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(event)
  76         local session, stanza = event.origin, event.stanza;
  77         if session.type ~= "c2s_unauthed" then return; end
  78
  79         if stanza.name == "auth" then
  80                 -- FIXME ignoring duplicates because ejabberd does
  81                 local mechanism = stanza.attr.mechanism;
  82                 if anonymous_login then
  83                         if mechanism ~= "ANONYMOUS" then
  84                                 session.send(build_reply("failure", "invalid-mechanism"));
  85                                 return true;
  86                         end
  87                 elseif mechanism == "ANONYMOUS" then
  88                         session.send(build_reply("failure", "mechanism-too-weak"));
  89                         return true;
  90                 end
  91                 if not session.secure and (secure_auth_only or (mechanism == "PLAIN" and not allow_unencrypted_plain_auth)) then
  92                         session.send(build_reply("failure", "encryption-required"));
  93                         return true;
  94                 end
  95                 local valid_mechanism = session.sasl_handler:select(mechanism);
  96                 if not valid_mechanism then
  97                         session.send(build_reply("failure", "invalid-mechanism"));
  98                         return true;
  99                 end
 100         elseif not session.sasl_handler then
 101                 return true; -- FIXME ignoring out of order stanzas because ejabberd does
 102         end
 103         local text = stanza[1];
 104         if text then
 105                 text = base64.decode(text);
 106                 --log("debug", "AUTH: %s", text:gsub("[%z\001-\008\011\012\014-\031]", " "));
 107                 if not text then
 108                         session.sasl_handler = nil;
 109                         session.send(build_reply("failure", "incorrect-encoding"));
 110                         return true;
 111                 end
 112         end
 113         local status, ret, err_msg = session.sasl_handler:process(text);
 114         status, ret, err_msg = handle_status(session, status, ret, err_msg);
 115         local s = build_reply(status, ret, err_msg);
 116         log("debug", "sasl reply: %s", tostring(s));
 117         session.send(s);
 118         return true;
 119 end
 120
 121 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:auth", sasl_handler);
 122 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:abort", sasl_handler);
 123 module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:response", sasl_handler);
 124
 125 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 126 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 127 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 128 module:hook("stream-features", function(event)
 129         local origin, features = event.origin, event.features;
 130         if not origin.username then
 131                 if secure_auth_only and not origin.secure then
 132                         return;
 133                 end
 134                 if anonymous_login then
 135                         origin.sasl_handler = new_sasl(module.host, anonymous_authentication_profile);
 136                 else
 137                         origin.sasl_handler = usermanager_get_sasl_handler(module.host);
 138                 end
 139                 features:tag("mechanisms", mechanisms_attr);
 140                 for mechanism in pairs(origin.sasl_handler:mechanisms()) do
 141                         if mechanism ~= "PLAIN" or origin.secure or allow_unencrypted_plain_auth then
 142                                 features:tag("mechanism"):text(mechanism):up();
 143                         end
 144                 end
 145                 features:up();
 146         else
 147                 features:tag("bind", bind_attr):tag("required"):up():up();
 148                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 149         end
 150 end);
 151
 152 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-bind:bind", function(event)
 153         local origin, stanza = event.origin, event.stanza;
 154         local resource;
 155         if stanza.attr.type == "set" then
 156                 local bind = stanza.tags[1];
 157                 resource = bind:child_with_name("resource");
 158                 resource = resource and #resource.tags == 0 and resource[1] or nil;
 159         end
 160         local success, err_type, err, err_msg = sm_bind_resource(origin, resource);
 161         if success then
 162                 origin.send(st.reply(stanza)
 163                         :tag("bind", { xmlns = xmlns_bind })
 164                         :tag("jid"):text(origin.full_jid));
 165                 origin.log("debug", "Resource bound: %s", origin.full_jid);
 166         else
 167                 origin.send(st.error_reply(stanza, err_type, err, err_msg));
 168                 origin.log("debug", "Resource bind failed: %s", err_msg or err);
 169         end
 170         return true;
 171 end);
 172
 173 module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-session:session", function(event)
 174         event.origin.send(st.reply(event.stanza));
 175         return true;
 176 end);