plugins/mod_saslauth.lua

   1 -- Prosody IM
   2 -- Copyright (C) 2008-2010 Matthew Wild
   3 -- Copyright (C) 2008-2010 Waqas Hussain
   4 --
   5 -- This project is MIT/X11 licensed. Please see the
   6 -- COPYING file in the source package for more information.
   7 --
   8
   9
  10
  11 local st = require "util.stanza";
  12 local sm_bind_resource = require "core.sessionmanager".bind_resource;
  13 local sm_make_authenticated = require "core.sessionmanager".make_authenticated;
  14 local base64 = require "util.encodings".base64;
  15
  16 local usermanager_get_sasl_handler = require "core.usermanager".get_sasl_handler;
  17 local tostring = tostring;
  18
  19 local secure_auth_only = module:get_option("c2s_require_encryption") or module:get_option("require_encryption");
  20 local allow_unencrypted_plain_auth = module:get_option("allow_unencrypted_plain_auth")
  21
  22 local log = module._log;
  23
  24 local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';
  25 local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';
  26
  27 local function build_reply(status, ret, err_msg)
  28         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  29         if status == "failure" then
  30                 reply:tag(ret):up();
  31                 if err_msg then reply:tag("text"):text(err_msg); end
  32         elseif status == "challenge" or status == "success" then
  33                 if ret == "" then
  34                         reply:text("=")
  35                 elseif ret then
  36                         reply:text(base64.encode(ret));
  37                 end
  38         else
  39                 module:log("error", "Unknown sasl status: %s", status);
  40         end
  41         return reply;
  42 end
  43
  44 local function handle_status(session, status, ret, err_msg)
  45         if status == "failure" then
  46                 module:fire_event("authentication-failure", { session = session, condition = ret, text = err_msg });
  47                 session.sasl_handler = session.sasl_handler:clean_clone();
  48         elseif status == "success" then
  49                 local ok, err = sm_make_authenticated(session, session.sasl_handler.username);
  50                 if ok then
  51                         module:fire_event("authentication-success", { session = session });
  52                         session.sasl_handler = nil;
  53                         session:reset_stream();
  54                 else
  55                         module:log("warn", "SASL succeeded but username was invalid");
  56                         module:fire_event("authentication-failure", { session = session, condition = "not-authorized", text = err });
  57                         session.sasl_handler = session.sasl_handler:clean_clone();
  58                         return "failure", "not-authorized", "User authenticated successfully, but username was invalid";
  59                 end
  60         end
  61         return status, ret, err_msg;
  62 end
  63
  64 local function sasl_process_cdata(session, stanza)
  65         local text = stanza[1];
  66         if text then
  67                 text = base64.decode(text);
  68                 --log("debug", "AUTH: %s", text:gsub("[%z\001-\008\011\012\014-\031]", " "));
  69                 if not text then
  70                         session.sasl_handler = nil;
  71                         session.send(build_reply("failure", "incorrect-encoding"));
  72                         return true;
  73                 end
  74         end
  75         local status, ret, err_msg = session.sasl_handler:process(text);
  76         status, ret, err_msg = handle_status(session, status, ret, err_msg);
  77         local s = build_reply(status, ret, err_msg);
  78         log("debug", "sasl reply: %s", tostring(s));
  79         session.send(s);
  80         return true;
  81 end
  82
  83 module:hook_stanza(xmlns_sasl, "success", function (session, stanza)
  84         if session.type ~= "s2sout_unauthed" or session.external_auth ~= "attempting" then return; end
  85         module:log("debug", "SASL EXTERNAL with %s succeeded", session.to_host);
  86         session.external_auth = "succeeded"
  87         session:reset_stream();
  88         session:open_stream(session.from_host, session.to_host);
  89
  90         module:fire_event("s2s-authenticated", { session = session, host = session.to_host });
  91         return true;
  92 end)
  93
  94 module:hook_stanza(xmlns_sasl, "failure", function (session, stanza)
  95         if session.type ~= "s2sout_unauthed" or session.external_auth ~= "attempting" then return; end
  96
  97         module:log("info", "SASL EXTERNAL with %s failed", session.to_host)
  98         -- TODO: Log the failure reason
  99         session.external_auth = "failed"
 100         session:close();
 101         return true;
 102 end, 500)
 103
 104 module:hook_stanza("http://etherx.jabber.org/streams", "features", function (session, stanza)
 105         if session.type ~= "s2sout_unauthed" or not session.secure then return; end
 106
 107         local mechanisms = stanza:get_child("mechanisms", xmlns_sasl)
 108         if mechanisms then
 109                 for mech in mechanisms:childtags() do
 110                         if mech[1] == "EXTERNAL" then
 111                                 module:log("debug", "Initiating SASL EXTERNAL with %s", session.to_host);
 112                                 local reply = st.stanza("auth", {xmlns = xmlns_sasl, mechanism = "EXTERNAL"});
 113                                 reply:text(base64.encode(session.from_host))
 114                                 session.sends2s(reply)
 115                                 session.external_auth = "attempting"
 116                                 return true
 117                         end
 118                 end
 119         end
 120 end, 150);
 121
 122 local function s2s_external_auth(session, stanza)
 123         if session.external_auth ~= "offered" then return end -- Unexpected request
 124
 125         local mechanism = stanza.attr.mechanism;
 126
 127         if mechanism ~= "EXTERNAL" then
 128                 session.sends2s(build_reply("failure", "invalid-mechanism"));
 129                 return true;
 130         end
 131
 132         if not session.secure then
 133                 session.sends2s(build_reply("failure", "encryption-required"));
 134                 return true;
 135         end
 136
 137         local text = stanza[1];
 138         if not text then
 139                 session.sends2s(build_reply("failure", "malformed-request"));
 140                 return true;
 141         end
 142
 143         text = base64.decode(text);
 144         if not text then
 145                 session.sends2s(build_reply("failure", "incorrect-encoding"));
 146                 return true;
 147         end
 148
 149         -- The text value is either "" or equals session.from_host
 150         if not ( text == "" or text == session.from_host ) then
 151                 session.sends2s(build_reply("failure", "invalid-authzid"));
 152                 return true;
 153         end
 154
 155         -- We've already verified the external cert identity before offering EXTERNAL
 156         if session.cert_chain_status ~= "valid" or session.cert_identity_status ~= "valid" then
 157                 session.sends2s(build_reply("failure", "not-authorized"));
 158                 session:close();
 159                 return true;
 160         end
 161
 162         -- Success!
 163         session.external_auth = "succeeded";
 164         session.sends2s(build_reply("success"));
 165         module:log("info", "Accepting SASL EXTERNAL identity from %s", session.from_host);
 166         module:fire_event("s2s-authenticated", { session = session, host = session.from_host });
 167         session:reset_stream();
 168         return true;
 169 end
 170
 171 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:auth", function(event)
 172         local session, stanza = event.origin, event.stanza;
 173         if session.type == "s2sin_unauthed" then
 174                 return s2s_external_auth(session, stanza)
 175         end
 176
 177         if session.type ~= "c2s_unauthed" or module:get_host_type() ~= "local" then return; end
 178
 179         if session.sasl_handler and session.sasl_handler.selected then
 180                 session.sasl_handler = nil; -- allow starting a new SASL negotiation before completing an old one
 181         end
 182         if not session.sasl_handler then
 183                 session.sasl_handler = usermanager_get_sasl_handler(module.host, session);
 184         end
 185         local mechanism = stanza.attr.mechanism;
 186         if not session.secure and (secure_auth_only or (mechanism == "PLAIN" and not allow_unencrypted_plain_auth)) then
 187                 session.send(build_reply("failure", "encryption-required"));
 188                 return true;
 189         end
 190         local valid_mechanism = session.sasl_handler:select(mechanism);
 191         if not valid_mechanism then
 192                 session.send(build_reply("failure", "invalid-mechanism"));
 193                 return true;
 194         end
 195         return sasl_process_cdata(session, stanza);
 196 end);
 197 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:response", function(event)
 198         local session = event.origin;
 199         if not(session.sasl_handler and session.sasl_handler.selected) then
 200                 session.send(build_reply("failure", "not-authorized", "Out of order SASL element"));
 201                 return true;
 202         end
 203         return sasl_process_cdata(session, event.stanza);
 204 end);
 205 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:abort", function(event)
 206         local session = event.origin;
 207         session.sasl_handler = nil;
 208         session.send(build_reply("failure", "aborted"));
 209         return true;
 210 end);
 211
 212 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 213 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 214 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 215 module:hook("stream-features", function(event)
 216         local origin, features = event.origin, event.features;
 217         if not origin.username then
 218                 if secure_auth_only and not origin.secure then
 219                         return;
 220                 end
 221                 origin.sasl_handler = usermanager_get_sasl_handler(module.host, origin);
 222                 if origin.encrypted then
 223                         -- check wether LuaSec has the nifty binding to the function needed for tls-unique
 224                         -- FIXME: would be nice to have this check only once and not for every socket
 225                         if origin.conn:socket().getpeerfinished and origin.sasl_handler.add_cb_handler then
 226                                 origin.sasl_handler:add_cb_handler("tls-unique", function(self)
 227                                         return self.userdata:getpeerfinished();
 228                                 end);
 229                                 origin.sasl_handler["userdata"] = origin.conn:socket();
 230                         end
 231                 end
 232                 local mechanisms = st.stanza("mechanisms", mechanisms_attr);
 233                 for mechanism in pairs(origin.sasl_handler:mechanisms()) do
 234                         if mechanism ~= "PLAIN" or origin.secure or allow_unencrypted_plain_auth then
 235                                 mechanisms:tag("mechanism"):text(mechanism):up();
 236                         end
 237                 end
 238                 if mechanisms[1] then features:add_child(mechanisms); end
 239         else
 240                 features:tag("bind", bind_attr):tag("required"):up():up();
 241                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 242         end
 243 end);
 244
 245 module:hook("s2s-stream-features", function(event)
 246         local origin, features = event.origin, event.features;
 247         if origin.secure and origin.type == "s2sin_unauthed" then
 248                 -- Offer EXTERNAL only if both chain and identity is valid.
 249                 if origin.cert_chain_status == "valid" and origin.cert_identity_status == "valid" then
 250                         module:log("debug", "Offering SASL EXTERNAL");
 251                         origin.external_auth = "offered"
 252                         features:tag("mechanisms", { xmlns = xmlns_sasl })
 253                                 :tag("mechanism"):text("EXTERNAL")
 254                         :up():up();
 255                 end
 256         end
 257 end);
 258
 259 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-bind:bind", function(event)
 260         local origin, stanza = event.origin, event.stanza;
 261         local resource;
 262         if stanza.attr.type == "set" then
 263                 local bind = stanza.tags[1];
 264                 resource = bind:get_child("resource");
 265                 resource = resource and #resource.tags == 0 and resource[1] or nil;
 266         end
 267         local success, err_type, err, err_msg = sm_bind_resource(origin, resource);
 268         if success then
 269                 origin.send(st.reply(stanza)
 270                         :tag("bind", { xmlns = xmlns_bind })
 271                         :tag("jid"):text(origin.full_jid));
 272                 origin.log("debug", "Resource bound: %s", origin.full_jid);
 273         else
 274                 origin.send(st.error_reply(stanza, err_type, err, err_msg));
 275                 origin.log("debug", "Resource bind failed: %s", err_msg or err);
 276         end
 277         return true;
 278 end);
 279
 280 local function handle_legacy_session(event)
 281         event.origin.send(st.reply(event.stanza));
 282         return true;
 283 end
 284
 285 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);
 286 module:hook("iq/host/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);