include/salmon.php

   1 <?php
   2
   3 require_once('library/asn1.php');
   4
   5 function salmon_key($pubkey) {
   6         $lines = explode("\n",$pubkey);
   7         unset($lines[0]);
   8         unset($lines[count($lines)]);
   9         $x = base64_decode(implode('',$lines));
  10
  11         $r = ASN_BASE::parseASNString($x);
  12
  13         $m = $r[0]->asnData[1]->asnData[0]->asnData[0]->asnData;
  14         $e = $r[0]->asnData[1]->asnData[0]->asnData[1]->asnData;
  15
  16
  17         return 'RSA' . '.' . $m . '.' . $e ;
  18 }
  19
  20
  21 function get_salmon_key($uri,$keyhash) {
  22         $ret = array();
  23
  24         logger('Fetching salmon key');
  25
  26         $arr = lrdd($uri);
  27
  28         if(is_array($arr)) {
  29                 foreach($arr as $a) {
  30                         if($a['@attributes']['rel'] === 'magic-public-key') {
  31                                 $ret[] = $a['@attributes']['href'];
  32                         }
  33                 }
  34         }
  35         else {
  36                 return '';
  37         }
  38
  39         // We have found at least one key URL
  40         // If it's inline, parse it - otherwise get the key
  41
  42         if(count($ret)) {
  43                 for($x = 0; $x < count($ret); $x ++) {
  44                         if(substr($ret[$x],0,5) === 'data:') {
  45                                 if(strstr($ret[$x],','))
  46                                         $ret[$x] = substr($ret[$x],strpos($ret[$x],',')+1);
  47                                 else
  48                                         $ret[$x] = substr($ret[$x],5);
  49                         }
  50                         else
  51                                 $ret[$x] = fetch_url($ret[$x]);
  52                 }
  53         }
  54
  55
  56         logger('Key located: ' . print_r($ret,true));
  57
  58         if(count($ret) == 1) {
  59
  60                 // We only found one one key so we don't care if the hash matches.
  61                 // If it's the wrong key we'll find out soon enough because
  62                 // message verification will fail. This also covers some older
  63                 // software which don't supply a keyhash. As long as they only
  64                 // have one key we'll be right.
  65
  66                 return $ret[0];
  67         }
  68         else {
  69                 foreach($ret as $a) {
  70                         $hash = base64url_encode(hash('sha256',$a));
  71                         if($hash == $keyhash)
  72                                 return $a;
  73                 }
  74         }
  75
  76         return '';
  77 }
  78
  79
  80
  81 function slapper($owner,$url,$slap) {
  82
  83         logger('slapper called. Data: ' . $slap);
  84
  85         // does contact have a salmon endpoint?
  86
  87         if(! strlen($url))
  88                 return;
  89
  90         // add all namespaces to item
  91
  92 $namespaces = <<< EOT
  93 <entry xmlns="http://www.w3.org/2005/Atom"
  94       xmlns:thr="http://purl.org/syndication/thread/1.0"
  95       xmlns:at="http://purl.org/atompub/tombstones/1.0"
  96       xmlns:media="http://purl.org/syndication/atommedia"
  97       xmlns:dfrn="http://purl.org/macgirvin/dfrn/1.0"
  98       xmlns:as="http://activitystrea.ms/spec/1.0/"
  99       xmlns:georss="http://www.georss.org/georss"
 100       xmlns:poco="http://portablecontacts.net/spec/1.0"
 101       xmlns:ostatus="http://ostatus.org/schema/1.0"
 102           xmlns:statusnet="http://status.net/schema/api/1/" >                                                                                                   >
 103 EOT;
 104
 105         $slap = str_replace('<entry>',$namespaces,$slap);
 106
 107         // create a magic envelope
 108
 109         $data      = base64url_encode($slap);
 110         $data_type = 'application/atom+xml';
 111         $encoding  = 'base64url';
 112         $algorithm = 'RSA-SHA256';
 113         $keyhash   = base64url_encode(hash('sha256',salmon_key($owner['spubkey'])));
 114
 115         // Setup RSA stuff to PKCS#1 sign the data
 116
 117         set_include_path(get_include_path() . PATH_SEPARATOR . 'library/phpsec');
 118
 119         require_once('library/phpsec/Crypt/RSA.php');
 120
 121     $rsa = new CRYPT_RSA();
 122     $rsa->signatureMode = CRYPT_RSA_SIGNATURE_PKCS1;
 123     $rsa->setHash('sha256');
 124         $rsa->loadKey($owner['sprvkey']);
 125
 126         // precomputed base64url encoding of data_type, encoding, algorithm concatenated with periods
 127
 128         $precomputed = '.YXBwbGljYXRpb24vYXRvbSt4bWw=.YmFzZTY0dXJs.UlNBLVNIQTI1Ng==';
 129
 130         $signature  = base64url_encode($rsa->sign($data . $precomputed));
 131
 132         $signature2  = base64url_encode($rsa->sign($data));
 133
 134         $salmon_tpl = get_markup_template('magicsig.tpl');
 135         $salmon = replace_macros($salmon_tpl,array(
 136                 '$data'      => $data,
 137                 '$encoding'  => $encoding,
 138                 '$algorithm' => $algorithm,
 139                 '$keyhash'   => $keyhash,
 140                 '$signature' => $signature
 141         ));
 142
 143         // slap them
 144         post_url($url,$salmon, array(
 145                 'Content-type: application/magic-envelope+xml',
 146                 'Content-length: ' . strlen($salmon)
 147         ));
 148
 149         $a = get_app();
 150         $return_code = $a->get_curl_code();
 151
 152         // check for success, e.g. 2xx
 153
 154         if($return_code > 299) {
 155
 156                 logger('slapper: compliant salmon failed. Falling back to status.net hack');
 157
 158                 // Entirely likely that their salmon implementation is
 159                 // non-compliant. Let's try once more, this time only signing
 160                 // the data, without the precomputed blob
 161
 162                 $salmon = replace_macros($salmon_tpl,array(
 163                         '$data'      => $data,
 164                         '$encoding'  => $encoding,
 165                         '$algorithm' => $algorithm,
 166                         '$keyhash'   => $keyhash,
 167                         '$signature' => $signature2
 168                 ));
 169
 170                 // slap them
 171                 post_url($url,$salmon, array(
 172                         'Content-type: application/magic-envelope+xml',
 173                         'Content-length: ' . strlen($salmon)
 174                 ));
 175                 $return_code = $a->get_curl_code();
 176
 177         }
 178         logger('slapper returned ' . $return_code);
 179         if(! $return_code)
 180                 return(-1);
 181         return ((($return_code >= 200) && ($return_code < 300)) ? 0 : 1);
 182 }
 183