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         if( function_exists( 'apache_request_headers' ) ) {
  16                 // More reliable than $_SERVER due to case and -/_ folding
  17                 $set = array ();
  18                 foreach ( apache_request_headers() as $tempName => $tempValue ) {
  19                         $set[ strtoupper( $tempName ) ] = $tempValue;
  20                 }
  21                 $index = strtoupper ( 'X-Forwarded-For' );
  22                 $index2 = strtoupper ( 'Client-ip' );
  23         } else {
  24                 // Subject to spoofing with headers like X_Forwarded_For
  25                 $set = $_SERVER;
  26                 $index = 'HTTP_X_FORWARDED_FOR';
  27                 $index2 = 'CLIENT-IP';
  28         }
  29
  30         #Try a couple of headers
  31         if( isset( $set[$index] ) ) {
  32                 return $set[$index];
  33         } else if( isset( $set[$index2] ) ) {
  34                 return $set[$index2];
  35         } else {
  36                 return null;
  37         }
  38 }
  39
  40 /**
  41  * Returns the browser/OS data from the request header
  42  * Note: headers are spoofable
  43  * @return string
  44  */
  45 function wfGetAgent() {
  46         if( function_exists( 'apache_request_headers' ) ) {
  47                 // More reliable than $_SERVER due to case and -/_ folding
  48                 $set = array ();
  49                 foreach ( apache_request_headers() as $tempName => $tempValue ) {
  50                         $set[ strtoupper( $tempName ) ] = $tempValue;
  51                 }
  52                 $index = strtoupper ( 'User-Agent' );
  53         } else {
  54                 // Subject to spoofing with headers like X_Forwarded_For
  55                 $set = $_SERVER;
  56                 $index = 'HTTP_USER_AGENT';
  57         }
  58         if( isset( $set[$index] ) ) {
  59                 return $set[$index];
  60         } else {
  61                 return '';
  62         }
  63 }
  64
  65 /**
  66  * Work out the IP address based on various globals
  67  * For trusted proxies, use the XFF client IP (first of the chain)
  68  * @return string
  69  */
  70 function wfGetIP() {
  71         global $wgIP, $wgUsePrivateIPs, $wgCommandLineMode;
  72
  73         # Return cached result
  74         if ( !empty( $wgIP ) ) {
  75                 return $wgIP;
  76         }
  77
  78         $ipchain = array();
  79         $ip = false;
  80
  81         /* collect the originating ips */
  82         # Client connecting to this webserver
  83         if ( isset( $_SERVER['REMOTE_ADDR'] ) ) {
  84                 $ip = IP::canonicalize( $_SERVER['REMOTE_ADDR'] );
  85         } elseif( $wgCommandLineMode ) {
  86                 $ip = '127.0.0.1';
  87         }
  88         if( $ip ) {
  89                 $ipchain[] = $ip;
  90         }
  91
  92         # Append XFF on to $ipchain
  93         $forwardedFor = wfGetForwardedFor();
  94         if ( isset( $forwardedFor ) ) {
  95                 $xff = array_map( 'trim', explode( ',', $forwardedFor ) );
  96                 $xff = array_reverse( $xff );
  97                 $ipchain = array_merge( $ipchain, $xff );
  98         }
  99
 100         # Step through XFF list and find the last address in the list which is a trusted server
 101         # Set $ip to the IP address given by that trusted server, unless the address is not sensible (e.g. private)
 102         foreach ( $ipchain as $i => $curIP ) {
 103                 $curIP = IP::canonicalize( $curIP );
 104                 if ( wfIsTrustedProxy( $curIP ) ) {
 105                         if ( isset( $ipchain[$i + 1] ) ) {
 106                                 if( $wgUsePrivateIPs || IP::isPublic( $ipchain[$i + 1 ] ) ) {
 107                                         $ip = $ipchain[$i + 1];
 108                                 }
 109                         }
 110                 } else {
 111                         break;
 112                 }
 113         }
 114
 115         if( !$ip ) {
 116                 throw new MWException( "Unable to determine IP" );
 117         }
 118
 119         wfDebug( "IP: $ip\n" );
 120         $wgIP = $ip;
 121         return $ip;
 122 }
 123
 124 /**
 125  * Checks if an IP is a trusted proxy providor
 126  * Useful to tell if X-Fowarded-For data is possibly bogus
 127  * Squid cache servers for the site and AOL are whitelisted
 128  * @param $ip String
 129  * @return bool
 130  */
 131 function wfIsTrustedProxy( $ip ) {
 132         global $wgSquidServers, $wgSquidServersNoPurge;
 133
 134         if ( in_array( $ip, $wgSquidServers ) ||
 135                 in_array( $ip, $wgSquidServersNoPurge )
 136         ) {
 137                 $trusted = true;
 138         } else {
 139                 $trusted = false;
 140         }
 141         wfRunHooks( 'IsTrustedProxy', array( &$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 }
 184
 185 /**
 186  * Convert a network specification in CIDR notation to an integer network and a number of bits
 187  * @return array(string, int)
 188  */
 189 function wfParseCIDR( $range ) {
 190         return IP::parseCIDR( $range );
 191 }
 192
 193 /**
 194  * Check if an IP address is in the local proxy list
 195  * @return bool
 196  */
 197 function wfIsLocallyBlockedProxy( $ip ) {
 198         global $wgProxyList;
 199
 200         if ( !$wgProxyList ) {
 201                 return false;
 202         }
 203         wfProfileIn( __METHOD__ );
 204
 205         if ( !is_array( $wgProxyList ) ) {
 206                 # Load from the specified file
 207                 $wgProxyList = array_map( 'trim', file( $wgProxyList ) );
 208         }
 209
 210         if ( !is_array( $wgProxyList ) ) {
 211                 $ret = false;
 212         } elseif ( array_search( $ip, $wgProxyList ) !== false ) {
 213                 $ret = true;
 214         } elseif ( array_key_exists( $ip, $wgProxyList ) ) {
 215                 # Old-style flipped proxy list
 216                 $ret = true;
 217         } else {
 218                 $ret = false;
 219         }
 220         wfProfileOut( __METHOD__ );
 221         return $ret;
 222 }
 223