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