diff options
| -rw-r--r-- | mod/post.php | 77 |
1 files changed, 75 insertions, 2 deletions
diff --git a/mod/post.php b/mod/post.php index 076f26039..56ab3e1e0 100644 --- a/mod/post.php +++ b/mod/post.php @@ -14,6 +14,72 @@ function post_init(&$a) { // 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 remote computer, a redirection is made to the zot endpoint with special GET parameters. + * + * Endpoint: https://example.com/post/name (name is now optional - we are authenticating to a site, not a channel) + * + * where 'name' is the left hand side of the channel webbie, for instance 'mike' where the webbie is 'mike@zothub.com' + * + * Additionally four GET parameters are supplied: + * + ** auth => the webbie of the person requesting access + ** dest => the desired destination URL (urlencoded) + ** sec => a random string which is also stored locally for use during the verification phase. + ** version => the zot revision + * + * When this packet is received, a zot message is sent to the site hosting the request auth identity. + * (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 the name attached to the request endpoint. e.g. 'mike' in this example. If this channel + * cannot be located, we will choose any local channel as the sender. The recipients will be a single recipient corresponding + * to the guid and guid_sig we have associated with the 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 source 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(argc() > 1) { $webbie = argv(1); } @@ -46,10 +112,17 @@ function post_init(&$a) { dbesc($webbie) ); if(! $c) { - logger('mod_zot: auth: unable to find channel ' . $webbie); + // They are authenticating ultimately to the site and not to a particular channel. + // Any channel will do. We just need to have an identity to attach to the + // packet we send back. + + $c = q("select * from channel where true limit 1"); + if(! $c) + logger('mod_zot: auth: unable to find channel ' . $webbie); // They'll get a notice when they hit the page, we don't need two of them. // In fact we only need the name to map the destination, auth can proceed // without it. + } } @@ -160,7 +233,7 @@ function post_init(&$a) { * 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 public key. + * $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. |