forked from GNUsocial/gnu-social
327 lines
12 KiB
PHP
327 lines
12 KiB
PHP
<?php
|
|
/**
|
|
* StatusNet - the distributed open-source microblogging tool
|
|
* Copyright (C) 2010, StatusNet, Inc.
|
|
*
|
|
* A sample module to show best practices for StatusNet plugins
|
|
*
|
|
* PHP version 5
|
|
*
|
|
* This program is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU Affero General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU Affero General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Affero General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
* @package StatusNet
|
|
* @author James Walker <james@status.net>
|
|
* @copyright 2010 StatusNet, Inc.
|
|
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
|
|
* @link http://status.net/
|
|
*/
|
|
class MagicEnvelope
|
|
{
|
|
const ENCODING = 'base64url';
|
|
|
|
const NS = 'http://salmon-protocol.org/ns/magic-env';
|
|
|
|
protected $data = null; // When stored here it is _always_ base64url encoded
|
|
protected $data_type = null;
|
|
protected $encoding = null;
|
|
protected $alg = null;
|
|
protected $sig = null;
|
|
|
|
/**
|
|
* Extract envelope data from an XML document containing an <me:env> or <me:provenance> element.
|
|
*
|
|
* @param string XML source
|
|
* @return mixed associative array of envelope data, or false on unrecognized input
|
|
*
|
|
* @fixme will spew errors to logs or output in case of XML parse errors
|
|
* @fixme may give fatal errors if some elements are missing or invalid XML
|
|
* @fixme calling DOMDocument::loadXML statically triggers warnings in strict mode
|
|
*/
|
|
public function __construct($xml=null) {
|
|
if (!empty($xml)) {
|
|
$dom = DOMDocument::loadXML($xml);
|
|
if (!$dom instanceof DOMDocument) {
|
|
throw new ServerException('Tried to load malformed XML as DOM');
|
|
} elseif (!$this->fromDom($dom)) {
|
|
throw new ServerException('Could not load MagicEnvelope from DOM');
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Get the Salmon keypair from a URI, uses XRD Discovery etc.
|
|
*
|
|
* @return Magicsig with loaded keypair
|
|
*/
|
|
public function getKeyPair($signer_uri)
|
|
{
|
|
$disco = new Discovery();
|
|
|
|
// Throws exception on lookup problems
|
|
$xrd = $disco->lookup($signer_uri);
|
|
|
|
$link = $xrd->get(Magicsig::PUBLICKEYREL);
|
|
if (is_null($link)) {
|
|
// TRANS: Exception.
|
|
throw new Exception(_m('Unable to locate signer public key.'));
|
|
}
|
|
|
|
// We have a public key element, let's hope it has proper key data.
|
|
$keypair = false;
|
|
$parts = explode(',', $link->href);
|
|
if (count($parts) == 2) {
|
|
$keypair = $parts[1];
|
|
} else {
|
|
// Backwards compatibility check for separator bug in 0.9.0
|
|
$parts = explode(';', $link->href);
|
|
if (count($parts) == 2) {
|
|
$keypair = $parts[1];
|
|
}
|
|
}
|
|
|
|
if ($keypair === false) {
|
|
// For debugging clarity. Keypair did not pass count()-check above.
|
|
// TRANS: Exception when public key was not properly formatted.
|
|
throw new Exception(_m('Incorrectly formatted public key element.'));
|
|
}
|
|
|
|
$magicsig = Magicsig::fromString($keypair);
|
|
if (!$magicsig instanceof Magicsig) {
|
|
common_debug('Salmon error: unable to parse keypair: '.var_export($keypair,true));
|
|
// TRANS: Exception when public key was properly formatted but not parsable.
|
|
throw new ServerException(_m('Retrieved Salmon keypair could not be parsed.'));
|
|
}
|
|
|
|
return $magicsig;
|
|
}
|
|
|
|
/**
|
|
* The current MagicEnvelope spec as used in StatusNet 0.9.7 and later
|
|
* includes both the original data and some signing metadata fields as
|
|
* the input plaintext for the signature hash.
|
|
*
|
|
* @return string
|
|
*/
|
|
public function signingText() {
|
|
return implode('.', array($this->data, // this field is pre-base64'd
|
|
Magicsig::base64_url_encode($this->data_type),
|
|
Magicsig::base64_url_encode($this->encoding),
|
|
Magicsig::base64_url_encode($this->alg)));
|
|
}
|
|
|
|
/**
|
|
*
|
|
* @param <type> $text
|
|
* @param <type> $mimetype
|
|
* @param Magicsig $magicsig Magicsig with private key available.
|
|
* @return MagicEnvelope object with all properties set
|
|
*/
|
|
public static function signMessage($text, $mimetype, Magicsig $magicsig)
|
|
{
|
|
$magic_env = new MagicEnvelope();
|
|
|
|
// Prepare text and metadata for signing
|
|
$magic_env->data = Magicsig::base64_url_encode($text);
|
|
$magic_env->data_type = $mimetype;
|
|
$magic_env->encoding = self::ENCODING;
|
|
$magic_env->alg = $magicsig->getName();
|
|
// Get the actual signature
|
|
$magic_env->sig = $magicsig->sign($magic_env->signingText());
|
|
|
|
return $magic_env;
|
|
}
|
|
|
|
/**
|
|
* Create an <me:env> XML representation of the envelope.
|
|
*
|
|
* @return string representation of XML document
|
|
*/
|
|
public function toXML() {
|
|
$xs = new XMLStringer();
|
|
$xs->startXML();
|
|
$xs->elementStart('me:env', array('xmlns:me' => self::NS));
|
|
$xs->element('me:data', array('type' => $this->data_type), $this->data);
|
|
$xs->element('me:encoding', null, $this->encoding);
|
|
$xs->element('me:alg', null, $this->alg);
|
|
$xs->element('me:sig', null, $this->sig);
|
|
$xs->elementEnd('me:env');
|
|
|
|
$string = $xs->getString();
|
|
common_debug('MagicEnvelope XML: ' . $string);
|
|
return $string;
|
|
}
|
|
|
|
/**
|
|
* Extract the contained XML payload, and insert a copy of the envelope
|
|
* signature data as an <me:provenance> section.
|
|
*
|
|
* @return string representation of modified XML document
|
|
*
|
|
* @fixme in case of XML parsing errors, this will spew to the error log or output
|
|
*/
|
|
public function unfold()
|
|
{
|
|
$dom = new DOMDocument();
|
|
$dom->loadXML(Magicsig::base64_url_decode($this->data));
|
|
|
|
if ($dom->documentElement->tagName != 'entry') {
|
|
return false;
|
|
}
|
|
|
|
$prov = $dom->createElementNS(self::NS, 'me:provenance');
|
|
$prov->setAttribute('xmlns:me', self::NS);
|
|
$data = $dom->createElementNS(self::NS, 'me:data', $this->data);
|
|
$data->setAttribute('type', $this->data_type);
|
|
$prov->appendChild($data);
|
|
$enc = $dom->createElementNS(self::NS, 'me:encoding', $this->encoding);
|
|
$prov->appendChild($enc);
|
|
$alg = $dom->createElementNS(self::NS, 'me:alg', $this->alg);
|
|
$prov->appendChild($alg);
|
|
$sig = $dom->createElementNS(self::NS, 'me:sig', $this->sig);
|
|
$prov->appendChild($sig);
|
|
|
|
$dom->documentElement->appendChild($prov);
|
|
|
|
return $dom->saveXML();
|
|
}
|
|
|
|
/**
|
|
* Find the author URI referenced in the given Atom entry.
|
|
*
|
|
* @param string $text string containing Atom entry XML
|
|
* @return mixed URI string or false if XML parsing fails, or null if no author URI can be found
|
|
*
|
|
* @fixme XML parsing failures will spew to error logs/output
|
|
*/
|
|
public function getAuthorUri($text) {
|
|
$doc = new DOMDocument();
|
|
if (!$doc->loadXML($text)) {
|
|
return FALSE;
|
|
}
|
|
|
|
if ($doc->documentElement->tagName == 'entry') {
|
|
$authors = $doc->documentElement->getElementsByTagName('author');
|
|
foreach ($authors as $author) {
|
|
$uris = $author->getElementsByTagName('uri');
|
|
foreach ($uris as $uri) {
|
|
return $uri->nodeValue;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Attempt to verify cryptographic signing for parsed envelope data.
|
|
* Requires network access to retrieve public key referenced by the envelope signer.
|
|
*
|
|
* Details of failure conditions are dumped to output log and not exposed to caller.
|
|
*
|
|
* @return boolean
|
|
*/
|
|
public function verify()
|
|
{
|
|
if ($this->alg != 'RSA-SHA256') {
|
|
common_log(LOG_DEBUG, "Salmon error: bad algorithm");
|
|
return false;
|
|
}
|
|
|
|
if ($this->encoding != self::ENCODING) {
|
|
common_log(LOG_DEBUG, "Salmon error: bad encoding");
|
|
return false;
|
|
}
|
|
|
|
// $this->data is base64_url_encoded and should contain XML which is passed to getAuthorUri
|
|
$text = Magicsig::base64_url_decode($this->data);
|
|
$signer_uri = $this->getAuthorUri($text);
|
|
|
|
try {
|
|
$magicsig = $this->getKeyPair($signer_uri);
|
|
} catch (Exception $e) {
|
|
common_log(LOG_DEBUG, "Salmon error: ".$e->getMessage());
|
|
return false;
|
|
}
|
|
|
|
return $magicsig->verify($this->signingText(), $this->sig);
|
|
}
|
|
|
|
/**
|
|
* Extract envelope data from an XML document containing an <me:env> or <me:provenance> element.
|
|
*
|
|
* @param DOMDocument $dom
|
|
* @return mixed associative array of envelope data, or false on unrecognized input
|
|
*
|
|
* @fixme may give fatal errors if some elements are missing
|
|
*/
|
|
protected function fromDom(DOMDocument $dom)
|
|
{
|
|
$env_element = $dom->getElementsByTagNameNS(self::NS, 'env')->item(0);
|
|
if (!$env_element) {
|
|
$env_element = $dom->getElementsByTagNameNS(self::NS, 'provenance')->item(0);
|
|
}
|
|
|
|
if (!$env_element) {
|
|
return false;
|
|
}
|
|
|
|
$data_element = $env_element->getElementsByTagNameNS(self::NS, 'data')->item(0);
|
|
$sig_element = $env_element->getElementsByTagNameNS(self::NS, 'sig')->item(0);
|
|
|
|
$this->data = preg_replace('/\s/', '', $data_element->nodeValue);
|
|
$this->data_type = $data_element->getAttribute('type');
|
|
$this->encoding = $env_element->getElementsByTagNameNS(self::NS, 'encoding')->item(0)->nodeValue;
|
|
$this->alg = $env_element->getElementsByTagNameNS(self::NS, 'alg')->item(0)->nodeValue;
|
|
$this->sig = preg_replace('/\s/', '', $sig_element->nodeValue);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Encode the given string as a signed MagicEnvelope XML document,
|
|
* using the keypair for the given local user profile. We can of
|
|
* course not sign a remote profile's slap, since we don't have the
|
|
* private key.
|
|
*
|
|
* Side effects: will create and store a keypair on-demand if one
|
|
* hasn't already been generated for this user. This can be very slow
|
|
* on some systems.
|
|
*
|
|
* @param string $text XML fragment to sign, assumed to be Atom
|
|
* @param Profile $actor Profile of a local user to use as signer
|
|
*
|
|
* @return string XML string representation of magic envelope
|
|
*
|
|
* @throws Exception on bad profile input or key generation problems
|
|
* @fixme if signing fails, this seems to return the original text without warning. Is there a reason for this?
|
|
*/
|
|
public static function signForProfile($text, Profile $actor)
|
|
{
|
|
// We only generate keys for our local users of course, so let
|
|
// getUser throw an exception if the profile is not local.
|
|
$user = $actor->getUser();
|
|
|
|
// Find already stored key
|
|
$magicsig = Magicsig::getKV('user_id', $user->id);
|
|
if (!$magicsig instanceof Magicsig) {
|
|
// No keypair yet, let's generate one.
|
|
$magicsig = new Magicsig();
|
|
$magicsig->generate($user->id);
|
|
}
|
|
|
|
$magic_env = self::signMessage($text, 'application/atom+xml', $magicsig);
|
|
|
|
assert($magicenv instanceof MagicEnvelope);
|
|
|
|
return $magic_env;
|
|
}
|
|
}
|