util.iterators: Add skip() to skip the first n items of an iterator
[prosody.git] / util / sasl.lua
index 515bcf8ab983901938aed8d8b53c341dcd70e87a..5d1b9f17f3d5e2e8e76f517b522bf45ebfee20c7 100644 (file)
+-- sasl.lua v0.4
+-- Copyright (C) 2008-2010 Tobias Markmann
+--
+--    All rights reserved.
+--
+--    Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+--
+--        * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+--        * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
+--        * Neither the name of Tobias Markmann nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
+--
+--    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-local base64 = require "base64"
+
+local md5 = require "util.hashes".md5;
 local log = require "util.logger".init("sasl");
-local tostring = tostring;
 local st = require "util.stanza";
+local set = require "util.set";
+local array = require "util.array";
+local to_unicode = require "util.encodings".idna.to_unicode;
+
+local tostring = tostring;
+local pairs, ipairs = pairs, ipairs;
+local t_insert, t_concat = table.insert, table.concat;
 local s_match = string.match;
+local type = type
+local error = error
+local setmetatable = setmetatable;
+local assert = assert;
+local require = require;
+
+require "util.iterators"
+local keys = keys
+
+local array = require "util.array"
 module "sasl"
 
+--[[
+Authentication Backend Prototypes:
 
-local function new_plain(onAuth, onSuccess, onFail, onWrite)
-       local object = { mechanism = "PLAIN", onAuth = onAuth, onSuccess = onSuccess, onFail = onFail,
-                                       onWrite = onWrite}
-       --local challenge = base64.encode("");
-       --onWrite(st.stanza("challenge", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):text(challenge))
-       object.feed =   function(self, stanza)
-                                               if stanza.name ~= "response" and stanza.name ~= "auth" then self.onFail("invalid-stanza-tag") end
-                                               if stanza.attr.xmlns ~= "urn:ietf:params:xml:ns:xmpp-sasl" then self.onFail("invalid-stanza-namespace") end
-                                               local response = base64.decode(stanza[1])
-                                               local authorization = s_match(response, "([^&%z]+)")
-                                               local authentication = s_match(response, "%z([^&%z]+)%z")
-                                               local password = s_match(response, "%z[^&%z]+%z([^&%z]+)")
-                                               if self.onAuth(authorization, password) == true then
-                                                       self.onWrite(st.stanza("success", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}))
-                                                       self.onSuccess(authentication)
-                                               else
-                                                       self.onWrite(st.stanza("failure", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):tag("temporary-auth-failure"));
-                                               end
-                                       end
-       return object
+state = false : disabled
+state = true : enabled
+state = nil : non-existant
+]]
+
+local method = {};
+method.__index = method;
+local mechanisms = {};
+local backend_mechanism = {};
+
+-- register a new SASL mechanims
+local function registerMechanism(name, backends, f)
+       assert(type(name) == "string", "Parameter name MUST be a string.");
+       assert(type(backends) == "string" or type(backends) == "table", "Parameter backends MUST be either a string or a table.");
+       assert(type(f) == "function", "Parameter f MUST be a function.");
+       mechanisms[name] = f
+       for _, backend_name in ipairs(backends) do
+               if backend_mechanism[backend_name] == nil then backend_mechanism[backend_name] = {}; end
+               t_insert(backend_mechanism[backend_name], name);
+       end
+end
+
+-- create a new SASL object which can be used to authenticate clients
+function new(realm, profile, forbidden)
+       local sasl_i = {profile = profile};
+       sasl_i.realm = realm;
+       local s = setmetatable(sasl_i, method);
+       if forbidden == nil then forbidden = {} end
+       s:forbidden(forbidden)
+       return s;
 end
 
+-- get a fresh clone with the same realm, profiles and forbidden mechanisms
+function method:clean_clone()
+       return new(self.realm, self.profile, self:forbidden())
+end
 
-function new(mechanism, onAuth, onSuccess, onFail, onWrite)
-       local object
-       if mechanism == "PLAIN" then object = new_plain(onAuth, onSuccess, onFail, onWrite)
+-- set the forbidden mechanisms
+function method:forbidden( restrict )
+       if restrict then
+               -- set forbidden
+               self.restrict = set.new(restrict);
        else
-               log("debug", "Unsupported SASL mechanism: "..tostring(mechanism));
-               onFail("unsupported-mechanism")
+               -- get forbidden
+               return array.collect(self.restrict:items());
+       end
+end
+
+-- get a list of possible SASL mechanims to use
+function method:mechanisms()
+       local mechanisms = self.mechs;
+       if not mechanisms then
+               mechanisms = {}
+               for backend, f in pairs(self.profile) do
+                       if backend_mechanism[backend] then
+                               for _, mechanism in ipairs(backend_mechanism[backend]) do
+                                       if not self.restrict:contains(mechanism) then
+                                               mechanisms[mechanism] = true;
+                                       end
+                               end
+                       end
+               end
+               self.mechs = mechanisms;
+       end
+       return mechanisms;
+end
+
+-- select a mechanism to use
+function method:select(mechanism)
+       if self.mech_i then
+               return false;
        end
-       return object
+       
+       self.mech_i = mechanisms[self:mechanisms()[mechanism] and mechanism];
+       return (self.mech_i ~= nil);
+end
+
+-- feed new messages to process into the library
+function method:process(message)
+       --if message == "" or message == nil then return "failure", "malformed-request" end
+       return self.mech_i(self, message);
+end
+
+-- load the mechanisms
+local load_mechs = {"plain", "digest-md5", "anonymous", "scram"}
+for _, mech in ipairs(load_mechs) do
+       local name = "util.sasl."..mech;
+       local m = require(name);
+       m.init(registerMechanism)
 end
 
-return _M;
\ No newline at end of file
+return _M;