<?php
// vim: foldmethod=marker
/* Generic exception class
*/
class OAuthException extends Exception {
// pass
}
class OAuthConsumer {
public $key;
public $secret;
function __construct($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();
}
}
/**
* A class for implementing a Signature Method
* See section 9 ("Signing Requests") in the spec
*/
abstract class OAuthSignatureMethod {
/**
* Needs to return the name of the Signature Method (ie HMAC-SHA1)
* @return string
*/
abstract public function get_name();
/**
* Build up the signature
* NOTE: The output of this function MUST NOT be urlencoded.
* the encoding is handled in OAuthRequest when the final
* request is serialized
* @param OAuthRequest $request
* @param OAuthConsumer $consumer
* @param OAuthToken $token
* @return string
*/
abstract public function build_signature($request, $consumer, $token);
/**
* Verifies that a given signature is correct
* @param OAuthRequest $request
* @param OAuthConsumer $consumer
* @param OAuthToken $token
* @param string $signature
* @return bool
*/
public function check_signature($request, $consumer, $token, $signature) {
$built = $this->build_signature($request, $consumer, $token);
return $built == $signature;
}
}
/**
* The HMAC-SHA1 signature method uses the HMAC-SHA1 signature algorithm as defined in [RFC2104]
* where the Signature Base String is the text and the key is the concatenated values (each first
* encoded per Parameter Encoding) of the Consumer Secret and Token Secret, separated by an '&'
* character (ASCII code 38) even if empty.
* - Chapter 9.2 ("HMAC-SHA1")
*/
class OAuthSignatureMethod_HMAC_SHA1 extends OAuthSignatureMethod {
function get_name() {
return "HMAC-SHA1";
}
public function build_signature($request, $consumer, $token) {
$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);
return base64_encode(hash_hmac('sha1', $base_string, $key, true));
}
}
/**
* The PLAINTEXT method does not provide any security protection and SHOULD only be used
* over a secure channel such as HTTPS. It does not use the Signature Base String.
* - Chapter 9.4 ("PLAINTEXT")
*/
class OAuthSignatureMethod_PLAINTEXT extends OAuthSignatureMethod {
public function get_name() {
return "PLAINTEXT";
}
/**
* oauth_signature is set to the concatenated encoded values of the Consumer Secret and
* Token Secret, separated by a '&' character (ASCII code 38), even if either secret is
* empty. The result MUST be encoded again.
* - Chapter 9.4.1 ("Generating Signatures")
*
* Please note that the second encoding MUST NOT happen in the SignatureMethod, as
* OAuthRequest handles this!
*/
public function build_signature($request, $consumer, $token) {
$key_parts = array(
$consumer->secret,
($token) ? $token->secret : ""
);
$key_parts = OAuthUtil::urlencode_rfc3986($key_parts);
$key = implode('&', $key_parts);
$request->base_string = $key;
return $key;
}
}
/**
* The RSA-SHA1 signature method uses the RSASSA-PKCS1-v1_5 signature algorithm as defined in
* [RFC3447] section 8.2 (more simply known as PKCS#1), using SHA-1 as the hash function for
* EMSA-PKCS1-v1_5. It is assumed that the Consumer has provided its RSA public key in a
* verified way to the Service Provider, in a manner which is beyond the scope of this
* specification.
* - Chapter 9.3 ("RSA-SHA1")
*/
abstract class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
public function get_name() {
return "RSA-SHA1";
}
// Up to the SP to implement this lookup of keys. Possible ideas are:
// (1) do a lookup in a table of trusted certs keyed off of consumer
// (2) fetch via http using a url provided by the requester
// (3) some sort of specific discovery code based on request
//
// Either way should return a string representation of the certificate
protected abstract function fetch_public_cert(&$request);
// Up to the SP to implement this lookup of keys. Possible 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
protected abstract function fetch_private_cert(&$request);
public function build_signature($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, $privatekeyid);
// Release the key resource
openssl_free_key($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, $publickeyid);
// Release the key resource
openssl_free_key($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();
$parameters = array_merge( OAuthUtil::parse_parameters(parse_url($http_url, PHP_URL_QUERY)), $parameters);
$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']) || $_SERVER['HTTPS'] != "on")
? 'http'
: 'https';
@$http_url or $http_url = $scheme .
'://' . $_SERVER['HTTP_HOST'] .
':' .
$_SERVER['SERVER_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']);
// It's a POST request of the proper content-type, so parse POST
// parameters and add those overriding any duplicates from GET
if ($http_method == "POST"
&& @strstr($request_headers["Content-Type"],
"application/x-www-form-urlencoded")
) {
$post_data = OAuthUtil::parse_parameters(
file_get_contents(self::$POST_INPUT)
);
$parameters = array_merge($parameters, $post_data);
}
// We have a Authorization-header with OAuth data. Parse the header
// and add those overriding any duplicates from GET or POST
if (@substr($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, $parameters);
return new OAuthRequest($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($realm=null) {
$first = true;
if($realm) {
$out = 'Authorization: OAuth realm="' . OAuthUtil::urlencode_rfc3986($realm) . '"';
$first = false;
} else
$out = 'Authorization: OAuth';
$total = array();
foreach ($this->parameters as $k => $v) {
if (substr($k, 0, 5) != "oauth") continue;
if (is_array($v)) {
throw new OAuthException('Arrays not supported in headers');
}
$out .= ($first) ? ' ' : ',';
$out .= OAuthUtil::urlencode_rfc3986($k) .
'="' .
OAuthUtil::urlencode_rfc3986($v) .
'"';
$first = false;
}
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);
// Rev A change
$callback = $request->get_parameter('oauth_callback');
$new_token = $this->data_store->new_request_token($consumer, $callback);
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);
// Rev A change
$verifier = $request->get_parameter('oauth_verifier');
$new_token = $this->data_store->new_access_token($token, $consumer, $verifier);
return $new_token;
}
/**
* verify an api call, checks all the parameters
*/
public function verify_request(&$request) {
$this->get_version($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) {
// Service Providers MUST assume the protocol version to be 1.0 if this parameter is not present.
// Chapter 7.0 ("Accessing Protected Ressources")
$version = '1.0';
}
if ($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 (!$signature_method) {
// According to chapter 7 ("Accessing Protected Ressources") the signature-method
// parameter is required, and we can't just fallback to PLAINTEXT
throw new OAuthException('No signature method parameter. This parameter is required');
}
if (!in_array($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');
$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
$timestamp = @$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) {
throw new OAuthException("Invalid signature");
}
}
/**
* check that the timestamp is new enough
*/
private function check_timestamp($timestamp) {
if( ! $timestamp )
throw new OAuthException(
'Missing timestamp parameter. The parameter is required'
);
// verify that timestamp is recentish
$now = time();
if (abs($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) {
if( ! $nonce )
throw new OAuthException(
'Missing nonce parameter. The parameter is required'
);
// 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, $callback = null) {
// return a new token attached to this consumer
}
function new_access_token($token, $consumer, $verifier = null) {
// return a new access token attached to this consumer
// for the user associated with this token if the request token
// is authorized
// should also invalidate the request token
}
}
class OAuthUtil {
public static function urlencode_rfc3986($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
$headers = apache_request_headers();
// sanitize the output of apache_request_headers because
// we always want the keys to be Cased-Like-This and arh()
// returns the headers in the same case as they are in the
// request
$out = array();
foreach( $headers AS $key => $value ) {
$key = str_replace(
" ",
"-",
ucwords(strtolower(str_replace("-", " ", $key)))
);
$out[$key] = $value;
}
} else {
// otherwise we don't have apache and are just going to have to hope
// that $_SERVER actually contains what we need
$out = array();
if( isset($_SERVER['CONTENT_TYPE']) )
$out['Content-Type'] = $_SERVER['CONTENT_TYPE'];
if( isset($_ENV['CONTENT_TYPE']) )
$out['Content-Type'] = $_ENV['CONTENT_TYPE'];
foreach ($_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);
}
}
?>
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