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| 1 | +<?php |
| 2 | + |
| 3 | +namespace Icinga\Module\Grafana\Helpers; |
| 4 | + |
| 5 | +use OpenSSLAsymmetricKey; |
| 6 | +use InvalidArgumentException; |
| 7 | +use RuntimeException; |
| 8 | + |
| 9 | +class JwtToken |
| 10 | +{ |
| 11 | + const RSA_KEY_BITS = 2048; |
| 12 | + const JWT_PRIVATEKEY_FILE = '/etc/icingaweb2/modules/grafana/jwt.key.priv'; |
| 13 | + const JWT_PUBLICKEY_FILE = '/etc/icingaweb2/modules/grafana/jwt.key.pub'; |
| 14 | + |
| 15 | + /** |
| 16 | + * Create JWT Token |
| 17 | + */ |
| 18 | + public static function create(string $sub, int $exp = 0, string $iss = null, array $claims = null): string |
| 19 | + { |
| 20 | + $privateKeyFile = JwtToken::JWT_PRIVATEKEY_FILE; |
| 21 | + |
| 22 | + $privateKey = openssl_pkey_get_private( |
| 23 | + file_get_contents($privateKeyFile), |
| 24 | + ); |
| 25 | + |
| 26 | + $payload = [ |
| 27 | + 'sub' => $sub, |
| 28 | + 'iat' => time(), |
| 29 | + 'nbf' => time(), |
| 30 | + ]; |
| 31 | + |
| 32 | + if (isset($claims)) { |
| 33 | + $payload = array_merge($payload, $claims); |
| 34 | + } |
| 35 | + |
| 36 | + if (!empty($iss)) { |
| 37 | + $payload['iss'] = $iss; |
| 38 | + } |
| 39 | + |
| 40 | + return JwtToken::encode($payload, $privateKey, 'RS256', $exp); |
| 41 | + } |
| 42 | + |
| 43 | + /** |
| 44 | + * Generate Private and Public RSA Keys |
| 45 | + */ |
| 46 | + public static function generateRsaKeys() |
| 47 | + { |
| 48 | + $ret = file_exists(JwtToken::JWT_PRIVATEKEY_FILE); |
| 49 | + if ($ret) { |
| 50 | + return; |
| 51 | + } |
| 52 | + |
| 53 | + $config = array( |
| 54 | + "private_key_bits" => JwtToken::RSA_KEY_BITS, |
| 55 | + "private_key_type" => OPENSSL_KEYTYPE_RSA, |
| 56 | + ); |
| 57 | + |
| 58 | + $res = openssl_pkey_new($config); |
| 59 | + openssl_pkey_export($res, $privKey); |
| 60 | + $pubKey = openssl_pkey_get_details($res); |
| 61 | + $pubKey = $pubKey["key"]; |
| 62 | + |
| 63 | + file_put_contents(JwtToken::JWT_PRIVATEKEY_FILE, $privKey); |
| 64 | + file_put_contents(JwtToken::JWT_PUBLICKEY_FILE, $pubKey); |
| 65 | + } |
| 66 | + |
| 67 | + private static function encode(array $payload, OpenSSLAsymmetricKey $privateKey, string $algorithm = 'RS256', int $expiration = 3600): string |
| 68 | + { |
| 69 | + // Verify that the algorithm is compatible with asymmetric keys |
| 70 | + if ($algorithm !== 'RS256' && $algorithm !== 'RS512') { |
| 71 | + throw new InvalidArgumentException("Unsupported algorithm for assymmetric keys: $algorithm"); |
| 72 | + } |
| 73 | + |
| 74 | + // Define the JWT header |
| 75 | + $header = json_encode([ |
| 76 | + 'alg' => $algorithm, |
| 77 | + 'typ' => 'JWT' |
| 78 | + ]); |
| 79 | + |
| 80 | + // Add expiration time to the payload |
| 81 | + if ($expiration > 0) { |
| 82 | + $payload['exp'] = time() + $expiration; |
| 83 | + } |
| 84 | + |
| 85 | + // Encode header and payload to base64 URL |
| 86 | + $base64Header = JwtToken::base64UrlEncode($header); |
| 87 | + $base64Payload = JwtToken::base64UrlEncode(json_encode($payload)); |
| 88 | + |
| 89 | + // Create the signature |
| 90 | + $dataToSign = "$base64Header.$base64Payload"; |
| 91 | + $signature = ''; |
| 92 | + $success = openssl_sign($dataToSign, $signature, $privateKey, OPENSSL_ALGO_SHA256); |
| 93 | + if (!$success) { |
| 94 | + throw new RuntimeException("Failed to sign the JWT with the private key."); |
| 95 | + } |
| 96 | + |
| 97 | + // Encode signature to base64 URL |
| 98 | + $base64Signature = JwtToken::base64UrlEncode($signature); |
| 99 | + |
| 100 | + // Return the complete token |
| 101 | + return "$base64Header.$base64Payload.$base64Signature"; |
| 102 | + } |
| 103 | + |
| 104 | + private static function base64UrlEncode(string $data): string |
| 105 | + { |
| 106 | + return rtrim(strtr(base64_encode($data), '+/', '-_'), '='); |
| 107 | + } |
| 108 | +} |
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