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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 2 | daniel-mar | 1 | <?php |
| 2 | |||
| 3 | /* |
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| 4 | * php_clientchallenge |
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| 5 | * Copyright 2021 Daniel Marschall, ViaThinkSoft |
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| 6 | * |
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| 7 | * Licensed under the Apache License, Version 2.0 (the "License"); |
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| 8 | * you may not use this file except in compliance with the License. |
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| 9 | * You may obtain a copy of the License at |
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| 10 | * |
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| 11 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 12 | * |
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| 13 | * Unless required by applicable law or agreed to in writing, software |
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| 14 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 15 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 16 | * See the License for the specific language governing permissions and |
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| 17 | * limitations under the License. |
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| 18 | */ |
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| 19 | |||
| 20 | namespace ViaThinkSoft\RateLimitingChallenge; |
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| 21 | |||
| 22 | class ClientChallenge { |
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| 23 | |||
| 24 | private static function sha3_512($password, $raw_output=false) { |
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| 25 | if (version_compare(PHP_VERSION, '7.1.0') >= 0) { |
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| 26 | return hash('sha3-512', $password, $raw_output); |
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| 27 | } else { |
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| 28 | return \bb\Sha3\Sha3::hash($password, 512, $raw_output); |
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| 29 | } |
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| 30 | } |
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| 31 | |||
| 32 | public static function checkValidation($max_time=10) { |
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| 33 | |||
| 34 | if (!isset($_REQUEST['vts_validation_result'])) throw new Exception('No challenge response found'); |
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| 35 | |||
| 36 | list($starttime, $ip_target, $challenge, $answer) = @json_decode($_REQUEST['vts_validation_result'], true); |
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| 37 | |||
| 38 | if ($ip_target != $_SERVER['REMOTE_ADDR']) { |
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| 39 | throw new Exception('Wrong IP'); |
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| 40 | } else if (time()-$starttime > $max_time) { |
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| 41 | throw new Exception('Challenge expired'); |
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| 42 | } else if ($challenge !== self::sha3_512($starttime.'/'.$ip_target.'/'.$answer)) { |
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| 43 | throw new Exception('Wrong answer'); |
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| 44 | } else { |
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| 45 | return true; |
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| 46 | } |
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| 47 | } |
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| 48 | |||
| 49 | // This is only called by ajax_get_challenge.php |
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| 50 | public static function createChallenge($complexity=500000) { |
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| 51 | |||
| 52 | $min = 0; |
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| 53 | $max = $complexity; |
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| 54 | |||
| 55 | $starttime = time(); |
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| 56 | |||
| 57 | $random = rand($min,$max); // TODO: cryptographic rand |
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| 58 | |||
| 59 | $ip_target = $_SERVER['REMOTE_ADDR']; |
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| 60 | |||
| 61 | $challenge = self::sha3_512($starttime.'/'.$ip_target.'/'.$random); |
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| 62 | |||
| 63 | $send_to_client = array($starttime, $ip_target, $challenge, $min, $max); |
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| 64 | |||
| 65 | header('Content-Type:application/json'); |
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| 66 | die(json_encode($send_to_client)); |
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| 67 | |||
| 68 | } |
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| 69 | |||
| 70 | } |