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 $wgUsePrivateIPs, $wgCommandLineMode;
  72         static $ip = false;
  73
  74         # Return cached result
  75         if ( !empty( $ip ) ) {
  76                 return $ip;
  77         }
  78
  79         $ipchain = array();
  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         # Allow extensions to improve our guess
 116         wfRunHooks( 'GetIP', array( &$ip ) );
 117
 118         if( !$ip ) {
 119                 throw new MWException( "Unable to determine IP" );
 120         }
 121
 122         wfDebug( "IP: $ip\n" );
 123         return $ip;
 124 }
 125
 126 /**
 127  * Checks if an IP is a trusted proxy providor
 128  * Useful to tell if X-Fowarded-For data is possibly bogus
 129  * Squid cache servers for the site and AOL are whitelisted
 130  * @param $ip String
 131  * @return bool
 132  */
 133 function wfIsTrustedProxy( $ip ) {
 134         global $wgSquidServers, $wgSquidServersNoPurge;
 135
 136         if ( in_array( $ip, $wgSquidServers ) ||
 137                 in_array( $ip, $wgSquidServersNoPurge )
 138         ) {
 139                 $trusted = true;
 140         } else {
 141                 $trusted = false;
 142         }
 143         wfRunHooks( 'IsTrustedProxy', array( &$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 }
 186
 187 /**
 188  * Convert a network specification in CIDR notation to an integer network and a number of bits
 189  *
 190  * @deprecated Call IP::parseCIDR() directly, will be removed in 1.19
 191  * @return array(string, int)
 192  */
 193 function wfParseCIDR( $range ) {
 194         wfDeprecated( __FUNCTION__ );
 195         return IP::parseCIDR( $range );
 196 }
 197
 198 /**
 199  * Check if an IP address is in the local proxy list
 200  * @return bool
 201  */
 202 function wfIsLocallyBlockedProxy( $ip ) {
 203         global $wgProxyList;
 204
 205         if ( !$wgProxyList ) {
 206                 return false;
 207         }
 208         wfProfileIn( __METHOD__ );
 209
 210         if ( !is_array( $wgProxyList ) ) {
 211                 # Load from the specified file
 212                 $wgProxyList = array_map( 'trim', file( $wgProxyList ) );
 213         }
 214
 215         if ( !is_array( $wgProxyList ) ) {
 216                 $ret = false;
 217         } elseif ( array_search( $ip, $wgProxyList ) !== false ) {
 218                 $ret = true;
 219         } elseif ( array_key_exists( $ip, $wgProxyList ) ) {
 220                 # Old-style flipped proxy list
 221                 $ret = true;
 222         } else {
 223                 $ret = false;
 224         }
 225         wfProfileOut( __METHOD__ );
 226         return $ret;
 227 }
 228