Proyectos de Subversion Moodle

<?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. */

  protected $callback_url;

  function __construct($key, $secret, $callback_url=NULL) {

    $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.

    if (!$ok) {

      throw new OAuthException("OpenSSL unable to sign data");

    }

    // TODO: Remove this block once PHP 8.0 becomes required.

    if (PHP_MAJOR_VERSION < 8) {

      // 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);

  }

}

?>