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   1  <?php
   2  /**
   3   * This is a PHP library that handles calling reCAPTCHA.
   4   *    - Documentation and latest version
   5   *          http://recaptcha.net/plugins/php/
   6   *    - Get a reCAPTCHA API Key
   7   *          https://www.google.com/recaptcha/admin/create
   8   *    - Discussion group
   9   *          http://groups.google.com/group/recaptcha
  10   *
  11   * Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
  12   * AUTHORS:
  13   *   Mike Crawford
  14   *   Ben Maurer
  15   *
  16   * Permission is hereby granted, free of charge, to any person obtaining a copy
  17   * of this software and associated documentation files (the "Software"), to deal
  18   * in the Software without restriction, including without limitation the rights
  19   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  20   * copies of the Software, and to permit persons to whom the Software is
  21   * furnished to do so, subject to the following conditions:
  22   *
  23   * The above copyright notice and this permission notice shall be included in
  24   * all copies or substantial portions of the Software.
  25   *
  26   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  27   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  28   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  29   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  30   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  31   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  32   * THE SOFTWARE.
  33   */
  34  
  35  /**
  36   * The reCAPTCHA server URL's
  37   */
  38  define( "RECAPTCHA_API_SERVER", "http://www.google.com/recaptcha/api" );
  39  define( "RECAPTCHA_API_SECURE_SERVER", "https://www.google.com/recaptcha/api" );
  40  define( "RECAPTCHA_VERIFY_SERVER", "www.google.com" );
  41  
  42  /**
  43   * Encodes the given data into a query string format
  44   * @param $data - array of string elements to be encoded
  45   * @return string - encoded request
  46   */
  47  function _recaptcha_qsencode ( $data ) {
  48          $req = "";
  49          foreach ( $data as $key => $value )
  50                  $req .= $key . '=' . urlencode( stripslashes( $value ) ) . '&';
  51  
  52          // Cut the last '&'
  53          $req = substr( $req, 0, strlen( $req ) -1 );
  54          return $req;
  55  }
  56  
  57  
  58  
  59  /**
  60   * Submits an HTTP POST to a reCAPTCHA server
  61   * @param string $host
  62   * @param string $path
  63   * @param array $data
  64   * @param int port
  65   * @return array response
  66   */
  67  function _recaptcha_http_post( $host, $path, $data, $port = 80 ) {
  68  
  69          $req = _recaptcha_qsencode ( $data );
  70  
  71          $http_request  = "POST $path HTTP/1.0\r\n";
  72          $http_request .= "Host: $host\r\n";
  73          $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
  74          $http_request .= "Content-Length: " . strlen( $req ) . "\r\n";
  75          $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
  76          $http_request .= "\r\n";
  77          $http_request .= $req;
  78  
  79          $response = '';
  80          if ( false == ( $fs = @fsockopen( $host, $port, $errno, $errstr, 10 ) ) ) {
  81                  die ( 'Could not open socket' );
  82          }
  83  
  84          fwrite( $fs, $http_request );
  85  
  86          while ( !feof( $fs ) )
  87                  $response .= fgets( $fs, 1160 ); // One TCP-IP packet
  88          fclose( $fs );
  89          $response = explode( "\r\n\r\n", $response, 2 );
  90  
  91          return $response;
  92  }
  93  
  94  
  95  
  96  /**
  97   * Gets the challenge HTML (javascript and non-javascript version).
  98   * This is called from the browser, and the resulting reCAPTCHA HTML widget
  99   * is embedded within the HTML form it was called from.
 100   * @param string $pubkey A public key for reCAPTCHA
 101   * @param string $error The error given by reCAPTCHA (optional, default is null)
 102   * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)
 103  
 104   * @return string - The HTML to be embedded in the user's form.
 105   */
 106  function recaptcha_get_html ( $pubkey, $error = null, $use_ssl = false )
 107  {
 108      if ( $pubkey == null || $pubkey == '' ) {
 109          die ( "To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>" );
 110      }
 111  
 112      if ( $use_ssl ) {
 113                  $server = RECAPTCHA_API_SECURE_SERVER;
 114          } else {
 115                  $server = RECAPTCHA_API_SERVER;
 116          }
 117  
 118          $errorpart = "";
 119          if ( $error ) {
 120             $errorpart = "&amp;error=" . $error;
 121          }
 122          return '<script type="text/javascript" src="' . $server . '/challenge?k=' . $pubkey . $errorpart . '"></script>
 123  
 124      <noscript>
 125            <iframe src="' . $server . '/noscript?k=' . $pubkey . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
 126            <textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
 127            <input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
 128      </noscript>';
 129  }
 130  
 131  
 132  
 133  
 134  /**
 135   * A ReCaptchaResponse is returned from recaptcha_check_answer()
 136   */
 137  class ReCaptchaResponse {
 138          public $is_valid;
 139          public $error;
 140  }
 141  
 142  
 143  /**
 144    * Calls an HTTP POST function to verify if the user's guess was correct
 145    * @param string $privkey
 146    * @param string $remoteip
 147    * @param string $challenge
 148    * @param string $response
 149    * @param array $extra_params an array of extra variables to post to the server
 150    * @return ReCaptchaResponse
 151    */
 152  function recaptcha_check_answer ( $privkey, $remoteip, $challenge, $response, $extra_params = array() )
 153  {
 154      if ( $privkey == null || $privkey == '' ) {
 155          die ( "To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>" );
 156      }
 157  
 158      if ( $remoteip == null || $remoteip == '' ) {
 159          die ( "For security reasons, you must pass the remote ip to reCAPTCHA" );
 160      }
 161  
 162  
 163  
 164          // discard spam submissions
 165          if ( $challenge == null || strlen( $challenge ) == 0 || $response == null || strlen( $response ) == 0 ) {
 166                  $recaptcha_response = new ReCaptchaResponse();
 167                  $recaptcha_response->is_valid = false;
 168                  $recaptcha_response->error = 'incorrect-captcha-sol';
 169                  return $recaptcha_response;
 170          }
 171  
 172          $response = _recaptcha_http_post ( RECAPTCHA_VERIFY_SERVER, "/recaptcha/api/verify",
 173                                            array (
 174                                                   'privatekey' => $privkey,
 175                                                   'remoteip' => $remoteip,
 176                                                   'challenge' => $challenge,
 177                                                   'response' => $response
 178                                                   ) + $extra_params
 179                                            );
 180  
 181          $answers = explode ( "\n", $response [1] );
 182          $recaptcha_response = new ReCaptchaResponse();
 183  
 184          if ( trim ( $answers [0] ) == 'true' ) {
 185                  $recaptcha_response->is_valid = true;
 186          }
 187          else {
 188                  $recaptcha_response->is_valid = false;
 189                  $recaptcha_response->error = $answers [1];
 190          }
 191          return $recaptcha_response;
 192  
 193  }
 194  
 195  /**
 196   * gets a URL where the user can sign up for reCAPTCHA. If your application
 197   * has a configuration page where you enter a key, you should provide a link
 198   * using this function.
 199   * @param string $domain The domain where the page is hosted
 200   * @param string $appname The name of your application
 201   */
 202  function recaptcha_get_signup_url ( $domain = null, $appname = null ) {
 203      return "https://www.google.com/recaptcha/admin/create?" .  _recaptcha_qsencode ( array ( 'domains' => $domain, 'app' => $appname ) );
 204  }
 205  
 206  function _recaptcha_aes_pad( $val ) {
 207      $block_size = 16;
 208      $numpad = $block_size - ( strlen ( $val ) % $block_size );
 209      return str_pad( $val, strlen ( $val ) + $numpad, chr( $numpad ) );
 210  }
 211  
 212  /* Mailhide related code */
 213  
 214  function _recaptcha_aes_encrypt( $val, $ky ) {
 215      if ( ! function_exists ( "mcrypt_encrypt" ) ) {
 216          die ( "To use reCAPTCHA Mailhide, you need to have the mcrypt php module installed." );
 217      }
 218      $mode = MCRYPT_MODE_CBC;
 219      $enc = MCRYPT_RIJNDAEL_128;
 220      $val = _recaptcha_aes_pad( $val );
 221      return mcrypt_encrypt( $enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" );
 222  }
 223  
 224  
 225  function _recaptcha_mailhide_urlbase64 ( $x ) {
 226      return strtr( base64_encode ( $x ), '+/', '-_' );
 227  }
 228  
 229  /* gets the reCAPTCHA Mailhide url for a given email, public key and private key */
 230  function recaptcha_mailhide_url( $pubkey, $privkey, $email ) {
 231      if ( $pubkey == '' || $pubkey == null || $privkey == "" || $privkey == null ) {
 232          die ( "To use reCAPTCHA Mailhide, you have to sign up for a public and private key, " .
 233               "you can do so at <a href='http://www.google.com/recaptcha/mailhide/apikey'>http://www.google.com/recaptcha/mailhide/apikey</a>" );
 234      }
 235  
 236  
 237      $ky = pack( 'H*', $privkey );
 238      $cryptmail = _recaptcha_aes_encrypt ( $email, $ky );
 239  
 240      return "http://www.google.com/recaptcha/mailhide/d?k=" . $pubkey . "&c=" . _recaptcha_mailhide_urlbase64 ( $cryptmail );
 241  }
 242  
 243  /**
 244   * gets the parts of the email to expose to the user.
 245   * eg, given johndoe@example,com return ["john", "example.com"].
 246   * the email is then displayed as [email protected]
 247   */
 248  function _recaptcha_mailhide_email_parts ( $email ) {
 249      $arr = preg_split( "/@/", $email );
 250  
 251      if ( strlen ( $arr[0] ) <= 4 ) {
 252          $arr[0] = substr ( $arr[0], 0, 1 );
 253      } elseif ( strlen ( $arr[0] ) <= 6 ) {
 254          $arr[0] = substr ( $arr[0], 0, 3 );
 255      } else {
 256          $arr[0] = substr ( $arr[0], 0, 4 );
 257      }
 258      return $arr;
 259  }
 260  
 261  /**
 262   * Gets html to display an email address given a public an private key.
 263   * to get a key, go to:
 264   *
 265   * http://www.google.com/recaptcha/mailhide/apikey
 266   */
 267  function recaptcha_mailhide_html( $pubkey, $privkey, $email ) {
 268      $emailparts = _recaptcha_mailhide_email_parts ( $email );
 269      $url = recaptcha_mailhide_url ( $pubkey, $privkey, $email );
 270  
 271      return htmlentities( $emailparts[0] ) . "<a href='" . htmlentities ( $url ) .
 272          "' onclick=\"window.open('" . htmlentities ( $url ) . "', '', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=500,height=300'); return false;\" title=\"Reveal this e-mail address\">...</a>@" . htmlentities ( $emailparts [1] );
 273  
 274  }