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", "c2s_require_encryption") or 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                 local username = nodeprep(session.sasl_handler.username);
  60                 session.sasl_handler = nil;
  61                 if not username then -- TODO move this to sessionmanager
  62                         module:log("warn", "SASL succeeded but we didn't get a username!");
  63                         session.sasl_handler = nil;
  64                         session:reset_stream();
  65                         return;
  66                 end
  67                 sm_make_authenticated(session, username);
  68                 session:reset_stream();
  69         end
  70 end
  71
  72 local function credentials_callback(mechanism, ...)
  73         if mechanism == "PLAIN" then
  74                 local username, hostname, password = ...;
  75                 username = nodeprep(username);
  76                 if not username then
  77                         return false;
  78                 end
  79                 local response = usermanager_validate_credentials(hostname, username, password, mechanism);
  80                 if response == nil then
  81                         return false;
  82                 else
  83                         return response;
  84                 end
  85         elseif mechanism == "DIGEST-MD5" then
  86                 local function func(x) return x; end
  87                 local node, domain, realm, decoder = ...;
  88                 local prepped_node = nodeprep(node);
  89                 if not prepped_node then
  90                         return func, nil;
  91                 end
  92                 local password = usermanager_get_password(prepped_node, domain);
  93                 if password then
  94                         if decoder then
  95                                 node, realm, password = decoder(node), decoder(realm), decoder(password);
  96                         end
  97                         return func, md5(node..":"..realm..":"..password);
  98                 else
  99                         return func, nil;
 100                 end
 101         end
 102 end
 103
 104 local function sasl_handler(session, stanza)
 105         if stanza.name == "auth" then
 106                 -- FIXME ignoring duplicates because ejabberd does
 107                 if config.get(session.host or "*", "core", "anonymous_login") then
 108                         if stanza.attr.mechanism ~= "ANONYMOUS" then
 109                                 return session.send(build_reply("failure", "invalid-mechanism"));
 110                         end
 111                 elseif stanza.attr.mechanism == "ANONYMOUS" then
 112                         return session.send(build_reply("failure", "mechanism-too-weak"));
 113                 end
 114                 session.sasl_handler = new_sasl(stanza.attr.mechanism, session.host, credentials_callback);
 115                 if not session.sasl_handler then
 116                         return session.send(build_reply("failure", "invalid-mechanism"));
 117                 end
 118         elseif not session.sasl_handler then
 119                 return; -- FIXME ignoring out of order stanzas because ejabberd does
 120         end
 121         local text = stanza[1];
 122         if text then
 123                 text = base64.decode(text);
 124                 log("debug", "%s", text);
 125                 if not text then
 126                         session.sasl_handler = nil;
 127                         session.send(build_reply("failure", "incorrect-encoding"));
 128                         return;
 129                 end
 130         end
 131         local status, ret, err_msg = session.sasl_handler:feed(text);
 132         handle_status(session, status);
 133         local s = build_reply(status, ret, err_msg);
 134         log("debug", "sasl reply: %s", tostring(s));
 135         session.send(s);
 136 end
 137
 138 module:add_handler("c2s_unauthed", "auth", xmlns_sasl, sasl_handler);
 139 module:add_handler("c2s_unauthed", "abort", xmlns_sasl, sasl_handler);
 140 module:add_handler("c2s_unauthed", "response", xmlns_sasl, sasl_handler);
 141
 142 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 143 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 144 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 145 module:add_event_hook("stream-features",
 146                 function (session, features)
 147                         if not session.username then
 148                                 if secure_auth_only and not session.secure then
 149                                         return;
 150                                 end
 151                                 features:tag("mechanisms", mechanisms_attr);
 152                                 -- 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.
 153                                         if config.get(session.host or "*", "core", "anonymous_login") then
 154                                                 features:tag("mechanism"):text("ANONYMOUS"):up();
 155                                         else
 156                                                 local mechanisms = usermanager_get_supported_methods(session.host or "*");
 157                                                 for k, v in pairs(mechanisms) do
 158                                                         features:tag("mechanism"):text(k):up();
 159                                                 end
 160                                         end
 161                                 features:up();
 162                         else
 163                                 features:tag("bind", bind_attr):tag("required"):up():up();
 164                                 features:tag("session", xmpp_session_attr):tag("optional"):up():up();
 165                         end
 166                 end);
 167
 168 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind",
 169                 function (session, stanza)
 170                         log("debug", "Client requesting a resource bind");
 171                         local resource;
 172                         if stanza.attr.type == "set" then
 173                                 local bind = stanza.tags[1];
 174                                 if bind and bind.attr.xmlns == xmlns_bind then
 175                                         resource = bind:child_with_name("resource");
 176                                         if resource then
 177                                                 resource = resource[1];
 178                                         end
 179                                 end
 180                         end
 181                         local success, err_type, err, err_msg = sm_bind_resource(session, resource);
 182                         if not success then
 183                                 session.send(st.error_reply(stanza, err_type, err, err_msg));
 184                         else
 185                                 session.send(st.reply(stanza)
 186                                         :tag("bind", { xmlns = xmlns_bind})
 187                                         :tag("jid"):text(session.full_jid));
 188                         end
 189                 end);
 190
 191 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session",
 192                 function (session, stanza)
 193                         log("debug", "Client requesting a session");
 194                         session.send(st.reply(stanza));
 195                 end);