Search moodle.org's
Developer Documentation

See Release Notes

  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.
<?php
// vim: foldmethod=marker

$OAuth_last_computed_siguature = false;

/* Generic exception class
 */
class OAuthException extends \Exception {
  // pass
}

class OAuthConsumer {
  public $key;
  public $secret;

> /** @var string|null To store callback_url. */ function __construct($key, $secret, $callback_url=NULL) { > protected $callback_url; $this->key = $key; >
$this->secret = $secret; $this->callback_url = $callback_url; } function __toString() { return "OAuthConsumer[key=$this->key,secret=$this->secret]"; } } class OAuthToken { // access tokens and request tokens public $key; public $secret; /** * key = the token * secret = the token secret */ function __construct($key, $secret) { $this->key = $key; $this->secret = $secret; } /** * generates the basic string serialization of a token that a server * would respond to request_token and access_token calls with */ function to_string() { return "oauth_token=" . OAuthUtil::urlencode_rfc3986($this->key) . "&oauth_token_secret=" . OAuthUtil::urlencode_rfc3986($this->secret); } function __toString() { return $this->to_string(); } } class OAuthSignatureMethod { public function check_signature(&$request, $consumer, $token, $signature) { $built = $this->build_signature($request, $consumer, $token); return $built == $signature; } } class OAuthSignatureMethod_HMAC_SHA1 extends OAuthSignatureMethod { function get_name() { return "HMAC-SHA1"; } public function build_signature($request, $consumer, $token) { global $OAuth_last_computed_signature; $OAuth_last_computed_signature = false; $base_string = $request->get_signature_base_string(); $request->base_string = $base_string; $key_parts = array( $consumer->secret, ($token) ? $token->secret : "" ); $key_parts = OAuthUtil::urlencode_rfc3986($key_parts); $key = implode('&', $key_parts); $computed_signature = base64_encode(hash_hmac('sha1', $base_string, $key, true)); $OAuth_last_computed_signature = $computed_signature; return $computed_signature; } } class OAuthSignatureMethod_PLAINTEXT extends OAuthSignatureMethod { public function get_name() { return "PLAINTEXT"; } public function build_signature($request, $consumer, $token) { $sig = array( OAuthUtil::urlencode_rfc3986($consumer->secret) ); if ($token) { array_push($sig, OAuthUtil::urlencode_rfc3986($token->secret)); } else { array_push($sig, ''); } $raw = implode("&", $sig); // for debug purposes $request->base_string = $raw; return OAuthUtil::urlencode_rfc3986($raw); } } class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod { public function get_name() { return "RSA-SHA1"; } protected function fetch_public_cert(&$request) { // not implemented yet, ideas are: // (1) do a lookup in a table of trusted certs keyed off of consumer // (2) fetch via http using a url provided by the requester // (3) some sort of specific discovery code based on request // // either way should return a string representation of the certificate throw Exception("fetch_public_cert not implemented"); } protected function fetch_private_cert(&$request) { // not implemented yet, ideas are: // (1) do a lookup in a table of trusted certs keyed off of consumer // // either way should return a string representation of the certificate throw Exception("fetch_private_cert not implemented"); } public function build_signature(&$request, $consumer, $token) { $base_string = $request->get_signature_base_string(); $request->base_string = $base_string; // Fetch the private key cert based on the request $cert = $this->fetch_private_cert($request); // Pull the private key ID from the certificate $privatekeyid = openssl_get_privatekey($cert); // Sign using the key $ok = openssl_sign($base_string, $signature, $privatekeyid);
> > // Avoid passing null values to base64_encode. // TODO: Remove this block once PHP 8.0 becomes required. > if (!$ok) { if (PHP_MAJOR_VERSION < 8) { > throw new OAuthException("OpenSSL unable to sign data"); // Release the key resource > }
openssl_free_key($privatekeyid); } return base64_encode($signature); } public function check_signature(&$request, $consumer, $token, $signature) { $decoded_sig = base64_decode($signature); $base_string = $request->get_signature_base_string(); // Fetch the public key cert based on the request $cert = $this->fetch_public_cert($request); // Pull the public key ID from the certificate $publickeyid = openssl_get_publickey($cert); // Check the computed signature against the one passed in the query $ok = openssl_verify($base_string, $decoded_sig, $publickeyid); // TODO: Remove this block once PHP 8.0 becomes required. if (PHP_MAJOR_VERSION < 8) { // Release the key resource openssl_free_key($publickeyid); } return $ok == 1; } } class OAuthRequest { private $parameters; private $http_method; private $http_url; // for debug purposes public $base_string; public static $version = '1.0'; public static $POST_INPUT = 'php://input'; function __construct($http_method, $http_url, $parameters=NULL) { @$parameters or $parameters = array(); $this->parameters = $parameters; $this->http_method = $http_method; $this->http_url = $http_url; } /** * attempt to build up a request from what was passed to the server */ public static function from_request($http_method=NULL, $http_url=NULL, $parameters=NULL) { $scheme = (!isset($_SERVER['HTTPS']) || $_SERVER['HTTPS'] != "on") ? 'http' : 'https'; $port = ""; if ( $_SERVER['SERVER_PORT'] != "80" && $_SERVER['SERVER_PORT'] != "443" && strpos(':', $_SERVER['HTTP_HOST']) < 0 ) { $port = ':' . $_SERVER['SERVER_PORT'] ; } @$http_url or $http_url = $scheme . '://' . $_SERVER['HTTP_HOST'] . $port . $_SERVER['REQUEST_URI']; @$http_method or $http_method = $_SERVER['REQUEST_METHOD']; // We weren't handed any parameters, so let's find the ones relevant to // this request. // If you run XML-RPC or similar you should use this to provide your own // parsed parameter-list if (!$parameters) { // Find request headers $request_headers = OAuthUtil::get_headers(); // Parse the query-string to find GET parameters $parameters = OAuthUtil::parse_parameters($_SERVER['QUERY_STRING']); $ourpost = $_POST; // Add POST Parameters if they exist $parameters = array_merge($parameters, $ourpost); // We have a Authorization-header with OAuth data. Parse the header // and add those overriding any duplicates from GET or POST if (@substr($request_headers['Authorization'], 0, 6) == "OAuth ") { $header_parameters = OAuthUtil::split_header( $request_headers['Authorization'] ); $parameters = array_merge($parameters, $header_parameters); } } return new OAuthRequest($http_method, $http_url, $parameters); } /** * pretty much a helper function to set up the request */ public static function from_consumer_and_token($consumer, $token, $http_method, $http_url, $parameters=NULL) { @$parameters or $parameters = array(); $defaults = array("oauth_version" => OAuthRequest::$version, "oauth_nonce" => OAuthRequest::generate_nonce(), "oauth_timestamp" => OAuthRequest::generate_timestamp(), "oauth_consumer_key" => $consumer->key); if ($token) $defaults['oauth_token'] = $token->key; $parameters = array_merge($defaults, $parameters); // Parse the query-string to find and add GET parameters $parts = parse_url($http_url); if ( !empty($parts['query']) ) { $qparms = OAuthUtil::parse_parameters($parts['query']); $parameters = array_merge($qparms, $parameters); } return new OAuthRequest($http_method, $http_url, $parameters); } public function set_parameter($name, $value, $allow_duplicates = true) { if ($allow_duplicates && isset($this->parameters[$name])) { // We have already added parameter(s) with this name, so add to the list if (is_scalar($this->parameters[$name])) { // This is the first duplicate, so transform scalar (string) // into an array so we can add the duplicates $this->parameters[$name] = array($this->parameters[$name]); } $this->parameters[$name][] = $value; } else { $this->parameters[$name] = $value; } } public function get_parameter($name) { return isset($this->parameters[$name]) ? $this->parameters[$name] : null; } public function get_parameters() { return $this->parameters; } public function unset_parameter($name) { unset($this->parameters[$name]); } /** * The request parameters, sorted and concatenated into a normalized string. * @return string */ public function get_signable_parameters() { // Grab all parameters $params = $this->parameters; // Remove oauth_signature if present // Ref: Spec: 9.1.1 ("The oauth_signature parameter MUST be excluded.") if (isset($params['oauth_signature'])) { unset($params['oauth_signature']); } return OAuthUtil::build_http_query($params); } /** * Returns the base string of this request * * The base string defined as the method, the url * and the parameters (normalized), each urlencoded * and the concated with &. */ public function get_signature_base_string() { $parts = array( $this->get_normalized_http_method(), $this->get_normalized_http_url(), $this->get_signable_parameters() ); $parts = OAuthUtil::urlencode_rfc3986($parts); return implode('&', $parts); } /** * just uppercases the http method */ public function get_normalized_http_method() { return strtoupper($this->http_method); } /** * parses the url and rebuilds it to be * scheme://host/path */ public function get_normalized_http_url() { $parts = parse_url($this->http_url); $port = @$parts['port']; $scheme = $parts['scheme']; $host = $parts['host']; $path = @$parts['path']; $port or $port = ($scheme == 'https') ? '443' : '80'; if (($scheme == 'https' && $port != '443') || ($scheme == 'http' && $port != '80')) { $host = "$host:$port"; } return "$scheme://$host$path"; } /** * builds a url usable for a GET request */ public function to_url() { $post_data = $this->to_postdata(); $out = $this->get_normalized_http_url(); if ($post_data) { $out .= '?'.$post_data; } return $out; } /** * builds the data one would send in a POST request */ public function to_postdata() { return OAuthUtil::build_http_query($this->parameters); } /** * builds the Authorization: header */ public function to_header() { $out ='Authorization: OAuth realm=""'; $total = array(); foreach ($this->parameters as $k => $v) { if (substr($k, 0, 5) != "oauth") continue; if (is_array($v)) { throw new OAuthException('Arrays not supported in headers'); } $out .= ',' . OAuthUtil::urlencode_rfc3986($k) . '="' . OAuthUtil::urlencode_rfc3986($v) . '"'; } return $out; } public function __toString() { return $this->to_url(); } public function sign_request($signature_method, $consumer, $token) { $this->set_parameter( "oauth_signature_method", $signature_method->get_name(), false ); $signature = $this->build_signature($signature_method, $consumer, $token); $this->set_parameter("oauth_signature", $signature, false); } public function build_signature($signature_method, $consumer, $token) { $signature = $signature_method->build_signature($this, $consumer, $token); return $signature; } /** * util function: current timestamp */ private static function generate_timestamp() { return time(); } /** * util function: current nonce */ private static function generate_nonce() { $mt = microtime(); $rand = mt_rand(); return md5($mt . $rand); // md5s look nicer than numbers } } class OAuthServer { protected $timestamp_threshold = 300; // in seconds, five minutes protected $version = 1.0; // hi blaine protected $signature_methods = array(); protected $data_store; function __construct($data_store) { $this->data_store = $data_store; } public function add_signature_method($signature_method) { $this->signature_methods[$signature_method->get_name()] = $signature_method; } // high level functions /** * process a request_token request * returns the request token on success */ public function fetch_request_token(&$request) { $this->get_version($request); $consumer = $this->get_consumer($request); // no token required for the initial token request $token = NULL; $this->check_signature($request, $consumer, $token); $new_token = $this->data_store->new_request_token($consumer); return $new_token; } /** * process an access_token request * returns the access token on success */ public function fetch_access_token(&$request) { $this->get_version($request); $consumer = $this->get_consumer($request); // requires authorized request token $token = $this->get_token($request, $consumer, "request"); $this->check_signature($request, $consumer, $token); $new_token = $this->data_store->new_access_token($token, $consumer); return $new_token; } /** * verify an api call, checks all the parameters */ public function verify_request(&$request) { global $OAuth_last_computed_signature; $OAuth_last_computed_signature = false; $this->get_version($request); $consumer = $this->get_consumer($request); $token = $this->get_token($request, $consumer, "access"); $this->check_signature($request, $consumer, $token); return array($consumer, $token); } // Internals from here /** * version 1 */ private function get_version(&$request) { $version = $request->get_parameter("oauth_version"); if (!$version) { $version = 1.0; } if ($version && $version != $this->version) { throw new OAuthException("OAuth version '$version' not supported"); } return $version; } /** * figure out the signature with some defaults */ private function get_signature_method(&$request) { $signature_method = @$request->get_parameter("oauth_signature_method"); if (!$signature_method) { $signature_method = "PLAINTEXT"; } if (!in_array($signature_method, array_keys($this->signature_methods))) { throw new OAuthException( "Signature method '$signature_method' not supported " . "try one of the following: " . implode(", ", array_keys($this->signature_methods)) ); } return $this->signature_methods[$signature_method]; } /** * try to find the consumer for the provided request's consumer key */ private function get_consumer(&$request) { $consumer_key = @$request->get_parameter("oauth_consumer_key"); if (!$consumer_key) { throw new OAuthException("Invalid consumer key"); } $consumer = $this->data_store->lookup_consumer($consumer_key); if (!$consumer) { throw new OAuthException("Invalid consumer"); } return $consumer; } /** * try to find the token for the provided request's token key */ private function get_token(&$request, $consumer, $token_type="access") { $token_field = @$request->get_parameter('oauth_token'); if ( !$token_field) return false; $token = $this->data_store->lookup_token( $consumer, $token_type, $token_field ); if (!$token) { throw new OAuthException("Invalid $token_type token: $token_field"); } return $token; } /** * all-in-one function to check the signature on a request * should guess the signature method appropriately */ private function check_signature(&$request, $consumer, $token) { // this should probably be in a different method global $OAuth_last_computed_signature; $OAuth_last_computed_signature = false; $timestamp = @$request->get_parameter('oauth_timestamp'); $nonce = @$request->get_parameter('oauth_nonce'); $this->check_timestamp($timestamp); $this->check_nonce($consumer, $token, $nonce, $timestamp); $signature_method = $this->get_signature_method($request); $signature = $request->get_parameter('oauth_signature'); $valid_sig = $signature_method->check_signature( $request, $consumer, $token, $signature ); if (!$valid_sig) { $ex_text = "Invalid signature"; if ( $OAuth_last_computed_signature ) { $ex_text = $ex_text . " ours= $OAuth_last_computed_signature yours=$signature"; } throw new OAuthException($ex_text); } } /** * check that the timestamp is new enough */ private function check_timestamp($timestamp) { // verify that timestamp is recentish $now = time(); if ($now - $timestamp > $this->timestamp_threshold) { throw new OAuthException( "Expired timestamp, yours $timestamp, ours $now" ); } } /** * check that the nonce is not repeated */ private function check_nonce($consumer, $token, $nonce, $timestamp) { // verify that the nonce is uniqueish $found = $this->data_store->lookup_nonce( $consumer, $token, $nonce, $timestamp ); if ($found) { throw new OAuthException("Nonce already used: $nonce"); } } } class OAuthDataStore { function lookup_consumer($consumer_key) { // implement me } function lookup_token($consumer, $token_type, $token) { // implement me } function lookup_nonce($consumer, $token, $nonce, $timestamp) { // implement me } function new_request_token($consumer) { // return a new token attached to this consumer } function new_access_token($token, $consumer) { // return a new access token attached to this consumer // for the user associated with this token if the request token // is authorized // should also invalidate the request token } } class OAuthUtil { public static function urlencode_rfc3986($input) { if (is_array($input)) { return array_map(array('OAuthUtil', 'urlencode_rfc3986'), $input); } else if (is_scalar($input)) { return str_replace( '+', ' ', str_replace('%7E', '~', rawurlencode($input)) ); } else { return ''; } } // This decode function isn't taking into consideration the above // modifications to the encoding process. However, this method doesn't // seem to be used anywhere so leaving it as is. public static function urldecode_rfc3986($string) { return urldecode($string); } // Utility function for turning the Authorization: header into // parameters, has to do some unescaping // Can filter out any non-oauth parameters if needed (default behaviour) public static function split_header($header, $only_allow_oauth_parameters = true) { $pattern = '/(([-_a-z]*)=("([^"]*)"|([^,]*)),?)/'; $offset = 0; $params = array(); while (preg_match($pattern, $header, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) { $match = $matches[0]; $header_name = $matches[2][0]; $header_content = (isset($matches[5])) ? $matches[5][0] : $matches[4][0]; if (preg_match('/^oauth_/', $header_name) || !$only_allow_oauth_parameters) { $params[$header_name] = OAuthUtil::urldecode_rfc3986($header_content); } $offset = $match[1] + strlen($match[0]); } if (isset($params['realm'])) { unset($params['realm']); } return $params; } // helper to try to sort out headers for people who aren't running apache public static function get_headers() { if (function_exists('apache_request_headers')) { // we need this to get the actual Authorization: header // because apache tends to tell us it doesn't exist return apache_request_headers(); } // otherwise we don't have apache and are just going to have to hope // that $_SERVER actually contains what we need $out = array(); foreach ($_SERVER as $key => $value) { if (substr($key, 0, 5) == "HTTP_") { // this is chaos, basically it is just there to capitalize the first // letter of every word that is not an initial HTTP and strip HTTP // code from przemek $key = str_replace( " ", "-", ucwords(strtolower(str_replace("_", " ", substr($key, 5)))) ); $out[$key] = $value; } } return $out; } // This function takes a input like a=b&a=c&d=e and returns the parsed // parameters like this // array('a' => array('b','c'), 'd' => 'e') public static function parse_parameters( $input ) { if (!isset($input) || !$input) return array(); $pairs = explode('&', $input); $parsed_parameters = array(); foreach ($pairs as $pair) { $split = explode('=', $pair, 2); $parameter = OAuthUtil::urldecode_rfc3986($split[0]); $value = isset($split[1]) ? OAuthUtil::urldecode_rfc3986($split[1]) : ''; if (isset($parsed_parameters[$parameter])) { // We have already recieved parameter(s) with this name, so add to the list // of parameters with this name if (is_scalar($parsed_parameters[$parameter])) { // This is the first duplicate, so transform scalar (string) into an array // so we can add the duplicates $parsed_parameters[$parameter] = array($parsed_parameters[$parameter]); } $parsed_parameters[$parameter][] = $value; } else { $parsed_parameters[$parameter] = $value; } } return $parsed_parameters; } public static function build_http_query($params) { if (!$params) return ''; // Urlencode both keys and values $keys = OAuthUtil::urlencode_rfc3986(array_keys($params)); $values = OAuthUtil::urlencode_rfc3986(array_values($params)); $params = array_combine($keys, $values); // Parameters are sorted by name, using lexicographical byte value ordering. // Ref: Spec: 9.1.1 (1) uksort($params, 'strcmp'); $pairs = array(); foreach ($params as $parameter => $value) { if (is_array($value)) { // If two or more parameters share the same name, they are sorted by their value // Ref: Spec: 9.1.1 (1) natsort($value); foreach ($value as $duplicate_value) { $pairs[] = $parameter . '=' . $duplicate_value; } } else { $pairs[] = $parameter . '=' . $value; } } // For each parameter, the name is separated from the corresponding value by an '=' character (ASCII code 61) // Each name-value pair is separated by an '&' character (ASCII code 38) return implode('&', $pairs); } } ?>