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 end, 500)
 103
 104 module:hook_stanza(xmlns_sasl, "failure", function (session, stanza)
 105         -- TODO: Dialback wasn't loaded.  Do something useful.
 106 end, 90)
 107
 108 module:hook_stanza("http://etherx.jabber.org/streams", "features", function (session, stanza)
 109         if session.type ~= "s2sout_unauthed" or not session.secure then return; end
 110
 111         local mechanisms = stanza:get_child("mechanisms", xmlns_sasl)
 112         if mechanisms then
 113                 for mech in mechanisms:childtags() do
 114                         if mech[1] == "EXTERNAL" then
 115                                 module:log("debug", "Initiating SASL EXTERNAL with %s", session.to_host);
 116                                 local reply = st.stanza("auth", {xmlns = xmlns_sasl, mechanism = "EXTERNAL"});
 117                                 reply:text(base64.encode(session.from_host))
 118                                 session.sends2s(reply)
 119                                 session.external_auth = "attempting"
 120                                 return true
 121                         end
 122                 end
 123         end
 124 end, 150);
 125
 126 local function s2s_external_auth(session, stanza)
 127         local mechanism = stanza.attr.mechanism;
 128
 129         if not session.secure then
 130                 if mechanism == "EXTERNAL" then
 131                         session.sends2s(build_reply("failure", "encryption-required"))
 132                 else
 133                         session.sends2s(build_reply("failure", "invalid-mechanism"))
 134                 end
 135                 return true;
 136         end
 137
 138         if mechanism ~= "EXTERNAL" or session.cert_chain_status ~= "valid" then
 139                 session.sends2s(build_reply("failure", "invalid-mechanism"))
 140                 return true;
 141         end
 142
 143         local text = stanza[1]
 144         if not text then
 145                 session.sends2s(build_reply("failure", "malformed-request"))
 146                 return true
 147         end
 148
 149         -- Either the value is "=" and we've already verified the external
 150         -- cert identity, or the value is a string and either matches the
 151         -- from_host (
 152
 153         text = base64.decode(text)
 154         if not text then
 155                 session.sends2s(build_reply("failure", "incorrect-encoding"))
 156                 return true;
 157         end
 158
 159         if session.cert_identity_status == "valid" then
 160                 if text ~= "" and text ~= session.from_host then
 161                         session.sends2s(build_reply("failure", "invalid-authzid"))
 162                         return true
 163                 end
 164         else
 165                 if text == "" then
 166                         session.sends2s(build_reply("failure", "invalid-authzid"))
 167                         return true
 168                 end
 169
 170                 local cert = session.conn:socket():getpeercertificate()
 171                 if (cert_verify_identity(text, "xmpp-server", cert)) then
 172                         session.cert_identity_status = "valid"
 173                 else
 174                         session.cert_identity_status = "invalid"
 175                         session.sends2s(build_reply("failure", "invalid-authzid"))
 176                         return true
 177                 end
 178         end
 179
 180         session.external_auth = "succeeded"
 181
 182         if not session.from_host then
 183                 session.from_host = text;
 184         end
 185         session.sends2s(build_reply("success"))
 186
 187         local domain = text ~= "" and text or session.from_host;
 188         module:log("info", "Accepting SASL EXTERNAL identity from %s", domain);
 189         module:fire_event("s2s-authenticated", { session = session, host = domain });
 190         session:reset_stream();
 191         return true
 192 end
 193
 194 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:auth", function(event)
 195         local session, stanza = event.origin, event.stanza;
 196         if session.type == "s2sin_unauthed" then
 197                 return s2s_external_auth(session, stanza)
 198         end
 199
 200         if session.type ~= "c2s_unauthed" or module:get_host_type() ~= "local" then return; end
 201
 202         if session.sasl_handler and session.sasl_handler.selected then
 203                 session.sasl_handler = nil; -- allow starting a new SASL negotiation before completing an old one
 204         end
 205         if not session.sasl_handler then
 206                 session.sasl_handler = usermanager_get_sasl_handler(module.host, session);
 207         end
 208         local mechanism = stanza.attr.mechanism;
 209         if not session.secure and (secure_auth_only or (mechanism == "PLAIN" and not allow_unencrypted_plain_auth)) then
 210                 session.send(build_reply("failure", "encryption-required"));
 211                 return true;
 212         end
 213         local valid_mechanism = session.sasl_handler:select(mechanism);
 214         if not valid_mechanism then
 215                 session.send(build_reply("failure", "invalid-mechanism"));
 216                 return true;
 217         end
 218         return sasl_process_cdata(session, stanza);
 219 end);
 220 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:response", function(event)
 221         local session = event.origin;
 222         if not(session.sasl_handler and session.sasl_handler.selected) then
 223                 session.send(build_reply("failure", "not-authorized", "Out of order SASL element"));
 224                 return true;
 225         end
 226         return sasl_process_cdata(session, event.stanza);
 227 end);
 228 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:abort", function(event)
 229         local session = event.origin;
 230         session.sasl_handler = nil;
 231         session.send(build_reply("failure", "aborted"));
 232         return true;
 233 end);
 234
 235 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 236 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 237 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 238 module:hook("stream-features", function(event)
 239         local origin, features = event.origin, event.features;
 240         if not origin.username then
 241                 if secure_auth_only and not origin.secure then
 242                         return;
 243                 end
 244                 origin.sasl_handler = usermanager_get_sasl_handler(module.host, origin);
 245                 local mechanisms = st.stanza("mechanisms", mechanisms_attr);
 246                 for mechanism in pairs(origin.sasl_handler:mechanisms()) do
 247                         if mechanism ~= "PLAIN" or origin.secure or allow_unencrypted_plain_auth then
 248                                 mechanisms:tag("mechanism"):text(mechanism):up();
 249                         end
 250                 end
 251                 if mechanisms[1] then features:add_child(mechanisms); end
 252         else
 253                 features:tag("bind", bind_attr):tag("required"):up():up();
 254                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 255         end
 256 end);
 257
 258 module:hook("s2s-stream-features", function(event)
 259         local origin, features = event.origin, event.features;
 260         if origin.secure and origin.type == "s2sin_unauthed" then
 261                 -- Offer EXTERNAL if chain is valid and either we didn't validate
 262                 -- the identity or it passed.
 263                 if origin.cert_chain_status == "valid" and origin.cert_identity_status ~= "invalid" then --TODO: Configurable
 264                         module:log("debug", "Offering SASL EXTERNAL")
 265                         features:tag("mechanisms", { xmlns = xmlns_sasl })
 266                                 :tag("mechanism"):text("EXTERNAL")
 267                         :up():up();
 268                 end
 269         end
 270 end);
 271
 272 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-bind:bind", function(event)
 273         local origin, stanza = event.origin, event.stanza;
 274         local resource;
 275         if stanza.attr.type == "set" then
 276                 local bind = stanza.tags[1];
 277                 resource = bind:child_with_name("resource");
 278                 resource = resource and #resource.tags == 0 and resource[1] or nil;
 279         end
 280         local success, err_type, err, err_msg = sm_bind_resource(origin, resource);
 281         if success then
 282                 origin.send(st.reply(stanza)
 283                         :tag("bind", { xmlns = xmlns_bind })
 284                         :tag("jid"):text(origin.full_jid));
 285                 origin.log("debug", "Resource bound: %s", origin.full_jid);
 286         else
 287                 origin.send(st.error_reply(stanza, err_type, err, err_msg));
 288                 origin.log("debug", "Resource bind failed: %s", err_msg or err);
 289         end
 290         return true;
 291 end);
 292
 293 local function handle_legacy_session(event)
 294         event.origin.send(st.reply(event.stanza));
 295         return true;
 296 end
 297
 298 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);
 299 module:hook("iq/host/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);