-- sasl.lua v0.4
--- Copyright (C) 2008-2009 Tobias Markmann
+-- Copyright (C) 2008-2010 Tobias Markmann
--
-- All rights reserved.
--
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 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 to_byte, to_char = string.byte, string.char;
-local to_unicode = require "util.encodings".idna.to_unicode;
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
local setmetatable = setmetatable;
local assert = assert;
+local require = require;
require "util.iterators"
local keys = keys
--[[
Authentication Backend Prototypes:
-plain:
- function(username, realm)
- return password, state;
- end
-
-plain-test:
- function(username, realm, password)
- return true or false, state;
- end
-
-digest-md5:
- function(username, realm, encoding)
- return digesthash, state;
- end
-
-digest-md5-test:
- function(username, realm, encoding, digesthash)
- return true or false, state;
- end
+state = false : disabled
+state = true : enabled
+state = nil : non-existant
]]
local method = {};
end
-- create a new SASL object which can be used to authenticate clients
-function new(realm, profile)
- sasl_i = {profile = profile};
+function new(realm, profile, forbidden)
+ local sasl_i = {profile = profile};
sasl_i.realm = realm;
- return setmetatable(sasl_i, method);
+ 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
+
+-- 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
-- get a list of possible SASL mechanims to use
function method:mechanisms()
local mechanisms = {}
for backend, f in pairs(self.profile) do
- print(backend)
if backend_mechanism[backend] then
for _, mechanism in ipairs(backend_mechanism[backend]) do
- mechanisms[mechanism] = true;
+ if not self.restrict:contains(mechanism) then
+ mechanisms[mechanism] = true;
+ end
end
end
end
-- 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;
-- feed new messages to process into the library
function method:process(message)
- if message == "" or message == nil then return "failure", "malformed-request" end
+ --if message == "" or message == nil then return "failure", "malformed-request" end
return self.mech_i(self, message);
end
---=========================
---SASL PLAIN according to RFC 4616
-local function sasl_mechanism_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
-
- 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";
- end
-end
-registerMechanism("PLAIN", {"plain", "plain_test"}, sasl_mechanism_plain);
-
---=========================
---SASL DIGEST-MD5 according to RFC 2831
-local function new_digest_md5(realm, credentials_handler)
- --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 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 gmatch(data, [[([%w%-]+)="?([^",]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
- message[k] = v;
- end
- return message;
- 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
-
- 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"];
- 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.."@"..self.realm then
- -- COMPAT
- log("warn", "Client is violating XMPP RFC. See section 6.1 of RFC 3920.");
- A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
- else
- A1 = "?";
- 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;
+-- 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;
projects / prosody.git / blobdiff