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;
  71
  72         # Return cached result
  73         if ( !empty( $wgIP ) ) {
  74                 return $wgIP;
  75         }
  76
  77         /* collect the originating ips */
  78         # Client connecting to this webserver
  79         if ( isset( $_SERVER['REMOTE_ADDR'] ) ) {
  80                 $ipchain = array( IP::canonicalize( $_SERVER['REMOTE_ADDR'] ) );
  81         } else {
  82                 # Running on CLI?
  83                 $ipchain = array( '127.0.0.1' );
  84         }
  85         $ip = $ipchain[0];
  86
  87         # Append XFF on to $ipchain
  88         $forwardedFor = wfGetForwardedFor();
  89         if ( isset( $forwardedFor ) ) {
  90                 $xff = array_map( 'trim', explode( ',', $forwardedFor ) );
  91                 $xff = array_reverse( $xff );
  92                 $ipchain = array_merge( $ipchain, $xff );
  93         }
  94
  95         # Step through XFF list and find the last address in the list which is a trusted server
  96         # Set $ip to the IP address given by that trusted server, unless the address is not sensible (e.g. private)
  97         foreach ( $ipchain as $i => $curIP ) {
  98                 $curIP = IP::canonicalize( $curIP );
  99                 if ( wfIsTrustedProxy( $curIP ) ) {
 100                         if ( isset( $ipchain[$i + 1] ) ) {
 101                                 if( $wgUsePrivateIPs || IP::isPublic( $ipchain[$i + 1 ] ) ) {
 102                                         $ip = $ipchain[$i + 1];
 103                                 }
 104                         }
 105                 } else {
 106                         break;
 107                 }
 108         }
 109
 110         wfDebug( "IP: $ip\n" );
 111         $wgIP = $ip;
 112         return $ip;
 113 }
 114
 115 /**
 116  * Checks if an IP is a trusted proxy providor
 117  * Useful to tell if X-Fowarded-For data is possibly bogus
 118  * Squid cache servers for the site and AOL are whitelisted
 119  * @param string $ip
 120  * @return bool
 121  */
 122 function wfIsTrustedProxy( $ip ) {
 123         global $wgSquidServers, $wgSquidServersNoPurge;
 124
 125         if ( in_array( $ip, $wgSquidServers ) ||
 126                 in_array( $ip, $wgSquidServersNoPurge )
 127         ) {
 128                 $trusted = true;
 129         } else {
 130                 $trusted = false;
 131         }
 132         wfRunHooks( 'IsTrustedProxy', array( &$ip, &$trusted ) );
 133         return $trusted;
 134 }
 135
 136 /**
 137  * Forks processes to scan the originating IP for an open proxy server
 138  * MemCached can be used to skip IPs that have already been scanned
 139  */
 140 function wfProxyCheck() {
 141         global $wgBlockOpenProxies, $wgProxyPorts, $wgProxyScriptPath;
 142         global $wgMemc, $wgProxyMemcExpiry;
 143         global $wgProxyKey;
 144
 145         if ( !$wgBlockOpenProxies ) {
 146                 return;
 147         }
 148
 149         $ip = wfGetIP();
 150
 151         # Get MemCached key
 152         $mcKey = wfMemcKey( 'proxy', 'ip', $ip );
 153         $mcValue = $wgMemc->get( $mcKey );
 154         $skip = (bool)$mcValue;
 155
 156         # Fork the processes
 157         if ( !$skip ) {
 158                 $title = SpecialPage::getTitleFor( 'Blockme' );
 159                 $iphash = md5( $ip . $wgProxyKey );
 160                 $url = $title->getFullURL( 'ip='.$iphash );
 161
 162                 foreach ( $wgProxyPorts as $port ) {
 163                         $params = implode( ' ', array(
 164                                                 escapeshellarg( $wgProxyScriptPath ),
 165                                                 escapeshellarg( $ip ),
 166                                                 escapeshellarg( $port ),
 167                                                 escapeshellarg( $url )
 168                                                 ));
 169                         exec( "php $params &>/dev/null &" );
 170                 }
 171                 # Set MemCached key
 172                 $wgMemc->set( $mcKey, 1, $wgProxyMemcExpiry );
 173         }
 174 }
 175
 176 /**
 177  * Convert a network specification in CIDR notation to an integer network and a number of bits
 178  * @return array(string, int)
 179  */
 180 function wfParseCIDR( $range ) {
 181         return IP::parseCIDR( $range );
 182 }
 183
 184 /**
 185  * Check if an IP address is in the local proxy list
 186  * @return bool
 187  */
 188 function wfIsLocallyBlockedProxy( $ip ) {
 189         global $wgProxyList;
 190         $fname = 'wfIsLocallyBlockedProxy';
 191
 192         if ( !$wgProxyList ) {
 193                 return false;
 194         }
 195         wfProfileIn( $fname );
 196
 197         if ( !is_array( $wgProxyList ) ) {
 198                 # Load from the specified file
 199                 $wgProxyList = array_map( 'trim', file( $wgProxyList ) );
 200         }
 201
 202         if ( !is_array( $wgProxyList ) ) {
 203                 $ret = false;
 204         } elseif ( array_search( $ip, $wgProxyList ) !== false ) {
 205                 $ret = true;
 206         } elseif ( array_key_exists( $ip, $wgProxyList ) ) {
 207                 # Old-style flipped proxy list
 208                 $ret = true;
 209         } else {
 210                 $ret = false;
 211         }
 212         wfProfileOut( $fname );
 213         return $ret;
 214 }
 215