3 * StatusNet - the distributed open-source microblogging tool
4 * Copyright (C) 2010, StatusNet, Inc.
6 * A sample module to show best practices for StatusNet plugins
10 * This program is free software: you can redistribute it and/or modify
11 * it under the terms of the GNU Affero General Public License as published by
12 * the Free Software Foundation, either version 3 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU Affero General Public License for more details.
20 * You should have received a copy of the GNU Affero General Public License
21 * along with this program. If not, see <http://www.gnu.org/licenses/>.
24 * @author James Walker <james@status.net>
25 * @copyright 2010 StatusNet, Inc.
26 * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
27 * @link http://status.net/
32 const ENCODING = 'base64url';
34 const NS = 'http://salmon-protocol.org/ns/magic-env';
36 private function normalizeUser($user_id)
38 if (substr($user_id, 0, 5) == 'http:' ||
39 substr($user_id, 0, 6) == 'https:' ||
40 substr($user_id, 0, 5) == 'acct:') {
44 if (strpos($user_id, '@') !== FALSE) {
45 return 'acct:' . $user_id;
48 return 'http://' . $user_id;
51 public function getKeyPair($signer_uri)
53 $disco = new Discovery();
56 $xrd = $disco->lookup($signer_uri);
57 } catch (Exception $e) {
61 if ($link = Discovery::getService($xrd->links, Magicsig::PUBLICKEYREL)) {
63 $parts = explode(',', $link['href']);
64 if (count($parts) == 2) {
67 // Backwards compatibility check for separator bug in 0.9.0
68 $parts = explode(';', $link['href']);
69 if (count($parts) == 2) {
80 throw new Exception(_m('Unable to locate signer public key.'));
84 * The current MagicEnvelope spec as used in StatusNet 0.9.7 and later
85 * includes both the original data and some signing metadata fields as
86 * the input plaintext for the signature hash.
91 public function signingText($env) {
92 return implode('.', array($env['data'], // this field is pre-base64'd
93 Magicsig::base64_url_encode($env['data_type']),
94 Magicsig::base64_url_encode($env['encoding']),
95 Magicsig::base64_url_encode($env['alg'])));
100 * @param <type> $text
101 * @param <type> $mimetype
102 * @param <type> $keypair
103 * @return array: associative array of envelope properties
104 * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
106 public function signMessage($text, $mimetype, $keypair)
108 $signature_alg = Magicsig::fromString($keypair);
109 $armored_text = Magicsig::base64_url_encode($text);
111 'data' => $armored_text,
112 'encoding' => MagicEnvelope::ENCODING,
113 'data_type' => $mimetype,
115 'alg' => $signature_alg->getName()
118 $env['sig'] = $signature_alg->sign($this->signingText($env));
124 * Create an <me:env> XML representation of the envelope.
126 * @param array $env associative array with envelope data
127 * @return string representation of XML document
128 * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
130 public function toXML($env) {
131 $xs = new XMLStringer();
133 $xs->elementStart('me:env', array('xmlns:me' => MagicEnvelope::NS));
134 $xs->element('me:data', array('type' => $env['data_type']), $env['data']);
135 $xs->element('me:encoding', null, $env['encoding']);
136 $xs->element('me:alg', null, $env['alg']);
137 $xs->element('me:sig', null, $env['sig']);
138 $xs->elementEnd('me:env');
140 $string = $xs->getString();
141 common_debug($string);
146 * Extract the contained XML payload, and insert a copy of the envelope
147 * signature data as an <me:provenance> section.
149 * @param array $env associative array with envelope data
150 * @return string representation of modified XML document
152 * @fixme in case of XML parsing errors, this will spew to the error log or output
153 * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
155 public function unfold($env)
157 $dom = new DOMDocument();
158 $dom->loadXML(Magicsig::base64_url_decode($env['data']));
160 if ($dom->documentElement->tagName != 'entry') {
164 $prov = $dom->createElementNS(MagicEnvelope::NS, 'me:provenance');
165 $prov->setAttribute('xmlns:me', MagicEnvelope::NS);
166 $data = $dom->createElementNS(MagicEnvelope::NS, 'me:data', $env['data']);
167 $data->setAttribute('type', $env['data_type']);
168 $prov->appendChild($data);
169 $enc = $dom->createElementNS(MagicEnvelope::NS, 'me:encoding', $env['encoding']);
170 $prov->appendChild($enc);
171 $alg = $dom->createElementNS(MagicEnvelope::NS, 'me:alg', $env['alg']);
172 $prov->appendChild($alg);
173 $sig = $dom->createElementNS(MagicEnvelope::NS, 'me:sig', $env['sig']);
174 $prov->appendChild($sig);
176 $dom->documentElement->appendChild($prov);
178 return $dom->saveXML();
182 * Find the author URI referenced in the given Atom entry.
184 * @param string $text string containing Atom entry XML
185 * @return mixed URI string or false if XML parsing fails, or null if no author URI can be found
187 * @fixme XML parsing failures will spew to error logs/output
189 public function getAuthor($text) {
190 $doc = new DOMDocument();
191 if (!$doc->loadXML($text)) {
195 if ($doc->documentElement->tagName == 'entry') {
196 $authors = $doc->documentElement->getElementsByTagName('author');
197 foreach ($authors as $author) {
198 $uris = $author->getElementsByTagName('uri');
199 foreach ($uris as $uri) {
200 return $this->normalizeUser($uri->nodeValue);
207 * Check if the author in the Atom entry fragment claims to match
208 * the given identifier URI.
210 * @param string $text string containing Atom entry XML
211 * @param string $signer_uri
214 public function checkAuthor($text, $signer_uri)
216 return ($this->getAuthor($text) == $signer_uri);
220 * Attempt to verify cryptographic signing for parsed envelope data.
221 * Requires network access to retrieve public key referenced by the envelope signer.
223 * Details of failure conditions are dumped to output log and not exposed to caller.
225 * @param array $env array representation of magic envelope data, as returned from MagicEnvelope::parse()
228 * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
230 public function verify($env)
232 if ($env['alg'] != 'RSA-SHA256') {
233 common_log(LOG_DEBUG, "Salmon error: bad algorithm");
237 if ($env['encoding'] != MagicEnvelope::ENCODING) {
238 common_log(LOG_DEBUG, "Salmon error: bad encoding");
242 $text = Magicsig::base64_url_decode($env['data']);
243 $signer_uri = $this->getAuthor($text);
246 $keypair = $this->getKeyPair($signer_uri);
247 } catch (Exception $e) {
248 common_log(LOG_DEBUG, "Salmon error: ".$e->getMessage());
252 $verifier = Magicsig::fromString($keypair);
255 common_log(LOG_DEBUG, "Salmon error: unable to parse keypair");
259 return $verifier->verify($this->signingText($env), $env['sig']);
263 * Extract envelope data from an XML document containing an <me:env> or <me:provenance> element.
265 * @param string XML source
266 * @return mixed associative array of envelope data, or false on unrecognized input
268 * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
269 * @fixme will spew errors to logs or output in case of XML parse errors
270 * @fixme may give fatal errors if some elements are missing or invalid XML
271 * @fixme calling DOMDocument::loadXML statically triggers warnings in strict mode
273 public function parse($text)
275 $dom = DOMDocument::loadXML($text);
276 return $this->fromDom($dom);
280 * Extract envelope data from an XML document containing an <me:env> or <me:provenance> element.
282 * @param DOMDocument $dom
283 * @return mixed associative array of envelope data, or false on unrecognized input
285 * @fixme it might be easier to work with storing envelope data these in the object instead of passing arrays around
286 * @fixme may give fatal errors if some elements are missing
288 public function fromDom($dom)
290 $env_element = $dom->getElementsByTagNameNS(MagicEnvelope::NS, 'env')->item(0);
292 $env_element = $dom->getElementsByTagNameNS(MagicEnvelope::NS, 'provenance')->item(0);
299 $data_element = $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'data')->item(0);
300 $sig_element = $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'sig')->item(0);
302 'data' => preg_replace('/\s/', '', $data_element->nodeValue),
303 'data_type' => $data_element->getAttribute('type'),
304 'encoding' => $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'encoding')->item(0)->nodeValue,
305 'alg' => $env_element->getElementsByTagNameNS(MagicEnvelope::NS, 'alg')->item(0)->nodeValue,
306 'sig' => preg_replace('/\s/', '', $sig_element->nodeValue),
312 * Variant of MagicEnvelope using the earlier signature form listed in the MagicEnvelope
313 * spec in early 2010; this was used in StatusNet up through 0.9.6, so for backwards compatiblity
314 * we still need to accept and sometimes send this format.
316 class MagicEnvelopeCompat extends MagicEnvelope {
319 * StatusNet through 0.9.6 used an earlier version of the MagicEnvelope spec
320 * which used only the input data, without the additional fields, as the plaintext
326 public function signingText($env) {