Implement new reCAPTCHA interface

Summary:
Fixes T12195. For the past few years, Recaptcha (now part of Google) has supported
a new, "no captcha" one-click user interface. This new UI is stable, doesn't
require any typing or reading words, and can even work without JavaScript (if
the administrator enables it on the Recaptcha side).

Furthermore, the new Recaptcha has a completely trivial API that can be dealt
with in a few lines of code. Thus, the external `recaptcha` php library is now
gone.

This API is a complete replacement for the old one, and does not require any
upgrade path for users or Phabricator administrators - public and secret keys
for the "new" Recaptcha UI are the exact same as the "classic" Recaptcha. Any
old Recaptcha keys for a domain will continue to work.

Note that Google is currently testing Yet Another new Captcha API, called
"Invisible reCAPTCHA", that will not require user interaction at all. In fact,
the user will not even be aware there //is even a captcha form//, as far as I
understand. However, this new API is 1) in beta, 2) requires new Recaptcha keys
(so it cannot be a drop-in replacement), and 3) requires more drastic API
changes, as form submission buttons must instead invoke JavaScript code, rather
than a token being passed along with the form submission. This would require far
more extensive changes to the controllers. Maybe when it's several years old, it
can be considered.

Signed-off-by: Austin Seipp <aseipp@pobox.com>

Test Plan:
Created a brand-new Phabricator installation, saw the new Captcha UI
on administrator sign up. Logged out, made 5 invalid login attempts, and saw the
new Captcha UI. Reworked the conditional to invert the condition, etc to test
and make sure the API responded properly.

Reviewers: epriestley, #blessed_reviewers, chad

Reviewed By: epriestley, #blessed_reviewers

Subscribers: avivey, Korvin

Maniphest Tasks: T12195

Differential Revision: https://secure.phabricator.com/D17304

externals/recaptcha/LICENSE

@@ -1,22 +0,0 @@
-Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
-AUTHORS:
-  Mike Crawford
-  Ben Maurer
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.

externals/recaptcha/recaptchalib.php

@@ -1,277 +0,0 @@
-<?php
-/*
- * This is a PHP library that handles calling reCAPTCHA.
- *    - Documentation and latest version
- *          http://recaptcha.net/plugins/php/
- *    - Get a reCAPTCHA API Key
- *          https://www.google.com/recaptcha/admin/create
- *    - Discussion group
- *          http://groups.google.com/group/recaptcha
- *
- * Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
- * AUTHORS:
- *   Mike Crawford
- *   Ben Maurer
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-/**
- * The reCAPTCHA server URL's
- */
-define("RECAPTCHA_API_SERVER", "http://www.google.com/recaptcha/api");
-define("RECAPTCHA_API_SECURE_SERVER", "https://www.google.com/recaptcha/api");
-define("RECAPTCHA_VERIFY_SERVER", "www.google.com");
-
-/**
- * Encodes the given data into a query string format
- * @param $data - array of string elements to be encoded
- * @return string - encoded request
- */
-function _recaptcha_qsencode ($data) {
-        $req = "";
-        foreach ( $data as $key => $value )
-                $req .= $key . '=' . urlencode( stripslashes($value) ) . '&';
-
-        // Cut the last '&'
-        $req=substr($req,0,strlen($req)-1);
-        return $req;
-}
-
-
-
-/**
- * Submits an HTTP POST to a reCAPTCHA server
- * @param string $host
- * @param string $path
- * @param array $data
- * @param int port
- * @return array response
- */
-function _recaptcha_http_post($host, $path, $data, $port = 80) {
-
-        $req = _recaptcha_qsencode ($data);
-
-        $http_request  = "POST $path HTTP/1.0\r\n";
-        $http_request .= "Host: $host\r\n";
-        $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
-        $http_request .= "Content-Length: " . strlen($req) . "\r\n";
-        $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
-        $http_request .= "\r\n";
-        $http_request .= $req;
-
-        $response = '';
-        if( false == ( $fs = @fsockopen($host, $port, $errno, $errstr, 10) ) ) {
-                die ('Could not open socket');
-        }
-
-        fwrite($fs, $http_request);
-
-        while ( !feof($fs) )
-                $response .= fgets($fs, 1160); // One TCP-IP packet
-        fclose($fs);
-        $response = explode("\r\n\r\n", $response, 2);
-
-        return $response;
-}
-
-
-
-/**
- * Gets the challenge HTML (javascript and non-javascript version).
- * This is called from the browser, and the resulting reCAPTCHA HTML widget
- * is embedded within the HTML form it was called from.
- * @param string $pubkey A public key for reCAPTCHA
- * @param string $error The error given by reCAPTCHA (optional, default is null)
- * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)
-
- * @return string - The HTML to be embedded in the user's form.
- */
-function recaptcha_get_html ($pubkey, $error = null, $use_ssl = false)
-{
-	if ($pubkey == null || $pubkey == '') {
-		die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
-	}
-	
-	if ($use_ssl) {
-                $server = RECAPTCHA_API_SECURE_SERVER;
-        } else {
-                $server = RECAPTCHA_API_SERVER;
-        }
-
-        $errorpart = "";
-        if ($error) {
-           $errorpart = "&amp;error=" . $error;
-        }
-        return '<script type="text/javascript" src="'. $server . '/challenge?k=' . $pubkey . $errorpart . '"></script>
-
-	<noscript>
-  		<iframe src="'. $server . '/noscript?k=' . $pubkey . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
-  		<textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
-  		<input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
-	</noscript>';
-}
-
-
-
-
-/**
- * A ReCaptchaResponse is returned from recaptcha_check_answer()
- */
-class ReCaptchaResponse {
-        var $is_valid;
-        var $error;
-}
-
-
-/**
-  * Calls an HTTP POST function to verify if the user's guess was correct
-  * @param string $privkey
-  * @param string $remoteip
-  * @param string $challenge
-  * @param string $response
-  * @param array $extra_params an array of extra variables to post to the server
-  * @return ReCaptchaResponse
-  */
-function recaptcha_check_answer ($privkey, $remoteip, $challenge, $response, $extra_params = array())
-{
-	if ($privkey == null || $privkey == '') {
-		die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
-	}
-
-	if ($remoteip == null || $remoteip == '') {
-		die ("For security reasons, you must pass the remote ip to reCAPTCHA");
-	}
-
-	
-	
-        //discard spam submissions
-        if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
-                $recaptcha_response = new ReCaptchaResponse();
-                $recaptcha_response->is_valid = false;
-                $recaptcha_response->error = 'incorrect-captcha-sol';
-                return $recaptcha_response;
-        }
-
-        $response = _recaptcha_http_post (RECAPTCHA_VERIFY_SERVER, "/recaptcha/api/verify",
-                                          array (
-                                                 'privatekey' => $privkey,
-                                                 'remoteip' => $remoteip,
-                                                 'challenge' => $challenge,
-                                                 'response' => $response
-                                                 ) + $extra_params
-                                          );
-
-        $answers = explode ("\n", $response [1]);
-        $recaptcha_response = new ReCaptchaResponse();
-
-        if (trim ($answers [0]) == 'true') {
-                $recaptcha_response->is_valid = true;
-        }
-        else {
-                $recaptcha_response->is_valid = false;
-                $recaptcha_response->error = $answers [1];
-        }
-        return $recaptcha_response;
-
-}
-
-/**
- * gets a URL where the user can sign up for reCAPTCHA. If your application
- * has a configuration page where you enter a key, you should provide a link
- * using this function.
- * @param string $domain The domain where the page is hosted
- * @param string $appname The name of your application
- */
-function recaptcha_get_signup_url ($domain = null, $appname = null) {
-	return "https://www.google.com/recaptcha/admin/create?" .  _recaptcha_qsencode (array ('domains' => $domain, 'app' => $appname));
-}
-
-function _recaptcha_aes_pad($val) {
-	$block_size = 16;
-	$numpad = $block_size - (strlen ($val) % $block_size);
-	return str_pad($val, strlen ($val) + $numpad, chr($numpad));
-}
-
-/* Mailhide related code */
-
-function _recaptcha_aes_encrypt($val,$ky) {
-	if (! function_exists ("mcrypt_encrypt")) {
-		die ("To use reCAPTCHA Mailhide, you need to have the mcrypt php module installed.");
-	}
-	$mode=MCRYPT_MODE_CBC;   
-	$enc=MCRYPT_RIJNDAEL_128;
-	$val=_recaptcha_aes_pad($val);
-	return mcrypt_encrypt($enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
-}
-
-
-function _recaptcha_mailhide_urlbase64 ($x) {
-	return strtr(base64_encode ($x), '+/', '-_');
-}
-
-/* gets the reCAPTCHA Mailhide url for a given email, public key and private key */
-function recaptcha_mailhide_url($pubkey, $privkey, $email) {
-	if ($pubkey == '' || $pubkey == null || $privkey == "" || $privkey == null) {
-		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>");
-	}
-	
-
-	$ky = pack('H*', $privkey);
-	$cryptmail = _recaptcha_aes_encrypt ($email, $ky);
-	
-	return "http://www.google.com/recaptcha/mailhide/d?k=" . $pubkey . "&c=" . _recaptcha_mailhide_urlbase64 ($cryptmail);
-}
-
-/**
- * gets the parts of the email to expose to the user.
- * eg, given johndoe@example,com return ["john", "example.com"].
- * the email is then displayed as john...@example.com
- */
-function _recaptcha_mailhide_email_parts ($email) {
-	$arr = preg_split("/@/", $email );
-
-	if (strlen ($arr[0]) <= 4) {
-		$arr[0] = substr ($arr[0], 0, 1);
-	} else if (strlen ($arr[0]) <= 6) {
-		$arr[0] = substr ($arr[0], 0, 3);
-	} else {
-		$arr[0] = substr ($arr[0], 0, 4);
-	}
-	return $arr;
-}
-
-/**
- * Gets html to display an email address given a public an private key.
- * to get a key, go to:
- *
- * http://www.google.com/recaptcha/mailhide/apikey
- */
-function recaptcha_mailhide_html($pubkey, $privkey, $email) {
-	$emailparts = _recaptcha_mailhide_email_parts ($email);
-	$url = recaptcha_mailhide_url ($pubkey, $privkey, $email);
-	
-	return htmlentities($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]);
-
-}
-
-
-?>

src/applications/config/option/PhabricatorRecaptchaConfigOptions.php

@@ -23,6 +23,7 @@ final class PhabricatorRecaptchaConfigOptions
 
     return array(
       $this->newOption('recaptcha.enabled', 'bool', false)
+        ->setLocked(true)
         ->setBoolOptions(
           array(
             pht('Enable Recaptcha'),
@@ -35,6 +36,7 @@ final class PhabricatorRecaptchaConfigOptions
             'failed login attempts. This hinders brute-force attacks against '.
             'user passwords. For more information, see http://recaptcha.net/')),
       $this->newOption('recaptcha.public-key', 'string', null)
+        ->setLocked(true)
         ->setDescription(
           pht('Recaptcha public key, obtained by signing up for Recaptcha.')),
       $this->newOption('recaptcha.private-key', 'string', null)

src/view/form/control/AphrontFormRecaptchaControl.php

@@ -1,10 +1,5 @@
 <?php
 
-/**
- *
- * @phutil-external-symbol function recaptcha_get_html
- * @phutil-external-symbol function recaptcha_check_answer
- */
 final class AphrontFormRecaptchaControl extends AphrontFormControl {
 
   protected function getCustomControlClass() {
@@ -19,13 +14,8 @@ final class AphrontFormRecaptchaControl extends AphrontFormControl {
     return PhabricatorEnv::getEnvConfig('recaptcha.enabled');
   }
 
-  private static function requireLib() {
-    $root = phutil_get_library_root('phabricator');
-    require_once dirname($root).'/externals/recaptcha/recaptchalib.php';
-  }
-
   public static function hasCaptchaResponse(AphrontRequest $request) {
-    return $request->getBool('recaptcha_response_field');
+    return $request->getBool('g-recaptcha-response');
   }
 
   public static function processCaptcha(AphrontRequest $request) {
@@ -33,30 +23,35 @@ final class AphrontFormRecaptchaControl extends AphrontFormControl {
       return true;
     }
 
-    self::requireLib();
+    $uri = 'https://www.google.com/recaptcha/api/siteverify';
+    $params = array(
+      'secret'   => PhabricatorEnv::getEnvConfig('recaptcha.private-key'),
+      'response' => $request->getStr('g-recaptcha-response'),
+      'remoteip' => $request->getRemoteAddress(),
+    );
 
-    $challenge = $request->getStr('recaptcha_challenge_field');
-    $response = $request->getStr('recaptcha_response_field');
-    $resp = recaptcha_check_answer(
-      PhabricatorEnv::getEnvConfig('recaptcha.private-key'),
-      $_SERVER['REMOTE_ADDR'],
-      $challenge,
-      $response);
+    list($body) = id(new HTTPSFuture($uri, $params))
+      ->setMethod('POST')
+      ->resolvex();
 
-    return (bool)@$resp->is_valid;
+    $json = phutil_json_decode($body);
+    return (bool)idx($json, 'success');
   }
 
   protected function renderInput() {
-    self::requireLib();
+    $js = 'https://www.google.com/recaptcha/api.js';
+    $pubkey = PhabricatorEnv::getEnvConfig('recaptcha.public-key');
 
-    $uri = new PhutilURI(PhabricatorEnv::getEnvConfig('phabricator.base-uri'));
-    $protocol = $uri->getProtocol();
-    $use_ssl = ($protocol == 'https');
+    return array(
+      phutil_tag('div', array(
+        'class'        => 'g-recaptcha',
+        'data-sitekey' => $pubkey,
+      )),
 
-    return phutil_safe_html(recaptcha_get_html(
-      PhabricatorEnv::getEnvConfig('recaptcha.public-key'),
-      $error = null,
-      $use_ssl));
+      phutil_tag('script', array(
+        'type' => 'text/javascript',
+        'src'  => $js,
+      )),
+    );
   }
-
 }