<?php require_once('library/asn1.php'); function salmon_key($pubkey) { $lines = explode("\n",$pubkey); unset($lines[0]); unset($lines[count($lines)]); $x = base64_decode(implode('',$lines)); $r = ASN_BASE::parseASNString($x); $m = $r[0]->asnData[1]->asnData[0]->asnData[0]->asnData; $e = $r[0]->asnData[1]->asnData[0]->asnData[1]->asnData; return 'RSA' . '.' . $m . '.' . $e ; } function base64url_encode($s, $strip_padding = false) { $s = strtr(base64_encode($s),'+/','-_'); if($strip_padding) $s = str_replace('=','',$s); return $s; } function base64url_decode($s) { /* * // Placeholder for new rev of salmon which strips base64 padding. * // PHP base64_decode handles the un-padded input without requiring this step * // Uncomment if you find you need it. * * $l = strlen($s); * if(! strpos($s,'=')) { * $m = $l % 4; * if($m == 2) * $s .= '=='; * if($m == 3) * $s .= '='; * } * */ return base64_decode(strtr($s,'-_','+/')); } function get_salmon_key($uri,$keyhash) { $ret = array(); logger('Fetching salmon key'); $arr = lrdd($uri); if(is_array($arr)) { foreach($arr as $a) { if($a['@attributes']['rel'] === 'magic-public-key') { $ret[] = $a['@attributes']['href']; } } } else { return ''; } // We have found at least one key URL // If it's inline, parse it - otherwise get the key if(count($ret)) { for($x = 0; $x < count($ret); $x ++) { if(substr($ret[$x],0,5) === 'data:') { if(strstr($ret[$x],',')) $ret[$x] = substr($ret[$x],strpos($ret[$x],',')+1); else $ret[$x] = substr($ret[$x],5); } else $ret[$x] = fetch_url($ret[$x]); } } logger('Key located: ' . print_r($ret,true)); if(count($ret) == 1) { // We only found one one key so we don't care if the hash matches. // If it's the wrong key we'll find out soon enough because // message verification will fail. This also covers some older // software which don't supply a keyhash. As long as they only // have one key we'll be right. return $ret[0]; } else { foreach($ret as $a) { $hash = base64url_encode(hash('sha256',$a)); if($hash == $keyhash) return $a; } } return ''; } function slapper($owner,$url,$slap) { logger('slapper called. Data: ' . $slap); // does contact have a salmon endpoint? if(! strlen($url)) return; // add all namespaces to item $namespaces = <<< EOT <entry xmlns="http://www.w3.org/2005/Atom" xmlns:thr="http://purl.org/syndication/thread/1.0" xmlns:at="http://purl.org/atompub/tombstones/1.0" xmlns:media="http://purl.org/syndication/atommedia" xmlns:dfrn="http://purl.org/macgirvin/dfrn/1.0" xmlns:as="http://activitystrea.ms/spec/1.0/" xmlns:georss="http://www.georss.org/georss" xmlns:poco="http://portablecontacts.net/spec/1.0" > EOT; $slap = str_replace('<entry>',$namespaces,$slap); // create a magic envelope $data = base64url_encode($slap); $data_type = 'application/atom+xml'; $encoding = 'base64url'; $algorithm = 'RSA-SHA256'; $keyhash = base64url_encode(hash('sha256',salmon_key($owner['spubkey']))); // Setup RSA stuff to PKCS#1 sign the data set_include_path(get_include_path() . PATH_SEPARATOR . 'phpsec'); require_once('phpsec/Crypt/RSA.php'); $rsa = new CRYPT_RSA(); $rsa->signatureMode = CRYPT_RSA_SIGNATURE_PKCS1; $rsa->setHash('sha256'); $rsa->loadKey($owner['sprvkey']); // precomputed base64url encoding of data_type, encoding, algorithm concatenated with periods $precomputed = '.YXBwbGljYXRpb24vYXRvbSt4bWw=.YmFzZTY0dXJs.UlNBLVNIQTI1Ng=='; $signature = base64url_encode($rsa->sign($data . $precomputed)); $signature2 = base64url_encode($rsa->sign($data)); $salmon_tpl = load_view_file('view/magicsig.tpl'); $salmon = replace_macros($salmon_tpl,array( '$data' => $data, '$encoding' => $encoding, '$algorithm' => $algorithm, '$keyhash' => $keyhash, '$signature' => $signature )); // slap them post_url($url,$salmon, array( 'Content-type: application/magic-envelope+xml', 'Content-length: ' . strlen($salmon) )); $a = get_app(); $return_code = $a->get_curl_code(); // check for success, e.g. 2xx if($return_code > 299) { logger('slapper: compliant salmon failed. Falling back to status.net hack'); // Entirely likely that their salmon implementation is // non-compliant. Let's try once more, this time only signing // the data, without the precomputed blob $salmon = replace_macros($salmon_tpl,array( '$data' => $data, '$encoding' => $encoding, '$algorithm' => $algorithm, '$keyhash' => $keyhash, '$signature' => $signature2 )); // slap them post_url($url,$salmon, array( 'Content-type: application/magic-envelope+xml', 'Content-length: ' . strlen($salmon) )); $return_code = $a->get_curl_code(); } logger('slapper returned ' . $return_code); if(! $return_code) return(-1); return ((($return_code >= 200) && ($return_code < 300)) ? 0 : 1); }