plugins/mod_saslauth.lua

   1 -- Prosody IM
   2 -- Copyright (C) 2008-2009 Matthew Wild
   3 -- Copyright (C) 2008-2009 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 datamanager_load = require "util.datamanager".load;
  18 local usermanager_validate_credentials = require "core.usermanager".validate_credentials;
  19 local usermanager_get_supported_methods = require "core.usermanager".get_supported_methods;
  20 local usermanager_user_exists = require "core.usermanager".user_exists;
  21 local usermanager_get_password = require "core.usermanager".get_password;
  22 local t_concat, t_insert = table.concat, table.insert;
  23 local tostring = tostring;
  24 local jid_split = require "util.jid".split;
  25 local md5 = require "util.hashes".md5;
  26 local config = require "core.configmanager";
  27
  28 local secure_auth_only = module:get_option("c2s_require_encryption") or module:get_option("require_encryption");
  29 local sasl_backend = module:get_option("sasl_backend") or "builtin";
  30
  31 local log = module._log;
  32
  33 local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';
  34 local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';
  35 local xmlns_stanzas ='urn:ietf:params:xml:ns:xmpp-stanzas';
  36
  37 local new_sasl;
  38 if sasl_backend == "cyrus" then
  39         prosody.unlock_globals(); --FIXME: Figure out why this is needed and
  40                                   -- why cyrussasl isn't caught by the sandbox
  41         local ok, cyrus = pcall(require, "util.sasl_cyrus");
  42         prosody.lock_globals();
  43         if ok then
  44                 local cyrus_new = cyrus.new;
  45                 new_sasl = function(realm)
  46                         return cyrus_new(realm, module:get_option("cyrus_service_name") or "xmpp");
  47                 end
  48         else
  49                 sasl_backend = "builtin";
  50                 module:log("warn", "Failed to load Cyrus SASL, falling back to builtin auth mechanisms");
  51                 module:log("debug", "Failed to load Cyrus because: %s", cyrus);
  52         end
  53 end
  54 if not new_sasl then
  55         if sasl_backend ~= "builtin" then module:log("warn", "Unknown SASL backend %s", sasl_backend); end;
  56         new_sasl = require "util.sasl".new;
  57 end
  58
  59 local default_authentication_profile = {
  60         plain = function(username, realm)
  61                 local prepped_username = nodeprep(username);
  62                 if not prepped_username then
  63                         log("debug", "NODEprep failed on username: %s", username);
  64                         return "", nil;
  65                 end
  66                 local password = usermanager_get_password(prepped_username, realm);
  67                 if not password then
  68                         return "", nil;
  69                 end
  70                 return password, true;
  71         end
  72 };
  73
  74 local anonymous_authentication_profile = {
  75         anonymous = function(username, realm)
  76                 return true; -- for normal usage you should always return true here
  77         end
  78 };
  79
  80 local function build_reply(status, ret, err_msg)
  81         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  82         if status == "challenge" then
  83                 --log("debug", "CHALLENGE: %s", ret or "");
  84                 reply:text(base64.encode(ret or ""));
  85         elseif status == "failure" then
  86                 reply:tag(ret):up();
  87                 if err_msg then reply:tag("text"):text(err_msg); end
  88         elseif status == "success" then
  89                 --log("debug", "SUCCESS: %s", ret or "");
  90                 reply:text(base64.encode(ret or ""));
  91         else
  92                 module:log("error", "Unknown sasl status: %s", status);
  93         end
  94         return reply;
  95 end
  96
  97 local function handle_status(session, status)
  98         if status == "failure" then
  99                 session.sasl_handler = session.sasl_handler:clean_clone();
 100         elseif status == "success" then
 101                 local username = nodeprep(session.sasl_handler.username);
 102                 if not username then -- TODO move this to sessionmanager
 103                         module:log("warn", "SASL succeeded but we didn't get a username!");
 104                         session.sasl_handler = nil;
 105                         session:reset_stream();
 106                         return;
 107                 end
 108                 sm_make_authenticated(session, session.sasl_handler.username);
 109                 session.sasl_handler = nil;
 110                 session:reset_stream();
 111         end
 112 end
 113
 114 local function sasl_handler(session, stanza)
 115         if stanza.name == "auth" then
 116                 -- FIXME ignoring duplicates because ejabberd does
 117                 if config.get(session.host or "*", "core", "anonymous_login") then
 118                         if stanza.attr.mechanism ~= "ANONYMOUS" then
 119                                 return session.send(build_reply("failure", "invalid-mechanism"));
 120                         end
 121                 elseif stanza.attr.mechanism == "ANONYMOUS" then
 122                         return session.send(build_reply("failure", "mechanism-too-weak"));
 123                 end
 124                 local valid_mechanism = session.sasl_handler:select(stanza.attr.mechanism);
 125                 if not valid_mechanism then
 126                         return session.send(build_reply("failure", "invalid-mechanism"));
 127                 end
 128                 if secure_auth_only and not session.secure then
 129                         return session.send(build_reply("failure", "encryption-required"));
 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         handle_status(session, status);
 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 module:get_option("anonymous_login") then
 165                         origin.sasl_handler = new_sasl(origin.host, anonymous_authentication_profile);
 166                 else
 167                         origin.sasl_handler = new_sasl(origin.host, default_authentication_profile);
 168                         if not (module:get_option("allow_unencrypted_plain_auth")) and not origin.secure then
 169                                 origin.sasl_handler:forbidden({"PLAIN"});
 170                         end
 171                 end
 172                 features:tag("mechanisms", mechanisms_attr);
 173                 for k, v in pairs(origin.sasl_handler:mechanisms()) do
 174                         features:tag("mechanism"):text(v):up();
 175                 end
 176                 features:up();
 177         else
 178                 features:tag("bind", bind_attr):tag("required"):up():up();
 179                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 180         end
 181 end);
 182
 183 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind", function(session, stanza)
 184         log("debug", "Client requesting a resource bind");
 185         local resource;
 186         if stanza.attr.type == "set" then
 187                 local bind = stanza.tags[1];
 188                 if bind and bind.attr.xmlns == xmlns_bind then
 189                         resource = bind:child_with_name("resource");
 190                         if resource then
 191                                 resource = resource[1];
 192                         end
 193                 end
 194         end
 195         local success, err_type, err, err_msg = sm_bind_resource(session, resource);
 196         if not success then
 197                 session.send(st.error_reply(stanza, err_type, err, err_msg));
 198         else
 199                 session.send(st.reply(stanza)
 200                         :tag("bind", { xmlns = xmlns_bind})
 201                         :tag("jid"):text(session.full_jid));
 202         end
 203 end);
 204
 205 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session", function(session, stanza)
 206         log("debug", "Client requesting a session");
 207         session.send(st.reply(stanza));
 208 end);