-- sasl.lua v0.4
--- Copyright (C) 2008-2009 Tobias Markmann
+-- Copyright (C) 2008-2010 Tobias Markmann
--
-- All rights reserved.
--
-- 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 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 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 t_insert = table.insert;
local type = type
-local error = error
-local print = print
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:
-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 = {};
-- create a new SASL object which can be used to authenticate clients
function new(realm, profile)
- sasl_i = {profile = profile};
- sasl_i.realm = realm;
- return setmetatable(sasl_i, method);
+ local mechanisms = profile.mechanisms;
+ if not mechanisms then
+ mechanisms = {};
+ for backend, f in pairs(profile) do
+ if backend_mechanism[backend] then
+ for _, mechanism in ipairs(backend_mechanism[backend]) do
+ mechanisms[mechanism] = true;
+ end
+ end
+ end
+ profile.mechanisms = mechanisms;
+ end
+ return setmetatable({ profile = profile, realm = realm, mechs = mechanisms }, method);
+end
+
+-- get a fresh clone with the same realm and profile
+function method:clean_clone()
+ return new(self.realm, self.profile)
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;
- end
- end
- end
- self["possible_mechanisms"] = mechanisms;
- return array.collect(keys(mechanisms));
+ return self.mechs;
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;
+ if not self.selected and self.mechs[mechanism] then
+ self.selected = mechanism;
+ return true;
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);
+ --if message == "" or message == nil then return "failure", "malformed-request" end
+ return mechanisms[self.selected](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 sasl_mechanism_digest_md5(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 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
-
- 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 = 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
+-- load the mechanisms
+require "util.sasl.plain" .init(registerMechanism);
+require "util.sasl.digest-md5".init(registerMechanism);
+require "util.sasl.anonymous" .init(registerMechanism);
+require "util.sasl.scram" .init(registerMechanism);
return _M;
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