includes/ProxyTools.php

   1 <?php
   2 /**
   3  * Functions for dealing with proxies
   4  * @file
   5  */
   6
   7 /**
   8  * Extracts the XFF string from the request header
   9  * Checks first for "X-Forwarded-For", then "Client-ip"
  10  * Note: headers are spoofable
  11  * @return string
  12  */
  13 function wfGetForwardedFor() {
  14         if( function_exists( 'apache_request_headers' ) ) {
  15                 // More reliable than $_SERVER due to case and -/_ folding
  16                 $set = array ();
  17                 foreach ( apache_request_headers() as $tempName => $tempValue ) {
  18                         $set[ strtoupper( $tempName ) ] = $tempValue;
  19                 }
  20                 $index = strtoupper ( 'X-Forwarded-For' );
  21                 $index2 = strtoupper ( 'Client-ip' );
  22         } else {
  23                 // Subject to spoofing with headers like X_Forwarded_For
  24                 $set = $_SERVER;
  25                 $index = 'HTTP_X_FORWARDED_FOR';
  26                 $index2 = 'CLIENT-IP';
  27         }
  28
  29         #Try a couple of headers
  30         if( isset( $set[$index] ) ) {
  31                 return $set[$index];
  32         } else if( isset( $set[$index2] ) ) {
  33                 return $set[$index2];
  34         } else {
  35                 return null;
  36         }
  37 }
  38
  39 /**
  40  * Returns the browser/OS data from the request header
  41  * Note: headers are spoofable
  42  * @return string
  43  */
  44 function wfGetAgent() {
  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  * @return string
  68  */
  69 function wfGetIP() {
  70         global $wgIP, $wgUsePrivateIPs, $wgCommandLineMode;
  71
  72         # Return cached result
  73         if ( !empty( $wgIP ) ) {
  74                 return $wgIP;
  75         }
  76
  77         $ipchain = array();
  78         $ip = false;
  79
  80         /* collect the originating ips */
  81         # Client connecting to this webserver
  82         if ( isset( $_SERVER['REMOTE_ADDR'] ) ) {
  83                 $ip = IP::canonicalize( $_SERVER['REMOTE_ADDR'] );
  84         } elseif( $wgCommandLineMode ) {
  85                 $ip = '127.0.0.1';
  86         }
  87         if( $ip ) {
  88                 $ipchain[] = $ip;
  89         }
  90
  91         # Append XFF on to $ipchain
  92         $forwardedFor = wfGetForwardedFor();
  93         if ( isset( $forwardedFor ) ) {
  94                 $xff = array_map( 'trim', explode( ',', $forwardedFor ) );
  95                 $xff = array_reverse( $xff );
  96                 $ipchain = array_merge( $ipchain, $xff );
  97         }
  98
  99         # Step through XFF list and find the last address in the list which is a trusted server
 100         # Set $ip to the IP address given by that trusted server, unless the address is not sensible (e.g. private)
 101         foreach ( $ipchain as $i => $curIP ) {
 102                 $curIP = IP::canonicalize( $curIP );
 103                 if ( wfIsTrustedProxy( $curIP ) ) {
 104                         if ( isset( $ipchain[$i + 1] ) ) {
 105                                 if( $wgUsePrivateIPs || IP::isPublic( $ipchain[$i + 1 ] ) ) {
 106                                         $ip = $ipchain[$i + 1];
 107                                 }
 108                         }
 109                 } else {
 110                         break;
 111                 }
 112         }
 113
 114         if( !$ip ) {
 115                 throw new MWException( "Unable to determine IP" );
 116         }
 117
 118         wfDebug( "IP: $ip\n" );
 119         $wgIP = $ip;
 120         return $ip;
 121 }
 122
 123 /**
 124  * Checks if an IP is a trusted proxy providor
 125  * Useful to tell if X-Fowarded-For data is possibly bogus
 126  * Squid cache servers for the site and AOL are whitelisted
 127  * @param $ip String
 128  * @return bool
 129  */
 130 function wfIsTrustedProxy( $ip ) {
 131         global $wgSquidServers, $wgSquidServersNoPurge;
 132
 133         if ( in_array( $ip, $wgSquidServers ) ||
 134                 in_array( $ip, $wgSquidServersNoPurge )
 135         ) {
 136                 $trusted = true;
 137         } else {
 138                 $trusted = false;
 139         }
 140         wfRunHooks( 'IsTrustedProxy', array( &$ip, &$trusted ) );
 141         return $trusted;
 142 }
 143
 144 /**
 145  * Forks processes to scan the originating IP for an open proxy server
 146  * MemCached can be used to skip IPs that have already been scanned
 147  */
 148 function wfProxyCheck() {
 149         global $wgBlockOpenProxies, $wgProxyPorts, $wgProxyScriptPath;
 150         global $wgMemc, $wgProxyMemcExpiry;
 151         global $wgProxyKey;
 152
 153         if ( !$wgBlockOpenProxies ) {
 154                 return;
 155         }
 156
 157         $ip = wfGetIP();
 158
 159         # Get MemCached key
 160         $mcKey = wfMemcKey( 'proxy', 'ip', $ip );
 161         $mcValue = $wgMemc->get( $mcKey );
 162         $skip = (bool)$mcValue;
 163
 164         # Fork the processes
 165         if ( !$skip ) {
 166                 $title = SpecialPage::getTitleFor( 'Blockme' );
 167                 $iphash = md5( $ip . $wgProxyKey );
 168                 $url = $title->getFullURL( 'ip='.$iphash );
 169
 170                 foreach ( $wgProxyPorts as $port ) {
 171                         $params = implode( ' ', array(
 172                                                 escapeshellarg( $wgProxyScriptPath ),
 173                                                 escapeshellarg( $ip ),
 174                                                 escapeshellarg( $port ),
 175                                                 escapeshellarg( $url )
 176                                                 ));
 177                         exec( "php $params >" . wfGetNull() . " 2>&1 &" );
 178                 }
 179                 # Set MemCached key
 180                 $wgMemc->set( $mcKey, 1, $wgProxyMemcExpiry );
 181         }
 182 }
 183
 184 /**
 185  * Convert a network specification in CIDR notation to an integer network and a number of bits
 186  * @return array(string, int)
 187  */
 188 function wfParseCIDR( $range ) {
 189         return IP::parseCIDR( $range );
 190 }
 191
 192 /**
 193  * Check if an IP address is in the local proxy list
 194  * @return bool
 195  */
 196 function wfIsLocallyBlockedProxy( $ip ) {
 197         global $wgProxyList;
 198
 199         if ( !$wgProxyList ) {
 200                 return false;
 201         }
 202         wfProfileIn( __METHOD__ );
 203
 204         if ( !is_array( $wgProxyList ) ) {
 205                 # Load from the specified file
 206                 $wgProxyList = array_map( 'trim', file( $wgProxyList ) );
 207         }
 208
 209         if ( !is_array( $wgProxyList ) ) {
 210                 $ret = false;
 211         } elseif ( array_search( $ip, $wgProxyList ) !== false ) {
 212                 $ret = true;
 213         } elseif ( array_key_exists( $ip, $wgProxyList ) ) {
 214                 # Old-style flipped proxy list
 215                 $ret = true;
 216         } else {
 217                 $ret = false;
 218         }
 219         wfProfileOut( __METHOD__ );
 220         return $ret;
 221 }
 222