forked from GNUsocial/gnu-social
309 lines
11 KiB
PHP
309 lines
11 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';
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* @param array $env
|
|
* @return string
|
|
*/
|
|
public function signingText($env) {
|
|
return implode('.', array($env['data'], // this field is pre-base64'd
|
|
Magicsig::base64_url_encode($env['data_type']),
|
|
Magicsig::base64_url_encode($env['encoding']),
|
|
Magicsig::base64_url_encode($env['alg'])));
|
|
}
|
|
|
|
/**
|
|
*
|
|
* @param <type> $text
|
|
* @param <type> $mimetype
|
|
* @param <type> $keypair
|
|
* @return array: associative array of envelope properties
|
|
* @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
|
|
*/
|
|
public function signMessage($text, $mimetype, $keypair)
|
|
{
|
|
$signature_alg = Magicsig::fromString($keypair);
|
|
$armored_text = Magicsig::base64_url_encode($text);
|
|
$env = array(
|
|
'data' => $armored_text,
|
|
'encoding' => MagicEnvelope::ENCODING,
|
|
'data_type' => $mimetype,
|
|
'sig' => '',
|
|
'alg' => $signature_alg->getName()
|
|
);
|
|
|
|
$env['sig'] = $signature_alg->sign($this->signingText($env));
|
|
|
|
return $env;
|
|
}
|
|
|
|
/**
|
|
* Create an <me:env> XML representation of the envelope.
|
|
*
|
|
* @param array $env associative array with envelope data
|
|
* @return string representation of XML document
|
|
* @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
|
|
*/
|
|
public function toXML($env) {
|
|
$xs = new XMLStringer();
|
|
$xs->startXML();
|
|
$xs->elementStart('me:env', array('xmlns:me' => MagicEnvelope::NS));
|
|
$xs->element('me:data', array('type' => $env['data_type']), $env['data']);
|
|
$xs->element('me:encoding', null, $env['encoding']);
|
|
$xs->element('me:alg', null, $env['alg']);
|
|
$xs->element('me:sig', null, $env['sig']);
|
|
$xs->elementEnd('me:env');
|
|
|
|
$string = $xs->getString();
|
|
common_debug($string);
|
|
return $string;
|
|
}
|
|
|
|
/**
|
|
* Extract the contained XML payload, and insert a copy of the envelope
|
|
* signature data as an <me:provenance> section.
|
|
*
|
|
* @param array $env associative array with envelope data
|
|
* @return string representation of modified XML document
|
|
*
|
|
* @fixme in case of XML parsing errors, this will spew to the error log or output
|
|
* @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
|
|
*/
|
|
public function unfold($env)
|
|
{
|
|
$dom = new DOMDocument();
|
|
$dom->loadXML(Magicsig::base64_url_decode($env['data']));
|
|
|
|
if ($dom->documentElement->tagName != 'entry') {
|
|
return false;
|
|
}
|
|
|
|
$prov = $dom->createElementNS(MagicEnvelope::NS, 'me:provenance');
|
|
$prov->setAttribute('xmlns:me', MagicEnvelope::NS);
|
|
$data = $dom->createElementNS(MagicEnvelope::NS, 'me:data', $env['data']);
|
|
$data->setAttribute('type', $env['data_type']);
|
|
$prov->appendChild($data);
|
|
$enc = $dom->createElementNS(MagicEnvelope::NS, 'me:encoding', $env['encoding']);
|
|
$prov->appendChild($enc);
|
|
$alg = $dom->createElementNS(MagicEnvelope::NS, 'me:alg', $env['alg']);
|
|
$prov->appendChild($alg);
|
|
$sig = $dom->createElementNS(MagicEnvelope::NS, 'me:sig', $env['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.
|
|
*
|
|
* @param array $env array representation of magic envelope data, as returned from MagicEnvelope::parse()
|
|
* @return boolean
|
|
*
|
|
* @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
|
|
*/
|
|
public function verify($env)
|
|
{
|
|
if ($env['alg'] != 'RSA-SHA256') {
|
|
common_log(LOG_DEBUG, "Salmon error: bad algorithm");
|
|
return false;
|
|
}
|
|
|
|
if ($env['encoding'] != MagicEnvelope::ENCODING) {
|
|
common_log(LOG_DEBUG, "Salmon error: bad encoding");
|
|
return false;
|
|
}
|
|
|
|
$text = Magicsig::base64_url_decode($env['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($env), $env['sig']);
|
|
}
|
|
|
|
/**
|
|
* Extract envelope data from an XML document containing an <me:env> or <me:provenance> element.
|
|
*
|
|
* @param string XML source
|
|
* @return mixed associative array of envelope data, or false on unrecognized input
|
|
*
|
|
* @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
|
|
* @fixme will spew errors to logs or output in case of XML parse errors
|
|
* @fixme may give fatal errors if some elements are missing or invalid XML
|
|
* @fixme calling DOMDocument::loadXML statically triggers warnings in strict mode
|
|
*/
|
|
public function parse($text)
|
|
{
|
|
$dom = DOMDocument::loadXML($text);
|
|
return $this->fromDom($dom);
|
|
}
|
|
|
|
/**
|
|
* Extract envelope data from an XML document containing an <me:env> or <me:provenance> element.
|
|
*
|
|
* @param DOMDocument $dom
|
|
* @return mixed associative array of envelope data, or false on unrecognized input
|
|
*
|
|
* @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
|
|
* @fixme may give fatal errors if some elements are missing
|
|
*/
|
|
public function fromDom($dom)
|
|
{
|
|
$env_element = $dom->getElementsByTagNameNS(MagicEnvelope::NS, 'env')->item(0);
|
|
if (!$env_element) {
|
|
$env_element = $dom->getElementsByTagNameNS(MagicEnvelope::NS, 'provenance')->item(0);
|
|
}
|
|
|
|
if (!$env_element) {
|
|
return false;
|
|
}
|
|
|
|
$data_element = $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'data')->item(0);
|
|
$sig_element = $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'sig')->item(0);
|
|
return array(
|
|
'data' => preg_replace('/\s/', '', $data_element->nodeValue),
|
|
'data_type' => $data_element->getAttribute('type'),
|
|
'encoding' => $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'encoding')->item(0)->nodeValue,
|
|
'alg' => $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'alg')->item(0)->nodeValue,
|
|
'sig' => preg_replace('/\s/', '', $sig_element->nodeValue),
|
|
);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Variant of MagicEnvelope using the earlier signature form listed in the MagicEnvelope
|
|
* spec in early 2010; this was used in StatusNet up through 0.9.6, so for backwards compatiblity
|
|
* we still need to accept and sometimes send this format.
|
|
*/
|
|
class MagicEnvelopeCompat extends MagicEnvelope {
|
|
|
|
/**
|
|
* StatusNet through 0.9.6 used an earlier version of the MagicEnvelope spec
|
|
* which used only the input data, without the additional fields, as the plaintext
|
|
* for signing.
|
|
*
|
|
* @param array $env
|
|
* @return string
|
|
*/
|
|
public function signingText($env) {
|
|
return $env['data'];
|
|
}
|
|
}
|