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 s2s_make_authenticated = require "core.s2smanager".make_authenticated;
  15 local base64 = require "util.encodings".base64;
  16
  17 local cert_verify_identity = require "util.x509".verify_identity;
  18
  19 local usermanager_get_sasl_handler = require "core.usermanager".get_sasl_handler;
  20 local tostring = tostring;
  21
  22 local secure_auth_only = module:get_option("c2s_require_encryption") or module:get_option("require_encryption");
  23 local allow_unencrypted_plain_auth = module:get_option("allow_unencrypted_plain_auth")
  24
  25 local log = module._log;
  26
  27 local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';
  28 local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';
  29
  30 local function build_reply(status, ret, err_msg)
  31         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  32         if status == "challenge" then
  33                 --log("debug", "CHALLENGE: %s", ret or "");
  34                 reply:text(base64.encode(ret or ""));
  35         elseif status == "failure" then
  36                 reply:tag(ret):up();
  37                 if err_msg then reply:tag("text"):text(err_msg); end
  38         elseif status == "success" then
  39                 --log("debug", "SUCCESS: %s", ret or "");
  40                 reply:text(base64.encode(ret or ""));
  41         else
  42                 module:log("error", "Unknown sasl status: %s", status);
  43         end
  44         return reply;
  45 end
  46
  47 local function handle_status(session, status, ret, err_msg)
  48         if status == "failure" then
  49                 module:fire_event("authentication-failure", { session = session, condition = ret, text = err_msg });
  50                 session.sasl_handler = session.sasl_handler:clean_clone();
  51         elseif status == "success" then
  52                 local ok, err = sm_make_authenticated(session, session.sasl_handler.username);
  53                 if ok then
  54                         module:fire_event("authentication-success", { session = session });
  55                         session.sasl_handler = nil;
  56                         session:reset_stream();
  57                 else
  58                         module:log("warn", "SASL succeeded but username was invalid");
  59                         module:fire_event("authentication-failure", { session = session, condition = "not-authorized", text = err });
  60                         session.sasl_handler = session.sasl_handler:clean_clone();
  61                         return "failure", "not-authorized", "User authenticated successfully, but username was invalid";
  62                 end
  63         end
  64         return status, ret, err_msg;
  65 end
  66
  67 local function sasl_process_cdata(session, stanza)
  68         local text = stanza[1];
  69         if text then
  70                 text = base64.decode(text);
  71                 --log("debug", "AUTH: %s", text:gsub("[%z\001-\008\011\012\014-\031]", " "));
  72                 if not text then
  73                         session.sasl_handler = nil;
  74                         session.send(build_reply("failure", "incorrect-encoding"));
  75                         return true;
  76                 end
  77         end
  78         local status, ret, err_msg = session.sasl_handler:process(text);
  79         status, ret, err_msg = handle_status(session, status, ret, err_msg);
  80         local s = build_reply(status, ret, err_msg);
  81         log("debug", "sasl reply: %s", tostring(s));
  82         session.send(s);
  83         return true;
  84 end
  85
  86 module:hook_stanza(xmlns_sasl, "success", function (session, stanza)
  87         if session.type ~= "s2sout_unauthed" or session.external_auth ~= "attempting" then return; end
  88         module:log("debug", "SASL EXTERNAL with %s succeeded", session.to_host);
  89         session.external_auth = "succeeded"
  90         session:reset_stream();
  91         session:open_stream();
  92
  93         s2s_make_authenticated(session, session.to_host);
  94         return true;
  95 end)
  96
  97 module:hook_stanza(xmlns_sasl, "failure", function (session, stanza)
  98         if session.type ~= "s2sout_unauthed" or session.external_auth ~= "attempting" then return; end
  99
 100         module:log("info", "SASL EXTERNAL with %s failed", session.to_host)
 101         -- TODO: Log the failure reason
 102         session.external_auth = "failed"
 103 end, 500)
 104
 105 module:hook_stanza(xmlns_sasl, "failure", function (session, stanza)
 106         -- TODO: Dialback wasn't loaded.  Do something useful.
 107 end, 90)
 108
 109 module:hook_stanza("http://etherx.jabber.org/streams", "features", function (session, stanza)
 110         if session.type ~= "s2sout_unauthed" or not session.secure then return; end
 111
 112         local mechanisms = stanza:get_child("mechanisms", xmlns_sasl)
 113         if mechanisms then
 114                 for mech in mechanisms:childtags() do
 115                         if mech[1] == "EXTERNAL" then
 116                                 module:log("debug", "Initiating SASL EXTERNAL with %s", session.to_host);
 117                                 local reply = st.stanza("auth", {xmlns = xmlns_sasl, mechanism = "EXTERNAL"});
 118                                 reply:text(base64.encode(session.from_host))
 119                                 session.sends2s(reply)
 120                                 session.external_auth = "attempting"
 121                                 return true
 122                         end
 123                 end
 124         end
 125 end, 150);
 126
 127 local function s2s_external_auth(session, stanza)
 128         local mechanism = stanza.attr.mechanism;
 129
 130         if not session.secure then
 131                 if mechanism == "EXTERNAL" then
 132                         session.sends2s(build_reply("failure", "encryption-required"))
 133                 else
 134                         session.sends2s(build_reply("failure", "invalid-mechanism"))
 135                 end
 136                 return true;
 137         end
 138
 139         if mechanism ~= "EXTERNAL" or session.cert_chain_status ~= "valid" then
 140                 session.sends2s(build_reply("failure", "invalid-mechanism"))
 141                 return true;
 142         end
 143
 144         local text = stanza[1]
 145         if not text then
 146                 session.sends2s(build_reply("failure", "malformed-request"))
 147                 return true
 148         end
 149
 150         -- Either the value is "=" and we've already verified the external
 151         -- cert identity, or the value is a string and either matches the
 152         -- from_host (
 153
 154         text = base64.decode(text)
 155         if not text then
 156                 session.sends2s(build_reply("failure", "incorrect-encoding"))
 157                 return true;
 158         end
 159
 160         if session.cert_identity_status == "valid" then
 161                 if text ~= "" and text ~= session.from_host then
 162                         session.sends2s(build_reply("failure", "invalid-authzid"))
 163                         return true
 164                 end
 165         else
 166                 if text == "" then
 167                         session.sends2s(build_reply("failure", "invalid-authzid"))
 168                         return true
 169                 end
 170
 171                 local cert = session.conn:socket():getpeercertificate()
 172                 if (cert_verify_identity(text, "xmpp-server", cert)) then
 173                         session.cert_identity_status = "valid"
 174                 else
 175                         session.cert_identity_status = "invalid"
 176                         session.sends2s(build_reply("failure", "invalid-authzid"))
 177                         return true
 178                 end
 179         end
 180
 181         session.external_auth = "succeeded"
 182
 183         if not session.from_host then
 184                 session.from_host = text;
 185         end
 186         session.sends2s(build_reply("success"))
 187
 188         local domain = text ~= "" and text or session.from_host;
 189         module:log("info", "Accepting SASL EXTERNAL identity from %s", domain);
 190         s2s_make_authenticated(session, domain);
 191         session:reset_stream();
 192         return true
 193 end
 194
 195 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:auth", function(event)
 196         local session, stanza = event.origin, event.stanza;
 197         if session.type == "s2sin_unauthed" then
 198                 return s2s_external_auth(session, stanza)
 199         end
 200
 201         if session.type ~= "c2s_unauthed" then return; end
 202
 203         if session.sasl_handler and session.sasl_handler.selected then
 204                 session.sasl_handler = nil; -- allow starting a new SASL negotiation before completing an old one
 205         end
 206         if not session.sasl_handler then
 207                 session.sasl_handler = usermanager_get_sasl_handler(module.host, session);
 208         end
 209         local mechanism = stanza.attr.mechanism;
 210         if not session.secure and (secure_auth_only or (mechanism == "PLAIN" and not allow_unencrypted_plain_auth)) then
 211                 session.send(build_reply("failure", "encryption-required"));
 212                 return true;
 213         end
 214         local valid_mechanism = session.sasl_handler:select(mechanism);
 215         if not valid_mechanism then
 216                 session.send(build_reply("failure", "invalid-mechanism"));
 217                 return true;
 218         end
 219         return sasl_process_cdata(session, stanza);
 220 end);
 221 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:response", function(event)
 222         local session = event.origin;
 223         if not(session.sasl_handler and session.sasl_handler.selected) then
 224                 session.send(build_reply("failure", "not-authorized", "Out of order SASL element"));
 225                 return true;
 226         end
 227         return sasl_process_cdata(session, event.stanza);
 228 end);
 229 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:abort", function(event)
 230         local session = event.origin;
 231         session.sasl_handler = nil;
 232         session.send(build_reply("failure", "aborted"));
 233         return true;
 234 end);
 235
 236 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 237 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 238 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 239 module:hook("stream-features", function(event)
 240         local origin, features = event.origin, event.features;
 241         if not origin.username then
 242                 if secure_auth_only and not origin.secure then
 243                         return;
 244                 end
 245                 origin.sasl_handler = usermanager_get_sasl_handler(module.host, origin);
 246                 local mechanisms = st.stanza("mechanisms", mechanisms_attr);
 247                 for mechanism in pairs(origin.sasl_handler:mechanisms()) do
 248                         if mechanism ~= "PLAIN" or origin.secure or allow_unencrypted_plain_auth then
 249                                 mechanisms:tag("mechanism"):text(mechanism):up();
 250                         end
 251                 end
 252                 if mechanisms[1] then features:add_child(mechanisms); end
 253         else
 254                 features:tag("bind", bind_attr):tag("required"):up():up();
 255                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 256         end
 257 end);
 258
 259 module:hook("s2s-stream-features", function(event)
 260         local origin, features = event.origin, event.features;
 261         if origin.secure and origin.type == "s2sin_unauthed" then
 262                 -- Offer EXTERNAL if chain is valid and either we didn't validate
 263                 -- the identity or it passed.
 264                 if origin.cert_chain_status == "valid" and origin.cert_identity_status ~= "invalid" then --TODO: Configurable
 265                         module:log("debug", "Offering SASL EXTERNAL")
 266                         features:tag("mechanisms", { xmlns = xmlns_sasl })
 267                                 :tag("mechanism"):text("EXTERNAL")
 268                         :up():up();
 269                 end
 270         end
 271 end);
 272
 273 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-bind:bind", function(event)
 274         local origin, stanza = event.origin, event.stanza;
 275         local resource;
 276         if stanza.attr.type == "set" then
 277                 local bind = stanza.tags[1];
 278                 resource = bind:child_with_name("resource");
 279                 resource = resource and #resource.tags == 0 and resource[1] or nil;
 280         end
 281         local success, err_type, err, err_msg = sm_bind_resource(origin, resource);
 282         if success then
 283                 origin.send(st.reply(stanza)
 284                         :tag("bind", { xmlns = xmlns_bind })
 285                         :tag("jid"):text(origin.full_jid));
 286                 origin.log("debug", "Resource bound: %s", origin.full_jid);
 287         else
 288                 origin.send(st.error_reply(stanza, err_type, err, err_msg));
 289                 origin.log("debug", "Resource bind failed: %s", err_msg or err);
 290         end
 291         return true;
 292 end);
 293
 294 local function handle_legacy_session(event)
 295         event.origin.send(st.reply(event.stanza));
 296         return true;
 297 end
 298
 299 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);
 300 module:hook("iq/host/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);