( $curIP ) ) {
 107                                 if ( isset( $ipchain[$i + 1] ) ) {
 108                                         if( $wgUsePrivateIPs || IP::isPublic( $ipchain[$i + 1 ] ) ) {
 109                                                 $ip = $ipchain[$i + 1];
 110                                         }
 111                                 }
 112                         } else {
 113                                 break;
 114                         }
 115                 }
 116         }
 117
 118         # Allow extensions to improve our guess
 119         wfRunHooks( 'GetIP', array( &$ip ) );
 120
 121         if( !$ip ) {
 122                 throw new MWException( "Unable to determine IP" );
 123         }
 124
 125         wfDebug( "IP: $ip\n" );
 126         return $ip;
 127 }
 128
 129 /**
 130  * Checks if an IP is a trusted proxy providor
 131  * Useful to tell if X-Fowarded-For data is possibly bogus
 132  * Squid cache servers for the site and AOL are whitelisted
 133  * @param $ip String
 134  * @return bool
 135  */
 136 function wfIsTrustedProxy( $ip ) {
 137         global $wgSquidServers, $wgSquidServersNoPurge;
 138
 139         $trusted = in_array( $ip, $wgSquidServers ) ||
 140                 in_array( $ip, $wgSquidServersNoPurge );
 141         wfRunHooks( 'IsTrustedProxy', array( &$ip, &$trusted ) );
 142         return $trusted;
 143 }
 144
 145 /**
 146  * Forks processes to scan the originating IP for an open proxy server
 147  * MemCached can be used to skip IPs that have already been scanned
 148  */
 149 function wfProxyCheck() {
 150         global $wgBlockOpenProxies, $wgProxyPorts, $wgProxyScriptPath;
 151         global $wgMemc, $wgProxyMemcExpiry;
 152         global $wgProxyKey;
 153
 154         if ( !$wgBlockOpenProxies ) {
 155                 return;
 156         }
 157
 158         $ip = wfGetIP();
 159
 160         # Get MemCached key
 161         $mcKey = wfMemcKey( 'proxy', 'ip', $ip );
 162         $mcValue = $wgMemc->get( $mcKey );
 163         $skip = (bool)$mcValue;
 164
 165         # Fork the processes
 166         if ( !$skip ) {
 167                 $title = SpecialPage::getTitleFor( 'Blockme' );
 168                 $iphash = md5( $ip . $wgProxyKey );
 169                 $url = $title->getFullURL( 'ip='.$iphash );
 170
 171                 foreach ( $wgProxyPorts as $port ) {
 172                         $params = implode( ' ', array(
 173                                                 escapeshellarg( $wgProxyScriptPath ),
 174                                                 escapeshellarg( $ip ),
 175                                                 escapeshellarg( $port ),
 176                                                 escapeshellarg( $url )
 177                                                 ));
 178                         exec( "php $params >" . wfGetNull() . " 2>&1 &" );
 179                 }
 180                 # Set MemCached key
 181                 $wgMemc->set( $mcKey, 1, $wgProxyMemcExpiry );
 182         }
 183 }