yiisoft /
yii2
Complex classes like Security often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Security, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 31 | class Security extends Component |
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| 32 | { |
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| 33 | /** |
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| 34 | * @var string The cipher to use for encryption and decryption. |
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| 35 | */ |
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| 36 | public $cipher = 'AES-128-CBC'; |
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| 37 | /** |
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| 38 | * @var array[] Look-up table of block sizes and key sizes for each supported OpenSSL cipher. |
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| 39 | * |
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| 40 | * In each element, the key is one of the ciphers supported by OpenSSL (@see openssl_get_cipher_methods()). |
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| 41 | * The value is an array of two integers, the first is the cipher's block size in bytes and the second is |
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| 42 | * the key size in bytes. |
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| 43 | * |
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| 44 | * > Warning: All OpenSSL ciphers that we recommend are in the default value, i.e. AES in CBC mode. |
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| 45 | * |
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| 46 | * > Note: Yii's encryption protocol uses the same size for cipher key, HMAC signature key and key |
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| 47 | * derivation salt. |
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| 48 | */ |
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| 49 | public $allowedCiphers = [ |
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| 50 | 'AES-128-CBC' => [16, 16], |
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| 51 | 'AES-192-CBC' => [16, 24], |
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| 52 | 'AES-256-CBC' => [16, 32], |
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| 53 | ]; |
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| 54 | /** |
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| 55 | * @var string Hash algorithm for key derivation. Recommend sha256, sha384 or sha512. |
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| 56 | * @see hash_algos() |
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| 57 | */ |
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| 58 | public $kdfHash = 'sha256'; |
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| 59 | /** |
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| 60 | * @var string Hash algorithm for message authentication. Recommend sha256, sha384 or sha512. |
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| 61 | * @see hash_algos() |
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| 62 | */ |
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| 63 | public $macHash = 'sha256'; |
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| 64 | /** |
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| 65 | * @var string HKDF info value for derivation of message authentication key. |
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| 66 | * @see hkdf() |
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| 67 | */ |
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| 68 | public $authKeyInfo = 'AuthorizationKey'; |
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| 69 | /** |
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| 70 | * @var integer derivation iterations count. |
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| 71 | * Set as high as possible to hinder dictionary password attacks. |
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| 72 | */ |
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| 73 | public $derivationIterations = 100000; |
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| 74 | /** |
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| 75 | * @var string strategy, which should be used to generate password hash. |
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| 76 | * Available strategies: |
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| 77 | * - 'password_hash' - use of PHP `password_hash()` function with PASSWORD_DEFAULT algorithm. |
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| 78 | * This option is recommended, but it requires PHP version >= 5.5.0 |
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| 79 | * - 'crypt' - use PHP `crypt()` function. |
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| 80 | * @deprecated Since version 2.0.7, [[generatePasswordHash()]] ignores [[passwordHashStrategy]] and |
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| 81 | * uses `password_hash()` when available or `crypt()` when not. |
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| 82 | */ |
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| 83 | public $passwordHashStrategy; |
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| 84 | /** |
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| 85 | * @var integer Default cost used for password hashing. |
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| 86 | * Allowed value is between 4 and 31. |
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| 87 | * @see generatePasswordHash() |
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| 88 | * @since 2.0.6 |
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| 89 | */ |
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| 90 | public $passwordHashCost = 13; |
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| 91 | |||
| 92 | /** |
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| 93 | * @var resource|string|null Identifies the random source of the last successful call of [[generateRandomKey]]. |
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| 94 | * Caches the file pointer to /dev/urandom if it was fopened. |
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| 95 | */ |
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| 96 | private $_randomSource; |
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| 97 | |||
| 98 | /** |
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| 99 | * Encrypts data using a password. |
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| 100 | * Derives keys for encryption and authentication from the password using PBKDF2 and a random salt, |
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| 101 | * which is deliberately slow to protect against dictionary attacks. Use [[encryptByKey()]] to |
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| 102 | * encrypt fast using a cryptographic key rather than a password. Key derivation time is |
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| 103 | * determined by [[$derivationIterations]], which should be set as high as possible. |
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| 104 | * The encrypted data includes a keyed message authentication code (MAC) so there is no need |
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| 105 | * to hash input or output data. |
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| 106 | * > Note: Avoid encrypting with passwords wherever possible. Nothing can protect against |
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| 107 | * poor-quality or compromised passwords. |
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| 108 | * @param string $data the data to encrypt |
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| 109 | * @param string $password the password to use for encryption |
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| 110 | * @return string the encrypted data |
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| 111 | * @see decryptByPassword() |
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| 112 | * @see encryptByKey() |
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| 113 | */ |
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| 114 | 1 | public function encryptByPassword($data, $password) |
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| 118 | |||
| 119 | /** |
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| 120 | * Encrypts data using a cryptographic key. |
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| 121 | * Derives keys for encryption and authentication from the input key using HKDF and a random salt, |
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| 122 | * which is very fast relative to [[encryptByPassword()]]. The input key must be properly |
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| 123 | * random -- use [[generateRandomKey()]] to generate keys. |
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| 124 | * The encrypted data includes a keyed message authentication code (MAC) so there is no need |
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| 125 | * to hash input or output data. |
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| 126 | * @param string $data the data to encrypt |
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| 127 | * @param string $inputKey the input to use for encryption and authentication |
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| 128 | * @param string $info optional context and application specific information, see [[hkdf()]] |
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| 129 | * @return string the encrypted data |
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| 130 | * @see decryptByKey() |
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| 131 | * @see encryptByPassword() |
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| 132 | */ |
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| 133 | 1 | public function encryptByKey($data, $inputKey, $info = null) |
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| 137 | |||
| 138 | /** |
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| 139 | * Verifies and decrypts data encrypted with [[encryptByPassword()]]. |
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| 140 | * @param string $data the encrypted data to decrypt |
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| 141 | * @param string $password the password to use for decryption |
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| 142 | * @return bool|string the decrypted data or false on authentication failure |
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| 143 | * @see encryptByPassword() |
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| 144 | */ |
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| 145 | 10 | public function decryptByPassword($data, $password) |
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| 146 | { |
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| 147 | 10 | return $this->decrypt($data, true, $password, null); |
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| 148 | } |
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| 149 | |||
| 150 | /** |
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| 151 | * Verifies and decrypts data encrypted with [[encryptByPassword()]]. |
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| 152 | * @param string $data the encrypted data to decrypt |
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| 153 | * @param string $inputKey the input to use for encryption and authentication |
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| 154 | * @param string $info optional context and application specific information, see [[hkdf()]] |
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| 155 | * @return bool|string the decrypted data or false on authentication failure |
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| 156 | * @see encryptByKey() |
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| 157 | */ |
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| 158 | 10 | public function decryptByKey($data, $inputKey, $info = null) |
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| 159 | { |
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| 160 | 10 | return $this->decrypt($data, false, $inputKey, $info); |
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| 161 | } |
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| 162 | |||
| 163 | /** |
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| 164 | * Encrypts data. |
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| 165 | * |
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| 166 | * @param string $data data to be encrypted |
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| 167 | * @param boolean $passwordBased set true to use password-based key derivation |
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| 168 | * @param string $secret the encryption password or key |
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| 169 | * @param string $info context/application specific information, e.g. a user ID |
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| 170 | * See [RFC 5869 Section 3.2](https://tools.ietf.org/html/rfc5869#section-3.2) for more details. |
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| 171 | * |
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| 172 | * @return string the encrypted data |
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| 173 | * @throws InvalidConfigException on OpenSSL not loaded |
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| 174 | * @throws Exception on OpenSSL error |
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| 175 | * @see decrypt() |
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| 176 | */ |
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| 177 | 2 | protected function encrypt($data, $passwordBased, $secret, $info) |
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| 178 | { |
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| 179 | 2 | if (!extension_loaded('openssl')) { |
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| 180 | throw new InvalidConfigException('Encryption requires the OpenSSL PHP extension'); |
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| 181 | } |
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| 182 | 2 | if (!isset($this->allowedCiphers[$this->cipher][0], $this->allowedCiphers[$this->cipher][1])) { |
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| 183 | throw new InvalidConfigException($this->cipher . ' is not an allowed cipher'); |
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| 184 | } |
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| 185 | |||
| 186 | 2 | list($blockSize, $keySize) = $this->allowedCiphers[$this->cipher]; |
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| 187 | |||
| 188 | 2 | $keySalt = $this->generateRandomKey($keySize); |
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| 189 | 2 | if ($passwordBased) { |
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| 190 | 1 | $key = $this->pbkdf2($this->kdfHash, $secret, $keySalt, $this->derivationIterations, $keySize); |
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| 191 | 1 | } else { |
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| 192 | 1 | $key = $this->hkdf($this->kdfHash, $secret, $keySalt, $info, $keySize); |
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| 193 | } |
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| 194 | |||
| 195 | 2 | $iv = $this->generateRandomKey($blockSize); |
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| 196 | |||
| 197 | 2 | $encrypted = openssl_encrypt($data, $this->cipher, $key, OPENSSL_RAW_DATA, $iv); |
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| 198 | 2 | if ($encrypted === false) { |
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| 199 | throw new \yii\base\Exception('OpenSSL failure on encryption: ' . openssl_error_string()); |
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| 200 | } |
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| 201 | |||
| 202 | 2 | $authKey = $this->hkdf($this->kdfHash, $key, null, $this->authKeyInfo, $keySize); |
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| 203 | 2 | $hashed = $this->hashData($iv . $encrypted, $authKey); |
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| 204 | |||
| 205 | /* |
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| 206 | * Output: [keySalt][MAC][IV][ciphertext] |
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| 207 | * - keySalt is KEY_SIZE bytes long |
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| 208 | * - MAC: message authentication code, length same as the output of MAC_HASH |
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| 209 | * - IV: initialization vector, length $blockSize |
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| 210 | */ |
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| 211 | 2 | return $keySalt . $hashed; |
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| 212 | } |
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| 213 | |||
| 214 | /** |
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| 215 | * Decrypts data. |
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| 216 | * |
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| 217 | * @param string $data encrypted data to be decrypted. |
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| 218 | * @param boolean $passwordBased set true to use password-based key derivation |
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| 219 | * @param string $secret the decryption password or key |
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| 220 | * @param string $info context/application specific information, @see encrypt() |
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| 221 | * |
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| 222 | * @return bool|string the decrypted data or false on authentication failure |
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| 223 | * @throws InvalidConfigException on OpenSSL not loaded |
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| 224 | * @throws Exception on OpenSSL error |
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| 225 | * @see encrypt() |
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| 226 | */ |
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| 227 | 20 | protected function decrypt($data, $passwordBased, $secret, $info) |
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| 261 | |||
| 262 | /** |
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| 263 | * Derives a key from the given input key using the standard HKDF algorithm. |
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| 264 | * Implements HKDF specified in [RFC 5869](https://tools.ietf.org/html/rfc5869). |
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| 265 | * Recommend use one of the SHA-2 hash algorithms: sha224, sha256, sha384 or sha512. |
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| 266 | * @param string $algo a hash algorithm supported by `hash_hmac()`, e.g. 'SHA-256' |
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| 267 | * @param string $inputKey the source key |
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| 268 | * @param string $salt the random salt |
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| 269 | * @param string $info optional info to bind the derived key material to application- |
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| 270 | * and context-specific information, e.g. a user ID or API version, see |
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| 271 | * [RFC 5869](https://tools.ietf.org/html/rfc5869) |
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| 272 | * @param integer $length length of the output key in bytes. If 0, the output key is |
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| 273 | * the length of the hash algorithm output. |
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| 274 | * @throws InvalidParamException when HMAC generation fails. |
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| 275 | * @return string the derived key |
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| 276 | */ |
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| 277 | 27 | public function hkdf($algo, $inputKey, $salt = null, $info = null, $length = 0) |
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| 309 | |||
| 310 | /** |
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| 311 | * Derives a key from the given password using the standard PBKDF2 algorithm. |
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| 312 | * Implements HKDF2 specified in [RFC 2898](http://tools.ietf.org/html/rfc2898#section-5.2) |
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| 313 | * Recommend use one of the SHA-2 hash algorithms: sha224, sha256, sha384 or sha512. |
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| 314 | * @param string $algo a hash algorithm supported by `hash_hmac()`, e.g. 'SHA-256' |
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| 315 | * @param string $password the source password |
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| 316 | * @param string $salt the random salt |
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| 317 | * @param integer $iterations the number of iterations of the hash algorithm. Set as high as |
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| 318 | * possible to hinder dictionary password attacks. |
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| 319 | * @param integer $length length of the output key in bytes. If 0, the output key is |
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| 320 | * the length of the hash algorithm output. |
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| 321 | * @return string the derived key |
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| 322 | * @throws InvalidParamException when hash generation fails due to invalid params given. |
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| 323 | */ |
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| 324 | 19 | public function pbkdf2($algo, $password, $salt, $iterations, $length = 0) |
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| 370 | |||
| 371 | /** |
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| 372 | * Prefixes data with a keyed hash value so that it can later be detected if it is tampered. |
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| 373 | * There is no need to hash inputs or outputs of [[encryptByKey()]] or [[encryptByPassword()]] |
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| 374 | * as those methods perform the task. |
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| 375 | * @param string $data the data to be protected |
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| 376 | * @param string $key the secret key to be used for generating hash. Should be a secure |
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| 377 | * cryptographic key. |
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| 378 | * @param boolean $rawHash whether the generated hash value is in raw binary format. If false, lowercase |
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| 379 | * hex digits will be generated. |
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| 380 | * @return string the data prefixed with the keyed hash |
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| 381 | * @throws InvalidConfigException when HMAC generation fails. |
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| 382 | * @see validateData() |
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| 383 | * @see generateRandomKey() |
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| 384 | * @see hkdf() |
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| 385 | * @see pbkdf2() |
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| 386 | */ |
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| 387 | 3 | public function hashData($data, $key, $rawHash = false) |
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| 395 | |||
| 396 | /** |
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| 397 | * Validates if the given data is tampered. |
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| 398 | * @param string $data the data to be validated. The data must be previously |
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| 399 | * generated by [[hashData()]]. |
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| 400 | * @param string $key the secret key that was previously used to generate the hash for the data in [[hashData()]]. |
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| 401 | * function to see the supported hashing algorithms on your system. This must be the same |
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| 402 | * as the value passed to [[hashData()]] when generating the hash for the data. |
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| 403 | * @param boolean $rawHash this should take the same value as when you generate the data using [[hashData()]]. |
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| 404 | * It indicates whether the hash value in the data is in binary format. If false, it means the hash value consists |
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| 405 | * of lowercase hex digits only. |
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| 406 | * hex digits will be generated. |
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| 407 | * @return string the real data with the hash stripped off. False if the data is tampered. |
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| 408 | * @throws InvalidConfigException when HMAC generation fails. |
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| 409 | * @see hashData() |
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| 410 | */ |
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| 411 | 21 | public function validateData($data, $key, $rawHash = false) |
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| 430 | |||
| 431 | /** |
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| 432 | * Generates specified number of random bytes. |
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| 433 | * Note that output may not be ASCII. |
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| 434 | * @see generateRandomString() if you need a string. |
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| 435 | * |
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| 436 | * @param integer $length the number of bytes to generate |
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| 437 | * @return string the generated random bytes |
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| 438 | * @throws InvalidConfigException if OpenSSL extension is required (e.g. on Windows) but not installed. |
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| 439 | * @throws Exception on failure. |
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| 440 | */ |
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| 441 | 23 | public function generateRandomKey($length = 32) |
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| 567 | |||
| 568 | /** |
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| 569 | * Generates a random string of specified length. |
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| 570 | * The string generated matches [A-Za-z0-9_-]+ and is transparent to URL-encoding. |
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| 571 | * |
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| 572 | * @param integer $length the length of the key in characters |
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| 573 | * @return string the generated random key |
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| 574 | * @throws InvalidConfigException if OpenSSL extension is needed but not installed. |
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| 575 | * @throws Exception on failure. |
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| 576 | */ |
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| 577 | 20 | public function generateRandomString($length = 32) |
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| 592 | |||
| 593 | /** |
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| 594 | * Generates a secure hash from a password and a random salt. |
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| 595 | * |
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| 596 | * The generated hash can be stored in database. |
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| 597 | * Later when a password needs to be validated, the hash can be fetched and passed |
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| 598 | * to [[validatePassword()]]. For example, |
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| 599 | * |
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| 600 | * ```php |
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| 601 | * // generates the hash (usually done during user registration or when the password is changed) |
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| 602 | * $hash = Yii::$app->getSecurity()->generatePasswordHash($password); |
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| 603 | * // ...save $hash in database... |
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| 604 | * |
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| 605 | * // during login, validate if the password entered is correct using $hash fetched from database |
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| 606 | * if (Yii::$app->getSecurity()->validatePassword($password, $hash) { |
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| 607 | * // password is good |
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| 608 | * } else { |
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| 609 | * // password is bad |
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| 610 | * } |
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| 611 | * ``` |
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| 612 | * |
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| 613 | * @param string $password The password to be hashed. |
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| 614 | * @param integer $cost Cost parameter used by the Blowfish hash algorithm. |
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| 615 | * The higher the value of cost, |
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| 616 | * the longer it takes to generate the hash and to verify a password against it. Higher cost |
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| 617 | * therefore slows down a brute-force attack. For best protection against brute-force attacks, |
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| 618 | * set it to the highest value that is tolerable on production servers. The time taken to |
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| 619 | * compute the hash doubles for every increment by one of $cost. |
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| 620 | * @return string The password hash string. When [[passwordHashStrategy]] is set to 'crypt', |
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| 621 | * the output is always 60 ASCII characters, when set to 'password_hash' the output length |
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| 622 | * might increase in future versions of PHP (http://php.net/manual/en/function.password-hash.php) |
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| 623 | * @throws Exception on bad password parameter or cost parameter. |
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| 624 | * @throws InvalidConfigException when an unsupported password hash strategy is configured. |
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| 625 | * @see validatePassword() |
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| 626 | */ |
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| 627 | 1 | public function generatePasswordHash($password, $cost = null) |
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| 647 | |||
| 648 | /** |
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| 649 | * Verifies a password against a hash. |
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| 650 | * @param string $password The password to verify. |
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| 651 | * @param string $hash The hash to verify the password against. |
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| 652 | * @return boolean whether the password is correct. |
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| 653 | * @throws InvalidParamException on bad password/hash parameters or if crypt() with Blowfish hash is not available. |
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| 654 | * @throws InvalidConfigException when an unsupported password hash strategy is configured. |
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| 655 | * @see generatePasswordHash() |
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| 656 | */ |
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| 657 | 1 | public function validatePassword($password, $hash) |
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| 682 | |||
| 683 | /** |
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| 684 | * Generates a salt that can be used to generate a password hash. |
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| 685 | * |
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| 686 | * The PHP [crypt()](http://php.net/manual/en/function.crypt.php) built-in function |
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| 687 | * requires, for the Blowfish hash algorithm, a salt string in a specific format: |
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| 688 | * "$2a$", "$2x$" or "$2y$", a two digit cost parameter, "$", and 22 characters |
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| 689 | * from the alphabet "./0-9A-Za-z". |
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| 690 | * |
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| 691 | * @param integer $cost the cost parameter |
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| 692 | * @return string the random salt value. |
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| 693 | * @throws InvalidParamException if the cost parameter is out of the range of 4 to 31. |
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| 694 | */ |
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| 695 | protected function generateSalt($cost = 13) |
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| 711 | |||
| 712 | /** |
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| 713 | * Performs string comparison using timing attack resistant approach. |
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| 714 | * @see http://codereview.stackexchange.com/questions/13512 |
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| 715 | * @param string $expected string to compare. |
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| 716 | * @param string $actual user-supplied string. |
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| 717 | * @return boolean whether strings are equal. |
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| 718 | */ |
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| 719 | 41 | public function compareString($expected, $actual) |
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| 731 | } |
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| 732 |
If you define a variable conditionally, it can happen that it is not defined for all execution paths.
Let’s take a look at an example:
In the above example, the variable $x is defined if you pass “foo” or “bar” as argument for $a. However, since the switch statement has no default case statement, if you pass any other value, the variable $x would be undefined.
Available Fixes
Check for existence of the variable explicitly:
Define a default value for the variable:
Add a value for the missing path: