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         local text = stanza:get_child_text("text");
 100         local condition = "unknown-condition";
 101         for child in stanza:childtags() do
 102                 if child.name ~= "text" then
 103                         condition = child.name;
 104                         break;
 105                 end
 106         end
 107         if text and condition then
 108                 condition = condition .. ": " .. text;
 109         end
 110         module:log("info", "SASL EXTERNAL with %s failed: %s", session.to_host, condition);
 111
 112         session.external_auth = "failed"
 113 end, 500)
 114
 115 module:hook_stanza(xmlns_sasl, "failure", function (session, stanza)
 116         -- TODO: Dialback wasn't loaded.  Do something useful.
 117 end, 90)
 118
 119 module:hook_stanza("http://etherx.jabber.org/streams", "features", function (session, stanza)
 120         if session.type ~= "s2sout_unauthed" or not session.secure then return; end
 121
 122         local mechanisms = stanza:get_child("mechanisms", xmlns_sasl)
 123         if mechanisms then
 124                 for mech in mechanisms:childtags() do
 125                         if mech[1] == "EXTERNAL" then
 126                                 module:log("debug", "Initiating SASL EXTERNAL with %s", session.to_host);
 127                                 local reply = st.stanza("auth", {xmlns = xmlns_sasl, mechanism = "EXTERNAL"});
 128                                 reply:text(base64.encode(session.from_host))
 129                                 session.sends2s(reply)
 130                                 session.external_auth = "attempting"
 131                                 return true
 132                         end
 133                 end
 134         end
 135 end, 150);
 136
 137 local function s2s_external_auth(session, stanza)
 138         local mechanism = stanza.attr.mechanism;
 139
 140         if not session.secure then
 141                 if mechanism == "EXTERNAL" then
 142                         session.sends2s(build_reply("failure", "encryption-required"))
 143                 else
 144                         session.sends2s(build_reply("failure", "invalid-mechanism"))
 145                 end
 146                 return true;
 147         end
 148
 149         if mechanism ~= "EXTERNAL" or session.cert_chain_status ~= "valid" then
 150                 session.sends2s(build_reply("failure", "invalid-mechanism"))
 151                 return true;
 152         end
 153
 154         local text = stanza[1]
 155         if not text then
 156                 session.sends2s(build_reply("failure", "malformed-request"))
 157                 return true
 158         end
 159
 160         -- Either the value is "=" and we've already verified the external
 161         -- cert identity, or the value is a string and either matches the
 162         -- from_host (
 163
 164         text = base64.decode(text)
 165         if not text then
 166                 session.sends2s(build_reply("failure", "incorrect-encoding"))
 167                 return true;
 168         end
 169
 170         if session.cert_identity_status == "valid" then
 171                 if text ~= "" and text ~= session.from_host then
 172                         session.sends2s(build_reply("failure", "invalid-authzid"))
 173                         return true
 174                 end
 175         else
 176                 if text == "" then
 177                         session.sends2s(build_reply("failure", "invalid-authzid"))
 178                         return true
 179                 end
 180
 181                 local cert = session.conn:socket():getpeercertificate()
 182                 if (cert_verify_identity(text, "xmpp-server", cert)) then
 183                         session.cert_identity_status = "valid"
 184                 else
 185                         session.cert_identity_status = "invalid"
 186                         session.sends2s(build_reply("failure", "invalid-authzid"))
 187                         return true
 188                 end
 189         end
 190
 191         session.external_auth = "succeeded"
 192
 193         if not session.from_host then
 194                 session.from_host = text;
 195         end
 196         session.sends2s(build_reply("success"))
 197
 198         local domain = text ~= "" and text or session.from_host;
 199         module:log("info", "Accepting SASL EXTERNAL identity from %s", domain);
 200         module:fire_event("s2s-authenticated", { session = session, host = domain });
 201         session:reset_stream();
 202         return true
 203 end
 204
 205 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:auth", function(event)
 206         local session, stanza = event.origin, event.stanza;
 207         if session.type == "s2sin_unauthed" then
 208                 return s2s_external_auth(session, stanza)
 209         end
 210
 211         if session.type ~= "c2s_unauthed" or module:get_host_type() ~= "local" then return; end
 212
 213         if session.sasl_handler and session.sasl_handler.selected then
 214                 session.sasl_handler = nil; -- allow starting a new SASL negotiation before completing an old one
 215         end
 216         if not session.sasl_handler then
 217                 session.sasl_handler = usermanager_get_sasl_handler(module.host, session);
 218         end
 219         local mechanism = stanza.attr.mechanism;
 220         if not session.secure and (secure_auth_only or (mechanism == "PLAIN" and not allow_unencrypted_plain_auth)) then
 221                 session.send(build_reply("failure", "encryption-required"));
 222                 return true;
 223         end
 224         local valid_mechanism = session.sasl_handler:select(mechanism);
 225         if not valid_mechanism then
 226                 session.send(build_reply("failure", "invalid-mechanism"));
 227                 return true;
 228         end
 229         return sasl_process_cdata(session, stanza);
 230 end);
 231 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:response", function(event)
 232         local session = event.origin;
 233         if not(session.sasl_handler and session.sasl_handler.selected) then
 234                 session.send(build_reply("failure", "not-authorized", "Out of order SASL element"));
 235                 return true;
 236         end
 237         return sasl_process_cdata(session, event.stanza);
 238 end);
 239 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:abort", function(event)
 240         local session = event.origin;
 241         session.sasl_handler = nil;
 242         session.send(build_reply("failure", "aborted"));
 243         return true;
 244 end);
 245
 246 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 247 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 248 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 249 module:hook("stream-features", function(event)
 250         local origin, features = event.origin, event.features;
 251         if not origin.username then
 252                 if secure_auth_only and not origin.secure then
 253                         return;
 254                 end
 255                 origin.sasl_handler = usermanager_get_sasl_handler(module.host, origin);
 256                 local mechanisms = st.stanza("mechanisms", mechanisms_attr);
 257                 for mechanism in pairs(origin.sasl_handler:mechanisms()) do
 258                         if mechanism ~= "PLAIN" or origin.secure or allow_unencrypted_plain_auth then
 259                                 mechanisms:tag("mechanism"):text(mechanism):up();
 260                         end
 261                 end
 262                 if mechanisms[1] then features:add_child(mechanisms); end
 263         else
 264                 features:tag("bind", bind_attr):tag("required"):up():up();
 265                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 266         end
 267 end);
 268
 269 module:hook("s2s-stream-features", function(event)
 270         local origin, features = event.origin, event.features;
 271         if origin.secure and origin.type == "s2sin_unauthed" then
 272                 -- Offer EXTERNAL if chain is valid and either we didn't validate
 273                 -- the identity or it passed.
 274                 if origin.cert_chain_status == "valid" and origin.cert_identity_status ~= "invalid" then --TODO: Configurable
 275                         module:log("debug", "Offering SASL EXTERNAL")
 276                         features:tag("mechanisms", { xmlns = xmlns_sasl })
 277                                 :tag("mechanism"):text("EXTERNAL")
 278                         :up():up();
 279                 end
 280         end
 281 end);
 282
 283 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-bind:bind", function(event)
 284         local origin, stanza = event.origin, event.stanza;
 285         local resource;
 286         if stanza.attr.type == "set" then
 287                 local bind = stanza.tags[1];
 288                 resource = bind:child_with_name("resource");
 289                 resource = resource and #resource.tags == 0 and resource[1] or nil;
 290         end
 291         local success, err_type, err, err_msg = sm_bind_resource(origin, resource);
 292         if success then
 293                 origin.send(st.reply(stanza)
 294                         :tag("bind", { xmlns = xmlns_bind })
 295                         :tag("jid"):text(origin.full_jid));
 296                 origin.log("debug", "Resource bound: %s", origin.full_jid);
 297         else
 298                 origin.send(st.error_reply(stanza, err_type, err, err_msg));
 299                 origin.log("debug", "Resource bind failed: %s", err_msg or err);
 300         end
 301         return true;
 302 end);
 303
 304 local function handle_legacy_session(event)
 305         event.origin.send(st.reply(event.stanza));
 306         return true;
 307 end
 308
 309 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);
 310 module:hook("iq/host/urn:ietf:params:xml:ns:xmpp-session:session", handle_legacy_session);