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
   7 local usermanager_validate_credentials = require "core.usermanager".validate_credentials;
   8 local t_concat, t_insert = table.concat, table.insert;
   9 local tostring = tostring;
  10 local jid_split = require "util.jid".split
  11
  12 local log = require "util.logger".init("mod_saslauth");
  13
  14 local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';
  15 local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';
  16 local xmlns_stanzas ='urn:ietf:params:xml:ns:xmpp-stanzas';
  17
  18 local new_sasl = require "util.sasl".new;
  19
  20 local function build_reply(status, ret, err_msg)
  21         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  22         if status == "challenge" then
  23                 reply:text(ret or "");
  24         elseif status == "failure" then
  25                 reply:tag(ret):up();
  26                 if err_msg then reply:tag("text"); end
  27         elseif status == "success" then
  28                 reply:text(ret or "");
  29         else
  30                 error("Unknown sasl status: "..status);
  31         end
  32         return reply;
  33 end
  34
  35 local function handle_status(session, status)
  36         if status == "failure" then
  37                 session.sasl_handler = nil;
  38         elseif status == "success" then
  39                 if not session.sasl_handler.username then error("SASL succeeded but we didn't get a username!"); end -- TODO move this to sessionmanager
  40                 sessionmanager.make_authenticated(session, session.sasl_handler.username);
  41                 session.sasl_handler = nil;
  42                 session:reset_stream();
  43         end
  44 end
  45
  46 local function password_callback(node, host, mechanism)
  47         local password = (datamanager.load(node, host, "accounts") or {}).password; -- FIXME handle hashed passwords
  48         local func = function(x) return x; end;
  49         if password then
  50                 if mechanism == "PLAIN" then
  51                         return func, password;
  52                 elseif mechanism == "DIGEST-MD5" then
  53                         return func, require "hashes".md5(node..":"..host..":"..password);
  54                 end
  55         end
  56         return func, nil;
  57 end
  58
  59 function do_sasl(session, stanza)
  60         local text = stanza[1];
  61         if text then
  62                 text = base64.decode(text);
  63                 if not text then
  64                         session.sasl_handler = nil;
  65                         session.send(build_reply("failure", "incorrect-encoding"));
  66                         return;
  67                 end
  68         end
  69         local status, ret, err_msg = session.sasl_handler:feed(text);
  70         handle_status(session, status);
  71         local s = build_reply(status, ret, err_msg);
  72         log("debug", "sasl reply: "..tostring(s));
  73         session.send(s);
  74 end
  75
  76 add_handler("c2s_unauthed", "auth", xmlns_sasl,
  77                 function (session, stanza)
  78                         if not session.sasl_handler then
  79                                 session.sasl_handler = new_sasl(stanza.attr.mechanism, session.host, password_callback);
  80                                 do_sasl(session, stanza);
  81                         else
  82                                 error("Client tried to negotiate SASL again", 0);
  83                         end
  84                 end);
  85
  86 add_handler("c2s_unauthed", "abort", xmlns_sasl,
  87         function(session, stanza)
  88                 if not session.sasl_handler then error("Attempt to abort when sasl has not started"); end
  89                 do_sasl(session, stanza);
  90         end);
  91
  92 add_handler("c2s_unauthed", "response", xmlns_sasl,
  93         function(session, stanza)
  94                 if not session.sasl_handler then error("Attempt to respond when sasl has not started"); end
  95                 do_sasl(session, stanza);
  96         end);
  97
  98 add_event_hook("stream-features",
  99                                         function (session, features)
 100                                                 if not session.username then
 101                                                         t_insert(features, "<mechanisms xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>");
 102                                                         -- 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.
 103                                                                 t_insert(features, "<mechanism>PLAIN</mechanism>");
 104                                                                 -- t_insert(features, "<mechanism>DIGEST-MD5</mechanism>");
 105                                                         t_insert(features, "</mechanisms>");
 106                                                 else
 107                                                         t_insert(features, "<bind xmlns='urn:ietf:params:xml:ns:xmpp-bind'><required/></bind>");
 108                                                         t_insert(features, "<session xmlns='urn:ietf:params:xml:ns:xmpp-session'/>");
 109                                                 end
 110                                                 --send [[<register xmlns="http://jabber.org/features/iq-register"/> ]]
 111                                         end);
 112
 113 add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind",
 114                 function (session, stanza)
 115                         log("debug", "Client tried to bind to a resource");
 116                         local resource;
 117                         if stanza.attr.type == "set" then
 118                                 local bind = stanza.tags[1];
 119
 120                                 if bind and bind.attr.xmlns == xmlns_bind then
 121                                         resource = bind:child_with_name("resource");
 122                                         if resource then
 123                                                 resource = resource[1];
 124                                         end
 125                                 end
 126                         end
 127                         local success, err = sm_bind_resource(session, resource);
 128                         if not success then
 129                                 local reply = st.reply(stanza);
 130                                 reply.attr.type = "error";
 131                                 if err == "conflict" then
 132                                         reply:tag("error", { type = "modify" })
 133                                                 :tag("conflict", { xmlns = xmlns_stanzas });
 134                                 elseif err == "constraint" then
 135                                         reply:tag("error", { type = "cancel" })
 136                                                 :tag("resource-constraint", { xmlns = xmlns_stanzas });
 137                                 elseif err == "auth" then
 138                                         reply:tag("error", { type = "cancel" })
 139                                                 :tag("not-allowed", { xmlns = xmlns_stanzas });
 140                                 end
 141                                 send(session, reply);
 142                         else
 143                                 local reply = st.reply(stanza);
 144                                 reply:tag("bind", { xmlns = xmlns_bind})
 145                                         :tag("jid"):text(session.full_jid);
 146                                 send(session, reply);
 147                         end
 148                 end);
 149
 150 add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session",
 151                 function (session, stanza)
 152                         log("debug", "Client tried to bind to a resource");
 153                         send(session, st.reply(stanza));
 154                 end);