3 * GNU Social - a federating social network
4 * Copyright (C) 2015, Free Software Foundation, Inc.
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU Affero General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU Affero General Public License for more details.
16 * You should have received a copy of the GNU Affero General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 if (!defined('GNUSOCIAL')) { exit(1); }
23 * Diaspora federation protocol plugin for GNU Social
29 * @package ProtocolDiasporaPlugin
30 * @maintainer Mikael Nordfeldth <mmn@hethane.se>
33 // Depends on OStatus of course.
36 //Since Magicsig hasn't loaded yet
37 require_once('Crypt/AES.php');
39 class DiasporaPlugin extends Plugin
41 const REL_SEED_LOCATION = 'http://joindiaspora.com/seed_location';
42 const REL_GUID = 'http://joindiaspora.com/guid';
43 const REL_PUBLIC_KEY = 'diaspora-public-key';
45 public function onEndAttachPubkeyToUserXRD(Magicsig $magicsig, XML_XRD $xrd, Profile $target)
47 // So far we've only handled RSA keys, but it can change in the future,
48 // so be prepared. And remember to change the statically assigned type attribute below!
49 assert($magicsig->publicKey instanceof Crypt_RSA);
50 $xrd->links[] = new XML_XRD_Element_Link(self::REL_PUBLIC_KEY,
51 base64_encode($magicsig->exportPublicKey()), 'RSA');
53 // Instead of choosing a random string, we calculate our GUID from the public key
54 // by fingerprint through a sha256 hash.
55 $xrd->links[] = new XML_XRD_Element_Link(self::REL_GUID,
56 strtolower($magicsig->toFingerprint()));
59 public function onMagicsigPublicKeyFromXRD(XML_XRD $xrd, &$pubkey)
61 // See if we have a Diaspora public key in the XRD response
62 $link = $xrd->get(self::REL_PUBLIC_KEY, 'RSA');
63 if (!is_null($link)) {
64 // If we do, decode it so we have the PKCS1 format (starts with -----BEGIN PUBLIC KEY-----)
65 $pkcs1 = base64_decode($link->href);
66 $magicsig = new Magicsig(Magicsig::DEFAULT_SIGALG); // Diaspora uses RSA-SHA256 (we do too)
68 // Try to load the public key so we can get it in the standard Magic signature format
69 $magicsig->loadPublicKeyPKCS1($pkcs1);
70 // We found it and will now store it in $pubkey in a proper format!
71 // This is how it would be found in a well implemented XRD according to the standard.
72 $pubkey = 'data:application/magic-public-key,'.$magicsig->toString();
73 common_debug('magic-public-key found in diaspora-public-key: '.$pubkey);
75 } catch (ServerException $e) {
76 common_log(LOG_WARNING, $e->getMessage());
82 public function onPluginVersion(array &$versions)
84 $versions[] = array('name' => 'Diaspora',
86 'author' => 'Mikael Nordfeldth',
87 'homepage' => 'https://gnu.io/social',
88 // TRANS: Plugin description.
89 'rawdescription' => _m('Follow people across social networks that implement '.
90 'the <a href="https://diasporafoundation.org/">Diaspora</a> federation protocol.'));
95 public function onStartMagicEnvelopeToXML(MagicEnvelope $magic_env, XMLStringer $xs, $flavour=null, Profile $target=null)
97 // Since Diaspora doesn't use a separate namespace for their "extended"
98 // salmon slap, we'll have to resort to this workaround hack.
99 if ($flavour !== 'diaspora') {
103 // WARNING: This changes the $magic_env contents! Be aware of it.
106 * https://wiki.diasporafoundation.org/Federation_protocol_overview
107 * http://www.rubydoc.info/github/Raven24/diaspora-federation/master/DiasporaFederation/Salmon/EncryptedSlap
109 * Constructing the encryption header
112 // For some reason diaspora wants the salmon slap in a <diaspora> header.
113 $xs->elementStart('diaspora', array('xmlns'=>'https://joindiaspora.com/protocol'));
116 * Choose an AES key and initialization vector, suitable for the
117 * aes-256-cbc cipher. I shall refer to this as the “inner key”
118 * and the “inner initialization vector (iv)”.
120 $inner_key = new \phpseclib\Crypt\AES(\phpseclib\Crypt\AES::MODE_CBC);
121 $inner_key->setKeyLength(256); // set length to 256 bits (could be calculated, but let's be sure)
122 $inner_key->setKey(common_random_rawstr(32)); // 32 bytes from a (pseudo) random source
123 $inner_key->setIV(common_random_rawstr(16)); // 16 bytes is the block length
126 * Construct the following XML snippet:
128 * <iv>((base64-encoded inner iv))</iv>
129 * <aes_key>((base64-encoded inner key))</aes_key>
131 * <name>Alice Exampleman</name>
132 * <uri>acct:user@sender.example</uri>
134 * </decrypted_header>
136 $decrypted_header = sprintf('<decrypted_header><iv>%1$s</iv><aes_key>%2$s</aes_key><author_id>%3$s</author_id></decrypted_header>',
137 base64_encode($inner_key->iv),
138 base64_encode($inner_key->key),
139 $magic_env->getActor()->getAcctUri());
142 * Construct another AES key and initialization vector suitable
143 * for the aes-256-cbc cipher. I shall refer to this as the
144 * “outer key” and the “outer initialization vector (iv)”.
146 $outer_key = new \phpseclib\Crypt\AES(\phpseclib\Crypt\AES::MODE_CBC);
147 $outer_key->setKeyLength(256); // set length to 256 bits (could be calculated, but let's be sure)
148 $outer_key->setKey(common_random_rawstr(32)); // 32 bytes from a (pseudo) random source
149 $outer_key->setIV(common_random_rawstr(16)); // 16 bytes is the block length
152 * Encrypt your <decrypted_header> XML snippet using the “outer key”
153 * and “outer iv” (using the aes-256-cbc cipher). This encrypted
154 * blob shall be referred to as “the ciphertext”.
156 $ciphertext = $outer_key->encrypt($decrypted_header);
159 * Construct the following JSON object, which shall be referred to
160 * as “the outer aes key bundle”:
162 * "iv": ((base64-encoded AES outer iv)),
163 * "key": ((base64-encoded AES outer key))
166 $outer_bundle = json_encode(array(
167 'iv' => base64_encode($outer_key->iv),
168 'key' => base64_encode($outer_key->key),
171 * Encrypt the “outer aes key bundle” with Bob’s RSA public key.
172 * I shall refer to this as the “encrypted outer aes key bundle”.
174 common_debug('Diaspora creating "outer aes key bundle", will require magic-public-key');
175 $key_fetcher = new MagicEnvelope();
176 $remote_keys = $key_fetcher->getKeyPair($target, true); // actually just gets the public key
177 $enc_outer = $remote_keys->publicKey->encrypt($outer_bundle);
180 * Construct the following JSON object, which I shall refer to as
181 * the “encrypted header json object”:
183 * "aes_key": ((base64-encoded encrypted outer aes key bundle)),
184 * "ciphertext": ((base64-encoded ciphertextm from above))
187 $enc_header = json_encode(array(
188 'aes_key' => base64_encode($enc_outer),
189 'ciphertext' => base64_encode($ciphertext),
193 * Construct the xml snippet:
194 * <encrypted_header>((base64-encoded encrypted header json object))</encrypted_header>
196 $xs->element('encrypted_header', null, base64_encode($enc_header));
199 * In order to prepare the payload message for inclusion in your
200 * salmon slap, you will:
202 * 1. Encrypt the payload message using the aes-256-cbc cipher and
203 * the “inner encryption key” and “inner encryption iv” you
205 * 2. Base64-encode the encrypted payload message.
207 $payload = $inner_key->encrypt($magic_env->getData());
208 //FIXME: This means we don't actually put an <atom:entry> in the payload,
209 // since Diaspora has its own update method! Silly me. Read up on:
210 // https://wiki.diasporafoundation.org/Federation_Message_Semantics
211 $magic_env->signMessage(base64_encode($payload), 'application/xml');
214 // Since we have to change the content of me:data we'll just write the
215 // whole thing from scratch. We _could_ otherwise have just manipulated
216 // that element and added the encrypted_header in the EndMagicEnvelopeToXML event.
217 $xs->elementStart('me:env', array('xmlns:me' => MagicEnvelope::NS));
218 $xs->element('me:data', array('type' => $magic_env->getDataType()), $magic_env->getData());
219 $xs->element('me:encoding', null, $magic_env->getEncoding());
220 $xs->element('me:alg', null, $magic_env->getSignatureAlgorithm());
221 $xs->element('me:sig', null, $magic_env->getSignature());
222 $xs->elementEnd('me:env');
224 $xs->elementEnd('entry');
229 public function onSalmonSlap($endpoint_uri, MagicEnvelope $magic_env, Profile $target=null)
231 $envxml = $magic_env->toXML($target, 'diaspora');
233 // Diaspora wants another POST format (base64url-encoded POST variable 'xml')
234 $headers = array('Content-Type: application/x-www-form-urlencoded');
236 // Another way to distinguish Diaspora from GNU social is that a POST with
237 // $headers=array('Content-Type: application/magic-envelope+xml') would return
238 // HTTP status code 422 Unprocessable Entity, at least as of 2015-10-04.
240 $client = new HTTPClient();
241 $client->setBody('xml=' . Magicsig::base64_url_encode($envxml));
242 $response = $client->post($endpoint_uri, $headers);
243 } catch (Exception $e) {
244 common_log(LOG_ERR, "Diaspora-flavoured Salmon post to $endpoint_uri failed: " . $e->getMessage());
248 // 200 OK is the best response
249 // 202 Accepted is what we get from Diaspora for example
250 if (!in_array($response->getStatus(), array(200, 202))) {
251 common_log(LOG_ERR, sprintf('Salmon (from profile %d) endpoint %s returned status %s: %s',
252 $magic_env->getActor()->getID(), $endpoint_uri, $response->getStatus(), $response->getBody()));