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 datamanager_load = require "util.datamanager".load;
  17 local usermanager_validate_credentials = require "core.usermanager".validate_credentials;
  18 local usermanager_get_supported_methods = require "core.usermanager".get_supported_methods;
  19 local usermanager_user_exists = require "core.usermanager".user_exists;
  20 local usermanager_get_password = require "core.usermanager".get_password;
  21 local t_concat, t_insert = table.concat, table.insert;
  22 local tostring = tostring;
  23 local jid_split = require "util.jid".split
  24 local md5 = require "util.hashes".md5;
  25 local config = require "core.configmanager";
  26
  27 local secure_auth_only = config.get(module:get_host(), "core", "require_encryption");
  28
  29 local log = module._log;
  30
  31 local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';
  32 local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';
  33 local xmlns_stanzas ='urn:ietf:params:xml:ns:xmpp-stanzas';
  34
  35 local new_sasl = require "util.sasl".new;
  36
  37 local function build_reply(status, ret, err_msg)
  38         local reply = st.stanza(status, {xmlns = xmlns_sasl});
  39         if status == "challenge" then
  40                 log("debug", "%s", ret or "");
  41                 reply:text(base64.encode(ret or ""));
  42         elseif status == "failure" then
  43                 reply:tag(ret):up();
  44                 if err_msg then reply:tag("text"):text(err_msg); end
  45         elseif status == "success" then
  46                 log("debug", "%s", ret or "");
  47                 reply:text(base64.encode(ret or ""));
  48         else
  49                 module:log("error", "Unknown sasl status: %s", status);
  50         end
  51         return reply;
  52 end
  53
  54 local function handle_status(session, status)
  55         if status == "failure" then
  56                 session.sasl_handler = nil;
  57         elseif status == "success" then
  58                 if not session.sasl_handler.username then -- TODO move this to sessionmanager
  59                         module:log("warn", "SASL succeeded but we didn't get a username!");
  60                         session.sasl_handler = nil;
  61                         session:reset_stream();
  62                         return;
  63                 end
  64                 sm_make_authenticated(session, session.sasl_handler.username);
  65                 session.sasl_handler = nil;
  66                 session:reset_stream();
  67         end
  68 end
  69
  70 local function credentials_callback(mechanism, ...)
  71         if mechanism == "PLAIN" then
  72                 local username, hostname, password = arg[1], arg[2], arg[3];
  73                 local response = usermanager_validate_credentials(hostname, username, password, mechanism)
  74                 if response == nil then return false
  75                 else return response end
  76         elseif mechanism == "DIGEST-MD5" then
  77                 function func(x) return x; end
  78                 local node, domain, realm, decoder = arg[1], arg[2], arg[3], arg[4];
  79                 local password = usermanager_get_password(node, domain)
  80                 if password then
  81                         if decoder then node, realm, password = decoder(node), decoder(realm), decoder(password); end
  82                         return func, md5(node..":"..realm..":"..password);
  83                 else
  84                         return func, nil;
  85                 end
  86         end
  87 end
  88
  89 local function sasl_handler(session, stanza)
  90         if stanza.name == "auth" then
  91                 -- FIXME ignoring duplicates because ejabberd does
  92                 if config.get(session.host or "*", "core", "anonymous_login") then
  93                         if stanza.attr.mechanism ~= "ANONYMOUS" then
  94                                 return session.send(build_reply("failure", "invalid-mechanism"));
  95                         end
  96                 elseif stanza.attr.mechanism == "ANONYMOUS" then
  97                         return session.send(build_reply("failure", "mechanism-too-weak"));
  98                 end
  99                 session.sasl_handler = new_sasl(stanza.attr.mechanism, session.host, credentials_callback);
 100                 if not session.sasl_handler then
 101                         return session.send(build_reply("failure", "invalid-mechanism"));
 102                 end
 103         elseif not session.sasl_handler then
 104                 return; -- FIXME ignoring out of order stanzas because ejabberd does
 105         end
 106         local text = stanza[1];
 107         if text then
 108                 text = base64.decode(text);
 109                 log("debug", "%s", text);
 110                 if not text then
 111                         session.sasl_handler = nil;
 112                         session.send(build_reply("failure", "incorrect-encoding"));
 113                         return;
 114                 end
 115         end
 116         local status, ret, err_msg = session.sasl_handler:feed(text);
 117         handle_status(session, status);
 118         local s = build_reply(status, ret, err_msg);
 119         log("debug", "sasl reply: %s", tostring(s));
 120         session.send(s);
 121 end
 122
 123 module:add_handler("c2s_unauthed", "auth", xmlns_sasl, sasl_handler);
 124 module:add_handler("c2s_unauthed", "abort", xmlns_sasl, sasl_handler);
 125 module:add_handler("c2s_unauthed", "response", xmlns_sasl, sasl_handler);
 126
 127 local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
 128 local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
 129 local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
 130 module:add_event_hook("stream-features",
 131                 function (session, features)
 132                         if not session.username then
 133                                 if secure_auth_only and not session.secure then
 134                                         return;
 135                                 end
 136                                 features:tag("mechanisms", mechanisms_attr);
 137                                 -- 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.
 138                                         if config.get(session.host or "*", "core", "anonymous_login") then
 139                                                 features:tag("mechanism"):text("ANONYMOUS"):up();
 140                                         else
 141                                                 mechanisms = usermanager_get_supported_methods(session.host or "*");
 142                                                 for k, v in pairs(mechanisms) do
 143                                                         features:tag("mechanism"):text(k):up();
 144                                                 end
 145                                         end
 146                                 features:up();
 147                         else
 148                                 features:tag("bind", bind_attr):tag("required"):up():up();
 149                                 features:tag("session", xmpp_session_attr):up();
 150                         end
 151                 end);
 152
 153 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind",
 154                 function (session, stanza)
 155                         log("debug", "Client requesting a resource bind");
 156                         local resource;
 157                         if stanza.attr.type == "set" then
 158                                 local bind = stanza.tags[1];
 159                                 if bind and bind.attr.xmlns == xmlns_bind then
 160                                         resource = bind:child_with_name("resource");
 161                                         if resource then
 162                                                 resource = resource[1];
 163                                         end
 164                                 end
 165                         end
 166                         local success, err_type, err, err_msg = sm_bind_resource(session, resource);
 167                         if not success then
 168                                 session.send(st.error_reply(stanza, err_type, err, err_msg));
 169                         else
 170                                 session.send(st.reply(stanza)
 171                                         :tag("bind", { xmlns = xmlns_bind})
 172                                         :tag("jid"):text(session.full_jid));
 173                         end
 174                 end);
 175
 176 module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session",
 177                 function (session, stanza)
 178                         log("debug", "Client requesting a session");
 179                         session.send(st.reply(stanza));
 180                 end);