include/salmon.php

   1 <?php
   2
   3 require_once('include/crypto.php');
   4
   5
   6
   7 function get_salmon_key($uri,$keyhash) {
   8         $ret = array();
   9
  10         logger('Fetching salmon key for '.$uri);
  11
  12         $arr = lrdd($uri);
  13
  14         if(is_array($arr)) {
  15                 foreach($arr as $a) {
  16                         if($a['@attributes']['rel'] === 'magic-public-key') {
  17                                 $ret[] = $a['@attributes']['href'];
  18                         }
  19                 }
  20         }
  21         else {
  22                 return '';
  23         }
  24
  25         // We have found at least one key URL
  26         // If it's inline, parse it - otherwise get the key
  27
  28         if(count($ret)) {
  29                 for($x = 0; $x < count($ret); $x ++) {
  30                         if(substr($ret[$x],0,5) === 'data:') {
  31                                 if(strstr($ret[$x],','))
  32                                         $ret[$x] = substr($ret[$x],strpos($ret[$x],',')+1);
  33                                 else
  34                                         $ret[$x] = substr($ret[$x],5);
  35                         }
  36                         else
  37                                 $ret[$x] = fetch_url($ret[$x]);
  38                 }
  39         }
  40
  41
  42         logger('Key located: ' . print_r($ret,true));
  43
  44         if(count($ret) == 1) {
  45
  46                 // We only found one one key so we don't care if the hash matches.
  47                 // If it's the wrong key we'll find out soon enough because
  48                 // message verification will fail. This also covers some older
  49                 // software which don't supply a keyhash. As long as they only
  50                 // have one key we'll be right.
  51
  52                 return $ret[0];
  53         }
  54         else {
  55                 foreach($ret as $a) {
  56                         $hash = base64url_encode(hash('sha256',$a));
  57                         if($hash == $keyhash)
  58                                 return $a;
  59                 }
  60         }
  61
  62         return '';
  63 }
  64
  65
  66
  67 function slapper($owner,$url,$slap) {
  68
  69         // does contact have a salmon endpoint?
  70
  71         if(! strlen($url))
  72                 return;
  73
  74
  75         if(! $owner['sprvkey']) {
  76                 logger(sprintf("user '%s' (%d) does not have a salmon private key. Send failed.",
  77                 $owner['username'],$owner['uid']));
  78                 return;
  79         }
  80
  81         // add all namespaces to item
  82
  83 $namespaces = <<< EOT
  84 <entry xmlns="http://www.w3.org/2005/Atom"
  85       xmlns:thr="http://purl.org/syndication/thread/1.0"
  86       xmlns:at="http://purl.org/atompub/tombstones/1.0"
  87       xmlns:media="http://purl.org/syndication/atommedia"
  88       xmlns:dfrn="http://purl.org/macgirvin/dfrn/1.0"
  89       xmlns:as="http://activitystrea.ms/spec/1.0/"
  90       xmlns:georss="http://www.georss.org/georss"
  91       xmlns:poco="http://portablecontacts.net/spec/1.0"
  92       xmlns:ostatus="http://ostatus.org/schema/1.0"
  93           xmlns:statusnet="http://status.net/schema/api/1/" >                                                                                                   >
  94 EOT;
  95
  96         $slap = str_replace('<entry>',$namespaces,$slap);
  97
  98         logger('slapper called for '.$url.'. Data: ' . $slap);
  99
 100         // create a magic envelope
 101
 102         $data      = base64url_encode($slap);
 103         $data_type = 'application/atom+xml';
 104         $encoding  = 'base64url';
 105         $algorithm = 'RSA-SHA256';
 106         $keyhash   = base64url_encode(hash('sha256',salmon_key($owner['spubkey'])),true);
 107
 108         // precomputed base64url encoding of data_type, encoding, algorithm concatenated with periods
 109
 110         $precomputed = '.YXBwbGljYXRpb24vYXRvbSt4bWw=.YmFzZTY0dXJs.UlNBLVNIQTI1Ng==';
 111
 112         $signature   = base64url_encode(rsa_sign(str_replace('=','',$data . $precomputed),$owner['sprvkey']));
 113
 114         $signature2  = base64url_encode(rsa_sign($data . $precomputed,$owner['sprvkey']));
 115
 116         $signature3  = base64url_encode(rsa_sign($data,$owner['sprvkey']));
 117
 118         $salmon_tpl = get_markup_template('magicsig.tpl');
 119
 120         $salmon = replace_macros($salmon_tpl,array(
 121                 '$data'      => $data,
 122                 '$encoding'  => $encoding,
 123                 '$algorithm' => $algorithm,
 124                 '$keyhash'   => $keyhash,
 125                 '$signature' => $signature
 126         ));
 127
 128         // slap them
 129         post_url($url,$salmon, array(
 130                 'Content-type: application/magic-envelope+xml',
 131                 'Content-length: ' . strlen($salmon)
 132         ));
 133
 134         $a = get_app();
 135         $return_code = $a->get_curl_code();
 136
 137         // check for success, e.g. 2xx
 138
 139         if($return_code > 299) {
 140
 141                 logger('compliant salmon failed. Falling back to status.net hack2');
 142
 143                 // Entirely likely that their salmon implementation is
 144                 // non-compliant. Let's try once more, this time only signing
 145                 // the data, without stripping '=' chars
 146
 147                 $salmon = replace_macros($salmon_tpl,array(
 148                         '$data'      => $data,
 149                         '$encoding'  => $encoding,
 150                         '$algorithm' => $algorithm,
 151                         '$keyhash'   => $keyhash,
 152                         '$signature' => $signature2
 153                 ));
 154
 155                 // slap them
 156                 post_url($url,$salmon, array(
 157                         'Content-type: application/magic-envelope+xml',
 158                         'Content-length: ' . strlen($salmon)
 159                 ));
 160                 $return_code = $a->get_curl_code();
 161
 162
 163                 if($return_code > 299) {
 164
 165                         logger('compliant salmon failed. Falling back to status.net hack3');
 166
 167                         // Entirely likely that their salmon implementation is
 168                         // non-compliant. Let's try once more, this time only signing
 169                         // the data, without the precomputed blob
 170
 171                         $salmon = replace_macros($salmon_tpl,array(
 172                                 '$data'      => $data,
 173                                 '$encoding'  => $encoding,
 174                                 '$algorithm' => $algorithm,
 175                                 '$keyhash'   => $keyhash,
 176                                 '$signature' => $signature3
 177                         ));
 178
 179                         // slap them
 180                         post_url($url,$salmon, array(
 181                                 'Content-type: application/magic-envelope+xml',
 182                                 'Content-length: ' . strlen($salmon)
 183                         ));
 184                         $return_code = $a->get_curl_code();
 185                 }
 186         }
 187         logger('slapper for '.$url.' returned ' . $return_code);
 188         if(! $return_code)
 189                 return(-1);
 190         if(($return_code == 503) && (stristr($a->get_curl_headers(),'retry-after')))
 191                 return(-1);
 192
 193         return ((($return_code >= 200) && ($return_code < 300)) ? 0 : 1);
 194 }
 195