Diff

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/util/sasl/digest-md5.lua	Mon Nov 16 21:43:57 2009 +0100
@@ -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 "plain"
+
+--=========================
+--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 = {}
+		for k, v in s_gmatch(data, [[([%w%-]+)="?([^",]*)"?,?]]) 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;
+			--TODO: considering sending the rspauth in a success node for saving one roundtrip; allowed according to http://tools.ietf.org/html/draft-saintandre-rfc3920bis-09#section-7.3.6
+			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
+
+function init(registerMechanism)
+	registerMechanism("DIGEST-MD5", {"plain"}, digest);
+end
+
+return _M;
\ No newline at end of file