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 cert_verify_identity = require "util.x509".verify_identity;
  17
  18 local usermanager_get_sasl_handler = require "core.usermanager".get_sasl_handler;
  19 local tostring = tostring;
  20
  21 local secure_auth_only = module:get_option("c2s_require_encryption") or module:get_option("require_encryption");
  22 local allow_unencrypted_plain_auth = module:get_option("allow_unencrypted_plain_auth")
  23
  24 local log = module._log;
  25
  26 local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';
  27 local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';
  28
  29 local function build_reply(status, ret, err_msg)
  30         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  31         if status == "challenge" then
  32                 --log("debug", "CHALLENGE: %s", ret or "");
  33                 reply:text(base64.encode(ret or ""));
  34         elseif status == "failure" then
  35                 reply:tag(ret):up();
  36                 if err_msg then reply:tag("text"):text(err_msg); end
  37         elseif status == "success" then
  38                 --log("debug", "SUCCESS: %s", ret or "");
  39                 reply:text(base64.encode(ret or ""));
  40         else
  41                 module:log("error", "Unknown sasl status: %s", status);
  42         end
  43         return reply;
  44 end
  45
  46 local function handle_status(session, status, ret, err_msg)
  47         if status == "failure" then
  48                 module:fire_event("authentication-failure", { session = session, condition = ret, text = err_msg });
  49                 session.sasl_handler = session.sasl_handler:clean_clone();
  50         elseif status == "success" then
  51                 local ok, err = sm_make_authenticated(session, session.sasl_handler.username);
  52                 if ok then
  53                         module:fire_event("authentication-success", { session = session });
  54                         session.sasl_handler = nil;
  55                         session:reset_stream();
  56                 else
  57                         module:log("warn", "SASL succeeded but username was invalid");
  58                         module:fire_event("authentication-failure", { session = session, condition = "not-authorized", text = err });
  59                         session.sasl_handler = session.sasl_handler:clean_clone();
  60                         return "failure", "not-authorized", "User authenticated successfully, but username was invalid";
  61                 end
  62         end
  63         return status, ret, err_msg;
  64 end
  65
  66 local function sasl_process_cdata(session, stanza)
  67         local text = stanza[1];
  68         if text then
  69                 text = base64.decode(text);
  70                 --log("debug", "AUTH: %s", text:gsub("[%z\001-\008\011\012\014-\031]", " "));
  71                 if not text then
  72                         session.sasl_handler = nil;
  73                         session.send(build_reply("failure", "incorrect-encoding"));
  74                         return true;
  75                 end
  76         end
  77         local status, ret, err_msg = session.sasl_handler:process(text);
  78         status, ret, err_msg = handle_status(session, status, ret, err_msg);
  79         local s = build_reply(status, ret, err_msg);
  80         log("debug", "sasl reply: %s", tostring(s));
  81         session.send(s);
  82         return true;
  83 end
  84
  85 module:hook_stanza(xmlns_sasl, "success", function (session, stanza)
  86         if session.type ~= "s2sout_unauthed" or session.external_auth ~= "attempting" then return; end
  87         module:log("debug", "SASL EXTERNAL with %s succeeded", session.to_host);
  88         session.external_auth = "succeeded"
  89         session:reset_stream();
  90         session:open_stream(session.from_host, session.to_host);
  91
  92         module:fire_event("s2s-authenticated", { session = session, host = session.to_host });
  93         return true;
  94 end)
  95
  96 module:hook_stanza(xmlns_sasl, "failure", function (session, stanza)
  97         if session.type ~= "s2sout_unauthed" or session.external_auth ~= "attempting" then return; end
  98
  99         module:log("info", "SASL EXTERNAL with %s failed", session.to_host)
 100         -- TODO: Log the failure reason
 101         session.external_auth = "failed"
 102         session:close();
 103         return true;
 104 end, 500)
 105
 106 module:hook_stanza("http://etherx.jabber.org/streams", "features", function (session, stanza)
 107         if session.type ~= "s2sout_unauthed" or not session.secure then return; end
 108
 109         local mechanisms = stanza:get_child("mechanisms", xmlns_sasl)
 110         if mechanisms then
 111                 for mech in mechanisms:childtags() do
 112                         if mech[1] == "EXTERNAL" then
 113                                 module:log("debug", "Initiating SASL EXTERNAL with %s", session.to_host);
 114                                 local reply = st.stanza("auth", {xmlns = xmlns_sasl, mechanism = "EXTERNAL"});
 115                                 reply:text(base64.encode(session.from_host))
 116                                 session.sends2s(reply)
 117                                 session.external_auth = "attempting"
 118                                 return true
 119                         end
 120                 end
 121         end
 122 end, 150);
 123
 124 local function s2s_external_auth(session, stanza)
 125         local mechanism = stanza.attr.mechanism;
 126
 127         if not session.secure then
 128                 if mechanism == "EXTERNAL" then
 129                         session.sends2s(build_reply("failure", "encryption-required"))
 130                 else
 131                         session.sends2s(build_reply("failure", "invalid-mechanism"))
 132                 end
 133                 return true;
 134         end
 135
 136         if mechanism ~= "EXTERNAL" or session.cert_chain_status ~= "valid" then
 137                 session.sends2s(build_reply("failure", "invalid-mechanism"))
 138                 return true;
 139         end
 140
 141         local text = stanza[1]
 142         if not text then
 143                 session.sends2s(build_reply("failure", "malformed-request"))
 144                 return true
 145         end
 146
 147         -- Either the value is "=" and we've already verified the external
 148         -- cert identity, or the value is a string and either matches the
 149         -- from_host (
 150
 151         text = base64.decode(text)
 152         if not text then
 153                 session.sends2s(build_reply("failure", "incorrect-encoding"))
 154                 return true;
 155         end
 156
 157         if session.cert_identity_status == "valid" then
 158                 if text ~= "" and text ~= session.from_host then
 159                         session.sends2s(build_reply("failure", "invalid-authzid"))
 160                         return true
 161                 end
 162         else
 163                 if text == "" then
 164                         session.sends2s(build_reply("failure", "invalid-authzid"))
 165                         return true
 166                 end
 167
 168                 local cert = session.conn:socket():getpeercertificate()
 169                 if (cert_verify_identity(text, "xmpp-server", cert)) then
 170                         session.cert_identity_status = "valid"
 171                 else
 172                         session.cert_identity_status = "invalid"
 173                         session.sends2s(build_reply("failure", "invalid-authzid"))
 174                         return true
 175                 end
 176         end
 177
 178         session.external_auth = "succeeded"
 179
 180         if not session.from_host then
 181                 session.from_host = text;
 182         end
 183         session.sends2s(build_reply("success"))
 184
 185         local domain = text ~= "" and text or session.from_host;
 186         module:log("info", "Accepting SASL EXTERNAL identity from %s", domain);
 187         module:fire_event("s2s-authenticated", { session = session, host = domain });
 188         session:reset_stream();
 189         return true
 190 end
 191
 192 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:auth", function(event)
 193         local session, stanza = event.origin, event.stanza;
 194         if session.type == "s2sin_unauthed" then
 195                 return s2s_external_auth(session, stanza)
 196         end
 197
 198         if session.type ~= "c2s_unauthed" or module:get_host_type() ~= "local" then return; end
 199
 200         if session.sasl_handler and session.sasl_handler.selected then
 201                 session.sasl_handler = nil; -- allow starting a new SASL negotiation before completing an old one
 202         end
 203         if not session.sasl_handler then
 204                 session.sasl_handler = usermanager_get_sasl_handler(module.host, session);
 205         end
 206         local mechanism = stanza.attr.mechanism;
 207         if not session.secure and (secure_auth_only or (mechanism == "PLAIN" and not allow_unencrypted_plain_auth)) then
 208                 session.send(build_reply("failure", "encryption-required"));
 209                 return true;
 210         end
 211         local valid_mechanism = session.sasl_handler:select(mechanism);
 212         if not valid_mechanism then
 213                 session.send(build_reply("failure", "invalid-mechanism"));
 214                 return true;
 215         end
 216         return sasl_process_cdata(session, stanza);
 217 end);
 218 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:response", function(event)
 219         local session = event.origin;
 220         if not(session.sasl_handler and session.sasl_handler.selected) then
 221                 session.send(build_reply("failure", "not-authorized", "Out of order SASL element"));
 222                 return true;
 223         end
 224         return sasl_process_cdata(session, event.stanza);
 225 end);
 226 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:abort", function(event)
 227         local session = event.origin;
 228         session.sasl_handler = nil;
 229         session.send(build_reply("failure", "aborted"));
 230         return true;
 231 end);
 232
 233 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 234 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 235 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 236 module:hook("stream-features", function(event)
 237         local origin, features = event.origin, event.features;
 238         if not origin.username then
 239                 if secure_auth_only and not origin.secure then
 240                         return;
 241                 end
 242                 origin.sasl_handler = usermanager_get_sasl_handler(module.host, origin);
 243                 if origin.encrypted then
 244                         -- check wether LuaSec has the nifty binding to the function needed for tls-unique
 245                         -- FIXME: would be nice to have this check only once and not for every socket
 246                         if origin.conn:socket().getpeerfinished and origin.sasl_handler.add_cb_handler then
 247                                 origin.sasl_handler:add_cb_handler("tls-unique", function(self)
 248                                         return self.userdata:getpeerfinished();
 249                                 end);
 250                                 origin.sasl_handler["userdata"] = origin.conn:socket();
 251                         end
 252                 end
 253                 local mechanisms = st.stanza("mechanisms", mechanisms_attr);
 254                 for mechanism in pairs(origin.sasl_handler:mechanisms()) do
 255                         if mechanism ~= "PLAIN" or origin.secure or allow_unencrypted_plain_auth then
 256                                 mechanisms:tag("mechanism"):text(mechanism):up();
 257                         end
 258                 end
 259                 if mechanisms[1] then features:add_child(mechanisms); end
 260         else
 261                 features:tag("bind", bind_attr):tag("required"):up():up();
 262                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 263         end
 264 end);
 265
 266 module:hook("s2s-stream-features", function(event)
 267         local origin, features = event.origin, event.features;
 268         if origin.secure and origin.type == "s2sin_unauthed" then
 269                 -- Offer EXTERNAL if chain is valid and either we didn't validate
 270                 -- the identity or it passed.
 271                 if origin.cert_chain_status == "valid" and origin.cert_identity_status ~= "invalid" then --TODO: Configurable
 272                         module:log("debug", "Offering SASL EXTERNAL")
 273                         features:tag("mechanisms", { xmlns = xmlns_sasl })
 274                                 :tag("mechanism"):text("EXTERNAL")
 275                         :up():up();
 276                 end
 277         end
 278 end);
 279
 280 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-bind:bind", function(event)
 281         local origin, stanza = event.origin, event.stanza;
 282         local resource;
 283         if stanza.attr.type == "set" then
 284                 local bind = stanza.tags[1];
 285                 resource = bind:get_child("resource");
 286                 resource = resource and #resource.tags == 0 and resource[1] or nil;
 287         end
 288         local success, err_type, err, err_msg = sm_bind_resource(origin, resource);
 289         if success then
 290                 origin.send(st.reply(stanza)
 291                         :tag("bind", { xmlns = xmlns_bind })
 292                         :tag("jid"):text(origin.full_jid));
 293                 origin.log("debug", "Resource bound: %s", origin.full_jid);
 294         else
 295                 origin.send(st.error_reply(stanza, err_type, err, err_msg));
 296                 origin.log("debug", "Resource bind failed: %s", err_msg or err);
 297         end
 298         return true;
 299 end);
 300
 301 local function handle_legacy_session(event)
 302         event.origin.send(st.reply(event.stanza));
 303         return true;
 304 end
 305
 306 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);
 307 module:hook("iq/host/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);