diff options
Diffstat (limited to 'util/sasl.lua')
| -rw-r--r-- | util/sasl.lua | 328 |
1 files changed, 105 insertions, 223 deletions
diff --git a/util/sasl.lua b/util/sasl.lua index f65e7062..eb71956b 100644 --- a/util/sasl.lua +++ b/util/sasl.lua @@ -14,258 +14,140 @@ 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 +-- create a new SASL object which can be used to authenticate clients +function new(realm, profile, forbidden) + local sasl_i = {profile = profile}; + sasl_i.realm = realm; + local s = setmetatable(sasl_i, method); + if forbidden == nil then forbidden = {} end + s:forbidden(forbidden) + return s; +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 +-- 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 - 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 self.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 +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; |