@ -15,21 +15,11 @@ use Yii;
* *
* In particular, Security supports the following features: * In particular, Security supports the following features:
* *
* - Encryption/decryption: [[encrypt()]] and [[decrypt()]] * - Encryption/decryption: [[encryptByKey()]], [[decryptByKey()]], [[encryptByPassword()]] and [[decryptByPassword()]]
* - Key derivation using standard algorithms: [[pbkdf2()]] and [[hkdf()]]
* - Data tampering prevention: [[hashData()]] and [[validateData()]] * - Data tampering prevention: [[hashData()]] and [[validateData()]]
* - Password validation: [[generatePasswordHash()]] and [[validatePassword()]] * - Password validation: [[generatePasswordHash()]] and [[validatePassword()]]
* *
* Additionally, Security provides [[getSecretKey()]] to support generating
* named secret keys. These secret keys, once generated, will be stored in a file
* and made available in future requests.
*
* This component provides several configuration parameters, which allow tuning your own balance
* between high security and high performance.
*
* > Tip: you may add several `Security` components with different configurations to your application,
* this allows usage of different encryption strategies for different use cases or migrate encrypted data
* from outdated strategy to the new one.
*
* > Note: this class requires 'mcrypt' PHP extension. For the highest security level PHP version >= 5.5.0 is recommended. * > Note: this class requires 'mcrypt' PHP extension. For the highest security level PHP version >= 5.5.0 is recommended.
* *
* @author Qiang Xue < qiang.xue @ gmail . com > * @author Qiang Xue < qiang.xue @ gmail . com >
@ -40,114 +30,208 @@ use Yii;
class Security extends Component class Security extends Component
{ {
/** /**
* @var integer crypt block size in bytes. * @var integer derivation iterations count.
* For AES-128, AES-192, block size is 128-bit (16 bytes). * Only used when @see $deriveKeyStrategy = 'password'. Set as
* For AES-256, block size is 256-bit (32 bytes). * high as possible to hinder dictionary password attacks.
* Recommended value: 32
*/
public $cryptBlockSize = 32;
/**
* @var integer crypt key size in bytes.
* For AES-192, key size is 192-bit (24 bytes).
* For AES-256, key size is 256-bit (32 bytes).
* Recommended value: 32
*/ */
public $cryptKeySize = 32 ; public $derivationIterations = 100000;
/** /**
* @var string derivation hash algorithm name. * @var string strategy, which should be used to generate password hash.
* Recommended value: 'sha256' * Available strategies:
* - 'password_hash' - use of PHP `password_hash()` function with PASSWORD_DEFAULT algorithm.
* This option is recommended, but it requires PHP version >= 5.5.0
* - 'crypt' - use PHP `crypt()` function.
*/ */
public $derivationHash = 'sha256'; public $passwordHashStrategy = 'crypt';
// AES has 128-bit block size and three key sizes: 128, 192 and 256 bits.
// mcrypt offers the Rijndael cipher with block sizes of 128, 192 and 256
// bits but only the 128-bit Rijndael is standardized in AES.
// So to use AES in mycrypt, specify `'rijndael-128'` cipher and mcrypt
// chooses the appropriate AES based on the length of the supplied key.
const MCRYPT_CIPHER = 'rijndael-128';
const MCRYPT_MODE = 'cbc';
// Same size for encryption keys, auth keys and KDF salt
const KEY_SIZE = 16;
// Hash algorithm for key derivation.
const KDF_HASH = 'sha256';
// Hash algorithm for authentication.
const MAC_HASH = 'sha256';
// HKDF info value for auth keys
const AUTH_KEY_INFO = 'AuthorizationKey';
private $_cryptModule;
/** /**
* @var integer derivation iterations count. * Encrypts data using a password.
* Recommended value: 1000000 * Derives keys for encryption and authentication from the password using PBKDF2 and a random salt,
* which is deliberately slow to protect against dictionary attacks. Use [[encryptByKey()]] to
* encrypt fast using a cryptographic key rather than a password. Key derivation time is
* determined by [[$derivationIterations]], which should be set as high as possible.
* The encrypted data includes a keyed message authentication code (MAC) so there is no need
* to hash input or output data.
* > Note: Avoid encrypting with passwords wherever possible. Nothing can protect against
* poor-quality or compromosed passwords.
* @param string $data the data to encrypt
* @param string $password the password to use for encryption
* @return string the encrypted data
* @see decryptByPassword()
* @see encryptByKey()
*/ */
public $derivationIterations = 1000000; public function encryptByPassword($data, $password)
{
return $this->encrypt($data, true, $password, null);
}
/** /**
* @var string strategy, which should be used to derive a key for encryption. * Encrypts data using a cyptograhic key.
* Available strategies: * Derives keys for encryption and authentication from the input key using HKDF and a random salt,
* - 'pbkdf2' - PBKDF2 key derivation. This option is recommended, but it requires PHP version >= 5.5.0 * which is very fast relative to [[encryptByPassword()]]. The input key must be properly
* - 'hmac' - HMAC hash key derivation. * random -- use [[generateRandomKey()]] to generate keys.
* The encrypted data includes a keyed message authentication code (MAC) so there is no need
* to hash input or output data.
* @param string $data the data to encrypt
* @param string $inputKey the input to use for encryption and authentication
* @param string $info optional context and application specific information, see [[hkdf()]]
* @return string the encrypted data
* @see decryptByPassword()
* @see encryptByKey()
*/ */
public $deriveKeyStrategy = 'hmac'; public function encryptByKey($data, $inputKey, $info = null)
{
return $this->encrypt($data, false, $inputKey, $info);
}
/** /**
* @var string strategy, which should be used to generate password hash. * Verifies and decrypts data encrypted with [[encryptByPassword()]] .
* Available strategies: * @param string $data the encrypted data to decrypt
* - 'password_hash' - use of PHP `password_hash()` function with PASSWORD_DEFAULT algorithm. This option is recommended, * @param string $password the password to use for decryption
* but it requires PHP version >= 5.5.0 * @return bool|string the decrypted data or false on authentication failure
* - 'crypt' - use PHP `crypt()` function. * @see encryptByPassword()
*/ */
public $passwordHashStrategy = 'crypt'; public function decryptByPassword($data, $password)
{
return $this->decrypt($data, true, $password, null);
}
/** /**
* @var boolean whether to generate unique salt while deriving encryption key. * Verifies and decrypts data encrypted with [[encryptByPassword()]].
* If enabled (recommended) this option increases encrypted text length, but provide more security. * @param string $data the encrypted data to decrypt
* If disabled this option reduces encrypted text length, but also reduces security. * @param string $inputKey the input to use for encryption and authentication
* @param string $info optional context and application specific information, see [[hkdf()]]
* @return bool|string the decrypted data or false on authentication failure
* @see encryptByKey()
*/ */
public $useDeriveKeyUniqueSalt = true; public function decryptByKey($data, $inputKey, $info = null)
{
return $this->decrypt($data, false, $inputKey, $info);
}
/** /**
* @var string the path or alias of a file that stores the secret keys automatically generated by [[getSecretKey()]]. * Initializes the mcrypt module.
* The file must be writable by Web server process. It contains a JSON hash of key names and key values. * @return resource the mcrypt module handle.
* @throws InvalidConfigException if mcrypt extension is not installed
* @throws Exception if mcrypt initialization fails
*/ */
public $secretKeyFile = '@runtime/keys.json'; protected function getCryptModule()
{
if ($this->_cryptModule === null) {
if (!extension_loaded('mcrypt')) {
throw new InvalidConfigException('The mcrypt PHP extension is not installed.');
}
$this->_cryptModule = @mcrypt_module_open(self::MCRYPT_CIPHER, '', self::MCRYPT_MODE, '');
if ($this->_cryptModule === false) {
$this->_cryptModule = null;
throw new Exception('Failed to initialize the mcrypt module.');
}
}
return $this->_cryptModule;
}
public function __destruct()
{
if ($this->_cryptModule !== null) {
mcrypt_module_close($this->_cryptModule);
$this->_cryptModule = null;
}
}
/** /**
* Encrypts data. * Encrypts data.
* @param string $data data to be encrypted. * @param string $data data to be encrypted
* @param string $password the encryption password * @param bool $passwordBased set true to use password-based key derivation
* @param string $secret the encryption password or key
* @param string $info context/application specific information, e.g. a user ID
* Only used when $deriveKeyStrategy = 'key'.
* See RFC 5869 Section 3.2 @link https://tools.ietf.org/html/rfc5869
* @return string the encrypted data * @return string the encrypted data
* @throws Exception if PHP Mcrypt extension is not loaded or failed to be initialized * @throws Exception if PHP Mcrypt extension is not loaded or failed to be initialized
* @see decrypt() * @see decrypt()
*/ */
public function encrypt($data, $password) protected function encrypt($data, $passwordBased, $secret, $info )
{ {
$module = $this->openCryptModule(); $module = $this->getCryptModule();
$keySalt = $this->generateRandomKey(self::KEY_SIZE);
if ($passwordBased) {
$key = $this->pbkdf2(self::KDF_HASH, $secret, $keySalt, $this->derivationIterations, self::KEY_SIZE);
} else {
$key = $this->hkdf(self::KDF_HASH, $secret, $keySalt, $info, self::KEY_SIZE);
}
$data = $this->addPadding($data); $data = $this->addPadding($data);
$ivSize = mcrypt_enc_get_iv_size($module); $ivSize = mcrypt_enc_get_iv_size($module);
$iv = mcrypt_create_iv($ivSize, MCRYPT_DEV_URANDOM); $iv = mcrypt_create_iv($ivSize, MCRYPT_DEV_URANDOM);
if ($this->useDeriveKeyUniqueSalt) {
$keySalt = mcrypt_create_iv($ivSize, MCRYPT_DEV_URANDOM);
$encrypted = $keySalt;
} else {
$keySalt = $iv;
$encrypted = '';
}
$key = $this->deriveKey($password, $keySalt);
mcrypt_generic_init($module, $key, $iv); mcrypt_generic_init($module, $key, $iv);
$encrypted . = $iv . mcrypt_generic($module, $data); $encrypted = mcrypt_generic($module, $data);
mcrypt_generic_deinit($module); mcrypt_generic_deinit($module);
mcrypt_module_close($module);
return $encrypted; $authKey = $this->hkdf(self::KDF_HASH, $key, null, self::AUTH_KEY_INFO, self::KEY_SIZE);
$hashed = $this->hashData($iv . $encrypted, $authKey);
/*
* Output: [keySalt][MAC][IV][ciphertext]
* - keySalt is KEY_SIZE bytes long
* - MAC: message authentication code, length same as the output of MAC_HASH
* - IV: initialization vector, length set by CRYPT_CIPHER and CRYPT_MODE, mcrypt_enc_get_iv_size()
*/
return $keySalt . $hashed;
} }
/** /**
* Decrypts data * Decrypts data.
* @param string $data data to be decrypted. * @param string $data encrypted data to be decrypted.
* @param string $password the decryption password * @param bool $passwordBased set true to use password-based key derivation
* @return string the decrypted data * @param string $secret the decryption password or key
* @throws Exception if PHP Mcrypt extension is not loaded or failed to be initialized * @param string $info context/application specific information, @see encrypt()
* @return bool|string the decrypted data or false on authentication failure
* @see encrypt() * @see encrypt()
*/ */
public function decrypt($data, $password ) protected function decrypt($data, $passwordBased, $secret, $info )
{ {
if ($data === null) { $keySalt = StringHelper::byteSubstr($data, 0, self::KEY_SIZE);
return null; if ($passwordBased) {
$key = $this->pbkdf2(self::KDF_HASH, $secret, $keySalt, $this->derivationIterations, self::KEY_SIZE);
} else {
$key = $this->hkdf(self::KDF_HASH, $secret, $keySalt, $info, self::KEY_SIZE);
}
$authKey = $this->hkdf(self::KDF_HASH, $key, null, self::AUTH_KEY_INFO, self::KEY_SIZE);
$data = $this->validateData(StringHelper::byteSubstr($data, self::KEY_SIZE, null), $authKey);
if ($data === false) {
return false;
} }
$module = $this->openCryptModule();
$module = $this->getCryptModule();
$ivSize = mcrypt_enc_get_iv_size($module); $ivSize = mcrypt_enc_get_iv_size($module);
$iv = StringHelper::byteSubstr($data, 0, $ivSize); $iv = StringHelper::byteSubstr($data, 0, $ivSize);
$keySalt = $iv; $encrypted = StringHelper::byteSubstr($data, $ivSize, null);
$encrypted = StringHelper::byteSubstr($data, $ivSize, StringHelper::byteLength($data));
if ($this->useDeriveKeyUniqueSalt) {
$iv = StringHelper::byteSubstr($encrypted, 0, $ivSize);
$encrypted = StringHelper::byteSubstr($encrypted, $ivSize, StringHelper::byteLength($encrypted));
}
$key = $this->deriveKey($password, $keySalt);
mcrypt_generic_init($module, $key, $iv); mcrypt_generic_init($module, $key, $iv);
$decrypted = mdecrypt_generic($module, $encrypted); $decrypted = mdecrypt_generic($module, $encrypted);
mcrypt_generic_deinit($module); mcrypt_generic_deinit($module);
mcrypt_module_close($module);
return $this->stripPadding($decrypted); return $this->stripPadding($decrypted);
} }
@ -159,7 +243,9 @@ class Security extends Component
*/ */
protected function addPadding($data) protected function addPadding($data)
{ {
$pad = $this->cryptBlockSize - (StringHelper::byteLength($data) % $this->cryptBlockSize); $module = $this->getCryptModule();
$blockSize = mcrypt_enc_get_block_size($module);
$pad = $blockSize - (StringHelper::byteLength($data) % $blockSize);
return $data . str_repeat(chr($pad), $pad); return $data . str_repeat(chr($pad), $pad);
} }
@ -182,70 +268,135 @@ class Security extends Component
} }
/** /**
* Derives a key from the given password (PBKDF2). * Derives a key from the given input key using the standard HKDF algorithm.
* @param string $password the source password * Implements HKDF spcified in [RFC 5869](https://tools.ietf.org/html/rfc5869).
* Recommend use one of the SHA-2 hash algorithms: sha224, sha256, sha384 or sha512.
* @param string $algo a hash algorithm supported by `hash_hmac()`, e.g. 'SHA-256'
* @param string $inputKey the source key
* @param string $salt the random salt * @param string $salt the random salt
* @throws InvalidConfigException if unsupported derive key strategy is configured. * @param string $info optional info to bind the derived key material to application-
* and context-specific information, e.g. a user ID or API version, see
* [RFC 5869](https://tools.ietf.org/html/rfc5869)
* @param int $length length of the output key in bytes. If 0, the output key is
* the length of the hash algorithm output.
* @throws InvalidParamException
* @return string the derived key * @return string the derived key
*/ */
protected function deriveKey($password, $salt) public function hkdf($algo, $inputKey, $salt = null, $info = null, $length = 0 )
{ {
switch ($this->deriveKeyStrategy) { $test = @hash_hmac($algo, '', '', true);
case 'pbkdf2': if (!$test) {
return $this->deriveKeyPbkdf2($password, $salt); throw new InvalidParamException('Failed to generate HMAC with hash algorithm: ' . $algo);
case 'hmac': }
return $this->deriveKeyHmac($password, $salt); $hashLength = StringHelper::byteLength($test);
default: if (is_string($length) & & preg_match('{^\d{1,16}$}', $length)) {
throw new InvalidConfigException("Unknown derive key strategy '{$this->deriveKeyStrategy}'"); $length = (int) $length;
}
if (!is_integer($length) || $length < 0 | | $ length > 255 * $hashLength) {
throw new InvalidParamException('Invalid length');
}
$blocks = $length !== 0 ? ceil($length / $hashLength) : 1;
if ($salt === null) {
$salt = str_repeat("\0", $hashLength);
} }
$prKey = hash_hmac($algo, $inputKey, $salt, true);
$hmac = '';
$outputKey = '';
for ($i = 1; $i < = $blocks; $i++) {
$hmac = hash_hmac($algo, $hmac . $info . chr($i), $prKey, true);
$outputKey .= $hmac;
}
if ($length !== 0) {
$outputKey = StringHelper::byteSubstr($outputKey, 0, $length);
}
return $outputKey;
} }
/** /**
* Derives a key from the given password using PBKDF2. * Derives a key from the given password using the standard PBKDF2 algorithm.
* Implements HKDF2 specified in [RFC 2898](http://tools.ietf.org/html/rfc2898#section-5.2)
* Recommend use one of the SHA-2 hash algorithms: sha224, sha256, sha384 or sha512.
* @param string $algo a hash algorithm supported by `hash_hmac()`, e.g. 'SHA-256'
* @param string $password the source password * @param string $password the source password
* @param string $salt the random salt * @param string $salt the random salt
* @throws InvalidConfigException if environment does not allows PBKDF2. * @param int $iterations the number of iterations of the hash algorithm. Set as high as
* possible to hinder dictionary password attacks.
* @param int $length length of the output key in bytes. If 0, the output key is
* the length of the hash algorithm output.
* @throws InvalidParamException
* @return string the derived key * @return string the derived key
*/ */
protected function deriveKeyPbkdf2($password, $salt) public function pbkdf2($algo, $password, $salt, $iterations, $length = 0 )
{ {
if (function_exists('hash_pbkdf2')) { if (function_exists('hash_pbkdf2')) {
return hash_pbkdf2($this->derivationHash, $password, $salt, $this->derivationIterations, $this->cryptKeySize, true); $outputKey = hash_pbkdf2($algo, $password, $salt, $iterations, $length , true);
} else { if ($outputKey === false) {
throw new InvalidConfigException('Security::$deriveKeyStrategy is set to "pbkdf2", which requires PHP >= 5.5.0. Either upgrade your run-time environment or use another strategy. '); throw new InvalidParamException('Invalid parameters to hash_pbkdf2() ');
} }
return $outputKey;
} }
/** // todo: is there a nice way to reduce the code repetition in hkdf() and pbkdf2()?
* Derives a key from the given password using HMAC. $test = @hash_hmac($algo, '', '', true);
* @param string $password the source password if (!$test) {
* @param string $salt the random salt throw new InvalidParamException('Failed to generate HMAC with hash algorithm: ' . $algo);
* @return string the derived key }
*/ if (is_string($iterations) & & preg_match('{^\d{1,16}$}', $iterations)) {
protected function deriveKeyHmac($password, $salt) $iterations = (int) $iterations;
{ }
$hmac = hash_hmac($this->derivationHash, $salt . pack('N', 1), $password, true); if (!is_integer($iterations) || $iterations < 1 ) {
throw new InvalidParamException('Invalid iterations');
}
if (is_string($length) & & preg_match('{^\d{1,16}$}', $length)) {
$length = (int) $length;
}
if (!is_integer($length) || $length < 0 ) {
throw new InvalidParamException('Invalid length');
}
$hashLength = StringHelper::byteLength($test);
$blocks = $length !== 0 ? ceil($length / $hashLength) : 1;
$outputKey = '';
for ($j = 1; $j < = $blocks; $j++) {
$hmac = hash_hmac($algo, $salt . pack('N', $j), $password, true);
$xorsum = $hmac; $xorsum = $hmac;
for ($i = 1; $i < $this->derivationIterations; $i++) { for ($i = 1; $i < $iterations; $i++) {
$hmac = hash_hmac($this->derivationHash, $hmac, $password, true); $hmac = hash_hmac($algo , $hmac, $password, true);
$xorsum ^= $hmac; $xorsum ^= $hmac;
} }
return substr($xorsum, 0, $this->cryptKeySize); $outputKey .= $xorsum;
}
if ($length !== 0) {
$outputKey = StringHelper::byteSubstr($outputKey, 0, $length);
}
return $outputKey;
} }
/** /**
* Prefixes data with a keyed hash value so that it can later be detected if it is tampered. * Prefixes data with a keyed hash value so that it can later be detected if it is tampered.
* There is no need to hash inputs or outputs of [[encryptByKey()]] or [[encryptByPassword()]]
* as those methods perform the task.
* @param string $data the data to be protected * @param string $data the data to be protected
* @param string $key the secret key to be used for generating hash * @param string $key the secret key to be used for generating hash. Should be a secure
* @param string $algorithm the hashing algorithm (e.g. "md5", "sha1", "sha256", etc.). Call PHP "hash_algos()" * cryptographic key.
* function to see the supported hashing algorithms on your system. * @throws InvalidConfigException
* @return string the data prefixed with the keyed hash * @return string the data prefixed with the keyed hash
* @see validateData() * @see validateData()
* @see getSecretKey() * @see generateRandomKey()
* @see hkdf()
* @see pbkdf2()
*/ */
public function hashData($data, $key, $algorithm = 'sha256') public function hashData($data, $key)
{ {
return hash_hmac($algorithm, $data, $key) . $data; $hash = hash_hmac(self::MAC_HASH, $data, $key, true);
if (!$hash) {
throw new InvalidConfigException('Failed to generate HMAC with hash algorithm: ' . self::MAC_HASH);
}
return $hash . $data;
} }
/** /**
@ -253,21 +404,24 @@ class Security extends Component
* @param string $data the data to be validated. The data must be previously * @param string $data the data to be validated. The data must be previously
* generated by [[hashData()]]. * generated by [[hashData()]].
* @param string $key the secret key that was previously used to generate the hash for the data in [[hashData()]]. * @param string $key the secret key that was previously used to generate the hash for the data in [[hashData()]].
* @param string $algorithm the hashing algorithm (e.g. "md5", "sha1", "sha256", etc.). Call PHP "hash_algos()"
* function to see the supported hashing algorithms on your system. This must be the same * function to see the supported hashing algorithms on your system. This must be the same
* as the value passed to [[hashData()]] when generating the hash for the data. * as the value passed to [[hashData()]] when generating the hash for the data.
* @throws InvalidConfigException
* @return string the real data with the hash stripped off. False if the data is tampered. * @return string the real data with the hash stripped off. False if the data is tampered.
* @see hashData() * @see hashData()
*/ */
public function validateData($data, $key, $algorithm = 'sha256' ) public function validateData($data, $key)
{ {
$hashSize = StringHelper::byteLength(hash_hmac($algorithm, 'test', $key)); $test = @hash_hmac(self::MAC_HASH, '', '', true);
$n = StringHelper::byteLength($data); if (!$test) {
if ($n >= $hashSize) { throw new InvalidConfigException('Failed to generate HMAC with hash algorithm: ' . self::MAC_HASH);
$hash = StringHelper::byteSubstr($data, 0, $hashSize); }
$pureData = StringHelper::byteSubstr($data, $hashSize, $n - $hashSize); $hashLength = StringHelper::byteLength($test);
if (StringHelper::byteLength($data) >= $hashLength) {
$hash = StringHelper::byteSubstr($data, 0, $hashLength);
$pureData = StringHelper::byteSubstr($data, $hashLength, null);
$calculatedHash = hash_hmac($algorithm, $pureData, $key); $calculatedHash = hash_hmac(self::MAC_HASH, $pureData, $key, true );
if ($this->compareString($hash, $calculatedHash)) { if ($this->compareString($hash, $calculatedHash)) {
return $pureData; return $pureData;
@ -279,32 +433,6 @@ class Security extends Component
} }
} }
private $_keys;
/**
* Returns a secret key associated with the specified name.
* If the secret key does not exist, it will be automatically generated and saved in [[secretKeyFile]].
* @param string $name the name that is associated with the secret key
* @param integer $length the length of the key that should be generated if not exists
* @param boolean $regenerate whether to regenerate a secret if it already exists
* @return string the secret key associated with the specified name
*/
public function getSecretKey($name, $length = 32, $regenerate = false)
{
$keyFile = Yii::getAlias($this->secretKeyFile);
if ($this->_keys === null) {
$this->_keys = is_file($keyFile) ? json_decode(file_get_contents($keyFile), true) : [];
}
if (!isset($this->_keys[$name]) || $regenerate) {
$this->_keys[$name] = $this->generateRandomKey($length);
file_put_contents($keyFile, json_encode($this->_keys));
}
return $this->_keys[$name];
}
/** /**
* Generates specified number of random bytes. * Generates specified number of random bytes.
* Note that output may not be ASCII. * Note that output may not be ASCII.
@ -314,7 +442,7 @@ class Security extends Component
* @throws Exception on failure. * @throws Exception on failure.
* @return string the generated random bytes * @return string the generated random bytes
*/ */
public function generateRandomBytes ($length = 32) public function generateRandomKey ($length = 32)
{ {
if (!extension_loaded('mcrypt')) { if (!extension_loaded('mcrypt')) {
throw new InvalidConfigException('The mcrypt PHP extension is not installed.'); throw new InvalidConfigException('The mcrypt PHP extension is not installed.');
@ -328,43 +456,24 @@ class Security extends Component
/** /**
* Generates a random string of specified length. * Generates a random string of specified length.
* The string generated matches [A-Za-z0-9_. -]+ * The string generated matches [A-Za-z0-9_-]+ and is transparent to URL-encoding.
* *
* @param integer $length the length of the key in characters * @param integer $length the length of the key in characters
* @throws Exception Exception on failure. * @throws Exception Exception on failure.
* @return string the generated random key * @return string the generated random key
*/ */
public function generateRandomKey($length = 32) public function generateRandomString($length = 32)
{
$bytes = $this->generateRandomBytes($length);
return strtr(StringHelper::byteSubstr(base64_encode($bytes), 0, $length), '+/=', '_-.');
}
/**
* Opens the mcrypt module.
* @return resource the mcrypt module handle.
* @throws InvalidConfigException if mcrypt extension is not installed
* @throws Exception if mcrypt initialization fails
*/
protected function openCryptModule()
{ {
if (!extension_loaded('mcrypt')) { $bytes = $this->generateRandomKey($length);
throw new InvalidConfigException('The mcrypt PHP extension is not installed.'); // '=' character(s) returned by base64_encode() are always discarded because
} // they are guaranteed to be after position $length in the base64_encode() output.
// AES version depending on crypt block size return strtr(substr(base64_encode($bytes), 0, $length), '+/', '_-');
$algorithmName = 'rijndael-' . ($this->cryptBlockSize * 8);
$module = @mcrypt_module_open($algorithmName, '', 'cbc', '');
if ($module === false) {
throw new Exception('Failed to initialize the mcrypt module.');
}
return $module;
} }
/** /**
* Generates a secure hash from a password and a random salt. * Generates a secure hash from a password and a random salt.
* *
* The generated hash can be stored in database (e.g. `CHAR(64) CHARACTER SET latin1` on MySQL) . * The generated hash can be stored in database.
* Later when a password needs to be validated, the hash can be fetched and passed * Later when a password needs to be validated, the hash can be fetched and passed
* to [[validatePassword()]]. For example, * to [[validatePassword()]]. For example,
* *
@ -387,11 +496,12 @@ class Security extends Component
* the longer it takes to generate the hash and to verify a password against it. Higher cost * the longer it takes to generate the hash and to verify a password against it. Higher cost
* therefore slows down a brute-force attack. For best protection against brute for attacks, * therefore slows down a brute-force attack. For best protection against brute for attacks,
* set it to the highest value that is tolerable on production servers. The time taken to * set it to the highest value that is tolerable on production servers. The time taken to
* compute the hash doubles for every increment by one of $cost. So, for example, if the * compute the hash doubles for every increment by one of $cost.
* hash takes 1 second to compute when $cost is 14 then then the compute time varies as
* 2^($cost - 14) seconds.
* @throws Exception on bad password parameter or cost parameter * @throws Exception on bad password parameter or cost parameter
* @return string The password hash string, ASCII and not longer than 64 characters. * @throws InvalidConfigException
* @return string The password hash string. When [[passwordHashStrategy]] is set to 'crypt',
* the output is alwaus 60 ASCII characters, when set to 'password_hash' the output length
* might increase in future versions of PHP (http://php.net/manual/en/function.password-hash.php)
* @see validatePassword() * @see validatePassword()
*/ */
public function generatePasswordHash($password, $cost = 13) public function generatePasswordHash($password, $cost = 13)
@ -401,12 +511,13 @@ class Security extends Component
if (!function_exists('password_hash')) { if (!function_exists('password_hash')) {
throw new InvalidConfigException('Password hash key strategy "password_hash" requires PHP >= 5.5.0, either upgrade your environment or use another strategy.'); throw new InvalidConfigException('Password hash key strategy "password_hash" requires PHP >= 5.5.0, either upgrade your environment or use another strategy.');
} }
/** @noinspection PhpUndefinedConstantInspection */
return password_hash($password, PASSWORD_DEFAULT, ['cost' => $cost]); return password_hash($password, PASSWORD_DEFAULT, ['cost' => $cost]);
case 'crypt': case 'crypt':
$salt = $this->generateSalt($cost); $salt = $this->generateSalt($cost);
$hash = crypt($password, $salt); $hash = crypt($password, $salt);
// strlen() is safe since crypt() returns only ascii
if (!is_string($hash) || strlen($hash) < 32 ) { if (!is_string($hash) || strlen($hash) !== 60) {
throw new Exception('Unknown error occurred while generating hash.'); throw new Exception('Unknown error occurred while generating hash.');
} }
return $hash; return $hash;
@ -443,7 +554,7 @@ class Security extends Component
case 'crypt': case 'crypt':
$test = crypt($password, $hash); $test = crypt($password, $hash);
$n = strlen($test); $n = strlen($test);
if ($n < 32 | | $ n ! = = strlen ( $ hash ) ) { if ($n !== 60) {
return false; return false;
} }
return $this->compareString($test, $hash); return $this->compareString($test, $hash);
@ -471,14 +582,9 @@ class Security extends Component
throw new InvalidParamException('Cost must be between 4 and 31.'); throw new InvalidParamException('Cost must be between 4 and 31.');
} }
// Get 20 * 8bits of random entropy // Get a 20-byte random string
$rand = $this->generateRandomBytes(20); $rand = $this->generateRandomKey(20);
// Form the prefix that specifies Blowfish (bcrypt) algorithm and cost parameter.
// Add the microtime for a little more entropy.
$rand .= microtime(true);
// Mix the bits cryptographically into a 20-byte binary string.
$rand = sha1($rand, true);
// Form the prefix that specifies Blowfish algorithm and cost parameter.
$salt = sprintf("$2y$%02d$", $cost); $salt = sprintf("$2y$%02d$", $cost);
// Append the random salt data in the required base64 format. // Append the random salt data in the required base64 format.
$salt .= str_replace('+', '.', substr(base64_encode($rand), 0, 22)); $salt .= str_replace('+', '.', substr(base64_encode($rand), 0, 22));
@ -496,8 +602,12 @@ class Security extends Component
protected function compareString($expected, $actual) protected function compareString($expected, $actual)
{ {
// timing attack resistant approach: // timing attack resistant approach:
$length = StringHelper::byteLength($expected);
if ($length !== StringHelper::byteLength($actual)) {
return false;
}
$diff = 0; $diff = 0;
for ($i = 0, $length = StringHelper::byteLength($actual); $i < $length; $i++) { for ($i = 0; $i < $length; $i++) {
$diff |= (ord($actual[$i]) ^ ord($expected[$i])); $diff |= (ord($actual[$i]) ^ ord($expected[$i]));
} }
return $diff === 0; return $diff === 0;
tom--
10 years ago
committed by
Alexander Makarov