plugins/mod_saslauth.lua

   1
   2 local st = require "util.stanza";
   3 local send = require "core.sessionmanager".send_to_session;
   4 local sm_bind_resource = require "core.sessionmanager".bind_resource;
   5 local jid
   6 local base64 = require "base64"
   7
   8 local usermanager_validate_credentials = require "core.usermanager".validate_credentials;
   9 local t_concat, t_insert = table.concat, table.insert;
  10 local tostring = tostring;
  11 local jid_split = require "util.jid".split
  12
  13 local log = require "util.logger".init("mod_saslauth");
  14
  15 local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';
  16 local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';
  17 local xmlns_stanzas ='urn:ietf:params:xml:ns:xmpp-stanzas';
  18
  19 local new_sasl = require "util.sasl".new;
  20
  21 local function build_reply(status, ret, err_msg)
  22         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  23         if status == "challenge" then
  24                 reply:text(base64.encode(ret or ""));
  25         elseif status == "failure" then
  26                 reply:tag(ret):up();
  27                 if err_msg then reply:tag("text"):text(err_msg); end
  28         elseif status == "success" then
  29                 reply:text(base64.encode(ret or ""));
  30         else
  31                 error("Unknown sasl status: "..status);
  32         end
  33         return reply;
  34 end
  35
  36 local function handle_status(session, status)
  37         if status == "failure" then
  38                 session.sasl_handler = nil;
  39         elseif status == "success" then
  40                 if not session.sasl_handler.username then error("SASL succeeded but we didn't get a username!"); end -- TODO move this to sessionmanager
  41                 sessionmanager.make_authenticated(session, session.sasl_handler.username);
  42                 session.sasl_handler = nil;
  43                 session:reset_stream();
  44         end
  45 end
  46
  47 local function password_callback(node, host, mechanism)
  48         local password = (datamanager.load(node, host, "accounts") or {}).password; -- FIXME handle hashed passwords
  49         local func = function(x) return x; end;
  50         if password then
  51                 if mechanism == "PLAIN" then
  52                         return func, password;
  53                 elseif mechanism == "DIGEST-MD5" then
  54                         return func, require "md5".sum(node..":"..host..":"..password);
  55                 end
  56         end
  57         return func, nil;
  58 end
  59
  60 function sasl_handler(session, stanza)
  61         if stanza.name == "auth" then
  62                 -- FIXME ignoring duplicates because ejabberd does
  63                 session.sasl_handler = new_sasl(stanza.attr.mechanism, session.host, password_callback);
  64         elseif not session.sasl_handler then
  65                 return; -- FIXME ignoring out of order stanzas because ejabberd does
  66         end
  67         local text = stanza[1];
  68         if text then
  69                 text = base64.decode(text);
  70                 if not text then
  71                         session.sasl_handler = nil;
  72                         session.send(build_reply("failure", "incorrect-encoding"));
  73                         return;
  74                 end
  75         end
  76         local status, ret, err_msg = session.sasl_handler:feed(text);
  77         handle_status(session, status);
  78         local s = build_reply(status, ret, err_msg);
  79         log("debug", "sasl reply: "..tostring(s));
  80         session.send(s);
  81 end
  82
  83 add_handler("c2s_unauthed", "auth", xmlns_sasl, sasl_handler);
  84 add_handler("c2s_unauthed", "abort", xmlns_sasl, sasl_handler);
  85 add_handler("c2s_unauthed", "response", xmlns_sasl, sasl_handler);
  86
  87 add_event_hook("stream-features",
  88                                         function (session, features)
  89                                                 if not session.username then
  90                                                         t_insert(features, "<mechanisms xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>");
  91                                                         -- TODO: Provide PLAIN only if TLS is active, this is a SHOULD from the introduction of RFC 4616. This behavior could be overridden via configuration but will issuing a warning or so.
  92                                                                 t_insert(features, "<mechanism>PLAIN</mechanism>");
  93                                                                 t_insert(features, "<mechanism>DIGEST-MD5</mechanism>");
  94                                                         t_insert(features, "</mechanisms>");
  95                                                 else
  96                                                         t_insert(features, "<bind xmlns='urn:ietf:params:xml:ns:xmpp-bind'><required/></bind>");
  97                                                         t_insert(features, "<session xmlns='urn:ietf:params:xml:ns:xmpp-session'/>");
  98                                                 end
  99                                                 --send [[<register xmlns="http://jabber.org/features/iq-register"/> ]]
 100                                         end);
 101
 102 add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind",
 103                 function (session, stanza)
 104                         log("debug", "Client tried to bind to a resource");
 105                         local resource;
 106                         if stanza.attr.type == "set" then
 107                                 local bind = stanza.tags[1];
 108
 109                                 if bind and bind.attr.xmlns == xmlns_bind then
 110                                         resource = bind:child_with_name("resource");
 111                                         if resource then
 112                                                 resource = resource[1];
 113                                         end
 114                                 end
 115                         end
 116                         local success, err = sm_bind_resource(session, resource);
 117                         if not success then
 118                                 local reply = st.reply(stanza);
 119                                 reply.attr.type = "error";
 120                                 if err == "conflict" then
 121                                         reply:tag("error", { type = "modify" })
 122                                                 :tag("conflict", { xmlns = xmlns_stanzas });
 123                                 elseif err == "constraint" then
 124                                         reply:tag("error", { type = "cancel" })
 125                                                 :tag("resource-constraint", { xmlns = xmlns_stanzas });
 126                                 elseif err == "auth" then
 127                                         reply:tag("error", { type = "cancel" })
 128                                                 :tag("not-allowed", { xmlns = xmlns_stanzas });
 129                                 end
 130                                 send(session, reply);
 131                         else
 132                                 local reply = st.reply(stanza);
 133                                 reply:tag("bind", { xmlns = xmlns_bind})
 134                                         :tag("jid"):text(session.full_jid);
 135                                 send(session, reply);
 136                         end
 137                 end);
 138
 139 add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session",
 140                 function (session, stanza)
 141                         log("debug", "Client tried to bind to a resource");
 142                         send(session, st.reply(stanza));
 143                 end);