plugins/mod_saslauth.lua

   1
   2 local st = require "util.stanza";
   3 local sm_bind_resource = require "core.sessionmanager".bind_resource;
   4 local jid
   5 local base64 = require "base64"
   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(base64.encode(ret or ""));
  24         elseif status == "failure" then
  25                 reply:tag(ret):up();
  26                 if err_msg then reply:tag("text"):text(err_msg); end
  27         elseif status == "success" then
  28                 reply:text(base64.encode(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 "md5".sum(node..":"..host..":"..password);
  54                 end
  55         end
  56         return func, nil;
  57 end
  58
  59 function sasl_handler(session, stanza)
  60         if stanza.name == "auth" then
  61                 -- FIXME ignoring duplicates because ejabberd does
  62                 session.sasl_handler = new_sasl(stanza.attr.mechanism, session.host, password_callback);
  63         elseif not session.sasl_handler then
  64                 return; -- FIXME ignoring out of order stanzas because ejabberd does
  65         end
  66         local text = stanza[1];
  67         if text then
  68                 text = base64.decode(text);
  69                 if not text then
  70                         session.sasl_handler = nil;
  71                         session.send(build_reply("failure", "incorrect-encoding"));
  72                         return;
  73                 end
  74         end
  75         local status, ret, err_msg = session.sasl_handler:feed(text);
  76         handle_status(session, status);
  77         local s = build_reply(status, ret, err_msg);
  78         log("debug", "sasl reply: "..tostring(s));
  79         session.send(s);
  80 end
  81
  82 add_handler("c2s_unauthed", "auth", xmlns_sasl, sasl_handler);
  83 add_handler("c2s_unauthed", "abort", xmlns_sasl, sasl_handler);
  84 add_handler("c2s_unauthed", "response", xmlns_sasl, sasl_handler);
  85
  86 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
  87 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
  88 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
  89 add_event_hook("stream-features",
  90                                         function (session, features)
  91                                                 if not session.username then
  92                                                         features:tag("mechanisms", mechanisms_attr);
  93                                                         -- 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.
  94                                                                 features:tag("mechanism"):text("PLAIN"):up();
  95                                                                 features:tag("mechanism"):text("DIGEST-MD5"):up();
  96                                                         features:up();
  97                                                 else
  98                                                         features:tag("bind", bind_attr):tag("required"):up():up();
  99                                                         features:tag("session", xmpp_session_attr):up();
 100                                                 end
 101                                         end);
 102
 103 add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind",
 104                 function (session, stanza)
 105                         log("debug", "Client tried to bind to a resource");
 106                         local resource;
 107                         if stanza.attr.type == "set" then
 108                                 local bind = stanza.tags[1];
 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_type, err, err_msg = sm_bind_resource(session, resource);
 117                         if not success then
 118                                 session.send(st.error_reply(stanza, err_type, err, err_msg));
 119                         else
 120                                 session.send(st.reply(stanza)
 121                                         :tag("bind", { xmlns = xmlns_bind})
 122                                         :tag("jid"):text(session.full_jid));
 123                         end
 124                 end);
 125
 126 add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session",
 127                 function (session, stanza)
 128                         log("debug", "Client tried to bind to a resource");
 129                         session.send(st.reply(stanza));
 130                 end);