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 $use_ssl Should the request be made over ssl? (optional, default is true)
103: 
104:  * @return string - The HTML to be embedded in the user's form.
105:  */
106: function recaptcha_get_html ($pubkey, $error = null, $use_ssl = true)
107: {
108:     if ($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:         var $is_valid;
139:         var $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 john...@example.com
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:     } else if (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: }
275: 
276: 
277: ?>
278: