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         local cyrus_new = require "util.sasl_cyrus".new;
  40         new_sasl = function(realm)
  41                 return cyrus_new(realm, module:get_option("cyrus_service_name") or "xmpp");
  42         end
  43 else
  44         if sasl_backend ~= "builtin" then module:log("warn", "Unknown SASL backend %s", sasl_backend); end;
  45         new_sasl = require "util.sasl".new;
  46 end
  47
  48 local default_authentication_profile = {
  49         plain = function(username, realm)
  50                 local prepped_username = nodeprep(username);
  51                 if not prepped_username then
  52                         log("debug", "NODEprep failed on username: %s", username);
  53                         return "", nil;
  54                 end
  55                 local password = usermanager_get_password(prepped_username, realm);
  56                 if not password then
  57                         return "", nil;
  58                 end
  59                 return password, true;
  60         end
  61 };
  62
  63 local anonymous_authentication_profile = {
  64         anonymous = function(username, realm)
  65                 return true; -- for normal usage you should always return true here
  66         end
  67 };
  68
  69 local function build_reply(status, ret, err_msg)
  70         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  71         if status == "challenge" then
  72                 log("debug", "%s", ret or "");
  73                 reply:text(base64.encode(ret or ""));
  74         elseif status == "failure" then
  75                 reply:tag(ret):up();
  76                 if err_msg then reply:tag("text"):text(err_msg); end
  77         elseif status == "success" then
  78                 log("debug", "%s", ret or "");
  79                 reply:text(base64.encode(ret or ""));
  80         else
  81                 module:log("error", "Unknown sasl status: %s", status);
  82         end
  83         return reply;
  84 end
  85
  86 local function handle_status(session, status)
  87         if status == "failure" then
  88                 session.sasl_handler = session.sasl_handler:clean_clone();
  89         elseif status == "success" then
  90                 local username = nodeprep(session.sasl_handler.username);
  91                 if not username then -- TODO move this to sessionmanager
  92                         module:log("warn", "SASL succeeded but we didn't get a username!");
  93                         session.sasl_handler = nil;
  94                         session:reset_stream();
  95                         return;
  96                 end
  97                 sm_make_authenticated(session, session.sasl_handler.username);
  98                 session.sasl_handler = nil;
  99                 session:reset_stream();
 100         end
 101 end
 102
 103 local function sasl_handler(session, stanza)
 104         if stanza.name == "auth" then
 105                 -- FIXME ignoring duplicates because ejabberd does
 106                 if config.get(session.host or "*", "core", "anonymous_login") then
 107                         if stanza.attr.mechanism ~= "ANONYMOUS" then
 108                                 return session.send(build_reply("failure", "invalid-mechanism"));
 109                         end
 110                 elseif stanza.attr.mechanism == "ANONYMOUS" then
 111                         return session.send(build_reply("failure", "mechanism-too-weak"));
 112                 end
 113                 local valid_mechanism = session.sasl_handler:select(stanza.attr.mechanism);
 114                 if not valid_mechanism then
 115                         return session.send(build_reply("failure", "invalid-mechanism"));
 116                 end
 117                 if secure_auth_only and not session.secure then
 118                         return session.send(build_reply("failure", "encryption-required"));
 119                 end
 120         elseif not session.sasl_handler then
 121                 return; -- FIXME ignoring out of order stanzas because ejabberd does
 122         end
 123         local text = stanza[1];
 124         if text then
 125                 text = base64.decode(text);
 126                 log("debug", "%s", text:gsub("[%z\001-\008\011\012\014-\031]", " "));
 127                 if not text then
 128                         session.sasl_handler = nil;
 129                         session.send(build_reply("failure", "incorrect-encoding"));
 130                         return;
 131                 end
 132         end
 133         local status, ret, err_msg = session.sasl_handler:process(text);
 134         handle_status(session, status);
 135         local s = build_reply(status, ret, err_msg);
 136         log("debug", "sasl reply: %s", tostring(s));
 137         session.send(s);
 138 end
 139
 140 module:add_handler("c2s_unauthed", "auth", xmlns_sasl, sasl_handler);
 141 module:add_handler("c2s_unauthed", "abort", xmlns_sasl, sasl_handler);
 142 module:add_handler("c2s_unauthed", "response", xmlns_sasl, sasl_handler);
 143
 144 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 145 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 146 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 147 module:add_event_hook("stream-features", function(session, features)
 148         if not session.username then
 149                 if secure_auth_only and not session.secure then
 150                         return;
 151                 end
 152                 if module:get_option("anonymous_login") then
 153                         session.sasl_handler = new_sasl(session.host, anonymous_authentication_profile);
 154                 else
 155                         session.sasl_handler = new_sasl(session.host, default_authentication_profile);
 156                         if not (module:get_option("allow_unencrypted_plain_auth")) and not session.secure then
 157                                 session.sasl_handler:forbidden({"PLAIN"});
 158                         end
 159                 end
 160                 features:tag("mechanisms", mechanisms_attr);
 161                 for k, v in pairs(session.sasl_handler:mechanisms()) do
 162                         features:tag("mechanism"):text(v):up();
 163                 end
 164                 features:up();
 165         else
 166                 features:tag("bind", bind_attr):tag("required"):up():up();
 167                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 168         end
 169 end);
 170
 171 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind", function(session, stanza)
 172         log("debug", "Client requesting a resource bind");
 173         local resource;
 174         if stanza.attr.type == "set" then
 175                 local bind = stanza.tags[1];
 176                 if bind and bind.attr.xmlns == xmlns_bind then
 177                         resource = bind:child_with_name("resource");
 178                         if resource then
 179                                 resource = resource[1];
 180                         end
 181                 end
 182         end
 183         local success, err_type, err, err_msg = sm_bind_resource(session, resource);
 184         if not success then
 185                 session.send(st.error_reply(stanza, err_type, err, err_msg));
 186         else
 187                 session.send(st.reply(stanza)
 188                         :tag("bind", { xmlns = xmlns_bind})
 189                         :tag("jid"):text(session.full_jid));
 190         end
 191 end);
 192
 193 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session", function(session, stanza)
 194         log("debug", "Client requesting a session");
 195         session.send(st.reply(stanza));
 196 end);