<?php
/*
* OIDplus 2.0
* Copyright 2019 - 2022 Daniel Marschall, ViaThinkSoft
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
namespace ViaThinkSoft\OIDplus;
class OIDplusCaptchaPluginVtsClientChallenge extends OIDplusCaptchaPlugin {
public static function id(): string {
return 'ViaThinkSoft Client Challenge';
}
public function isVisible(): bool {
return false;
}
public function csrfUnlock($actionID) {
if ($actionID == 'get_challenge') {
return true;
}
return false;
}
public function action($actionID, $params) {
if ($actionID == 'get_challenge') {
$server_secret='VtsClientChallenge:'.OIDplus::baseConfig()->getValue('SERVER_SECRET');
$offset = 0; // doesn't matter
$min = $offset;
$max = $offset + OIDplus::baseConfig()->getValue('VTS_CAPTCHA_COMPLEXITY', 50000);
$ip_target = isset($_SERVER['REMOTE_ADDR']) ?
$_SERVER['REMOTE_ADDR'] : 'unknown'; $challenge = sha3_512($starttime.'/'.$ip_target.'/'.$random);
$challenge_integrity = sha3_512_hmac($challenge,$server_secret);
$send_to_client = array($starttime, $ip_target, $challenge, $min, $max, $challenge_integrity);
$open_trans_file = self::getOpenTransFileName($ip_target, $random);
throw new OIDplusException(_L('Cannot write file %1', $open_trans_file));
}
"status" => 0,
"challenge" => $send_to_client,
// Autosolve on=calculate result on page load; off=calculate result on form submit
"autosolve" => OIDplus::baseConfig()->getValue('VTS_CAPTCHA_AUTOSOLVE', true)
);
}
}
private static function getOpenTransFileName($ip_target, $random) {
$dir = OIDplus::localpath().'/userdata/cache';
$server_secret='VtsClientChallenge:'.OIDplus::baseConfig()->getValue('SERVER_SECRET');
// First, delete challenges which were never completed
$files = glob($dir.'/vts_client_challenge_*.tmp'); foreach ($files as $file) {
}
return $dir.'/vts_client_challenge_'.sha3_512_hmac($ip_target.'/'.$random, $server_secret).'.tmp';
}
public function captchaGenerate($header_text=null, $footer_text=null) {
return '<noscript>'.
'<p><font color="red">'._L('You need to enable JavaScript to solve the CAPTCHA.').'</font></p>'.
'</noscript>'.
'<input type="hidden" id="vts_validation_result" name="vts_validation_result" value="">'.
'<script>'.
'OIDplusCaptchaPluginVtsClientChallenge.captchaShow('.js_escape(OIDplus::webpath(null,OIDplus::PATH_RELATIVE)).');'.
'</script>';
}
public function captchaVerify($params, $fieldname=null) {
if (is_null($fieldname)) $fieldname = 'vts_validation_result';
$server_secret='VtsClientChallenge:'.OIDplus::baseConfig()->getValue('SERVER_SECRET');
if (!isset($params[$fieldname])) throw new OIDplusException
(_L
('No challenge response found').' (A)');
$client_response = @json_decode($params[$fieldname], true);
if (!is_array($client_response)) throw new OIDplusException
(_L
('Challenge response is invalid').' (B)'); if (count($client_response) != 5) throw new OIDplusException
(_L
('Challenge response is invalid').' (C)'); list($starttime, $ip_target, $challenge, $answer, $challenge_integrity) = $client_response; if (!is_numeric($starttime)) throw new OIDplusException
(_L
('Challenge response is invalid').' (D)'); if (!is_string($ip_target)) throw new OIDplusException
(_L
('Challenge response is invalid').' (E)'); if (!is_string($challenge)) throw new OIDplusException
(_L
('Challenge response is invalid').' (F)'); if (!is_numeric($answer)) throw new OIDplusException
(_L
('Challenge response is invalid').' (G)'); if (!is_string($challenge_integrity)) throw new OIDplusException
(_L
('Challenge response is invalid').' (H)');
$open_trans_file = self::getOpenTransFileName($ip_target, $answer);
$current_ip = (isset($_SERVER['REMOTE_ADDR']) ?
$_SERVER['REMOTE_ADDR'] : 'unknown'); if ($ip_target != $current_ip) {
throw new OIDplusException(_L('IP address has changed. Please try again. (current IP %1, expected %2)', $current_ip, $ip_target));
} else if (time()-$starttime > OIDplus
::baseConfig()->getValue('VTS_CAPTCHA_MAXTIME', 10*60/*10 minutes*/)) { throw new OIDplusException(_L('Challenge expired. Please try again.'));
} else if ($challenge_integrity != sha3_512_hmac($challenge,$server_secret)) {
throw new OIDplusException(_L('Challenge integrity failed'));
} else if ($challenge !== sha3_512($starttime.'/'.$ip_target.'/'.$answer)) {
throw new OIDplusException(_L('Wrong answer'));
throw new OIDplusException(_L('Challenge submitted twice or transaction missing'));
} else {
}
}
public static function setupHTML(): string {
return '<div id="CAPTCHAPLUGIN_PARAMS_VtsClientChallenge">'.
'<p>'._L('ViaThinkSoft Client Challenge lets the client computer solve a cryptographic problem instead of letting the user solve a CAPTCHA. This slows down brute-force attacks.').'</p>'.
'</div>';
}
}