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2 | daniel-mar | 1 | <?php |
2 | |||
3 | /* |
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4 | * OIDplus 2.0 |
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5 | * Copyright 2019 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 | class OIDplusSessionHandler { |
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21 | |||
263 | daniel-mar | 22 | private $secret = ''; |
23 | protected $sessionLifetime = ''; |
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2 | daniel-mar | 24 | |
263 | daniel-mar | 25 | public function __construct() { |
261 | daniel-mar | 26 | $this->sessionLifetime = OIDplus::baseConfig()->getValue('SESSION_LIFETIME', 30*60); |
27 | $this->secret = OIDplus::baseConfig()->getValue('SERVER_SECRET'); |
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28 | |||
2 | daniel-mar | 29 | // **PREVENTING SESSION HIJACKING** |
30 | // Prevents javascript XSS attacks aimed to steal the session ID |
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87 | daniel-mar | 31 | @ini_set('session.cookie_httponly', 1); |
2 | daniel-mar | 32 | |
33 | // **PREVENTING SESSION FIXATION** |
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34 | // Session ID cannot be passed through URLs |
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87 | daniel-mar | 35 | @ini_set('session.use_only_cookies', 1); |
2 | daniel-mar | 36 | |
87 | daniel-mar | 37 | @ini_set('session.use_trans_sid', 0); |
85 | daniel-mar | 38 | |
2 | daniel-mar | 39 | // Uses a secure connection (HTTPS) if possible |
230 | daniel-mar | 40 | @ini_set('session.cookie_secure', OIDplus::isSslAvailable()); |
2 | daniel-mar | 41 | |
227 | daniel-mar | 42 | $path = OIDplus::getSystemUrl(true); |
83 | daniel-mar | 43 | if (!empty($path)) { |
87 | daniel-mar | 44 | @ini_set('session.cookie_path', $path); |
2 | daniel-mar | 45 | } |
46 | |||
87 | daniel-mar | 47 | @ini_set('session.cookie_samesite', 'Lax'); |
2 | daniel-mar | 48 | |
87 | daniel-mar | 49 | @ini_set('session.use_strict_mode', 1); |
2 | daniel-mar | 50 | |
261 | daniel-mar | 51 | @ini_set('session.gc_maxlifetime', $this->sessionLifetime); |
2 | daniel-mar | 52 | } |
53 | |||
86 | daniel-mar | 54 | protected function sessionSafeStart() { |
179 | daniel-mar | 55 | if (!isset($_SESSION)) { |
56 | // TODO: session_name() makes some problems. Leave it away for now. |
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261 | daniel-mar | 57 | //session_name('OIDplus_SESHDLR'); |
179 | daniel-mar | 58 | if (!session_start()) { |
360 | daniel-mar | 59 | throw new OIDplusException(_L('Session could not be started')); |
179 | daniel-mar | 60 | } |
61 | } |
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86 | daniel-mar | 62 | |
87 | daniel-mar | 63 | if (!isset($_SESSION['ip'])) { |
64 | if (!isset($_SERVER['REMOTE_ADDR'])) return; |
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86 | daniel-mar | 65 | |
87 | daniel-mar | 66 | // Remember the IP address of the user |
67 | $_SESSION['ip'] = $_SERVER['REMOTE_ADDR']; |
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68 | } else { |
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69 | if ($_SERVER['REMOTE_ADDR'] != $_SESSION['ip']) { |
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70 | // Was the session hijacked?! Get out of here! |
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71 | $this->destroySession(); |
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72 | } |
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86 | daniel-mar | 73 | } |
74 | } |
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75 | |||
2 | daniel-mar | 76 | function __destruct() { |
77 | session_write_close(); |
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78 | } |
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79 | |||
80 | public function setValue($name, $value) { |
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86 | daniel-mar | 81 | $this->sessionSafeStart(); |
261 | daniel-mar | 82 | setcookie(session_name(),session_id(),time()+$this->sessionLifetime, ini_get('session.cookie_path')); |
85 | daniel-mar | 83 | |
2 | daniel-mar | 84 | $_SESSION[$name] = self::encrypt($value, $this->secret); |
85 | } |
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86 | |||
87 | public function getValue($name) { |
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85 | daniel-mar | 88 | if (!isset($_COOKIE[session_name()])) return null; // GDPR: Only start a session when we really need one |
89 | |||
86 | daniel-mar | 90 | $this->sessionSafeStart(); |
261 | daniel-mar | 91 | setcookie(session_name(),session_id(),time()+$this->sessionLifetime, ini_get('session.cookie_path')); |
85 | daniel-mar | 92 | |
2 | daniel-mar | 93 | if (!isset($_SESSION[$name])) return null; |
94 | return self::decrypt($_SESSION[$name], $this->secret); |
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95 | } |
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96 | |||
85 | daniel-mar | 97 | public function destroySession() { |
98 | if (!isset($_COOKIE[session_name()])) return; |
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99 | |||
86 | daniel-mar | 100 | $this->sessionSafeStart(); |
261 | daniel-mar | 101 | setcookie(session_name(),session_id(),time()+$this->sessionLifetime, ini_get('session.cookie_path')); |
85 | daniel-mar | 102 | |
103 | $_SESSION = array(); |
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104 | session_destroy(); |
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105 | session_write_close(); |
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106 | setcookie(session_name(), "", time()-3600, ini_get('session.cookie_path')); // remove cookie, so GDPR people are happy |
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107 | } |
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108 | |||
83 | daniel-mar | 109 | public function exists($name) { |
110 | return isset($_SESSION[$name]); |
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111 | } |
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112 | |||
2 | daniel-mar | 113 | protected static function encrypt($data, $key) { |
6 | daniel-mar | 114 | $iv = random_bytes(16); // AES block size in CBC mode |
115 | // Encryption |
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116 | $ciphertext = openssl_encrypt( |
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117 | $data, |
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118 | 'AES-256-CBC', |
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119 | mb_substr($key, 0, 32, '8bit'), |
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120 | OPENSSL_RAW_DATA, |
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121 | $iv |
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122 | ); |
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123 | // Authentication |
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124 | $hmac = hash_hmac( |
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125 | 'SHA256', |
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126 | $iv . $ciphertext, |
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127 | mb_substr($key, 32, null, '8bit'), |
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128 | true |
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129 | ); |
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130 | return $hmac . $iv . $ciphertext; |
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131 | } |
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2 | daniel-mar | 132 | |
6 | daniel-mar | 133 | protected static function decrypt($data, $key) { |
134 | $hmac = mb_substr($data, 0, 32, '8bit'); |
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135 | $iv = mb_substr($data, 32, 16, '8bit'); |
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136 | $ciphertext = mb_substr($data, 48, null, '8bit'); |
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137 | // Authentication |
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138 | $hmacNew = hash_hmac( |
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139 | 'SHA256', |
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140 | $iv . $ciphertext, |
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141 | mb_substr($key, 32, null, '8bit'), |
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142 | true |
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143 | ); |
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144 | if (!hash_equals($hmac, $hmacNew)) { |
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360 | daniel-mar | 145 | throw new OIDplusException(_L('Authentication failed')); |
6 | daniel-mar | 146 | } |
147 | // Decryption |
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148 | return openssl_decrypt( |
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149 | $ciphertext, |
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150 | 'AES-256-CBC', |
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151 | mb_substr($key, 0, 32, '8bit'), |
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152 | OPENSSL_RAW_DATA, |
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153 | $iv |
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154 | ); |
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155 | } |
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360 | daniel-mar | 156 | } |