From 5edee3c4d1f84c07c1c54775072601188075a542 Mon Sep 17 00:00:00 2001 From: Mike Macgirvin Date: Thu, 21 Oct 2010 04:53:43 -0700 Subject: magic-envelope verification, status.net appears to do it wrong. Ultimately we need to do it right (or why bother having a spec?), and fallback to doing it wrong if we're talking to a broken system - which ironically seems to include most of the federated social web projects. --- mod/salmon.php | 170 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 163 insertions(+), 7 deletions(-) (limited to 'mod') diff --git a/mod/salmon.php b/mod/salmon.php index d68c74658..7ae29aafe 100644 --- a/mod/salmon.php +++ b/mod/salmon.php @@ -1,5 +1,15 @@ = 500) @@ -18,7 +28,7 @@ function salmon_post(&$a) { $debugging = get_config('system','debugging'); if($debugging) - file_put_contents('salmon.out',$xml,FILE_APPEND); + file_put_contents('salmon.out','New Salmon: ' . $xml . "\n",FILE_APPEND); $nick = (($a->argc > 1) ? notags(trim($a->argv[1])) : ''); $mentions = (($a->argc > 2 && $a->argv[2] === 'mention') ? true : false); @@ -31,22 +41,168 @@ function salmon_post(&$a) { $importer = $r[0]; - require_once('include/items.php'); + // parse the xml + + $dom = simplexml_load_string($xml,'SimpleXMLElement',0,NAMESPACE_SALMON_ME); + + + if($debugging) + file_put_contents('salmon.out', "\n" . print_r($dom,true) . "\n" , FILE_APPEND); + + // figure out where in the DOM tree our data is hiding + + if($dom->provenance->data) + $base = $dom->provenance; + elseif($dom->env->data) + $base = $dom->env; + elseif($dom->data) + $base = $dom; + + if(! $base) { + if($debugging) + file_put_contents('salmon.out', "\n" . 'Unable to find salmon data in XML' . "\n" , FILE_APPEND); + salmon_return(500); + } + + // 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); + if($debugging) + file_put_contents('salmon.out', "\n" . 'Encoded Signature: ' . $base->sig . "\n" , FILE_APPEND); + + // unpack our data element. + + // strip whitespace + $data = str_replace(array(" ","\t","\r","\n"),array("","","",""),$base->data); + $type = $base->data[0]->attributes()->type[0]; + $encoding = $base->encoding; + $alg = $base->alg; + + $signed_data = $data; + // . '.' . base64url_encode($type) . '.' . base64url_encode($encoding) . '.' . base64url_encode($alg); + // decode it + $data = base64url_decode($data); + + if($debugging) + file_put_contents('salmon.out', "\n" . 'Signed data:>>>' . $signed_data . "<<<\n" , FILE_APPEND); + + // Remove the xml declaration + $data = preg_replace('/\<\?xml[^\?].*\?\>/','',$data); // Create a fake feed wrapper so simplepie doesn't choke - $tpl = load_view_file('view/atom_feed.tpl'); + $tpl = load_view_file('view/fake_feed.tpl'); - $base = substr($xml,strpos($xml,''; + + if($debugging) { + file_put_contents('salmon.out', 'Processed feed: ' . $feedxml . "\n", FILE_APPEND); + } + + // 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); + $feed->init(); + + if($debugging) { + file_put_contents('salmon.out', "\n" . 'Feed parsed.' . "\n", FILE_APPEND); + } + + + if($feed->get_item_quantity()) { + foreach($feed->get_items() as $item) { + $author = $item->get_author(); + $author_link = unxmlify($author->get_link()); + break; + } + } + + if(! $author_link) { + if($debugging) + file_put_contents('salmon.out',"\n" . 'Could not retrieve author URI.' . "\n", FILE_APPEND); + salmon_return(500); + } - $xml = $tpl . $base . ''; + // Once we have the author URI, go to the web and find their public key -salmon_return(500); // until the handler is finished + if($debugging) { + file_put_contents('salmon.out', "\n" . 'Fetching key for ' . $author_link . "\n", FILE_APPEND); + } -// consume_salmon($xml,$importer); + $key = get_salmon_key($author_link,$keyhash); + + if(! $key) { + if($debugging) + file_put_contents('salmon.out',"\n" . 'Could not retrieve author key.' . "\n", FILE_APPEND); + salmon_return(500); + } + + // Setup RSA stuff to verify the signature + + set_include_path(get_include_path() . PATH_SEPARATOR . 'phpsec'); + + require_once('phpsec/Crypt/RSA.php'); + + $key_info = explode('.',$key); + + $m = base64url_decode($key_info[1]); + $e = base64url_decode($key_info[2]); + if($debugging) + file_put_contents('salmon.out',"\n" . print_r($key_info,true) . "\n", FILE_APPEND); + + $rsa = new CRYPT_RSA(); + $rsa->signatureMode = CRYPT_RSA_SIGNATURE_PKCS1; + $rsa->setHash('sha256'); + + $rsa->modulus = new Math_BigInteger($m, 256); + $rsa->k = strlen($rsa->modulus->toBytes()); + $rsa->exponent = new Math_BigInteger($e, 256); + + // We should have everything we need now. Let's see if it verifies. + + $verify = $rsa->verify($signed_data,$signature); + + if(! $verify) { + if($debugging) + file_put_contents('salmon.out',"\n" . 'Message did not verify. Discarding.' . "\n", FILE_APPEND); + salmon_return(500); + } + + if($debugging) + file_put_contents('salmon.out',"\n" . 'Message verified.' . "\n", FILE_APPEND); + + + /* + * + * If we reached this point, the message is good. Now let's figure out if the author is allowed to send us stuff. + * + */ + + $r = q("SELECT * FROM `contact` WHERE `network` = 'stat' AND `lrdd` = '%s' AND `uid` = %d LIMIT 1", + dbesc($author_link), + intval($importer['uid']) + ); + if(! count($r)) { + if($debugging) + file_put_contents('salmon.out',"\n" . 'Author unknown to us.' . "\n", FILE_APPEND); + salmon_return(500); + } + + + require_once('include/items.php'); + + $hub = ''; + + consume_feed($feedxml,$importer,$r[0],$hub); salmon_return(200); } + -- cgit v1.2.3