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 t_concat, t_insert = table.concat, table.insert;
  19 local tostring = tostring;
  20
  21 local secure_auth_only = module:get_option("c2s_require_encryption") or module:get_option("require_encryption");
  22 local anonymous_login = module:get_option("anonymous_login");
  23 local allow_unencrypted_plain_auth = module:get_option("allow_unencrypted_plain_auth")
  24
  25 local log = module._log;
  26
  27 local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';
  28 local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';
  29 local xmlns_stanzas ='urn:ietf:params:xml:ns:xmpp-stanzas';
  30
  31 local new_sasl = require "util.sasl".new;
  32
  33 local anonymous_authentication_profile = {
  34         anonymous = function(username, realm)
  35                 return true; -- for normal usage you should always return true here
  36         end
  37 };
  38
  39 local function build_reply(status, ret, err_msg)
  40         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  41         if status == "challenge" then
  42                 --log("debug", "CHALLENGE: %s", ret or "");
  43                 reply:text(base64.encode(ret or ""));
  44         elseif status == "failure" then
  45                 reply:tag(ret):up();
  46                 if err_msg then reply:tag("text"):text(err_msg); end
  47         elseif status == "success" then
  48                 --log("debug", "SUCCESS: %s", ret or "");
  49                 reply:text(base64.encode(ret or ""));
  50         else
  51                 module:log("error", "Unknown sasl status: %s", status);
  52         end
  53         return reply;
  54 end
  55
  56 local function handle_status(session, status, ret, err_msg)
  57         if status == "failure" then
  58                 session.sasl_handler = session.sasl_handler:clean_clone();
  59         elseif status == "success" then
  60                 local username = nodeprep(session.sasl_handler.username);
  61
  62                 local ok, err = sm_make_authenticated(session, session.sasl_handler.username);
  63                 if ok then
  64                         session.sasl_handler = nil;
  65                         session:reset_stream();
  66                 else
  67                         module:log("warn", "SASL succeeded but username was invalid");
  68                         session.sasl_handler = session.sasl_handler:clean_clone();
  69                         return "failure", "not-authorized", "User authenticated successfully, but username was invalid";
  70                 end
  71         end
  72         return status, ret, err_msg;
  73 end
  74
  75 local function sasl_handler(session, stanza)
  76         if stanza.name == "auth" then
  77                 -- FIXME ignoring duplicates because ejabberd does
  78                 local mechanism = stanza.attr.mechanism;
  79                 if anonymous_login then
  80                         if mechanism ~= "ANONYMOUS" then
  81                                 return session.send(build_reply("failure", "invalid-mechanism"));
  82                         end
  83                 elseif mechanism == "ANONYMOUS" then
  84                         return session.send(build_reply("failure", "mechanism-too-weak"));
  85                 end
  86                 if not session.secure and (secure_auth_only or (mechanism == "PLAIN" and not allow_unencrypted_plain_auth)) then
  87                         return session.send(build_reply("failure", "encryption-required"));
  88                 end
  89                 local valid_mechanism = session.sasl_handler:select(mechanism);
  90                 if not valid_mechanism then
  91                         return session.send(build_reply("failure", "invalid-mechanism"));
  92                 end
  93         elseif not session.sasl_handler then
  94                 return; -- FIXME ignoring out of order stanzas because ejabberd does
  95         end
  96         local text = stanza[1];
  97         if text then
  98                 text = base64.decode(text);
  99                 --log("debug", "AUTH: %s", text:gsub("[%z\001-\008\011\012\014-\031]", " "));
 100                 if not text then
 101                         session.sasl_handler = nil;
 102                         session.send(build_reply("failure", "incorrect-encoding"));
 103                         return;
 104                 end
 105         end
 106         local status, ret, err_msg = session.sasl_handler:process(text);
 107         status, ret, err_msg = handle_status(session, status, ret, err_msg);
 108         local s = build_reply(status, ret, err_msg);
 109         log("debug", "sasl reply: %s", tostring(s));
 110         session.send(s);
 111 end
 112
 113 module:add_handler("c2s_unauthed", "auth", xmlns_sasl, sasl_handler);
 114 module:add_handler("c2s_unauthed", "abort", xmlns_sasl, sasl_handler);
 115 module:add_handler("c2s_unauthed", "response", xmlns_sasl, sasl_handler);
 116
 117 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 118 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 119 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 120 module:hook("stream-features", function(event)
 121         local origin, features = event.origin, event.features;
 122         if not origin.username then
 123                 if secure_auth_only and not origin.secure then
 124                         return;
 125                 end
 126                 if anonymous_login then
 127                         origin.sasl_handler = new_sasl(module.host, anonymous_authentication_profile);
 128                 else
 129                         origin.sasl_handler = usermanager_get_sasl_handler(module.host);
 130                 end
 131                 features:tag("mechanisms", mechanisms_attr);
 132                 for mechanism in pairs(origin.sasl_handler:mechanisms()) do
 133                         if mechanism ~= "PLAIN" or origin.secure or allow_unencrypted_plain_auth then
 134                                 features:tag("mechanism"):text(mechanism):up();
 135                         end
 136                 end
 137                 features:up();
 138         else
 139                 features:tag("bind", bind_attr):tag("required"):up():up();
 140                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 141         end
 142 end);
 143
 144 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind", function(session, stanza)
 145         log("debug", "Client requesting a resource bind");
 146         local resource;
 147         if stanza.attr.type == "set" then
 148                 local bind = stanza.tags[1];
 149                 if bind and bind.attr.xmlns == xmlns_bind then
 150                         resource = bind:child_with_name("resource");
 151                         if resource then
 152                                 resource = resource[1];
 153                         end
 154                 end
 155         end
 156         local success, err_type, err, err_msg = sm_bind_resource(session, resource);
 157         if not success then
 158                 session.send(st.error_reply(stanza, err_type, err, err_msg));
 159         else
 160                 session.send(st.reply(stanza)
 161                         :tag("bind", { xmlns = xmlns_bind})
 162                         :tag("jid"):text(session.full_jid));
 163         end
 164 end);
 165
 166 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session", function(session, stanza)
 167         log("debug", "Client requesting a session");
 168         session.send(st.reply(stanza));
 169 end);