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basic diaspora decryption

pull/1/head
Friendika 11 years ago
parent
commit
a61ec584d6
  1. 17
      boot.php
  2. 134
      mod/receive.php

17
boot.php

@ -2969,4 +2969,19 @@ function generate_guid() {
$found = false;
} while ($found == true );
return $guid;
}
}
function pkcs5_pad ($text, $blocksize)
{
$pad = $blocksize - (strlen($text) % $blocksize);
return $text . str_repeat(chr($pad), $pad);
}
function pkcs5_unpad($text)
{
$pad = ord($text{strlen($text)-1});
if ($pad > strlen($text)) return false;
if (strspn($text, chr($pad), strlen($text) - $pad) != $pad) return false;
return substr($text, 0, -1 * $pad);
}

134
mod/receive.php

@ -43,10 +43,68 @@ function receive_post(&$a) {
if(! $xml)
receive_return(500);
// parse the xml
$dom = simplexml_load_string($xml,'SimpleXMLElement',0,NAMESPACE_SALMON_ME);
$basedom = parse_xml_string($xml);
if($basedom)
logger('parsed dom');
$atom = $basedom->children(NAMESPACE_ATOM1);
logger('atom: ' . count($atom));
$encrypted_header = json_decode(base64_decode($atom->encrypted_header));
print_r($encrypted_header);
$encrypted_aes_key_bundle = base64_decode($encrypted_header->aes_key);
$ciphertext = base64_decode($encrypted_header->ciphertext);
logger('encrypted_aes: ' . print_r($encrypted_aes_key_bundle,true));
logger('ciphertext: ' . print_r($ciphertext,true));
$outer_key_bundle = '';
openssl_private_decrypt($encrypted_aes_key_bundle,$outer_key_bundle,$localprvkey);
logger('outer_bundle: ' . print_r($outer_key_bundle,true));
$j_outer_key_bundle = json_decode($outer_key_bundle);
$outer_iv = base64_decode($j_outer_key_bundle->iv);
$outer_key = base64_decode($j_outer_key_bundle->key);
$decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $outer_key, $ciphertext, MCRYPT_MODE_CBC, $outer_iv);
$decrypted = pkcs5_unpad($decrypted);
logger('decrypted: ' . print_r($decrypted,true));
/**
* $decrypted now contains something like
*
* <decrypted_header>
* <iv>8e+G2+ET8l5BPuW0sVTnQw==</iv>
* <aes_key>UvSMb4puPeB14STkcDWq+4QE302Edu15oaprAQSkLKU=</aes_key>
* <author>
* <name>Ryan Hughes</name>
* <uri>acct:galaxor@diaspora.pirateship.org</uri>
* </author>
* </decrypted_header>
*/
$idom = parse_xml_string($decrypted,false);
print_r($idom);
$inner_iv = base64_decode($idom->iv);
$inner_aes_key = base64_decode($idom->aes_key);
logger('inner_iv: ' . $inner_iv);
$dom = $basedom->children(NAMESPACE_SALMON_ME);
if($dom)
logger('have dom');
logger('dom: ' . count($dom));
// figure out where in the DOM tree our data is hiding
if($dom->provenance->data)
@ -58,12 +116,22 @@ function receive_post(&$a) {
if(! $base) {
logger('mod-diaspora: unable to locate salmon data in xml ');
receive_return(400);
dt_return(400);
}
// Stash the signature away for now. We have to find their key or it won't be good for anything.
$signature = base64url_decode($base->sig);
logger('signature: ' . bin2hex($signature));
openssl_public_encrypt('test',$rrr,$ryanpubkey);
logger('rrr: ' . $rrr);
$pubdecsig = '';
openssl_public_decrypt($signature,$pubdecsig,$ryanpubkey);
logger('decsig: ' . bin2hex($pubdecsig));
// unpack the data
// strip whitespace so our data element will return to one big base64 blob
@ -76,40 +144,28 @@ function receive_post(&$a) {
$encoding = $base->encoding;
$alg = $base->alg;
$signed_data = $data . '.' . base64url_encode($type) . '.' . base64url_encode($encoding) . '.' . base64url_encode($alg);
$signed_data = $data . "\n" . '.' . base64url_encode($type) . "\n" . '.' . base64url_encode($encoding) . "\n" . '.' . base64url_encode($alg) . "\n";
logger('signed data: ' . $signed_data);
// decode the data
$data = base64url_decode($data);
// Remove the xml declaration
$data = preg_replace('/\<\?xml[^\?].*\?\>/','',$data);
// Now pull out the inner encrypted blob
// Create a fake feed wrapper so simplepie doesn't choke
$tpl = get_markup_template('fake_feed.tpl');
$base = substr($data,strpos($data,'<entry'));
$feedxml = $tpl . $base . '</feed>';
logger('mod-diaspora: Processed feed: ' . $feedxml);
$inner_encrypted = base64_decode($data);
$inner_decrypted =
$inner_decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $inner_aes_key, $inner_encrypted, MCRYPT_MODE_CBC, $inner_iv);
$inner_decrypted = pkcs5_unpad($inner_decrypted);
logger('inner_decrypted: ' . $inner_decrypted);
// Now parse it like a normal atom feed to scrape out the author URI
$feed = new SimplePie();
$feed->set_raw_data($feedxml);
$feed->enable_order_by_date(false);
$feed->init();
logger('mod-diaspora: Feed parsed.');
if($feed->get_item_quantity()) {
foreach($feed->get_items() as $item) {
$author = $item->get_author();
$author_link = unxmlify($author->get_link());
break;
}
}
if(! $author_link) {
logger('mod-diaspora: Could not retrieve author URI.');
@ -117,17 +173,25 @@ function receive_post(&$a) {
}
// Once we have the author URI, go to the web and try to find their public key
// *** or look it up locally ***
logger('mod-salmon: Fetching key for ' . $author_link );
logger('mod-diaspora: Fetching key for ' . $author_link );
// Get diaspora public key (pkcs#1) and convert to pkcs#8
// $key = get_diaspora_key($author_link);
$key = get_salmon_key($author_link,$keyhash);
// $key = get_salmon_key($author_link,$keyhash);
if(! $key) {
logger('mod-salmon: Could not retrieve author key.');
receive_return(400);
}
// FIXME
// Use non salmon compliant signature
/*
// Setup RSA stuff to verify the signature
set_include_path(get_include_path() . PATH_SEPARATOR . 'library' . PATH_SEPARATOR . 'phpsec');
@ -155,6 +219,7 @@ function receive_post(&$a) {
logger('mod-diaspora: Message did not verify. Discarding.');
receive_return(400);
}
*/
logger('mod-diaspora: Message verified.');
@ -204,7 +269,14 @@ function receive_post(&$a) {
$contact_rec = ((count($r)) ? $r[0] : null);
consume_feed($feedxml,$importer,$contact_rec,$hub);
// figure out what kind of diaspora message we have, and process accordingly.
receive_return(200);
}

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