src/Protocol/Salmon.php

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