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
  92         local default_stream_attr = {xmlns = "jabber:server", ["xmlns:stream"] = "http://etherx.jabber.org/streams",
  93                                     ["xmlns:db"] = 'jabber:server:dialback', version = "1.0", to = session.to_host, from = session.from_host};
  94         session.sends2s("<?xml version='1.0'?>");
  95         session.sends2s(st.stanza("stream:stream", default_stream_attr):top_tag());
  96
  97         s2s_make_authenticated(session, session.to_host);
  98         return true;
  99 end)
 100
 101 module:hook_stanza(xmlns_sasl, "failure", function (session, stanza)
 102         if session.type ~= "s2sout_unauthed" or session.external_auth ~= "attempting" then return; end
 103
 104         module:log("info", "SASL EXTERNAL with %s failed", session.to_host)
 105         -- TODO: Log the failure reason
 106         session.external_auth = "failed"
 107 end, 500)
 108
 109 module:hook_stanza(xmlns_sasl, "failure", function (session, stanza)
 110         -- TODO: Dialback wasn't loaded.  Do something useful.
 111 end, 90)
 112
 113 module:hook_stanza("http://etherx.jabber.org/streams", "features", function (session, stanza)
 114         if session.type ~= "s2sout_unauthed" or not session.secure then return; end
 115
 116         local mechanisms = stanza:get_child("mechanisms", xmlns_sasl)
 117         if mechanisms then
 118                 for mech in mechanisms:childtags() do
 119                         if mech[1] == "EXTERNAL" then
 120                                 module:log("debug", "Initiating SASL EXTERNAL with %s", session.to_host);
 121                                 local reply = st.stanza("auth", {xmlns = xmlns_sasl, mechanism = "EXTERNAL"});
 122                                 reply:text(base64.encode(session.from_host))
 123                                 session.sends2s(reply)
 124                                 session.external_auth = "attempting"
 125                                 return true
 126                         end
 127                 end
 128         end
 129 end, 150);
 130
 131 local function s2s_external_auth(session, stanza)
 132         local mechanism = stanza.attr.mechanism;
 133
 134         if not session.secure then
 135                 if mechanism == "EXTERNAL" then
 136                         session.sends2s(build_reply("failure", "encryption-required"))
 137                 else
 138                         session.sends2s(build_reply("failure", "invalid-mechanism"))
 139                 end
 140                 return true;
 141         end
 142
 143         if mechanism ~= "EXTERNAL" or session.cert_chain_status ~= "valid" then
 144                 session.sends2s(build_reply("failure", "invalid-mechanism"))
 145                 return true;
 146         end
 147
 148         local text = stanza[1]
 149         if not text then
 150                 session.sends2s(build_reply("failure", "malformed-request"))
 151                 return true
 152         end
 153
 154         -- Either the value is "=" and we've already verified the external
 155         -- cert identity, or the value is a string and either matches the
 156         -- from_host (
 157
 158         text = base64.decode(text)
 159         if not text then
 160                 session.sends2s(build_reply("failure", "incorrect-encoding"))
 161                 return true;
 162         end
 163
 164         if session.cert_identity_status == "valid" then
 165                 if text ~= "" and text ~= session.from_host then
 166                         session.sends2s(build_reply("failure", "invalid-authzid"))
 167                         return true
 168                 end
 169         else
 170                 if text == "" then
 171                         session.sends2s(build_reply("failure", "invalid-authzid"))
 172                         return true
 173                 end
 174
 175                 local cert = session.conn:socket():getpeercertificate()
 176                 if (cert_verify_identity(text, "xmpp-server", cert)) then
 177                         session.cert_identity_status = "valid"
 178                 else
 179                         session.cert_identity_status = "invalid"
 180                         session.sends2s(build_reply("failure", "invalid-authzid"))
 181                         return true
 182                 end
 183         end
 184
 185         session.external_auth = "succeeded"
 186
 187         if not session.from_host then
 188                 session.from_host = text;
 189         end
 190         session.sends2s(build_reply("success"))
 191
 192         local domain = text ~= "" and text or session.from_host;
 193         module:log("info", "Accepting SASL EXTERNAL identity from %s", domain);
 194         s2s_make_authenticated(session, domain);
 195         session:reset_stream();
 196         return true
 197 end
 198
 199 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:auth", function(event)
 200         local session, stanza = event.origin, event.stanza;
 201         if session.type == "s2sin_unauthed" then
 202                 return s2s_external_auth(session, stanza)
 203         end
 204
 205         if session.type ~= "c2s_unauthed" then return; end
 206
 207         if session.sasl_handler and session.sasl_handler.selected then
 208                 session.sasl_handler = nil; -- allow starting a new SASL negotiation before completing an old one
 209         end
 210         if not session.sasl_handler then
 211                 session.sasl_handler = usermanager_get_sasl_handler(module.host, session);
 212         end
 213         local mechanism = stanza.attr.mechanism;
 214         if not session.secure and (secure_auth_only or (mechanism == "PLAIN" and not allow_unencrypted_plain_auth)) then
 215                 session.send(build_reply("failure", "encryption-required"));
 216                 return true;
 217         end
 218         local valid_mechanism = session.sasl_handler:select(mechanism);
 219         if not valid_mechanism then
 220                 session.send(build_reply("failure", "invalid-mechanism"));
 221                 return true;
 222         end
 223         return sasl_process_cdata(session, stanza);
 224 end);
 225 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:response", function(event)
 226         local session = event.origin;
 227         if not(session.sasl_handler and session.sasl_handler.selected) then
 228                 session.send(build_reply("failure", "not-authorized", "Out of order SASL element"));
 229                 return true;
 230         end
 231         return sasl_process_cdata(session, event.stanza);
 232 end);
 233 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:abort", function(event)
 234         local session = event.origin;
 235         session.sasl_handler = nil;
 236         session.send(build_reply("failure", "aborted"));
 237         return true;
 238 end);
 239
 240 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 241 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 242 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 243 module:hook("stream-features", function(event)
 244         local origin, features = event.origin, event.features;
 245         if not origin.username then
 246                 if secure_auth_only and not origin.secure then
 247                         return;
 248                 end
 249                 origin.sasl_handler = usermanager_get_sasl_handler(module.host, origin);
 250                 local mechanisms = st.stanza("mechanisms", mechanisms_attr);
 251                 for mechanism in pairs(origin.sasl_handler:mechanisms()) do
 252                         if mechanism ~= "PLAIN" or origin.secure or allow_unencrypted_plain_auth then
 253                                 mechanisms:tag("mechanism"):text(mechanism):up();
 254                         end
 255                 end
 256                 if mechanisms[1] then features:add_child(mechanisms); end
 257         else
 258                 features:tag("bind", bind_attr):tag("required"):up():up();
 259                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 260         end
 261 end);
 262
 263 module:hook("s2s-stream-features", function(event)
 264         local origin, features = event.origin, event.features;
 265         if origin.secure and origin.type == "s2sin_unauthed" then
 266                 -- Offer EXTERNAL if chain is valid and either we didn't validate
 267                 -- the identity or it passed.
 268                 if origin.cert_chain_status == "valid" and origin.cert_identity_status ~= "invalid" then --TODO: Configurable
 269                         module:log("debug", "Offering SASL EXTERNAL")
 270                         features:tag("mechanisms", { xmlns = xmlns_sasl })
 271                                 :tag("mechanism"):text("EXTERNAL")
 272                         :up():up();
 273                 end
 274         end
 275 end);
 276
 277 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-bind:bind", function(event)
 278         local origin, stanza = event.origin, event.stanza;
 279         local resource;
 280         if stanza.attr.type == "set" then
 281                 local bind = stanza.tags[1];
 282                 resource = bind:child_with_name("resource");
 283                 resource = resource and #resource.tags == 0 and resource[1] or nil;
 284         end
 285         local success, err_type, err, err_msg = sm_bind_resource(origin, resource);
 286         if success then
 287                 origin.send(st.reply(stanza)
 288                         :tag("bind", { xmlns = xmlns_bind })
 289                         :tag("jid"):text(origin.full_jid));
 290                 origin.log("debug", "Resource bound: %s", origin.full_jid);
 291         else
 292                 origin.send(st.error_reply(stanza, err_type, err, err_msg));
 293                 origin.log("debug", "Resource bind failed: %s", err_msg or err);
 294         end
 295         return true;
 296 end);
 297
 298 local function handle_legacy_session(event)
 299         event.origin.send(st.reply(event.stanza));
 300         return true;
 301 end
 302
 303 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);
 304 module:hook("iq/host/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);