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