Friendica Communications Platform (please note that this is a clone of the repository at github, issues are handled there) https://friendi.ca
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<?php
require_once('include/crypto.php');
require_once('include/Probe.php');
function get_salmon_key($uri,$keyhash) {
$ret = array();
logger('Fetching salmon key for '.$uri);
$arr = Probe::lrdd($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) > 0) {
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);
}
} elseif (normalise_link($ret[$x]) == 'http://') {
$ret[$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) {
// does contact have a salmon endpoint?
if(! strlen($url))
return;
if(! $owner['sprvkey']) {
logger(sprintf("user '%s' (%d) does not have a salmon private key. Send failed.",
$owner['username'],$owner['uid']));
return;
}
logger('slapper called for '.$url.'. Data: ' . $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'])),true);
// precomputed base64url encoding of data_type, encoding, algorithm concatenated with periods
$precomputed = '.YXBwbGljYXRpb24vYXRvbSt4bWw=.YmFzZTY0dXJs.UlNBLVNIQTI1Ng==';
$signature = base64url_encode(rsa_sign(str_replace('=','',$data . $precomputed),$owner['sprvkey']));
$signature2 = base64url_encode(rsa_sign($data . $precomputed,$owner['sprvkey']));
$signature3 = base64url_encode(rsa_sign($data,$owner['sprvkey']));
$salmon_tpl = get_markup_template('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('compliant salmon failed. Falling back to status.net hack2');
// Entirely likely that their salmon implementation is
// non-compliant. Let's try once more, this time only signing
// the data, without stripping '=' chars
$salmon = replace_macros($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 = $a->get_curl_code();
if($return_code > 299) {
logger('compliant salmon failed. Falling back to status.net hack3');
// 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' => $signature3
));
// slap them
post_url($url,$salmon, array(
'Content-type: application/magic-envelope+xml',
'Content-length: ' . strlen($salmon)
));
$return_code = $a->get_curl_code();
}
}
logger('slapper for '.$url.' returned ' . $return_code);
if(! $return_code)
return(-1);
if(($return_code == 503) && (stristr($a->get_curl_headers(),'retry-after')))
return(-1);
return ((($return_code >= 200) && ($return_code < 300)) ? 0 : 1);
}