Sat, 13 Nov 2010 04:12:40 +0000
Backed out changeset bfc47564aaef (No need for _M with module.environment)
-- 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 s_match = string.match; local type = type local string = string local base64 = require "util.encodings".base64; 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"); local t_concat = table.concat; local char = string.char; local byte = string.byte; module "scram" --========================= --SASL SCRAM-SHA-1 according to RFC 5802 --[[ Supported Authentication Backends scram_{MECH}: -- MECH being a standard hash name (like those at IANA's hash registry) with '-' replaced with '_' function(username, realm) return stored_key, server_key, iteration_count, salt, state; end ]] 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 xor_map = {0;1;2;3;4;5;6;7;8;9;10;11;12;13;14;15;1;0;3;2;5;4;7;6;9;8;11;10;13;12;15;14;2;3;0;1;6;7;4;5;10;11;8;9;14;15;12;13;3;2;1;0;7;6;5;4;11;10;9;8;15;14;13;12;4;5;6;7;0;1;2;3;12;13;14;15;8;9;10;11;5;4;7;6;1;0;3;2;13;12;15;14;9;8;11;10;6;7;4;5;2;3;0;1;14;15;12;13;10;11;8;9;7;6;5;4;3;2;1;0;15;14;13;12;11;10;9;8;8;9;10;11;12;13;14;15;0;1;2;3;4;5;6;7;9;8;11;10;13;12;15;14;1;0;3;2;5;4;7;6;10;11;8;9;14;15;12;13;2;3;0;1;6;7;4;5;11;10;9;8;15;14;13;12;3;2;1;0;7;6;5;4;12;13;14;15;8;9;10;11;4;5;6;7;0;1;2;3;13;12;15;14;9;8;11;10;5;4;7;6;1;0;3;2;14;15;12;13;10;11;8;9;6;7;4;5;2;3;0;1;15;14;13;12;11;10;9;8;7;6;5;4;3;2;1;0;}; local result = {}; local function binaryXOR( a, b ) for i=1, #a do local x, y = byte(a, i), byte(b, i); local lowx, lowy = x % 16, y % 16; local hix, hiy = (x - lowx) / 16, (y - lowy) / 16; local lowr, hir = xor_map[lowx * 16 + lowy + 1], xor_map[hix * 16 + hiy + 1]; local r = hir * 16 + lowr; result[i] = char(r) end return t_concat(result); end -- hash algorithm independent Hi(PBKDF2) implementation function Hi(hmac, str, salt, i) local Ust = hmac(str, salt.."\0\0\0\1"); local res = Ust; for n=1,i-1 do local 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 = username:gsub("=2D", ","); username = username:gsub("=3D", "="); -- apply SASLprep username = saslprep(username); return username; end local function hashprep(hashname) return hashname:lower():gsub("-", "_"); end function getAuthenticationDatabaseSHA1(password, salt, iteration_count) if type(password) ~= "string" or type(salt) ~= "string" or type(iteration_count) ~= "number" then return false, "inappropriate argument types" end if iteration_count < 4096 then log("warn", "Iteration count < 4096 which is the suggested minimum according to RFC 5802.") end local salted_password = Hi(hmac_sha1, password, salt, iteration_count); local stored_key = sha1(hmac_sha1(salted_password, "Client Key")) local server_key = hmac_sha1(salted_password, "Server Key"); return true, stored_key, server_key end local function scram_gen(hash_name, H_f, HMAC_f) local function scram_hash(self, message) if not self.state then self["state"] = {} end if type(message) ~= "string" or #message == 0 then return "failure", "malformed-request" end if not self.state.name then -- we are processing client_first_message local client_first_message = message; -- TODO: fail if authzid is provided, since we don't support them yet self.state["client_first_message"] = client_first_message; self.state["gs2_cbind_flag"], self.state["authzid"], self.state["name"], self.state["clientnonce"] = client_first_message:match("^(%a),(.*),n=(.*),r=([^,]*).*"); -- we don't do any channel binding yet if self.state.gs2_cbind_flag ~= "n" and self.state.gs2_cbind_flag ~= "y" then return "failure", "malformed-request"; end if not self.state.name or not self.state.clientnonce then return "failure", "malformed-request", "Channel binding isn't support at this time."; 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(); -- retreive credentials if self.profile.plain then local 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 self.state.salt = generate_uuid(); self.state.iteration_count = default_i; local succ = false; succ, self.state.stored_key, self.state.server_key = getAuthenticationDatabaseSHA1(password, self.state.salt, default_i, self.state.iteration_count); if not succ then log("error", "Generating authentication database failed. Reason: %s", self.state.stored_key); return "failure", "temporary-auth-failure"; end elseif self.profile["scram_"..hashprep(hash_name)] then local stored_key, server_key, iteration_count, salt, state = self.profile["scram_"..hashprep(hash_name)](self.state.name, self.realm); if state == nil then return "failure", "not-authorized" elseif state == false then return "failure", "account-disabled" end self.state.stored_key = stored_key; self.state.server_key = server_key; self.state.iteration_count = iteration_count; self.state.salt = salt end local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..self.state.iteration_count; self.state["server_first_message"] = server_first_message; return "challenge", server_first_message else -- we are processing client_final_message local client_final_message = message; self.state["channelbinding"], self.state["nonce"], self.state["proof"] = client_final_message:match("^c=(.*),r=(.*),.*p=(.*)"); 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 if self.state.nonce ~= self.state.clientnonce..self.state.servernonce then return "failure", "malformed-request", "Wrong nonce in client-final-message."; end local ServerKey = self.state.server_key; local StoredKey = self.state.stored_key; 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_f(StoredKey, AuthMessage) local ClientKey = binaryXOR(ClientSignature, base64.decode(self.state.proof)) local ServerSignature = HMAC_f(ServerKey, AuthMessage) if StoredKey == H_f(ClientKey) 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 return scram_hash; end function init(registerMechanism) local function registerSCRAMMechanism(hash_name, hash, hmac_hash) registerMechanism("SCRAM-"..hash_name, {"plain", "scram_"..(hashprep(hash_name))}, scram_gen(hash_name:lower(), hash, hmac_hash)); end registerSCRAMMechanism("SHA-1", sha1, hmac_sha1); end return _M;