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 nodeprep = require "util.encodings".stringprep.nodeprep;
  17 local usermanager_get_sasl_handler = require "core.usermanager".get_sasl_handler;
  18 local usermanager_user_exists = require "core.usermanager".user_exists;
  19 local t_concat, t_insert = table.concat, table.insert;
  20 local tostring = tostring;
  21
  22 local secure_auth_only = module:get_option("c2s_require_encryption") or module:get_option("require_encryption");
  23 local sasl_backend = module:get_option("sasl_backend") or "builtin";
  24 local anonymous_login = module:get_option("anonymous_login");
  25 local allow_unencrypted_plain_auth = module:get_option("allow_unencrypted_plain_auth")
  26
  27 -- Cyrus config options
  28 local require_provisioning = module:get_option("cyrus_require_provisioning") or false;
  29 local cyrus_service_realm = module:get_option("cyrus_service_realm");
  30 local cyrus_service_name = module:get_option("cyrus_service_name");
  31 local cyrus_application_name = module:get_option("cyrus_application_name");
  32
  33 local log = module._log;
  34
  35 local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';
  36 local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';
  37 local xmlns_stanzas ='urn:ietf:params:xml:ns:xmpp-stanzas';
  38
  39 local new_sasl;
  40 if sasl_backend == "builtin" then
  41         new_sasl = require "util.sasl".new;
  42 elseif sasl_backend == "cyrus" then
  43         prosody.unlock_globals(); --FIXME: Figure out why this is needed and
  44                                   -- why cyrussasl isn't caught by the sandbox
  45         local ok, cyrus = pcall(require, "util.sasl_cyrus");
  46         prosody.lock_globals();
  47         if ok then
  48                 local cyrus_new = cyrus.new;
  49                 new_sasl = function(realm)
  50                         return cyrus_new(
  51                                 cyrus_service_realm or realm,
  52                                 cyrus_service_name or "xmpp",
  53                                 cyrus_application_name or "prosody"
  54                         );
  55                 end
  56         else
  57                 module:log("error", "Failed to load Cyrus SASL because: %s", cyrus);
  58                 error("Failed to load Cyrus SASL");
  59         end
  60 else
  61         module:log("error", "Unknown SASL backend: %s", sasl_backend);
  62         error("Unknown SASL backend");
  63 end
  64
  65 local anonymous_authentication_profile = {
  66         anonymous = function(username, realm)
  67                 return true; -- for normal usage you should always return true here
  68         end
  69 };
  70
  71 local function build_reply(status, ret, err_msg)
  72         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  73         if status == "challenge" then
  74                 --log("debug", "CHALLENGE: %s", ret or "");
  75                 reply:text(base64.encode(ret or ""));
  76         elseif status == "failure" then
  77                 reply:tag(ret):up();
  78                 if err_msg then reply:tag("text"):text(err_msg); end
  79         elseif status == "success" then
  80                 --log("debug", "SUCCESS: %s", ret or "");
  81                 reply:text(base64.encode(ret or ""));
  82         else
  83                 module:log("error", "Unknown sasl status: %s", status);
  84         end
  85         return reply;
  86 end
  87
  88 local function handle_status(session, status, ret, err_msg)
  89         if status == "failure" then
  90                 session.sasl_handler = session.sasl_handler:clean_clone();
  91         elseif status == "success" then
  92                 local username = nodeprep(session.sasl_handler.username);
  93
  94                 if not(require_provisioning) or usermanager_user_exists(username, session.host) then
  95                         local ok, err = sm_make_authenticated(session, session.sasl_handler.username);
  96                         if ok then
  97                                 session.sasl_handler = nil;
  98                                 session:reset_stream();
  99                         else
 100                                 module:log("warn", "SASL succeeded but username was invalid");
 101                                 session.sasl_handler = session.sasl_handler:clean_clone();
 102                                 return "failure", "not-authorized", "User authenticated successfully, but username was invalid";
 103                         end
 104                 else
 105                         module:log("warn", "SASL succeeded but we don't have an account provisioned for %s", username);
 106                         session.sasl_handler = session.sasl_handler:clean_clone();
 107                         return "failure", "not-authorized", "User authenticated successfully, but not provisioned for XMPP";
 108                 end
 109         end
 110         return status, ret, err_msg;
 111 end
 112
 113 local function sasl_handler(session, stanza)
 114         if stanza.name == "auth" then
 115                 -- FIXME ignoring duplicates because ejabberd does
 116                 local mechanism = stanza.attr.mechanism;
 117                 if anonymous_login then
 118                         if mechanism ~= "ANONYMOUS" then
 119                                 return session.send(build_reply("failure", "invalid-mechanism"));
 120                         end
 121                 elseif mechanism == "ANONYMOUS" then
 122                         return session.send(build_reply("failure", "mechanism-too-weak"));
 123                 end
 124                 if not session.secure and (secure_auth_only or (mechanism == "PLAIN" and not allow_unencrypted_plain_auth)) then
 125                         return session.send(build_reply("failure", "encryption-required"));
 126                 end
 127                 local valid_mechanism = session.sasl_handler:select(mechanism);
 128                 if not valid_mechanism then
 129                         return session.send(build_reply("failure", "invalid-mechanism"));
 130                 end
 131         elseif not session.sasl_handler then
 132                 return; -- FIXME ignoring out of order stanzas because ejabberd does
 133         end
 134         local text = stanza[1];
 135         if text then
 136                 text = base64.decode(text);
 137                 --log("debug", "AUTH: %s", text:gsub("[%z\001-\008\011\012\014-\031]", " "));
 138                 if not text then
 139                         session.sasl_handler = nil;
 140                         session.send(build_reply("failure", "incorrect-encoding"));
 141                         return;
 142                 end
 143         end
 144         local status, ret, err_msg = session.sasl_handler:process(text);
 145         status, ret, err_msg = handle_status(session, status, ret, err_msg);
 146         local s = build_reply(status, ret, err_msg);
 147         log("debug", "sasl reply: %s", tostring(s));
 148         session.send(s);
 149 end
 150
 151 module:add_handler("c2s_unauthed", "auth", xmlns_sasl, sasl_handler);
 152 module:add_handler("c2s_unauthed", "abort", xmlns_sasl, sasl_handler);
 153 module:add_handler("c2s_unauthed", "response", xmlns_sasl, sasl_handler);
 154
 155 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 156 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 157 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 158 module:hook("stream-features", function(event)
 159         local origin, features = event.origin, event.features;
 160         if not origin.username then
 161                 if secure_auth_only and not origin.secure then
 162                         return;
 163                 end
 164                 if anonymous_login then
 165                         origin.sasl_handler = new_sasl(module.host, anonymous_authentication_profile);
 166                 else
 167                         origin.sasl_handler = usermanager_get_sasl_handler(module.host);
 168                 end
 169                 features:tag("mechanisms", mechanisms_attr);
 170                 for mechanism in pairs(origin.sasl_handler:mechanisms()) do
 171                         if mechanism ~= "PLAIN" or origin.secure or allow_unencrypted_plain_auth then
 172                                 features:tag("mechanism"):text(mechanism):up();
 173                         end
 174                 end
 175                 features:up();
 176         else
 177                 features:tag("bind", bind_attr):tag("required"):up():up();
 178                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 179         end
 180 end);
 181
 182 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind", function(session, stanza)
 183         log("debug", "Client requesting a resource bind");
 184         local resource;
 185         if stanza.attr.type == "set" then
 186                 local bind = stanza.tags[1];
 187                 if bind and bind.attr.xmlns == xmlns_bind then
 188                         resource = bind:child_with_name("resource");
 189                         if resource then
 190                                 resource = resource[1];
 191                         end
 192                 end
 193         end
 194         local success, err_type, err, err_msg = sm_bind_resource(session, resource);
 195         if not success then
 196                 session.send(st.error_reply(stanza, err_type, err, err_msg));
 197         else
 198                 session.send(st.reply(stanza)
 199                         :tag("bind", { xmlns = xmlns_bind})
 200                         :tag("jid"):text(session.full_jid));
 201         end
 202 end);
 203
 204 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session", function(session, stanza)
 205         log("debug", "Client requesting a session");
 206         session.send(st.reply(stanza));
 207 end);