<?php
namespace Zotlabs\Zot;
class Auth {
protected $test;
protected $test_results;
protected $debug_msg;
protected $address;
protected $desturl;
protected $sec;
protected $version;
protected $delegate;
protected $success;
protected $delegate_success;
protected $remote;
protected $remote_service_class;
protected $remote_level;
protected $remote_hub;
protected $dnt;
function __construct($req) {
$this->test = ((array_key_exists('test',$req)) ? intval($req['test']) : 0);
$this->test_results = array('success' => false);
$this->debug_msg = '';
$this->success = false;
$this->address = $req['auth'];
$this->desturl = $req['dest'];
$this->sec = $req['sec'];
$this->version = $req['version'];
$this->delegate = $req['delegate'];
$c = get_sys_channel();
if(! $c) {
logger('unable to obtain response (sys) channel');
$this->Debug('no local channels found.');
$this->Finalise();
}
if(strpbrk($this->sec,'.:')) {
logger('illegal security context');
$this->Debug('illegal security context.');
$this->Finalise();
}
$x = $this->GetHublocs($this->address);
if($x) {
foreach($x as $xx) {
if($this->Verify($c,$xx))
break;
}
}
/**
* @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($this->desturl,z_root() . '/rmagic'))
goaway(z_root());
$this->Finalise();
}
function GetHublocs($address) {
// Try and find a hubloc for the person attempting to auth.
// Since we're matching by address, we have to return all entries
// some of which may be from re-installed hubs; and we'll need to
// try each sequentially to see if one can pass the test
$x = q("select * from hubloc left join xchan on xchan_hash = hubloc_hash
where hubloc_addr = '%s' order by hubloc_id desc",
dbesc($address)
);
if(! $x) {
// finger them if they can't be found.
$j = Finger::run($address, null);
if ($j['success']) {
import_xchan($j);
$x = q("select * from hubloc left join xchan on xchan_hash = hubloc_hash
where hubloc_addr = '%s' order by hubloc_id desc",
dbesc($address)
);
}
}
if(! $x) {
logger('mod_zot: auth: unable to finger ' . $address);
$this->Debug('no hubloc found for ' . $address . ' and probing failed.');
$this->Finalise();
}
return $x;
}
function Verify($channel,$hubloc) {
logger('auth request received from ' . $hubloc['hubloc_addr'] );
$this->remote = remote_channel();
$this->remote_service_class = '';
$this->remote_level = 0;
$this->remote_hub = $hubloc['hubloc_url'];
$this->dnt = 0;
if(! $this->sec) {
logger('missing security context.');
if($this->test)
$this->Debug('missing security context.');
return false;
}
// 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.
// Also check that they are coming from the same site as they authenticated with originally.
$already_authed = (((remote_channel()) && ($hubloc['hubloc_hash'] == remote_channel())
&& ($hubloc['hubloc_url'] === $_SESSION['remote_hub'])) ? true : false);
if($this->delegate && $this->delegate !== $_SESSION['delegate_channel'])
$already_authed = false;
if($already_authed)
return true;
if(local_channel()) {
// 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 (\App::$channel['channel_hash'] == $hubloc['xchan_hash']) {
return true;
}
else {
logger('already authenticated locally as somebody else.');
notice( t('Remote authentication blocked. You are logged into this site locally. Please logout and retry.') . EOL);
if($this->test) {
$this->Debug('already logged in locally with a conflicting identity.');
return false;
}
}
return false;
}
// Auth packets MUST use ultra top-secret hush-hush mode - e.g. the entire packet is encrypted using the
// site private key
// The actual channel sending the packet ($c[0]) is not important, but this provides a
// generic zot packet with a sender which can be verified
$x = q("select site_crypto from site where site_url = '%s' limit 1",
dbesc($hubloc['hubloc_url'])
);
// needs a nonce!!!!
$p = zot_build_packet($channel,$type = 'auth_check',
array(array('guid' => $hubloc['hubloc_guid'],'guid_sig' => $hubloc['hubloc_guid_sig'])),
$hubloc['hubloc_sitekey'], (($x) ? $x[0]['site_crypto'] : ''), $this->sec);
$this->Debug('auth check packet created using sitekey ' . $hubloc['hubloc_sitekey']);
$this->Debug('packet contents: ' . $p);
$result = zot_zot($hubloc['hubloc_callback'],$p);
if(! $result['success']) {
logger('auth_check callback failed.');
if($this->test)
$this->Debug('auth check request to your site returned .' . print_r($result, true));
return false;
}
$j = json_decode($result['body'], true);
if(! $j) {
logger('auth_check json data malformed.');
if($this->test)
$this->Debug('json malformed: ' . $result['body']);
return false;
}
$this->Debug('auth check request returned ' . print_r($j, true));
if(! $j['success'])
return false;
// legit response, but we do need to check that this wasn't answered by a man-in-middle
if (! rsa_verify($this->sec . $hubloc['xchan_hash'],base64url_decode($j['confirm']),$hubloc['xchan_pubkey'])) {
logger('final confirmation failed.');
if($this->test)
$this->Debug('final confirmation failed. ' . $sec . print_r($j,true) . print_r($hubloc,true));
return false;
}
if (array_key_exists('service_class',$j))
$this->remote_service_class = $j['service_class'];
if (array_key_exists('level',$j))
$this->remote_level = $j['level'];
if (array_key_exists('DNT',$j))
$this->dnt = $j['DNT'];
// log them in
if ($this->test) {
// testing only - return the success result
$this->test_results['success'] = true;
$this->Debug('Authentication Success!');
$this->Finalise();
}
$_SESSION['authenticated'] = 1;
// check for delegation and if all is well, log them in locally with delegation restrictions
$this->delegate_success = false;
if($this->delegate) {
$r = q("select * from channel left join xchan on channel_hash = xchan_hash where xchan_addr = '%s' limit 1",
dbesc($this->delegate)
);
if ($r && intval($r[0]['channel_id'])) {
$allowed = perm_is_allowed($r[0]['channel_id'],$hubloc['xchan_hash'],'delegate');
if($allowed) {
$_SESSION['delegate_channel'] = $r[0]['channel_id'];
$_SESSION['delegate'] = $hubloc['xchan_hash'];
$_SESSION['account_id'] = intval($r[0]['channel_account_id']);
require_once('include/security.php');
// this will set the local_channel authentication in the session
change_channel($r[0]['channel_id']);
$this->delegate_success = true;
}
}
}
if (! $this->delegate_success) {
// normal visitor (remote_channel) login session credentials
$_SESSION['visitor_id'] = $hubloc['xchan_hash'];
$_SESSION['my_url'] = $hubloc['xchan_url'];
$_SESSION['my_address'] = $this->address;
$_SESSION['remote_service_class'] = $this->remote_service_class;
$_SESSION['remote_level'] = $this->remote_level;
$_SESSION['remote_hub'] = $this->remote_hub;
$_SESSION['DNT'] = $this->dnt;
}
$arr = array('xchan' => $hubloc, 'url' => $this->desturl, 'session' => $_SESSION);
call_hooks('magic_auth_success',$arr);
\App::set_observer($hubloc);
require_once('include/security.php');
\App::set_groups(init_groups_visitor($_SESSION['visitor_id']));
info(sprintf( t('Welcome %s. Remote authentication successful.'),$hubloc['xchan_name']));
logger('mod_zot: auth success from ' . $hubloc['xchan_addr']);
$this->success = true;
return true;
}
function Debug($msg) {
$this->debug_msg .= $msg . EOL;
}
function Finalise() {
if($this->test) {
$this->test_results['message'] = $this->debug_msg;
json_return_and_die($this->test_results);
}
goaway($this->desturl);
}
}
/**
*
* Magic Auth
* ==========
*
* So-called "magic auth" takes place by a special exchange. On the site where the "channel to be authenticated" lives (e.g. $mysite),
* a redirection is made via $mysite/magic to the zot endpoint of the remote site ($remotesite) with special GET parameters.
*
* The endpoint is typically https://$remotesite/post - or whatever was specified as the callback url in prior communications
* (we will bootstrap an address and fetch a zot info packet if possible where no prior communications exist)
*
* Five GET parameters are supplied:
* * auth => 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
* * delegate => optional urlencoded webbie of a local channel to invoke delegation rights for
*
* * test => (optional 1 or 0 - debugs the authentication exchange and returns a json response instead of redirecting the browser session)
*
* 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 an arbitrary/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
*
* \code{.json}
* {
* "type":"auth_check",
* "sender":{
* "guid":"kgVFf_...",
* "guid_sig":"PT9-TApz...",
* "url":"http:\/\/podunk.edu",
* "url_sig":"T8Bp7j...",
* "sitekey":"aMtgKTiirXrICP..."
* },
* "recipients":{
* {
* "guid":"ZHSqb...",
* "guid_sig":"JsAAXi..."
* }
* }
* "callback":"\/post",
* "version":1,
* "secret":"1eaa661",
* "secret_sig":"eKV968b1..."
* }
* \endcode
*
* 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:
*
* \code{.json}
* {
* "success":1,
* "confirm":"q0Ysovd1u...",
* "service_class":(optional)
* "level":(optional)
* "DNT": (optional do-not-track - 1 or 0)
* }
* \endcode
*
* '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.
* Service_class can be used by cooperating sites to provide different access rights based on account rights and subscription plans. It is
* a string whose contents are not defined by protocol. Example: "basic" or "gold".
*
* @param[in,out] \App &$a
*/
