<?php
/**
* @file mod/post.php
*
* @brief Zot endpoint.
*
*/
require_once('include/zot.php');
/**
* @brief HTTP POST entry point for Zot.
*
* Most access to this endpoint is via the post method.
* Here we will pick out the magic auth params which arrive as a get request,
* and the only communications to arrive this way.
*
* 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
*
* 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..."
* },
* "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)
* }
* \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
*/
function post_init(&$a) {
if (array_key_exists('auth', $_REQUEST)) {
$ret = array('success' => false, 'message' => '');
logger('mod_zot: auth request received.');
$address = $_REQUEST['auth'];
$desturl = $_REQUEST['dest'];
$sec = $_REQUEST['sec'];
$version = $_REQUEST['version'];
$delegate = $_REQUEST['delegate'];
$test = ((x($_REQUEST, 'test')) ? intval($_REQUEST['test']) : 0);
// 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 channel_removed = 0 limit 1");
if (! $c) {
// nobody here
logger('mod_zot: auth: unable to find a response channel');
if ($test) {
$ret['message'] .= 'no local channels found.' . EOL;
json_return_and_die($ret);
}
goaway($desturl);
}
// Try and find a hubloc for the person attempting to auth
$x = q("select * from hubloc left join xchan on xchan_hash = hubloc_hash where hubloc_addr = '%s' order by hubloc_id desc",
dbesc($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);
$x = q("select * from hubloc left join xchan on xchan_hash = hubloc_hash where hubloc_addr = '%s' order by hubloc_id desc",
dbesc($address)
);
}
}
if(! $x) {
logger('mod_zot: auth: unable to finger ' . $address);
if($test) {
$ret['message'] .= 'no hubloc found for ' . $address . ' and probing failed.' . EOL;
json_return_and_die($ret);
}
goaway($desturl);
}
foreach($x as $xx) {
logger('mod_zot: auth request received from ' . $xx['hubloc_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_channel();
$result = null;
$remote_service_class = '';
$remote_level = 0;
$remote_hub = $xx['hubloc_url'];
$DNT = 0;
// Also check that they are coming from the same site as they authenticated with originally.
$already_authed = ((($remote) && ($xx['hubloc_hash'] == $remote) && ($xx['hubloc_url'] === $_SESSION['remote_hub'])) ? true : false);
if($delegate && $delegate !== $_SESSION['delegate_channel'])
$already_authed = false;
$j = array();
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' => $xx['hubloc_guid'],'guid_sig' => $xx['hubloc_guid_sig'])), $xx['hubloc_sitekey'], $sec);
if ($test) {
$ret['message'] .= 'auth check packet created using sitekey ' . $xx['hubloc_sitekey'] . EOL;
$ret['message'] .= 'packet contents: ' . $p . EOL;
}
$result = zot_zot($xx['hubloc_callback'],$p);
if (! $result['success']) {
logger('mod_zot: auth_check callback failed.');
if ($test) {
$ret['message'] .= 'auth check request to your site returned .' . print_r($result, true) . EOL;
continue;
}
continue;
}
$j = json_decode($result['body'], true);
if (! $j) {
logger('mod_zot: auth_check json data malformed.');
if($test) {
$ret['message'] .= 'json malformed: ' . $result['body'] . EOL;
continue;
}
}
}
if ($test) {
$ret['message'] .= 'auth check request returned .' . print_r($j, true) . EOL;
}
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 . $xx['xchan_hash'],base64url_decode($j['confirm']),$xx['xchan_pubkey'])) {
logger('mod_zot: auth: final confirmation failed.');
if ($test) {
$ret['message'] .= 'final confirmation failed. ' . $sec . print_r($j,true) . print_r($xx,true);
continue;
}
continue;
}
if (array_key_exists('service_class',$j))
$remote_service_class = $j['service_class'];
if (array_key_exists('level',$j))
$remote_level = $j['level'];
if (array_key_exists('DNT',$j))
$DNT = $j['DNT'];
}
// everything is good... maybe
if(local_channel()) {
// tell them to logout if they're logged in locally as anything but the target remote account
// in which case just shut up because they don't need to be doing this at all.
if ($a->channel['channel_hash'] != $xx['xchan_hash']) {
logger('mod_zot: auth: already authenticated locally as somebody else.');
notice( t('Remote authentication blocked. You are logged into this site locally. Please logout and retry.') . EOL);
if ($test) {
$ret['message'] .= 'already logged in locally with a conflicting identity.' . EOL;
continue;
}
}
continue;
}
// log them in
if ($test) {
$ret['success'] = true;
$ret['message'] .= 'Authentication Success!' . EOL;
json_return_and_die($ret);
}
$delegation_success = false;
if ($delegate) {
$r = q("select * from channel left join xchan on channel_hash = xchan_hash where xchan_addr = '%s' limit 1",
dbesc($delegate)
);
if ($r && intval($r[0]['channel_id'])) {
$allowed = perm_is_allowed($r[0]['channel_id'],$xx['xchan_hash'],'delegate');
if ($allowed) {
$_SESSION['delegate_channel'] = $r[0]['channel_id'];
$_SESSION['delegate'] = $xx['xchan_hash'];
$_SESSION['account_id'] = intval($r[0]['channel_account_id']);
require_once('include/security.php');
change_channel($r[0]['channel_id']);
$delegation_success = true;
}
}
}
$_SESSION['authenticated'] = 1;
if (! $delegation_success) {
$_SESSION['visitor_id'] = $xx['xchan_hash'];
$_SESSION['my_url'] = $xx['xchan_url'];
$_SESSION['my_address'] = $address;
$_SESSION['remote_service_class'] = $remote_service_class;
$_SESSION['remote_level'] = $remote_level;
$_SESSION['remote_hub'] = $remote_hub;
$_SESSION['DNT'] = $DNT;
}
$arr = array('xchan' => $xx, 'url' => $desturl, 'session' => $_SESSION);
call_hooks('magic_auth_success',$arr);
$a->set_observer($xx);
require_once('include/security.php');
$a->set_groups(init_groups_visitor($_SESSION['visitor_id']));
info(sprintf( t('Welcome %s. Remote authentication successful.'),$xx['xchan_name']));
logger('mod_zot: auth success from ' . $xx['xchan_addr']);
}
else {
if ($test) {
$ret['message'] .= 'auth failure. ' . print_r($_REQUEST,true) . print_r($j,true) . EOL;
continue;
}
logger('mod_zot: magic-auth failure - not authenticated: ' . $xx['xchan_addr']);
}
if ($test) {
$ret['message'] .= 'auth failure fallthrough ' . print_r($_REQUEST,true) . print_r($j,true) . EOL;
continue;
}
}
/**
* @FIXME we really want to save the return_url in the session before we
* visit rmagic. This does however prevent a recursion if you visit
* rmagic directly, as it would otherwise send you back here again.
* But z_root() probably isn't where you really want to go.
*/
if(strstr($desturl,z_root() . '/rmagic'))
goaway(z_root());
if ($test) {
json_return_and_die($ret);
}
goaway($desturl);
}
}
/**
* @brief zot communications and messaging.
*
* Sender HTTP posts to this endpoint ($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, force_refresh, auth_check, ping, and pickup
*
* Standard packet: (used by notify, purge, refresh, force_refresh, and auth_check)
* \code{.json}
* {
* "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..."
* }
* \endcode
*
* 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
* \code{.json}
* {
* "type":"pickup",
* "url":"http:\/\/example.com",
* "callback":"http:\/\/example.com\/post",
* "callback_sig":"teE1_fLI...",
* "secret":"1eaa...",
* "secret_sig":"O7nB4_..."
* }
* \endcode
*
* 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.
*
* \code{.json}
* {
* "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..."
* }
* }
* }
* }
* \endcode
*
* Currently defined message types are 'activity', 'mail', 'profile', 'location'
* 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.
*
* \code{.json}
* {
* "type": "ping"
* }
* \endcode
*
* On receipt of a ping packet a ping response will be returned:
*
* \code{.json}
* {
* "success" : 1,
* "site" {
* "url": "http:\/\/podunk.edu",
* "url_sig": "T8Bp7j5...",
* "sitekey": "-----BEGIN PUBLIC KEY-----
* MIICIjANBgkqhkiG9w0BAQE..."
* }
* }
* \endcode
*
* 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.
*
* @param[in,out] App &$a
*/
function post_post(&$a) {
require_once('Zotlabs/Zot/Receiver.php');
require_once('Zotlabs/Zot/ZotHandler.php');
$z = new Zotlabs\Zot\Receiver($_REQUEST['data'],get_config('system','prvkey'), new Zotlabs\Zot\ZotHandler());
// notreached;
exit;
}
