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