src/App/Request.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\App;
  23
  24 use Friendica\Core\Config\Capability\IManageConfigValues;
  25
  26 /**
  27  * Container for the whole request
  28  *
  29  * @see https://www.php-fig.org/psr/psr-7/#321-psrhttpmessageserverrequestinterface
  30  *
  31  * @todo future container class for whole requests, currently it's not :-)
  32  */
  33 class Request
  34 {
  35         /** @var string the default possible headers, which could contain the client IP */
  36         const ORDERED_FORWARD_FOR_HEADER = 'HTTP_X_FORWARDED_FOR';
  37
  38         /** @var string The remote IP address of the current request */
  39         protected $remoteAddress;
  40
  41         /**
  42          * @return string The remote IP address of the current request
  43          *
  44          * Do always use this instead of $_SERVER['REMOTE_ADDR']
  45          */
  46         public function getRemoteAddress(): string
  47         {
  48                 return $this->remoteAddress;
  49         }
  50
  51         public function __construct(IManageConfigValues $config, array $server = [])
  52         {
  53                 $this->remoteAddress = $this->determineRemoteAddress($config, $server);
  54         }
  55
  56         /**
  57          * Checks if given $remoteAddress matches given $trustedProxy.
  58          * If $trustedProxy is an IPv4 IP range given in CIDR notation, true will be returned if
  59          * $remoteAddress is an IPv4 address within that IP range.
  60          * Otherwise, $remoteAddress will be compared to $trustedProxy literally and the result
  61          * will be returned.
  62          *
  63          * @param string $trustedProxy  The current, trusted proxy to check
  64          * @param string $remoteAddress The current remote IP address
  65          *
  66          *
  67          * @return boolean true if $remoteAddress matches $trustedProxy, false otherwise
  68          */
  69         protected function matchesTrustedProxy(string $trustedProxy, string $remoteAddress): bool
  70         {
  71                 $cidrre = '/^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})\/([0-9]{1,2})$/';
  72
  73                 if (preg_match($cidrre, $trustedProxy, $match)) {
  74                         $net       = $match[1];
  75                         $shiftbits = min(32, max(0, 32 - intval($match[2])));
  76                         $netnum    = ip2long($net) >> $shiftbits;
  77                         $ipnum     = ip2long($remoteAddress) >> $shiftbits;
  78
  79                         return $ipnum === $netnum;
  80                 }
  81
  82                 return $trustedProxy === $remoteAddress;
  83         }
  84
  85         /**
  86          * Checks if given $remoteAddress matches any entry in the given array $trustedProxies.
  87          * For details regarding what "match" means, refer to `matchesTrustedProxy`.
  88          *
  89          * @param string[] $trustedProxies A list of the trusted proxies
  90          * @param string   $remoteAddress  The current remote IP address
  91          *
  92          * @return boolean true if $remoteAddress matches any entry in $trustedProxies, false otherwise
  93          */
  94         protected function isTrustedProxy(array $trustedProxies, string $remoteAddress): bool
  95         {
  96                 foreach ($trustedProxies as $tp) {
  97                         if ($this->matchesTrustedProxy($tp, $remoteAddress)) {
  98                                 return true;
  99                         }
 100                 }
 101
 102                 return false;
 103         }
 104
 105         /**
 106          * Determines the remote address, if the connection came from a trusted proxy
 107          * and `forwarded_for_headers` has been configured then the IP address
 108          * specified in this header will be returned instead.
 109          *
 110          * @param IManageConfigValues $config
 111          * @param array               $server
 112          *
 113          * @return string
 114          */
 115         protected function determineRemoteAddress(IManageConfigValues $config, array $server): string
 116         {
 117                 $remoteAddress  = $server['REMOTE_ADDR'] ?? '0.0.0.0';
 118                 $trustedProxies = preg_split('/(\s*,*\s*)*,+(\s*,*\s*)*/', $config->get('proxy', 'trusted_proxies', ''));
 119
 120                 if (\is_array($trustedProxies) && $this->isTrustedProxy($trustedProxies, $remoteAddress)) {
 121                         $forwardedForHeaders = preg_split('/(\s*,*\s*)*,+(\s*,*\s*)*/', $config->get('proxy', 'forwarded_for_headers')) ?? static::ORDERED_FORWARD_FOR_HEADER;
 122
 123                         foreach ($forwardedForHeaders as $header) {
 124                                 if (isset($server[$header])) {
 125                                         foreach (explode(',', $server[$header]) as $IP) {
 126                                                 $IP = trim($IP);
 127
 128                                                 // remove brackets from IPv6 addresses
 129                                                 if (strpos($IP, '[') === 0 && substr($IP, -1) === ']') {
 130                                                         $IP = substr($IP, 1, -1);
 131                                                 }
 132
 133                                                 // skip trusted proxies in the list itself
 134                                                 if ($this->isTrustedProxy($trustedProxies, $IP)) {
 135                                                         continue;
 136                                                 }
 137
 138                                                 if (filter_var($IP, FILTER_VALIDATE_IP) !== false) {
 139                                                         return $IP;
 140                                                 }
 141                                         }
 142                                 }
 143                         }
 144                 }
 145
 146                 return $remoteAddress;
 147         }
 148 }