src/Protocol/Salmon.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol;
  23
  24 use Friendica\Core\Logger;
  25 use Friendica\DI;
  26 use Friendica\Network\HTTPClient\Client\HttpClientAccept;
  27 use Friendica\Network\Probe;
  28 use Friendica\Util\Crypto;
  29 use Friendica\Util\Strings;
  30 use Friendica\Util\XML;
  31
  32 /**
  33  * Salmon Protocol class
  34  *
  35  * The Salmon Protocol is a message exchange protocol running over HTTP designed to decentralize commentary
  36  * and annotations made against newsfeed articles such as blog posts.
  37  */
  38 class Salmon
  39 {
  40         /**
  41          * @param string $uri     Uniform Resource Identifier
  42          * @param string $keyhash encoded key
  43          * @return mixed
  44          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
  45          */
  46         public static function getKey($uri, $keyhash)
  47         {
  48                 $ret = [];
  49
  50                 Logger::info('Fetching salmon key for '.$uri);
  51
  52                 $arr = Probe::lrdd($uri);
  53
  54                 if (is_array($arr)) {
  55                         foreach ($arr as $a) {
  56                                 if ($a['@attributes']['rel'] === 'magic-public-key') {
  57                                         $ret[] = $a['@attributes']['href'];
  58                                 }
  59                         }
  60                 } else {
  61                         return '';
  62                 }
  63
  64                 // We have found at least one key URL
  65                 // If it's inline, parse it - otherwise get the key
  66
  67                 if (count($ret) > 0) {
  68                         for ($x = 0; $x < count($ret); $x ++) {
  69                                 if (substr($ret[$x], 0, 5) === 'data:') {
  70                                         if (strstr($ret[$x], ',')) {
  71                                                 $ret[$x] = substr($ret[$x], strpos($ret[$x], ',') + 1);
  72                                         } else {
  73                                                 $ret[$x] = substr($ret[$x], 5);
  74                                         }
  75                                 } elseif (Strings::normaliseLink($ret[$x]) == 'http://') {
  76                                         $ret[$x] = DI::httpClient()->fetch($ret[$x], HttpClientAccept::MAGIC_KEY);
  77                                         Logger::debug('Fetched public key', ['url' => $ret[$x]]);
  78                                 }
  79                         }
  80                 }
  81
  82
  83                 Logger::notice('Key located', ['ret' => $ret]);
  84
  85                 if (count($ret) == 1) {
  86                         // We only found one one key so we don't care if the hash matches.
  87                         // If it's the wrong key we'll find out soon enough because
  88                         // message verification will fail. This also covers some older
  89                         // software which don't supply a keyhash. As long as they only
  90                         // have one key we'll be right.
  91
  92                         return $ret[0];
  93                 } else {
  94                         foreach ($ret as $a) {
  95                                 $hash = Strings::base64UrlEncode(hash('sha256', $a));
  96                                 if ($hash == $keyhash) {
  97                                         return $a;
  98                                 }
  99                         }
 100                 }
 101
 102                 return '';
 103         }
 104
 105         /**
 106          * @param array  $owner owner
 107          * @param string $url   url
 108          * @param string $slap  slap
 109          * @return integer
 110          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 111          */
 112         public static function slapper($owner, $url, $slap)
 113         {
 114                 // does contact have a salmon endpoint?
 115
 116                 if (!strlen($url)) {
 117                         return;
 118                 }
 119
 120                 if (!$owner['sprvkey']) {
 121                         Logger::notice(sprintf("user '%s' (%d) does not have a salmon private key. Send failed.",
 122                         $owner['name'], $owner['uid']));
 123                         return;
 124                 }
 125
 126                 Logger::info('slapper called for '.$url.'. Data: ' . $slap);
 127
 128                 // create a magic envelope
 129
 130                 $data      = Strings::base64UrlEncode($slap);
 131                 $data_type = 'application/atom+xml';
 132                 $encoding  = 'base64url';
 133                 $algorithm = 'RSA-SHA256';
 134                 $keyhash   = Strings::base64UrlEncode(hash('sha256', self::salmonKey($owner['spubkey'])), true);
 135
 136                 $precomputed = '.' . Strings::base64UrlEncode($data_type) . '.' . Strings::base64UrlEncode($encoding) . '.' . Strings::base64UrlEncode($algorithm);
 137
 138                 // GNU Social format
 139                 $signature   = Strings::base64UrlEncode(Crypto::rsaSign($data . $precomputed, $owner['sprvkey']));
 140
 141                 // Compliant format
 142                 $signature2  = Strings::base64UrlEncode(Crypto::rsaSign(str_replace('=', '', $data . $precomputed), $owner['sprvkey']));
 143
 144                 // Old Status.net format
 145                 $signature3  = Strings::base64UrlEncode(Crypto::rsaSign($data, $owner['sprvkey']));
 146
 147                 // At first try the non compliant method that works for GNU Social
 148                 $xmldata = ["me:env" => ["me:data" => $data,
 149                                 "@attributes" => ["type" => $data_type],
 150                                 "me:encoding" => $encoding,
 151                                 "me:alg" => $algorithm,
 152                                 "me:sig" => $signature,
 153                                 "@attributes2" => ["key_id" => $keyhash]]];
 154
 155                 $namespaces = ["me" => "http://salmon-protocol.org/ns/magic-env"];
 156
 157                 $salmon = XML::fromArray($xmldata, $xml, false, $namespaces);
 158
 159                 // slap them
 160                 $postResult = DI::httpClient()->post($url, $salmon, [
 161                         'Content-type' => 'application/magic-envelope+xml',
 162                         'Content-length' => strlen($salmon),
 163                 ]);
 164
 165                 $return_code = $postResult->getReturnCode();
 166
 167                 // check for success, e.g. 2xx
 168
 169                 if ($return_code > 299) {
 170                         Logger::notice('GNU Social salmon failed. Falling back to compliant mode');
 171
 172                         // Now try the compliant mode that normally isn't used for GNU Social
 173                         $xmldata = ["me:env" => ["me:data" => $data,
 174                                         "@attributes" => ["type" => $data_type],
 175                                         "me:encoding" => $encoding,
 176                                         "me:alg" => $algorithm,
 177                                         "me:sig" => $signature2,
 178                                         "@attributes2" => ["key_id" => $keyhash]]];
 179
 180                         $namespaces = ["me" => "http://salmon-protocol.org/ns/magic-env"];
 181
 182                         $salmon = XML::fromArray($xmldata, $xml, false, $namespaces);
 183
 184                         // slap them
 185                         $postResult = DI::httpClient()->post($url, $salmon, [
 186                                 'Content-type' => 'application/magic-envelope+xml',
 187                                 'Content-length' => strlen($salmon),
 188                         ]);
 189                         $return_code = $postResult->getReturnCode();
 190                 }
 191
 192                 if ($return_code > 299) {
 193                         Logger::notice('compliant salmon failed. Falling back to old status.net');
 194
 195                         // Last try. This will most likely fail as well.
 196                         $xmldata = ["me:env" => ["me:data" => $data,
 197                                         "@attributes" => ["type" => $data_type],
 198                                         "me:encoding" => $encoding,
 199                                         "me:alg" => $algorithm,
 200                                         "me:sig" => $signature3,
 201                                         "@attributes2" => ["key_id" => $keyhash]]];
 202
 203                         $namespaces = ["me" => "http://salmon-protocol.org/ns/magic-env"];
 204
 205                         $salmon = XML::fromArray($xmldata, $xml, false, $namespaces);
 206
 207                         // slap them
 208                         $postResult = DI::httpClient()->post($url, $salmon, [
 209                                 'Content-type' => 'application/magic-envelope+xml',
 210                                 'Content-length' => strlen($salmon)]);
 211                         $return_code = $postResult->getReturnCode();
 212                 }
 213
 214                 Logger::info('slapper for '.$url.' returned ' . $return_code);
 215
 216                 if (! $return_code) {
 217                         return -1;
 218                 }
 219
 220                 if (($return_code == 503) && $postResult->inHeader('retry-after')) {
 221                         return -1;
 222                 }
 223
 224                 return (($return_code >= 200) && ($return_code < 300)) ? 0 : 1;
 225         }
 226
 227         /**
 228          * @param string $pubkey public key
 229          * @return string
 230          * @throws \Exception
 231          */
 232         public static function salmonKey($pubkey)
 233         {
 234                 Crypto::pemToMe($pubkey, $modulus, $exponent);
 235                 return 'RSA' . '.' . Strings::base64UrlEncode($modulus, true) . '.' . Strings::base64UrlEncode($exponent, true);
 236         }
 237 }