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: 
 39: define('RECAPTCHA_API_SERVER', "http://www.google.com/recaptcha/api");
 40: define('RECAPTCHA_API_SECURE_SERVER', "https://www.google.com/recaptcha/api");
 41: define('RECAPTCHA_VERIFY_SERVER', "www.google.com");
 42: 
 43: /**
 44:  * Encodes the given data into a query string format
 45:  * @param $data - array of string elements to be encoded
 46:  *
 47:  * @return string - encoded request
 48:  */
 49: function _recaptcha_qsencode($data)
 50: {
 51:     $req = "";
 52:     foreach ($data as $key => $value) {
 53:         $req .= $key . '=' . urlencode(stripslashes($value)) . '&';
 54:     }
 55: 
 56:     // Cut the last '&'
 57:     $req = substr($req, 0, strlen($req) - 1);
 58:     return $req;
 59: }
 60: 
 61: 
 62: /**
 63:  * Submits an HTTP POST to a reCAPTCHA server
 64:  * @param string $host
 65:  * @param string $path
 66:  * @param array $data
 67:  * @param int $port
 68:  *
 69:  * @return array|string response
 70:  */
 71: function _recaptcha_http_post($host, $path, $data, $port = 80)
 72: {
 73: 
 74:     $req = _recaptcha_qsencode($data);
 75: 
 76:     $http_request = "POST $path HTTP/1.0\r\n";
 77:     $http_request .= "Host: $host\r\n";
 78:     $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
 79:     $http_request .= "Content-Length: " . strlen($req) . "\r\n";
 80:     $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
 81:     $http_request .= "\r\n";
 82:     $http_request .= $req;
 83: 
 84:     $response = '';
 85:     if (false == ($fs = @fsockopen($host, $port, $errno, $errstr, 10))) {
 86:         die ('Could not open socket');
 87:     }
 88: 
 89:     fwrite($fs, $http_request);
 90: 
 91:     while (!feof($fs)) {
 92:         $response .= fgets($fs, 1160);
 93:     } // One TCP-IP packet
 94:     fclose($fs);
 95:     $response = explode("\r\n\r\n", $response, 2);
 96: 
 97:     return $response;
 98: }
 99: 
100: 
101: /**
102:  * Gets the challenge HTML (javascript and non-javascript version).
103:  * This is called from the browser, and the resulting reCAPTCHA HTML widget
104:  * is embedded within the HTML form it was called from.
105:  * @param string $pubkey A public key for reCAPTCHA
106:  * @param string $error The error given by reCAPTCHA (optional, default is null)
107:  * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)
108: 
109:  * @return string - The HTML to be embedded in the user's form.
110:  */
111: function recaptcha_get_html($pubkey, $error = null, $use_ssl = false)
112: {
113:     if ($pubkey == null || $pubkey == '') {
114:         die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
115:     }
116: 
117:     if ($use_ssl) {
118:         $server = RECAPTCHA_API_SECURE_SERVER;
119:     } else {
120:         $server = RECAPTCHA_API_SERVER;
121:     }
122: 
123:     $errorpart = "";
124:     if ($error) {
125:         $errorpart = "&amp;error=" . $error;
126:     }
127:     return '<script type="text/javascript" src="' . $server . '/challenge?k=' . $pubkey . $errorpart . '"></script>
128: 
129:     <noscript>
130:         <iframe src="' . $server . '/noscript?k=' . $pubkey . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
131:         <textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
132:         <input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
133:     </noscript>';
134: }
135: 
136: 
137: /**
138:  * A ReCaptchaResponse is returned from recaptcha_check_answer()
139:  */
140: class ReCaptchaResponse
141: {
142:     var $is_valid;
143:     var $error;
144: }
145: 
146: /**
147:  * Calls an HTTP POST function to verify if the user's guess was correct
148:  * @param string $privkey
149:  * @param string $remoteip
150:  * @param string $challenge
151:  * @param string $response
152:  * @param array $extra_params an array of extra variables to post to the server
153:  *
154:  * @return ReCaptchaResponse
155:  */
156: function recaptcha_check_answer($privkey, $remoteip, $challenge, $response, $extra_params = array())
157: {
158:     if ($privkey == null || $privkey == '') {
159:         die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
160:     }
161: 
162:     if ($remoteip == null || $remoteip == '') {
163:         die ("For security reasons, you must pass the remote ip to reCAPTCHA");
164:     }
165: 
166:     //discard spam submissions
167:     if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
168:         $recaptcha_response = new ReCaptchaResponse();
169:         $recaptcha_response->is_valid = false;
170:         $recaptcha_response->error = 'incorrect-captcha-sol';
171:         return $recaptcha_response;
172:     }
173: 
174:     $response = _recaptcha_http_post(RECAPTCHA_VERIFY_SERVER,
175:         "/recaptcha/api/verify",
176:         array(
177:                'privatekey' => $privkey,
178:                'remoteip' => $remoteip,
179:                'challenge' => $challenge,
180:                'response' => $response
181:            ) + $extra_params);
182: 
183:     $answers = explode("\n", $response [1]);
184:     $recaptcha_response = new ReCaptchaResponse();
185: 
186:     if (trim($answers [0]) === 'true') {
187:         $recaptcha_response->is_valid = true;
188:     } else {
189:         $recaptcha_response->is_valid = false;
190:         $recaptcha_response->error = $answers [1];
191:     }
192:     return $recaptcha_response;
193: 
194: }
195: 
196: /**
197:  * gets a URL where the user can sign up for reCAPTCHA. If your application
198:  * has a configuration page where you enter a key, you should provide a link
199:  * using this function.
200:  * @param string $domain The domain where the page is hosted
201:  * @param string $appname The name of your application
202:  * @return string
203:  */
204: function recaptcha_get_signup_url($domain = null, $appname = null)
205: {
206:     return "https://www.google.com/recaptcha/admin/create?" . _recaptcha_qsencode(
207:         array('domains' => $domain, 'app' => $appname));
208: }
209: 
210: /**
211:  * @param $val
212:  * @return string
213:  */
214: function _recaptcha_aes_pad($val)
215: {
216:     $block_size = 16;
217:     $numpad = $block_size - (strlen($val) % $block_size);
218:     return str_pad($val, strlen($val) + $numpad, chr($numpad));
219: }
220: 
221: /**
222:  * Mailhide related code
223:  *
224:  * @param $val
225:  * @param $ky
226:  * @return string
227:  */
228: function _recaptcha_aes_encrypt($val, $ky)
229: {
230:     if (!function_exists("mcrypt_encrypt")) {
231:         die ("To use reCAPTCHA Mailhide, you need to have the mcrypt php module installed.");
232:     }
233:     $mode = MCRYPT_MODE_CBC;
234:     $enc = MCRYPT_RIJNDAEL_128;
235:     $val = _recaptcha_aes_pad($val);
236:     return mcrypt_encrypt($enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
237: }
238: 
239: /**
240:  * @param $x
241:  * @return string
242:  */
243: function _recaptcha_mailhide_urlbase64($x)
244: {
245:     return strtr(base64_encode($x), '+/', '-_');
246: }
247: 
248: /**
249:  * gets the reCAPTCHA Mailhide url for a given email, public key and private key
250:  *
251:  * @param $pubkey
252:  * @param $privkey
253:  * @param $email
254:  * @return string
255:  */
256: function recaptcha_mailhide_url($pubkey, $privkey, $email)
257: {
258:     if ($pubkey == '' || $pubkey == null || $privkey == "" || $privkey == null) {
259:         die ("To use reCAPTCHA Mailhide, you have to sign up for a public and private key, " . "you can do so at <a href='http://www.google.com/recaptcha/mailhide/apikey'>http://www.google.com/recaptcha/mailhide/apikey</a>");
260:     }
261: 
262:     $ky = pack('H*', $privkey);
263:     $cryptmail = _recaptcha_aes_encrypt($email, $ky);
264: 
265:     return "http://www.google.com/recaptcha/mailhide/d?k=" . $pubkey . "&c=" . _recaptcha_mailhide_urlbase64($cryptmail);
266: }
267: 
268: /**
269:  * gets the parts of the email to expose to the user.
270:  * eg, given johndoe@example,com return ["john", "example.com"].
271:  * the email is then displayed as john...@example.com
272:  *
273:  * @param $email
274:  * @return array
275:  */
276: function _recaptcha_mailhide_email_parts($email)
277: {
278:     $arr = preg_split("/@/", $email);
279: 
280:     if (strlen($arr[0]) <= 4) {
281:         $arr[0] = substr($arr[0], 0, 1);
282:     } else {
283:         if (strlen($arr[0]) <= 6) {
284:             $arr[0] = substr($arr[0], 0, 3);
285:         } else {
286:             $arr[0] = substr($arr[0], 0, 4);
287:         }
288:     }
289:     return $arr;
290: }
291: 
292: /**
293:  * Gets html to display an email address given a public an private key.
294:  * to get a key, go to:
295:  *
296:  * http://www.google.com/recaptcha/mailhide/apikey
297:  *
298:  * @param $pubkey
299:  * @param $privkey
300:  * @param $email
301:  * @return string
302:  */
303: function recaptcha_mailhide_html($pubkey, $privkey, $email)
304: {
305:     $emailparts = _recaptcha_mailhide_email_parts($email);
306:     $url = recaptcha_mailhide_url($pubkey, $privkey, $email);
307: 
308:     return htmlentities($emailparts[0]) . "<a href='" . htmlentities($url) . "' onclick=\"window.open('" . htmlentities($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]);
309: }
310: