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 = config.get(module:get_host(), "core", "require_encryption");
  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
  38 local function build_reply(status, ret, err_msg)
  39         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  40         if status == "challenge" then
  41                 log("debug", "%s", ret or "");
  42                 reply:text(base64.encode(ret or ""));
  43         elseif status == "failure" then
  44                 reply:tag(ret):up();
  45                 if err_msg then reply:tag("text"):text(err_msg); end
  46         elseif status == "success" then
  47                 log("debug", "%s", ret or "");
  48                 reply:text(base64.encode(ret or ""));
  49         else
  50                 module:log("error", "Unknown sasl status: %s", status);
  51         end
  52         return reply;
  53 end
  54
  55 local function handle_status(session, status)
  56         if status == "failure" then
  57                 session.sasl_handler = nil;
  58         elseif status == "success" then
  59                 if not session.sasl_handler.username then -- TODO move this to sessionmanager
  60                         module:log("warn", "SASL succeeded but we didn't get a username!");
  61                         session.sasl_handler = nil;
  62                         session:reset_stream();
  63                         return;
  64                 end
  65                 sm_make_authenticated(session, session.sasl_handler.username);
  66                 session.sasl_handler = nil;
  67                 session:reset_stream();
  68         end
  69 end
  70
  71 local function credentials_callback(mechanism, ...)
  72         if mechanism == "PLAIN" then
  73                 local username, hostname, password = ...;
  74                 username = nodeprep(username);
  75                 if not username then
  76                         return false;
  77                 end
  78                 local response = usermanager_validate_credentials(hostname, username, password, mechanism);
  79                 if response == nil then
  80                         return false;
  81                 else
  82                         return response;
  83                 end
  84         elseif mechanism == "DIGEST-MD5" then
  85                 function func(x) return x; end
  86                 local node, domain, realm, decoder = ...;
  87                 local password = usermanager_get_password(node, domain);
  88                 if password then
  89                         if decoder then
  90                                 node, realm, password = decoder(node), decoder(realm), decoder(password);
  91                         end
  92                         return func, md5(node..":"..realm..":"..password);
  93                 else
  94                         return func, nil;
  95                 end
  96         end
  97 end
  98
  99 local function sasl_handler(session, stanza)
 100         if stanza.name == "auth" then
 101                 -- FIXME ignoring duplicates because ejabberd does
 102                 if config.get(session.host or "*", "core", "anonymous_login") then
 103                         if stanza.attr.mechanism ~= "ANONYMOUS" then
 104                                 return session.send(build_reply("failure", "invalid-mechanism"));
 105                         end
 106                 elseif stanza.attr.mechanism == "ANONYMOUS" then
 107                         return session.send(build_reply("failure", "mechanism-too-weak"));
 108                 end
 109                 session.sasl_handler = new_sasl(stanza.attr.mechanism, session.host, credentials_callback);
 110                 if not session.sasl_handler then
 111                         return session.send(build_reply("failure", "invalid-mechanism"));
 112                 end
 113         elseif not session.sasl_handler then
 114                 return; -- FIXME ignoring out of order stanzas because ejabberd does
 115         end
 116         local text = stanza[1];
 117         if text then
 118                 text = base64.decode(text);
 119                 log("debug", "%s", text);
 120                 if not text then
 121                         session.sasl_handler = nil;
 122                         session.send(build_reply("failure", "incorrect-encoding"));
 123                         return;
 124                 end
 125         end
 126         local status, ret, err_msg = session.sasl_handler:feed(text);
 127         handle_status(session, status);
 128         local s = build_reply(status, ret, err_msg);
 129         log("debug", "sasl reply: %s", tostring(s));
 130         session.send(s);
 131 end
 132
 133 module:add_handler("c2s_unauthed", "auth", xmlns_sasl, sasl_handler);
 134 module:add_handler("c2s_unauthed", "abort", xmlns_sasl, sasl_handler);
 135 module:add_handler("c2s_unauthed", "response", xmlns_sasl, sasl_handler);
 136
 137 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 138 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 139 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 140 module:add_event_hook("stream-features",
 141                 function (session, features)
 142                         if not session.username then
 143                                 if secure_auth_only and not session.secure then
 144                                         return;
 145                                 end
 146                                 features:tag("mechanisms", mechanisms_attr);
 147                                 -- TODO: Provide PLAIN only if TLS is active, this is a SHOULD from the introduction of RFC 4616. This behavior could be overridden via configuration but will issuing a warning or so.
 148                                         if config.get(session.host or "*", "core", "anonymous_login") then
 149                                                 features:tag("mechanism"):text("ANONYMOUS"):up();
 150                                         else
 151                                                 mechanisms = usermanager_get_supported_methods(session.host or "*");
 152                                                 for k, v in pairs(mechanisms) do
 153                                                         features:tag("mechanism"):text(k):up();
 154                                                 end
 155                                         end
 156                                 features:up();
 157                         else
 158                                 features:tag("bind", bind_attr):tag("required"):up():up();
 159                                 features:tag("session", xmpp_session_attr):up();
 160                         end
 161                 end);
 162
 163 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind",
 164                 function (session, stanza)
 165                         log("debug", "Client requesting a resource bind");
 166                         local resource;
 167                         if stanza.attr.type == "set" then
 168                                 local bind = stanza.tags[1];
 169                                 if bind and bind.attr.xmlns == xmlns_bind then
 170                                         resource = bind:child_with_name("resource");
 171                                         if resource then
 172                                                 resource = resource[1];
 173                                         end
 174                                 end
 175                         end
 176                         local success, err_type, err, err_msg = sm_bind_resource(session, resource);
 177                         if not success then
 178                                 session.send(st.error_reply(stanza, err_type, err, err_msg));
 179                         else
 180                                 session.send(st.reply(stanza)
 181                                         :tag("bind", { xmlns = xmlns_bind})
 182                                         :tag("jid"):text(session.full_jid));
 183                         end
 184                 end);
 185
 186 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session",
 187                 function (session, stanza)
 188                         log("debug", "Client requesting a session");
 189                         session.send(st.reply(stanza));
 190                 end);