Merge with Tobias's SASL redesign branch

6 files changed, 627 insertions, 272 deletions

diff --git a/plugins/mod_saslauth.lua b/plugins/mod_saslauth.lua
index c0f57cd7..04e33b29 100644
--- a/plugins/mod_saslauth.lua
+++ b/plugins/mod_saslauth.lua
@@ -1,7 +1,7 @@
 -- Prosody IM
 -- Copyright (C) 2008-2009 Matthew Wild
 -- Copyright (C) 2008-2009 Waqas Hussain
--- 
+--
 -- This project is MIT/X11 licensed. Please see the
 -- COPYING file in the source package for more information.
 --
@@ -35,6 +35,27 @@ local xmlns_stanzas ='urn:ietf:params:xml:ns:xmpp-stanzas';
 
 local new_sasl = require "util.sasl".new;
 
+default_authentication_profile = {
+	plain = function(username, realm)
+			local prepped_username = nodeprep(username);
+			if not prepped_username then
+				log("debug", "NODEprep failed on username: %s", username);
+				return "", nil;
+			end
+			local password = usermanager_get_password(prepped_username, realm);
+			if not password then
+				return "", nil;
+			end
+			return password, true;
+		end
+};
+
+anonymous_authentication_profile = {
+	anonymous = function(username, realm)
+			return true; -- for normal usage you should always return true here
+		end
+}
+
 local function build_reply(status, ret, err_msg)
 	local reply = st.stanza(status, {xmlns = xmlns_sasl});
 	if status == "challenge" then
@@ -57,47 +78,15 @@ local function handle_status(session, status)
 		session.sasl_handler = nil;
 	elseif status == "success" then
 		local username = nodeprep(session.sasl_handler.username);
-		session.sasl_handler = nil;
 		if not username then -- TODO move this to sessionmanager
 			module:log("warn", "SASL succeeded but we didn't get a username!");
 			session.sasl_handler = nil;
 			session:reset_stream();
 			return;
-		end 
-		sm_make_authenticated(session, username);
-		session:reset_stream();
-	end
-end
-
-local function credentials_callback(mechanism, ...)
-	if mechanism == "PLAIN" then
-		local username, hostname, password = ...;
-		username = nodeprep(username);
-		if not username then
-			return false;
-		end
-		local response = usermanager_validate_credentials(hostname, username, password, mechanism);
-		if response == nil then
-			return false;
-		else
-			return response;
-		end
-	elseif mechanism == "DIGEST-MD5" then
-		local function func(x) return x; end
-		local node, domain, realm, decoder = ...;
-		local prepped_node = nodeprep(node);
-		if not prepped_node then
-			return func, nil;
-		end
-		local password = usermanager_get_password(prepped_node, domain);
-		if password then
-			if decoder then
-				node, realm, password = decoder(node), decoder(realm), decoder(password);
-			end
-			return func, md5(node..":"..realm..":"..password);
-		else
-			return func, nil;
 		end
+		sm_make_authenticated(session, session.sasl_handler.username);
+		session.sasl_handler = nil;
+		session:reset_stream();
 	end
 end
 
@@ -111,8 +100,8 @@ local function sasl_handler(session, stanza)
 		elseif stanza.attr.mechanism == "ANONYMOUS" then
 			return session.send(build_reply("failure", "mechanism-too-weak"));
 		end
-		session.sasl_handler = new_sasl(stanza.attr.mechanism, session.host, credentials_callback);
-		if not session.sasl_handler then
+		local valid_mechanism = session.sasl_handler:select(stanza.attr.mechanism);
+		if not valid_mechanism then
 			return session.send(build_reply("failure", "invalid-mechanism"));
 		end
 	elseif not session.sasl_handler then
@@ -128,7 +117,7 @@ local function sasl_handler(session, stanza)
 			return;
 		end
 	end
-	local status, ret, err_msg = session.sasl_handler:feed(text);
+	local status, ret, err_msg = session.sasl_handler:process(text);
 	handle_status(session, status);
 	local s = build_reply(status, ret, err_msg);
 	log("debug", "sasl reply: %s", tostring(s));
@@ -148,16 +137,18 @@ module:add_event_hook("stream-features",
 				if secure_auth_only and not session.secure then
 					return;
 				end
-				features:tag("mechanisms", mechanisms_attr);
-				-- 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.
-					if config.get(session.host or "*", "core", "anonymous_login") then
-						features:tag("mechanism"):text("ANONYMOUS"):up();
-					else
-						local mechanisms = usermanager_get_supported_methods(session.host or "*");
-						for k, v in pairs(mechanisms) do
-							features:tag("mechanism"):text(k):up();
-						end
+				if module:get_option("anonymous_login") then
+					session.sasl_handler = new_sasl(session.host, anonymous_authentication_profile);
+				else
+					session.sasl_handler = new_sasl(session.host, default_authentication_profile);
+					if not (module:get_option("allow_unencrypted_plain_auth")) and not session.secure then
+						session.sasl_handler:forbidden({"PLAIN"});
 					end
+				end
+				features:tag("mechanisms", mechanisms_attr);
+				for k, v in pairs(session.sasl_handler:mechanisms()) do
+					features:tag("mechanism"):text(v):up();
+				end
 				features:up();
 			else
 				features:tag("bind", bind_attr):tag("required"):up():up();
diff --git a/util/sasl.lua b/util/sasl.lua
index 402f05b4..7b7db024 100644
--- a/util/sasl.lua
+++ b/util/sasl.lua
@@ -14,258 +14,134 @@
 
 local md5 = require "util.hashes".md5;
 local log = require "util.logger".init("sasl");
-local tostring = tostring;
 local st = require "util.stanza";
-local generate_uuid = require "util.uuid".generate;
-local t_insert, t_concat = table.insert, table.concat;
-local to_byte, to_char = string.byte, string.char;
+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 gmatch = string.gmatch
-local string = string
-local math = require "math"
 local type = type
 local error = error
-local print = print
-
-module "sasl"
+local setmetatable = setmetatable;
+local assert = assert;
+local require = require;
 
--- Credentials handler:
---   Arguments: ("PLAIN", user, host, password)
---   Returns: true (success) | false (fail) | nil (user unknown)
-local function new_plain(realm, credentials_handler)
-	local object = { mechanism = "PLAIN", realm = realm, credentials_handler = credentials_handler}
-	function object.feed(self, message)
-		if message == "" or message == nil then return "failure", "malformed-request" end
-		local response = message
-		local authorization = s_match(response, "([^%z]+)")
-		local authentication = s_match(response, "%z([^%z]+)%z")
-		local password = s_match(response, "%z[^%z]+%z([^%z]+)")
+require "util.iterators"
+local keys = keys
 
-    if authentication == nil or password == nil then return "failure", "malformed-request" end
-    self.username = authentication
-    local auth_success = self.credentials_handler("PLAIN", self.username, self.realm, password)
-
-    if auth_success then
-      return "success"
-    elseif auth_success == nil then
-      return "failure", "account-disabled"
-    else
-      return "failure", "not-authorized"
-    end
-  end
-  return object
-end
-
--- credentials_handler:
---   Arguments: (mechanism, node, domain, realm, decoder)
---   Returns: Password encoding, (plaintext) password
--- implementing RFC 2831
-local function new_digest_md5(realm, credentials_handler)
-	--TODO complete support for authzid
+local array = require "util.array"
+module "sasl"
 
-	local function serialize(message)
-		local data = ""
+--[[
+Authentication Backend Prototypes:
 
-		if type(message) ~= "table" then error("serialize needs an argument of type table.") end
+state = false : disabled
+state = true : enabled
+state = nil : non-existant
 
-		-- testing all possible values
-		if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end
-		if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end
-		if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end
-		if message["charset"] then data = data..[[charset=]]..message.charset.."," end
-		if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end
-		if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end
-		data = data:gsub(",$", "")
-		return data
+plain:
+	function(username, realm)
+		return password, state;
 	end
 
-	local function utf8tolatin1ifpossible(passwd)
-		local i = 1;
-		while i <= #passwd do
-			local passwd_i = to_byte(passwd:sub(i, i));
-			if passwd_i > 0x7F then
-				if passwd_i < 0xC0 or passwd_i > 0xC3 then
-					return passwd;
-				end
-				i = i + 1;
-				passwd_i = to_byte(passwd:sub(i, i));
-				if passwd_i < 0x80 or passwd_i > 0xBF then
-					return passwd;
-				end
-			end
-			i = i + 1;
-		end
+plain-test:
+	function(username, realm, password)
+		return true or false, state;
+	end
 
-		local p = {};
-		local j = 0;
-		i = 1;
-		while (i <= #passwd) do
-			local passwd_i = to_byte(passwd:sub(i, i));
-			if passwd_i > 0x7F then
-				i = i + 1;
-				local passwd_i_1 = to_byte(passwd:sub(i, i));
-				t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever
-			else
-				t_insert(p, to_char(passwd_i));
-			end
-			i = i + 1;
-		end
-		return t_concat(p);
+digest-md5:
+	function(username, domain, realm, encoding) -- domain and realm are usually the same; for some broken
+												-- implementations it's not
+		return digesthash, state;
 	end
-	local function latin1toutf8(str)
-		local p = {};
-		for ch in gmatch(str, ".") do
-			ch = to_byte(ch);
-			if (ch < 0x80) then
-				t_insert(p, to_char(ch));
-			elseif (ch < 0xC0) then
-				t_insert(p, to_char(0xC2, ch));
-			else
-				t_insert(p, to_char(0xC3, ch - 64));
-			end
-		end
-		return t_concat(p);
+
+digest-md5-test:
+	function(username, domain, realm, encoding, digesthash)
+		return true or false, state;
 	end
-	local function parse(data)
-		local message = {}
-		-- COMPAT: %z in the pattern to work around jwchat bug (sends "charset=utf-8\0")
-		for k, v in gmatch(data, [[([%w%-]+)="?([^",%z]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
-			message[k] = v;
-		end
-		return message;
+]]
+
+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
 
-	local object = { mechanism = "DIGEST-MD5", realm = realm, credentials_handler = credentials_handler};
-
-	object.nonce = generate_uuid();
-	object.step = 0;
-	object.nonce_count = {};
-
-	function object.feed(self, message)
-		self.step = self.step + 1;
-		if (self.step == 1) then
-			local challenge = serialize({	nonce = object.nonce,
-											qop = "auth",
-											charset = "utf-8",
-											algorithm = "md5-sess",
-											realm = self.realm});
-			return "challenge", challenge;
-		elseif (self.step == 2) then
-			local response = parse(message);
-			-- check for replay attack
-			if response["nc"] then
-				if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
-			end
-
-			-- check for username, it's REQUIRED by RFC 2831
-			if not response["username"] then
-				return "failure", "malformed-request";
-			end
-			self["username"] = response["username"];
-
-			-- check for nonce, ...
-			if not response["nonce"] then
-				return "failure", "malformed-request";
-			else
-				-- check if it's the right nonce
-				if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
-			end
-
-			if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
-			if not response["qop"] then response["qop"] = "auth" end
-
-			if response["realm"] == nil or response["realm"] == "" then
-				response["realm"] = "";
-			elseif response["realm"] ~= self.realm then
-				return "failure", "not-authorized", "Incorrect realm value";
-			end
-
-			local decoder;
-			if response["charset"] == nil then
-				decoder = utf8tolatin1ifpossible;
-			elseif response["charset"] ~= "utf-8" then
-				return "failure", "incorrect-encoding", "The client's response uses "..response["charset"].." for encoding with isn't supported by sasl.lua. Supported encodings are latin or utf-8.";
-			end
+-- create a new SASL object which can be used to authenticate clients
+function new(realm, profile, forbidden)
+	sasl_i = {profile = profile};
+	sasl_i.realm = realm;
+	s = setmetatable(sasl_i, method);
+	s:forbidden(sasl_i, forbidden)
+	return s;
+end
 
-			local domain = "";
-			local protocol = "";
-			if response["digest-uri"] then
-				protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$");
-				if protocol == nil or domain == nil then return "failure", "malformed-request" end
-			else
-				return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
-			end
+-- set the forbidden mechanisms
+function method:forbidden( restrict )
+	if restrict then
+		-- set forbidden
+		self.restrict = set.new(restrict);
+	else
+		-- get forbidden
+		return array.collect(self.restrict:items());
+	end
+end
 
-			--TODO maybe realm support
-			self.username = response["username"];
-			local password_encoding, Y = self.credentials_handler("DIGEST-MD5", response["username"], self.realm, response["realm"], decoder);
-			if Y == nil then return "failure", "not-authorized"
-			elseif Y == false then return "failure", "account-disabled" end
-			local A1 = "";
-			if response.authzid then
-				if response.authzid == self.username or response.authzid == self.username.."@"..self.realm then
-					-- COMPAT
-					log("warn", "Client is violating RFC 3920 (section 6.1, point 7).");
-					A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
-				else
-					return "failure", "invalid-authzid";
+-- get a list of possible SASL mechanims to use
+function method:mechanisms()
+	local mechanisms = {}
+	for backend, f in pairs(self.profile) do
+		if backend_mechanism[backend] then
+			for _, mechanism in ipairs(backend_mechanism[backend]) do
+				if not sasl_i.restrict:contains(mechanism) then
+					mechanisms[mechanism] = true;
 				end
-			else
-				A1 = Y..":"..response["nonce"]..":"..response["cnonce"];
-			end
-			local A2 = "AUTHENTICATE:"..protocol.."/"..domain;
-
-			local HA1 = md5(A1, true);
-			local HA2 = md5(A2, true);
-
-			local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2;
-			local response_value = md5(KD, true);
-
-			if response_value == response["response"] then
-				-- calculate rspauth
-				A2 = ":"..protocol.."/"..domain;
-
-				HA1 = md5(A1, true);
-				HA2 = md5(A2, true);
-
-				KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
-				local rspauth = md5(KD, true);
-				self.authenticated = true;
-				return "challenge", serialize({rspauth = rspauth});
-			else
-				return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
 			end
-		elseif self.step == 3 then
-			if self.authenticated ~= nil then return "success"
-			else return "failure", "malformed-request" end
 		end
 	end
-	return object;
+	self["possible_mechanisms"] = mechanisms;
+	return array.collect(keys(mechanisms));
 end
 
--- Credentials handler: Can be nil. If specified, should take the mechanism as
--- the only argument, and return true for OK, or false for not-OK (TODO)
-local function new_anonymous(realm, credentials_handler)
-	local object = { mechanism = "ANONYMOUS", realm = realm, credentials_handler = credentials_handler}
-		function object.feed(self, message)
-			return "success"
-		end
-	object["username"] = generate_uuid()
-	return object
+-- select a mechanism to use
+function method:select(mechanism)
+	if self.mech_i then
+		return false;
+	end
+	
+	self.mech_i = mechanisms[mechanism]
+	if self.mech_i == nil then 
+		return false;
+	end
+	return true;
 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
 
-function new(mechanism, realm, credentials_handler)
-	local object
-	if mechanism == "PLAIN" then object = new_plain(realm, credentials_handler)
-	elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(realm, credentials_handler)
-	elseif mechanism == "ANONYMOUS" then object = new_anonymous(realm, credentials_handler)
-	else
-		log("debug", "Unsupported SASL mechanism: "..tostring(mechanism));
-		return nil
-	end
-	return object
+-- load the mechanisms
+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;
diff --git a/util/sasl/anonymous.lua b/util/sasl/anonymous.lua
new file mode 100644
index 00000000..65650294
--- /dev/null
+++ b/util/sasl/anonymous.lua
@@ -0,0 +1,36 @@
+-- sasl.lua v0.4
+-- Copyright (C) 2008-2009 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 s_match = string.match;
+
+local log = require "util.logger".init("sasl");
+local generate_uuid = require "util.uuid".generate;
+
+module "anonymous"
+
+--=========================
+--SASL ANONYMOUS according to RFC 4505
+local function anonymous(self, message)
+	local username;
+	repeat
+		username = generate_uuid();
+	until self.profile.anonymous(username, self.realm);
+	self["username"] = username;
+	return "success"
+end
+
+function init(registerMechanism)
+	registerMechanism("ANONYMOUS", {"anonymous"}, anonymous);
+end
+
+return _M;
\ No newline at end of file
diff --git a/util/sasl/digest-md5.lua b/util/sasl/digest-md5.lua
new file mode 100644
index 00000000..557858b3
--- /dev/null
+++ b/util/sasl/digest-md5.lua
@@ -0,0 +1,232 @@
+-- sasl.lua v0.4
+-- Copyright (C) 2008-2009 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 tostring = tostring;
+local type = type;
+
+local s_gmatch = string.gmatch;
+local s_match = string.match;
+local t_concat = table.concat;
+local t_insert = table.insert;
+local to_byte, to_char = string.byte, string.char;
+
+local md5 = require "util.hashes".md5;
+local log = require "util.logger".init("sasl");
+local generate_uuid = require "util.uuid".generate;
+
+module "digest-md5"
+
+--=========================
+--SASL DIGEST-MD5 according to RFC 2831
+local function digest_response()
+	
+	return response, A1, A2
+end
+
+local function digest(self, message)
+	--TODO complete support for authzid
+
+	local function serialize(message)
+		local data = ""
+
+		if type(message) ~= "table" then error("serialize needs an argument of type table.") end
+
+		-- testing all possible values
+		if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end
+		if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end
+		if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end
+		if message["charset"] then data = data..[[charset=]]..message.charset.."," end
+		if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end
+		if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end
+		data = data:gsub(",$", "")
+		return data
+	end
+
+	local function utf8tolatin1ifpossible(passwd)
+		local i = 1;
+		while i <= #passwd do
+			local passwd_i = to_byte(passwd:sub(i, i));
+			if passwd_i > 0x7F then
+				if passwd_i < 0xC0 or passwd_i > 0xC3 then
+					return passwd;
+				end
+				i = i + 1;
+				passwd_i = to_byte(passwd:sub(i, i));
+				if passwd_i < 0x80 or passwd_i > 0xBF then
+					return passwd;
+				end
+			end
+			i = i + 1;
+		end
+
+		local p = {};
+		local j = 0;
+		i = 1;
+		while (i <= #passwd) do
+			local passwd_i = to_byte(passwd:sub(i, i));
+			if passwd_i > 0x7F then
+				i = i + 1;
+				local passwd_i_1 = to_byte(passwd:sub(i, i));
+				t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever
+			else
+				t_insert(p, to_char(passwd_i));
+			end
+			i = i + 1;
+		end
+		return t_concat(p);
+	end
+	local function latin1toutf8(str)
+		local p = {};
+		for ch in s_gmatch(str, ".") do
+			ch = to_byte(ch);
+			if (ch < 0x80) then
+				t_insert(p, to_char(ch));
+			elseif (ch < 0xC0) then
+				t_insert(p, to_char(0xC2, ch));
+			else
+				t_insert(p, to_char(0xC3, ch - 64));
+			end
+		end
+		return t_concat(p);
+	end
+	local function parse(data)
+		local message = {}
+		-- COMPAT: %z in the pattern to work around jwchat bug (sends "charset=utf-8\0")
+		for k, v in gmatch(data, [[([%w%-]+)="?([^",%z]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
+			message[k] = v;
+		end
+		return message;
+	end
+
+	if not self.nonce then
+		self.nonce = generate_uuid();
+		self.step = 0;
+		self.nonce_count = {};
+	end
+
+	self.step = self.step + 1;
+	if (self.step == 1) then
+		local challenge = serialize({	nonce = self.nonce,
+										qop = "auth",
+										charset = "utf-8",
+										algorithm = "md5-sess",
+										realm = self.realm});
+		return "challenge", challenge;
+	elseif (self.step == 2) then
+		local response = parse(message);
+		-- check for replay attack
+		if response["nc"] then
+			if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
+		end
+
+		-- check for username, it's REQUIRED by RFC 2831
+		if not response["username"] then
+			return "failure", "malformed-request";
+		end
+		self["username"] = response["username"];
+
+		-- check for nonce, ...
+		if not response["nonce"] then
+			return "failure", "malformed-request";
+		else
+			-- check if it's the right nonce
+			if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
+		end
+
+		if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
+		if not response["qop"] then response["qop"] = "auth" end
+
+		if response["realm"] == nil or response["realm"] == "" then
+			response["realm"] = "";
+		elseif response["realm"] ~= self.realm then
+			return "failure", "not-authorized", "Incorrect realm value";
+		end
+
+		local decoder;
+		if response["charset"] == nil then
+			decoder = utf8tolatin1ifpossible;
+		elseif response["charset"] ~= "utf-8" then
+			return "failure", "incorrect-encoding", "The client's response uses "..response["charset"].." for encoding with isn't supported by sasl.lua. Supported encodings are latin or utf-8.";
+		end
+
+		local domain = "";
+		local protocol = "";
+		if response["digest-uri"] then
+			protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$");
+			if protocol == nil or domain == nil then return "failure", "malformed-request" end
+		else
+			return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
+		end
+
+		--TODO maybe realm support
+		self.username = response["username"];
+		if self.profile.plain then
+			local password, state = self.profile.plain(response["username"], self.realm)
+			if state == nil then return "failure", "not-authorized"
+			elseif state == false then return "failure", "account-disabled" end
+			Y = md5(response["username"]..":"..response["realm"]..":"..password);
+		elseif self.profile["digest-md5"] then
+			local Y, state = self.profile["digest-md5"](response["username"], self.realm, response["realm"], response["charset"])
+			if state == nil then return "failure", "not-authorized"
+			elseif state == false then return "failure", "account-disabled" end
+		elseif self.profile["digest-md5-test"] then
+			-- TODO
+		end
+		--local password_encoding, Y = self.credentials_handler("DIGEST-MD5", response["username"], self.realm, response["realm"], decoder);
+		--if Y == nil then return "failure", "not-authorized"
+		--elseif Y == false then return "failure", "account-disabled" end
+		local A1 = "";
+		if response.authzid then
+			if response.authzid == self.username or response.authzid == self.username.."@"..self.realm then
+				-- COMPAT
+				log("warn", "Client is violating RFC 3920 (section 6.1, point 7).");
+				A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
+			else
+				return "failure", "invalid-authzid";
+			end
+		else
+			A1 = Y..":"..response["nonce"]..":"..response["cnonce"];
+		end
+		local A2 = "AUTHENTICATE:"..protocol.."/"..domain;
+
+		local HA1 = md5(A1, true);
+		local HA2 = md5(A2, true);
+
+		local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2;
+		local response_value = md5(KD, true);
+
+		if response_value == response["response"] then
+			-- calculate rspauth
+			A2 = ":"..protocol.."/"..domain;
+
+			HA1 = md5(A1, true);
+			HA2 = md5(A2, true);
+
+			KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
+			local rspauth = md5(KD, true);
+			self.authenticated = true;
+			return "success", serialize({rspauth = rspauth});
+		else
+			return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
+		end
+	elseif self.step == 3 then
+		if self.authenticated ~= nil then return "success"
+		else return "failure", "malformed-request" end
+	end
+end
+
+function init(registerMechanism)
+	registerMechanism("DIGEST-MD5", {"plain"}, digest);
+end
+
+return _M;
\ No newline at end of file
diff --git a/util/sasl/plain.lua b/util/sasl/plain.lua
new file mode 100644
index 00000000..46a86bb9
--- /dev/null
+++ b/util/sasl/plain.lua
@@ -0,0 +1,66 @@
+-- sasl.lua v0.4
+-- Copyright (C) 2008-2009 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 s_match = string.match;
+local saslprep = require "util.encodings".stringprep.saslprep;
+local log = require "util.logger".init("sasl");
+
+module "plain"
+
+--=========================
+--SASL PLAIN according to RFC 4616
+local function plain(self, message)
+	local response = message
+	local authorization = s_match(response, "([^%z]+)")
+	local authentication = s_match(response, "%z([^%z]+)%z")
+	local password = s_match(response, "%z[^%z]+%z([^%z]+)")
+
+	if authentication == nil or password == nil then
+		return "failure", "malformed-request";
+	end
+	
+	-- SASLprep password and authentication
+	authentication = saslprep(authentication);
+	password = saslprep(password);
+	
+	if (not password) or (password == "") or (not authentication) or (authentication == "") then
+		log("debug", "Username or password violates SASLprep.");
+		return "failure", "malformed-request", "Invalid username or password.";
+	end
+
+	local correct, state = false, false;
+	if self.profile.plain then
+		local correct_password;
+		correct_password, state = self.profile.plain(authentication, self.realm);
+		if correct_password == password then correct = true; else correct = false; end
+	elseif self.profile.plain_test then
+		correct, state = self.profile.plain_test(authentication, self.realm, password);
+	end
+
+	self.username = authentication
+	if not state then
+		return "failure", "account-disabled";
+	end
+
+	if correct then
+		return "success";
+	else
+		return "failure", "not-authorized", "Unable to authorize you with the authentication credentials you've sent.";
+	end
+end
+
+function init(registerMechanism)
+	registerMechanism("PLAIN", {"plain", "plain_test"}, plain);
+end
+
+return _M;
\ No newline at end of file
diff --git a/util/sasl/scram.lua b/util/sasl/scram.lua
new file mode 100644
index 00000000..4413e2a6
--- /dev/null
+++ b/util/sasl/scram.lua
@@ -0,0 +1,154 @@
+-- sasl.lua v0.4
+-- Copyright (C) 2008-2009 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 s_match = string.match;
+local type = type
+local string = string
+local base64 = require "util.encodings".base64;
+local xor = require "bit".bxor
+local hmac_sha1 = require "util.hmac".sha1;
+local sha1 = require "util.hashes".sha1;
+local generate_uuid = require "util.uuid".generate;
+local saslprep = require "util.encodings".stringprep.saslprep;
+local log = require "util.logger".init("sasl");
+
+module "scram"
+
+--=========================
+--SASL SCRAM-SHA-1 according to draft-ietf-sasl-scram-10
+local default_i = 4096
+
+local function bp( b )
+	local result = ""
+	for i=1, b:len() do
+		result = result.."\\"..b:byte(i)
+	end
+	return result
+end
+
+local function binaryXOR( a, b )
+	if a:len() > b:len() then
+		b = string.rep("\0", a:len() - b:len())..b
+	elseif string.len(a) < string.len(b) then
+		a = string.rep("\0", b:len() - a:len())..a
+	end
+	local result = ""
+	for i=1, a:len() do
+		result = result..string.char(xor(a:byte(i), b:byte(i)))
+	end
+	return result
+end
+
+-- hash algorithm independent Hi(PBKDF2) implementation
+local function Hi(hmac, str, salt, i)
+	local Ust = hmac(str, salt.."\0\0\0\1");
+	local res = Ust;	
+	for n=1,i-1 do
+		Und = hmac(str, Ust)
+		res = binaryXOR(res, Und)
+		Ust = Und
+	end
+	return res
+end
+
+local function validate_username(username)
+	-- check for forbidden char sequences
+	for eq in username:gmatch("=(.?.?)") do
+		if eq ~= "2D" and eq ~= "3D" then
+			return false 
+		end 
+	end
+	
+	-- replace =2D with , and =3D with =
+	username:gsub("=2D", ",");
+	username:gsub("=3D", "=");
+	
+	-- apply SASLprep
+	username = saslprep(username);
+	return username;
+end
+
+local function scram_sha_1(self, message)
+	if not self.state then self["state"] = {} end
+	
+	if not self.state.name then
+		-- we are processing client_first_message
+		local client_first_message = message;
+		self.state["client_first_message"] = client_first_message;
+		self.state["name"] = client_first_message:match("n=(.+),r=")
+		self.state["clientnonce"] = client_first_message:match("r=([^,]+)")
+		
+		if not self.state.name or not self.state.clientnonce then
+			return "failure", "malformed-request";
+		end
+		
+		self.state.name = validate_username(self.state.name);
+		if not self.state.name then
+			log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
+			return "failure", "malformed-request", "Invalid username.";
+		end
+		
+		self.state["servernonce"] = generate_uuid();
+		self.state["salt"] = generate_uuid();
+		
+		local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..default_i;
+		self.state["server_first_message"] = server_first_message;
+		return "challenge", server_first_message
+	else
+		if type(message) ~= "string" then return "failure", "malformed-request" end
+		-- we are processing client_final_message
+		local client_final_message = message;
+		
+		self.state["proof"] = client_final_message:match("p=(.+)");
+		self.state["nonce"] = client_final_message:match("r=(.+),p=");
+		self.state["channelbinding"] = client_final_message:match("c=(.+),r=");
+		if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
+			return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message.";
+		end
+		
+		local password;
+		if self.profile.plain then
+			password, state = self.profile.plain(self.state.name, self.realm)
+			if state == nil then return "failure", "not-authorized"
+			elseif state == false then return "failure", "account-disabled" end
+			password = saslprep(password);
+			if not password then
+				log("debug", "Password violates SASLprep.");
+				return "failure", "not-authorized", "Invalid password."
+			end
+		end
+		
+		local SaltedPassword = Hi(hmac_sha1, password, self.state.salt, default_i)
+		local ClientKey = hmac_sha1(SaltedPassword, "Client Key")
+		local ServerKey = hmac_sha1(SaltedPassword, "Server Key")
+		local StoredKey = sha1(ClientKey)
+		local AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
+		local ClientSignature = hmac_sha1(StoredKey, AuthMessage)
+		local ClientProof     = binaryXOR(ClientKey, ClientSignature)
+		local ServerSignature = hmac_sha1(ServerKey, AuthMessage)
+		
+		if base64.encode(ClientProof) == self.state.proof then
+			local server_final_message = "v="..base64.encode(ServerSignature);
+			self["username"] = self.state.name;
+			return "success", server_final_message;
+		else
+			return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
+		end
+	end
+end
+
+function init(registerMechanism)
+	registerMechanism("SCRAM-SHA-1", {"plain"}, scram_sha_1);
+end
+
+return _M;
\ No newline at end of file