File "class-itsec-lib-jwt.php"
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<?php
/**
* JSON Web Token implementation, based on this spec:
* https://tools.ietf.org/html/rfc7519
*
* PHP version 5
*
* @category Authentication
* @package Authentication_JWT
* @author Neuman Vong <[email protected]>
* @author Anant Narayanan <[email protected]>
* @license http://opensource.org/licenses/BSD-3-Clause 3-clause BSD
* @link https://github.com/firebase/php-jwt
*
* Forked to follow WordPress Coding Standards and provide additional APIs.
*/
final class ITSEC_Lib_JWT {
/**
* When checking nbf, iat or expiration times,
* we want to provide some extra leeway time to
* account for clock skew.
*/
public static $leeway = 0;
/**
* Allow the current timestamp to be specified.
* Useful for fixing a value within unit testing.
*
* Will default to PHP time() value if null.
*/
public static $timestamp = null;
protected static $supported_algs = array(
'HS256' => array( 'hash_hmac', 'SHA256' ),
'HS512' => array( 'hash_hmac', 'SHA512' ),
'HS384' => array( 'hash_hmac', 'SHA384' ),
'RS256' => array( 'openssl', 'SHA256' ),
'RS384' => array( 'openssl', 'SHA384' ),
'RS512' => array( 'openssl', 'SHA512' ),
);
/**
* Decodes a JWT string into a PHP object.
*
* @param string $jwt The JWT
* @param string|array $key The key, or map of keys.
* If the algorithm used is asymmetric, this is the public key
* @param array $allowed_algs List of supported verification algorithms
* Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
* @param string $confirm_unsecure Must be set to "unsecure" to allow using the "none" algorithm.
*
* @return object|\WP_Error The JWT's payload as a PHP object
*
* @uses json_decode
* @uses url_safe_b64_decode
*/
public static function decode( $jwt, $key, array $allowed_algs = array(), $confirm_unsecure = '' ) {
$timestamp = is_null( static::$timestamp ) ? time() : static::$timestamp;
$allow_unsecured = in_array( 'none', $allowed_algs, true );
if ( $allow_unsecured && 'unsecure' !== $confirm_unsecure ) {
return new \WP_Error( 'jwt_unsecure_not_confirmed', __( 'Did not confirm that "none" is an allowed algorithm.', 'better-wp-security' ) );
}
if ( empty( $key ) && ! $allow_unsecured ) {
return new \WP_Error( 'jwt_empty_key', __( 'Key may not be empty', 'better-wp-security' ) );
}
$parsed = self::parse_jwt( $jwt );
if ( is_wp_error( $parsed ) ) {
return $parsed;
}
list( $header, $payload, $sig, $headb64, $bodyb64 ) = $parsed;
if ( empty( $header->alg ) ) {
return new \WP_Error( 'jwt_invalid_format', __( 'Empty algorithm', 'better-wp-security' ) );
}
if ( 'none' !== $header->alg || ! $allow_unsecured ) {
if ( empty( static::$supported_algs[ $header->alg ] ) ) {
return new \WP_Error( 'jwt_unsupported_algorithm', __( 'Algorithm not supported', 'better-wp-security' ) );
}
if ( ! in_array( $header->alg, $allowed_algs, true ) ) {
return new \WP_Error( 'jwt_disallowed_algorithm', __( 'Algorithm not allowed', 'better-wp-security' ) );
}
if ( is_array( $key ) || $key instanceof \ArrayAccess ) {
if ( isset( $header->kid ) ) {
if ( ! isset( $key[ $header->kid ] ) ) {
return new \WP_Error( 'jwt_invalid_key', __( '"kid" invalid, unable to lookup correct key', 'better-wp-security' ) );
}
$key = $key[ $header->kid ];
} else {
return new \WP_Error( 'jwt_invalid_key', __( '"kid" empty, unable to lookup correct key', 'better-wp-security' ) );
}
}
// Check the signature
$verified = static::verify( "$headb64.$bodyb64", $sig, $key, $header->alg );
if ( is_wp_error( $verified ) ) {
return $verified;
}
if ( true !== $verified ) {
return new \WP_Error( 'jwt_invalid_signature', __( 'Signature verification failed', 'better-wp-security' ) );
}
}
// Check if the nbf if it is defined. This is the time that the
// token can actually be used. If it's not yet that time, abort.
if ( isset( $payload->nbf ) && $payload->nbf > ( $timestamp + static::$leeway ) ) {
return new \WP_Error(
'jwt_before_valid',
sprintf(
/* translators: %s Date/Time the JWT is valid. */
__( 'Cannot handle token prior to %s.', 'better-wp-security' ),
wp_date( get_option( 'date_format' ) . ' ' . get_option( 'time_format' ), $payload->nbf )
),
array( 'nbf' => $payload->nbf )
);
}
// Check that this token has been created before 'now'. This prevents
// using tokens that have been created for later use (and haven't
// correctly used the nbf claim).
if ( isset( $payload->iat ) && $payload->iat > ( $timestamp + static::$leeway ) ) {
return new \WP_Error(
'jwt_before_valid',
sprintf(
/* translators: %s Date/Time the JWT is valid. */
__( 'Cannot handle token prior to %s.', 'better-wp-security' ),
wp_date( get_option( 'date_format' ) . ' ' . get_option( 'time_format' ), $payload->iat )
),
array( 'iat' => $payload->iat )
);
}
// Check if this token has expired.
if ( isset( $payload->exp ) && ( $timestamp - static::$leeway ) >= $payload->exp ) {
return new \WP_Error( 'jwt_expired', __( 'Expired token', 'better-wp-security' ), array( 'exp' => $payload->exp ) );
}
return $payload;
}
/**
* Parses a JWT into it's component parts.
*
* @param string $jwt
*
* @return array|\WP_Error
*/
protected static function parse_jwt( $jwt ) {
$tks = explode( '.', $jwt );
if ( 3 !== count( $tks ) ) {
return new \WP_Error( 'jwt_invalid_format', __( 'Wrong number of segments', 'better-wp-security' ) );
}
list( $headb64, $bodyb64, $cryptob64 ) = $tks;
if ( null === ( $header = static::json_decode( static::url_safe_b64_decode( $headb64 ) ) ) ) {
return new \WP_Error( 'jwt_invalid_format', __( 'Invalid header encoding', 'better-wp-security' ) );
}
if ( null === $payload = static::json_decode( static::url_safe_b64_decode( $bodyb64 ) ) ) {
return new \WP_Error( 'jwt_invalid_format', __( 'Invalid claims encoding', 'better-wp-security' ) );
}
if ( false === ( $sig = static::url_safe_b64_decode( $cryptob64 ) ) ) {
return new \WP_Error( 'jwt_invalid_format', __( 'Invalid signature encoding', 'better-wp-security' ) );
}
return array( $header, $payload, $sig, $headb64, $bodyb64, $cryptob64 );
}
/**
* Converts and signs a PHP object or array into a JWT string.
*
* @param object|array $payload PHP object or array
* @param string $key The secret key.
* If the algorithm used is asymmetric, this is the private key
* @param string $alg The signing algorithm.
* Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
* @param mixed $key_id
* @param array $head An array with header elements to attach
*
* @return string A signed JWT
*
* @uses json_encode
* @uses url_safe_b64_encode
*/
public static function encode( $payload, $key, $alg = 'HS256', $key_id = null, $head = null ) {
$header = array( 'typ' => 'JWT', 'alg' => $alg );
if ( $key_id !== null ) {
$header['kid'] = $key_id;
}
if ( is_array( $head ) ) {
$header = array_merge( $head, $header );
}
$segments = array();
$segments[] = static::url_safe_b64_encode( static::json_encode( $header ) );
$segments[] = static::url_safe_b64_encode( static::json_encode( $payload ) );
$signing_input = implode( '.', $segments );
if ( 'none' === $alg ) {
$signature = '';
} else {
$signature = static::sign( $signing_input, $key, $alg );
}
if ( is_wp_error( $signature ) ) {
return $signature;
}
$segments[] = static::url_safe_b64_encode( $signature );
return implode( '.', $segments );
}
/**
* Gets the list of support algorithms.
*
* @return \string[][]
*/
public static function get_supported_algos() {
return static::$supported_algs;
}
/**
* Sign a string with a given key and algorithm.
*
* @param string $msg The message to sign
* @param string|resource $key The secret key
* @param string $alg The signing algorithm.
* Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
*
* @return string|\WP_Error An encrypted message
*/
protected static function sign( $msg, $key, $alg = 'HS256' ) {
if ( empty( static::$supported_algs[ $alg ] ) ) {
return new \WP_Error( 'jwt_unsupported_algorithm', __( 'Algorithm not supported', 'better-wp-security' ) );
}
list( $function, $algorithm ) = static::$supported_algs[ $alg ];
switch ( $function ) {
case 'hash_hmac':
return hash_hmac( $algorithm, $msg, $key, true );
case 'openssl':
$signature = '';
$success = openssl_sign( $msg, $signature, $key, $algorithm );
if ( ! $success ) {
return new \WP_Error( 'jwt_openssl_error', __( 'OpenSSL unable to sign data', 'better-wp-security' ) );
}
return $signature;
}
return new \WP_Error( 'jwt_unsupported_algorithm', __( 'Algorithm not supported', 'better-wp-security' ) );
}
/**
* Verify a signature with the message, key and method. Not all methods
* are symmetric, so we must have a separate verify and sign method.
*
* @param string $msg The original message (header and body)
* @param string $signature The original signature
* @param string|resource $key For HS*, a string key works. for RS*, must be a resource of an openssl public key
* @param string $alg The algorithm
*
* @return bool|\WP_Error
*/
protected static function verify( $msg, $signature, $key, $alg ) {
if ( empty( static::$supported_algs[ $alg ] ) ) {
return new \WP_Error( 'jwt_unsupported_algorithm', __( 'Algorithm not supported', 'better-wp-security' ) );
}
list( $function, $algorithm ) = static::$supported_algs[ $alg ];
switch ( $function ) {
case 'openssl':
$success = openssl_verify( $msg, $signature, $key, $algorithm );
if ( $success === 1 ) {
return true;
}
if ( $success === 0 ) {
return false;
}
return new \WP_Error( 'jwt_openssl_error', openssl_error_string() );
case 'hash_hmac':
default:
$hash = hash_hmac( $algorithm, $msg, $key, true );
return hash_equals( $signature, $hash );
}
}
/**
* Decode a JSON string into a PHP object.
*
* @param string $input JSON string
*
* @return object|\WP_Error Object representation of JSON string
*/
protected static function json_decode( $input ) {
$obj = json_decode( $input, false, 512, JSON_BIGINT_AS_STRING );
if ( $errno = json_last_error() ) {
return new \WP_Error( 'jwt_cannot_decode_json', json_last_error_msg(), array( 'code' => $errno ) );
}
return $obj;
}
/**
* Encode a PHP object into a JSON string.
*
* @param object|array $input A PHP object or array
*
* @return string|\WP_Error JSON representation of the PHP object or array
*/
protected static function json_encode( $input ) {
$json = json_encode( $input );
if ( $errno = json_last_error() ) {
return new \WP_Error( 'jwt_cannot_encode_json', json_last_error_msg(), array( 'code' => $errno ) );
}
return $json;
}
/**
* Decode a string with URL-safe Base64.
*
* @param string $input A Base64 encoded string
*
* @return string A decoded string
*/
protected static function url_safe_b64_decode( $input ) {
$remainder = strlen( $input ) % 4;
if ( $remainder ) {
$padlen = 4 - $remainder;
$input .= str_repeat( '=', $padlen );
}
return base64_decode( strtr( $input, '-_', '+/' ) );
}
/**
* Encode a string with URL-safe Base64.
*
* @param string $input The string you want encoded
*
* @return string The base64 encode of what you passed in
*/
protected static function url_safe_b64_encode( $input ) {
return str_replace( '=', '', strtr( base64_encode( $input ), '+/', '-_' ) );
}
}