the urlencoded webbie (channel@host.domain) of the channel requesting access ** dest => the desired destination URL (urlencoded) ** sec => a random string which is also stored on $mysite for use during the verification phase. ** version => the zot revision * * When this packet is received, an "auth-check" zot message is sent to $mysite. * (e.g. if $_GET['auth'] is foobar@podunk.edu, a zot packet is sent to the podunk.edu zot endpoint, which is typically /post) * If no information has been recorded about the requesting identity a zot information packet will be retrieved before * continuing. * * The sender of this packet is a random site channel. The recipients will be a single recipient corresponding * to the guid and guid_sig we have associated with the requesting auth identity * * * { * "type":"auth_check", * "sender":{ * "guid":"kgVFf_...", * "guid_sig":"PT9-TApz...", * "url":"http:\/\/podunk.edu", * "url_sig":"T8Bp7j..." * }, * "recipients":{ * { * "guid":"ZHSqb...", * "guid_sig":"JsAAXi..." * } * } * "callback":"\/post", * "version":1, * "secret":"1eaa661", * "secret_sig":"eKV968b1..." * } * * * auth_check messages MUST use encapsulated encryption. This message is sent to the origination site, which checks the 'secret' to see * if it is the same as the 'sec' which it passed originally. It also checks the secret_sig which is the secret signed by the * destination channel's private key and base64url encoded. If everything checks out, a json packet is returned: * * { * "success":1, * "confirm":"q0Ysovd1u..." * } * * 'confirm' in this case is the base64url encoded RSA signature of the concatenation of 'secret' with the * base64url encoded whirlpool hash of the requestor's guid and guid_sig; signed with the source channel private key. * This prevents a man-in-the-middle from inserting a rogue success packet. Upon receipt and successful * verification of this packet, the destination site will redirect to the original destination URL and indicate a successful remote login. * * * */ if(array_key_exists('auth',$_REQUEST)) { logger('mod_zot: auth request received.'); $address = $_REQUEST['auth']; $desturl = $_REQUEST['dest']; $sec = $_REQUEST['sec']; $version = $_REQUEST['version']; // They are authenticating ultimately to the site and not to a particular channel. // Any channel will do, providing it's currently active. We just need to have an // identity to attach to the packet we send back. So find one. $c = q("select * from channel where not ( channel_pageflags & %d ) limit 1", intval(PAGE_REMOVED) ); if(! $c) { // nobody here logger('mod_zot: auth: unable to find a response channel'); goaway($desturl); } // Try and find a hubloc for the person attempting to auth $x = q("select * from hubloc left join xchan on xchan_hash = hubloc_hash where hubloc_addr = '%s' order by hubloc_id desc limit 1", dbesc($address) ); if(! $x) { // finger them if they can't be found. $ret = zot_finger($address,null); if($ret['success']) { $j = json_decode($ret['body'],true); if($j) import_xchan($j); $x = q("select * from hubloc left join xchan on xchan_hash = hubloc_hash where hubloc_addr = '%s' order by hubloc_id desc limit 1", dbesc($address) ); } } if(! $x) { logger('mod_zot: auth: unable to finger ' . $address); goaway($desturl); } logger('mod_zot: auth request received from ' . $x[0]['xchan_addr'] ); // check credentials and access // If they are already authenticated and haven't changed credentials, // we can save an expensive network round trip and improve performance. $remote = remote_user(); $result = null; $already_authed = ((($remote) && ($x[0]['hubloc_hash'] == $remote)) ? true : false); if(! $already_authed) { // Auth packets MUST use ultra top-secret hush-hush mode - e.g. the entire packet is encrypted using the site private key // The actual channel sending the packet ($c[0]) is not important, but this provides a generic zot packet with a sender // which can be verified $p = zot_build_packet($c[0],$type = 'auth_check', array(array('guid' => $x[0]['hubloc_guid'],'guid_sig' => $x[0]['hubloc_guid_sig'])), $x[0]['hubloc_sitekey'], $sec); $result = zot_zot($x[0]['hubloc_callback'],$p); if(! $result['success']) { logger('mod_zot: auth_check callback failed.'); goaway($desturl); } $j = json_decode($result['body'],true); } if($already_authed || $j['success']) { if($j['success']) { // legit response, but we do need to check that this wasn't answered by a man-in-middle if(! rsa_verify($sec . $x[0]['xchan_hash'],base64url_decode($j['confirm']),$x[0]['xchan_pubkey'])) { logger('mod_zot: auth: final confirmation failed.'); goaway($desturl); } } // everything is good... maybe if(local_user()) { // tell them to logout if they're logged in locally as anything but the target remote account // in which case just shut up because they don't need to be doing this at all. if($a->channel['channel_hash'] != $x[0]['xchan_hash']) { logger('mod_zot: auth: already authenticated locally as somebody else.'); notice( t('Remote authentication blocked. You are logged into this site locally. Please logout and retry.') . EOL); } goaway($desturl); } // log them in $_SESSION['authenticated'] = 1; $_SESSION['visitor_id'] = $x[0]['xchan_hash']; $_SESSION['my_address'] = $address; $arr = array('xchan' => $x[0], 'url' => $desturl, 'channel_address' => $webbie); call_hooks('magic_auth_success',$arr); $a->set_observer($x[0]); require_once('include/security.php'); $a->set_groups(init_groups_visitor($_SESSION['visitor_id'])); info(sprintf( t('Welcome %s. Remote authentication successful.'),$x[0]['xchan_name'])); logger('mod_zot: auth success from ' . $x[0]['xchan_addr'] . ' for ' . $webbie); } else { logger('mod_zot: magic-auth failure - not authenticated: ' . $x[0]['xchan_addr']); q("update hubloc set hubloc_status = (hubloc_status | %d ) where hubloc_addr = '%s'", intval(HUBLOC_RECEIVE_ERROR), dbesc($x[0]['xchan_addr']) ); } // FIXME - we really want to save the return_url in the session before we visit rmagic. // This does however prevent a recursion if you visit rmagic directly, as it would otherwise send you back here again. // But z_root() probably isn't where you really want to go. if(strstr($desturl,z_root() . '/rmagic')) goaway(z_root()); goaway($desturl); } return; } /** * @function post_post(&$a) * zot communications and messaging * * Sender HTTP posts to this endpoint ($site/post typically) with 'data' parameter set to json zot message packet. * This packet is optionally encrypted, which we will discover if the json has an 'iv' element. * $contents => array( 'alg' => 'aes256cbc', 'iv' => initialisation vector, 'key' => decryption key, 'data' => encrypted data); * $contents->iv and $contents->key are random strings encrypted with this site's RSA public key and then base64url encoded. * Currently only 'aes256cbc' is used, but this is extensible should that algorithm prove inadequate. * * Once decrypted, one will find the normal json_encoded zot message packet. * * Defined packet types are: notify, purge, refresh, auth_check, ping, and pickup * * Standard packet: (used by notify, purge, refresh, and auth_check) * * { * "type": "notify", * "sender":{ * "guid":"kgVFf_1...", * "guid_sig":"PT9-TApzp...", * "url":"http:\/\/podunk.edu", * "url_sig":"T8Bp7j5...", * }, * "recipients": { optional recipient array }, * "callback":"\/post", * "version":1, * "secret":"1eaa...", * "secret_sig": "df89025470fac8..." * } * * Signature fields are all signed with the sender channel private key and base64url encoded. * Recipients are arrays of guid and guid_sig, which were previously signed with the recipients private * key and base64url encoded and later obtained via channel discovery. Absence of recipients indicates * a public message or visible to all potential listeners on this site. * * "pickup" packet: * The pickup packet is sent in response to a notify packet from another site * * { * "type":"pickup", * "url":"http:\/\/example.com", * "callback":"http:\/\/example.com\/post", * "callback_sig":"teE1_fLI...", * "secret":"1eaa...", * "secret_sig":"O7nB4_..." * } * * In the pickup packet, the sig fields correspond to the respective data element signed with this site's system * private key and then base64url encoded. * The "secret" is the same as the original secret from the notify packet. * * If verification is successful, a json structure is returned * containing a success indicator and an array of type 'pickup'. * Each pickup element contains the original notify request and a message field whose contents are * dependent on the message type * * This JSON array is AES encapsulated using the site public key of the site that sent the initial zot pickup packet. * Using the above example, this would be example.com. * * * { * "success":1, * "pickup":{ * "notify":{ * "type":"notify", * "sender":{ * "guid":"kgVFf_...", * "guid_sig":"PT9-TApz...", * "url":"http:\/\/z.podunk.edu", * "url_sig":"T8Bp7j5D..." * }, * "callback":"\/post", * "version":1, * "secret":"1eaa661..." * }, * "message":{ * "type":"activity", * "message_id":"10b049ce384cbb2da9467319bc98169ab36290b8bbb403aa0c0accd9cb072e76@podunk.edu", * "message_top":"10b049ce384cbb2da9467319bc98169ab36290b8bbb403aa0c0accd9cb072e76@podunk.edu", * "message_parent":"10b049ce384cbb2da9467319bc98169ab36290b8bbb403aa0c0accd9cb072e76@podunk.edu", * "created":"2012-11-20 04:04:16", * "edited":"2012-11-20 04:04:16", * "title":"", * "body":"Hi Nickordo", * "app":"", * "verb":"post", * "object_type":"", * "target_type":"", * "permalink":"", * "location":"", * "longlat":"", * "owner":{ * "name":"Indigo", * "address":"indigo@podunk.edu", * "url":"http:\/\/podunk.edu", * "photo":{ * "mimetype":"image\/jpeg", * "src":"http:\/\/podunk.edu\/photo\/profile\/m\/5" * }, * "guid":"kgVFf_...", * "guid_sig":"PT9-TAp...", * }, * "author":{ * "name":"Indigo", * "address":"indigo@podunk.edu", * "url":"http:\/\/podunk.edu", * "photo":{ * "mimetype":"image\/jpeg", * "src":"http:\/\/podunk.edu\/photo\/profile\/m\/5" * }, * "guid":"kgVFf_...", * "guid_sig":"PT9-TAp..." * } * } * } *} * * Currently defined message types are 'activity', 'mail', 'profile' and 'channel_sync', which each have * different content schemas. * * Ping packet: * A ping packet does not require any parameters except the type. It may or may not be encrypted. * * { * "type": "ping" * } * * On receipt of a ping packet a ping response will be returned: * * { * "success" : 1, * "site" { * "url":"http:\/\/podunk.edu", * "url_sig":"T8Bp7j5...", * "sitekey": "-----BEGIN PUBLIC KEY----- * MIICIjANBgkqhkiG9w0BAQE..." * } * } * * The ping packet can be used to verify that a site has not been re-installed, and to * initiate corrective action if it has. The url_sig is signed with the site private key * and base64url encoded - and this should verify with the enclosed sitekey. Failure to * verify indicates the site is corrupt or otherwise unable to communicate using zot. * This return packet is not otherwise verified, so should be compared with other * results obtained from this site which were verified prior to taking action. For instance * if you have one verified result with this signature and key, and other records for this * url which have different signatures and keys, it indicates that the site was re-installed * and corrective action may commence (remove or mark invalid any entries with different * signatures). * If you have no records which match this url_sig and key - no corrective action should * be taken as this packet may have been returned by an imposter. * */ function post_post(&$a) { logger('mod_zot: ' . print_r($_REQUEST,true), LOGGER_DEBUG); $encrypted_packet = false; $ret = array('success' => false); $data = json_decode($_REQUEST['data'],true); logger('mod_zot: data: ' . print_r($data,true), LOGGER_DATA); /** * Many message packets will arrive encrypted. The existence of an 'iv' element * tells us we need to unencapsulate the AES-256-CBC content using the site private key */ if(array_key_exists('iv',$data)) { $encrypted_packet = true; $data = crypto_unencapsulate($data,get_config('system','prvkey')); logger('mod_zot: decrypt1: ' . $data, LOGGER_DATA); $data = json_decode($data,true); } if(! $data) { // possible Bleichenbacher's attack, just treat it as a // message we have no handler for. It should fail a bit // further along with "no hub". Our public key is public // knowledge. There's no reason why anybody should get the // encryption wrong unless they're fishing or hacking. If // they're developing and made a goof, this can be discovered // in the logs of the destination site. If they're fishing or // hacking, the bottom line is we can't verify their hub. // That's all we're going to tell them. $data = array('type' => 'bogus'); } logger('mod_zot: decoded data: ' . print_r($data,true), LOGGER_DATA); $msgtype = ((array_key_exists('type',$data)) ? $data['type'] : ''); if($msgtype === 'ping') { // Useful to get a health check on a remote site. // This will let us know if any important communication details // that we may have stored are no longer valid, regardless of xchan details. $ret['success'] = true; $ret['site'] = array(); $ret['site']['url'] = z_root(); $ret['site']['url_sig'] = base64url_encode(rsa_sign(z_root(),get_config('system','prvkey'))); $ret['site']['sitekey'] = get_config('system','pubkey'); json_return_and_die($ret); } if($msgtype === 'pickup') { /** * The 'pickup' message arrives with a tracking ID which is associated with a particular outq_hash * First verify that that the returned signatures verify, then check that we have an outbound queue item * with the correct hash. * If everything verifies, find any/all outbound messages in the queue for this hubloc and send them back * */ if((! $data['secret']) || (! $data['secret_sig'])) { $ret['message'] = 'no verification signature'; logger('mod_zot: pickup: ' . $ret['message'], LOGGER_DEBUG); json_return_and_die($ret); } $r = q("select distinct hubloc_sitekey from hubloc where hubloc_url = '%s' and hubloc_callback = '%s' and hubloc_sitekey != '' group by hubloc_sitekey ", dbesc($data['url']), dbesc($data['callback']) ); if(! $r) { $ret['message'] = 'site not found'; logger('mod_zot: pickup: ' . $ret['message']); json_return_and_die($ret); } foreach ($r as $hubsite) { // verify the url_sig // If the server was re-installed at some point, there could be multiple hubs with the same url and callback. // Only one will have a valid key. $forgery = true; $secret_fail = true; $sitekey = $hubsite['hubloc_sitekey']; logger('mod_zot: Checking sitekey: ' . $sitekey); if(rsa_verify($data['callback'],base64url_decode($data['callback_sig']),$sitekey)) { $forgery = false; } if(rsa_verify($data['secret'],base64url_decode($data['secret_sig']),$sitekey)) { $secret_fail = false; } if((! $forgery) && (! $secret_fail)) break; } if($forgery) { $ret['message'] = 'possible site forgery'; logger('mod_zot: pickup: ' . $ret['message']); json_return_and_die($ret); } if($secret_fail) { $ret['message'] = 'secret validation failed'; logger('mod_zot: pickup: ' . $ret['message']); json_return_and_die($ret); } /** * If we made it to here, the signatures verify, but we still don't know if the tracking ID is valid. * It wouldn't be an error if the tracking ID isn't found, because we may have sent this particular * queue item with another pickup (after the tracking ID for the other pickup was verified). */ $r = q("select outq_posturl from outq where outq_hash = '%s' and outq_posturl = '%s' limit 1", dbesc($data['secret']), dbesc($data['callback']) ); if(! $r) { $ret['message'] = 'nothing to pick up'; logger('mod_zot: pickup: ' . $ret['message']); json_return_and_die($ret); } /** * Everything is good if we made it here, so find all messages that are going to this location * and send them all. */ $r = q("select * from outq where outq_posturl = '%s'", dbesc($data['callback']) ); if($r) { $ret['success'] = true; $ret['pickup'] = array(); foreach($r as $rr) { $ret['pickup'][] = array('notify' => json_decode($rr['outq_notify'],true),'message' => json_decode($rr['outq_msg'],true)); $x = q("delete from outq where outq_hash = '%s' limit 1", dbesc($rr['outq_hash']) ); } } $encrypted = crypto_encapsulate(json_encode($ret),$sitekey); json_return_and_die($encrypted); /** pickup: end */ } /** * All other message types require us to verify the sender. This is a generic check, so we * will do it once here and bail if anything goes wrong. */ if(array_key_exists('sender',$data)) { $sender = $data['sender']; } /** Check if the sender is already verified here */ $hub = zot_gethub($sender); if(! $hub) { /** Have never seen this guid or this guid coming from this location. Check it and register it. */ // (!!) this will validate the sender $result = zot_register_hub($sender); if((! $result['success']) || (! ($hub = zot_gethub($sender)))) { $ret['message'] = 'Hub not available.'; logger('mod_zot: no hub'); json_return_and_die($ret); } } // Update our DB to show when we last communicated successfully with this hub // This will allow us to prune dead hubs from using up resources $r = q("update hubloc set hubloc_connected = '%s' where hubloc_id = %d limit 1", dbesc(datetime_convert()), intval($hub['hubloc_id']) ); /** * This hub has now been proven to be valid. * Any hub with the same URL and a different sitekey cannot be valid. * Get rid of them (mark them deleted). There's a good chance they were re-installs. * */ q("update hubloc set hubloc_flags = ( hubloc_flags | %d ) where hubloc_url = '%s' and hubloc_sitekey != '%s' ", intval(HUBLOC_FLAGS_DELETED), dbesc($hub['hubloc_url']), dbesc($hub['hubloc_sitekey']) ); // TODO: check which hub is primary and take action if mismatched if(array_key_exists('recipients',$data)) $recipients = $data['recipients']; if($msgtype === 'auth_check') { /** * Requestor visits /magic/?dest=somewhere on their own site with a browser * magic redirects them to $destsite/post [with auth args....] * $destsite sends an auth_check packet to originator site * The auth_check packet is handled here by the originator's site * - the browser session is still waiting * inside $destsite/post for everything to verify * If everything checks out we'll return a token to $destsite * and then $destsite will verify the token, authenticate the browser * session and then redirect to the original destination. * If authentication fails, the redirection to the original destination * will still take place but without authentication. */ logger('mod_zot: auth_check', LOGGER_DEBUG); if(! $encrypted_packet) { logger('mod_zot: auth_check packet was not encrypted.'); json_return_and_die($ret); } $arr = $data['sender']; $sender_hash = base64url_encode(hash('whirlpool',$arr['guid'] . $arr['guid_sig'], true)); // garbage collect any old unused notifications q("delete from verify where type = 'auth' and created < UTC_TIMESTAMP() - INTERVAL 10 MINUTE"); $y = q("select xchan_pubkey from xchan where xchan_hash = '%s' limit 1", dbesc($sender_hash) ); // We created a unique hash in mod/magic.php when we invoked remote auth, and stored it in // the verify table. It is now coming back to us as 'secret' and is signed by a channel at the other end. // First verify their signature. We will have obtained a zot-info packet from them as part of the sender // verification. if((! $y) || (! rsa_verify($data['secret'],base64url_decode($data['secret_sig']),$y[0]['xchan_pubkey']))) { logger('mod_zot: auth_check: sender not found or secret_sig invalid.'); json_return_and_die($ret); } // There should be exactly one recipient, the original auth requestor if($data['recipients']) { $arr = $data['recipients'][0]; $recip_hash = base64url_encode(hash('whirlpool',$arr['guid'] . $arr['guid_sig'], true)); $c = q("select channel_id, channel_prvkey from channel where channel_hash = '%s' limit 1", dbesc($recip_hash) ); if(! $c) { logger('mod_zot: auth_check: recipient channel not found.'); json_return_and_die($ret); } $confirm = base64url_encode(rsa_sign($data['secret'] . $recip_hash,$c[0]['channel_prvkey'])); // This additionally checks for forged sites since we already stored the expected result in meta // and we've already verified that this is them via zot_gethub() and that their key signed our token $z = q("select id from verify where channel = %d and type = 'auth' and token = '%s' and meta = '%s' limit 1", intval($c[0]['channel_id']), dbesc($data['secret']), dbesc($data['sender']['url']) ); if(! $z) { logger('mod_zot: auth_check: verification key not found.'); json_return_and_die($ret); } $r = q("delete from verify where id = %d limit 1", intval($z[0]['id']) ); logger('mod_zot: auth_check: success', LOGGER_DEBUG); $ret['success'] = true; $ret['confirm'] = $confirm; json_return_and_die($ret); } json_return_and_die($ret); } if($msgtype === 'purge') { if($recipients) { // basically this means "unfriend" foreach($recipients as $recip) { $r = q("select channel.*,xchan.* from channel left join xchan on channel_hash = xchan_hash where channel_guid = '%s' and channel_guid_sig = '%s' limit 1", dbesc($recip['guid']), dbesc($recip['guid_sig']) ); if($r) { $r = q("select abook_id from abook where uid = %d and abook_xchan = '%s' limit 1", intval($r[0]['channel_id']), dbesc(base64url_encode(hash('whirlpool',$sender['guid'] . $sender['guid_sig'], true))) ); if($r) { contact_remove($r[0]['channel_id'],$r[0]['abook_id']); } } } } else { // Unfriend everybody - basically this means the channel has committed suicide $arr = $data['sender']; $sender_hash = base64url_encode(hash('whirlpool',$arr['guid'] . $arr['guid_sig'], true)); require_once('include/Contact.php'); remove_all_xchan_resources($sender_hash); $ret['success'] = true; json_return_and_die($ret); } } if($msgtype === 'refresh') { // remote channel info (such as permissions or photo or something) // has been updated. Grab a fresh copy and sync it. if($recipients) { // This would be a permissions update, typically for one connection foreach($recipients as $recip) { $r = q("select channel.*,xchan.* from channel left join xchan on channel_hash = xchan_hash where channel_guid = '%s' and channel_guid_sig = '%s' limit 1", dbesc($recip['guid']), dbesc($recip['guid_sig']) ); $x = zot_refresh(array( 'xchan_guid' => $sender['guid'], 'xchan_guid_sig' => $sender['guid_sig'], 'hubloc_url' => $sender['url'] ),$r[0]); } } else { // system wide refresh $x = zot_refresh(array( 'xchan_guid' => $sender['guid'], 'xchan_guid_sig' => $sender['guid_sig'], 'hubloc_url' => $sender['url'] ),null); } $ret['success'] = true; json_return_and_die($ret); } if($msgtype === 'notify') { $async = get_config('system','queued_fetch'); if($async) { // add to receive queue // qreceive_add($data); } else { $x = zot_fetch($data); $ret['delivery_report'] = $x; } $ret['success'] = true; json_return_and_die($ret); } // catchall json_return_and_die($ret); }