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local base64 = require "base64"
local md5 = require "md5"
local crypto = require "crypto"
local log = require "util.logger".init("sasl");
local tostring = tostring;
local st = require "util.stanza";
local generate_uuid = require "util.uuid".generate;
local s_match = string.match;
local gmatch = string.gmatch
local math = require "math"
local type = type
local error = error
local print = print
module "sasl"
local function new_plain(onAuth, onSuccess, onFail, onWrite)
local object = { mechanism = "PLAIN", onAuth = onAuth, onSuccess = onSuccess, onFail = onFail,
onWrite = onWrite}
local challenge = base64.encode("");
--onWrite(st.stanza("challenge", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):text(challenge))
object.feed = function(self, stanza)
if stanza.name ~= "response" and stanza.name ~= "auth" then self.onFail("invalid-stanza-tag") end
if stanza.attr.xmlns ~= "urn:ietf:params:xml:ns:xmpp-sasl" then self.onFail("invalid-stanza-namespace") end
local response = base64.decode(stanza[1])
local authorization = s_match(response, "([^&%z]+)")
local authentication = s_match(response, "%z([^&%z]+)%z")
local password = s_match(response, "%z[^&%z]+%z([^&%z]+)")
if self.onAuth(authentication, password) == true then
self.onWrite(st.stanza("success", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}))
self.onSuccess(authentication)
else
self.onWrite(st.stanza("failure", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):tag("temporary-auth-failure"));
end
end
return object
end
--[[
SERVER:
nonce="3145176401",qop="auth",charset=utf-8,algorithm=md5-sess
CLIENT: username="tobiasfar",nonce="3145176401",cnonce="pJiW7hzeZLvOSAf7gBzwTzLWe4obYOVDlnNESzQCzGg=",nc=00000001,digest-uri="xmpp/jabber.org",qop=auth,response=99a93ba75235136e6403c3a2ba37089d,charset=utf-8
username="tobias",nonce="4406697386",cnonce="wUnT7vYrOB0V8D/lKd5bhpaNCk+hLJwc8T4CBCqp7WM=",nc=00000001,digest-uri="xmpp/luaetta.ath.cx",qop=auth,response=d202b8a1bdf8204816fb23c5f87b6b63,charset=utf-8
SERVER:
rspauth=ab66d28c260e97da577ce3aac46a8991
]]--
local function new_digest_md5(onAuth, onSuccess, onFail, onWrite)
local function H(s)
return md5.sum(s)
end
local function KD(k, s)
return H(k..":"..s)
end
local function HEX(n)
return md5.sumhexa(n)
end
local function HMAC(k, s)
return crypto.hmac.digest("md5", s, k, true)
end
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["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.algorith.."," end
data = data:gsub(",$", "")
return data
end
local function parse(data)
message = {}
for k, v in gmatch(data, [[([%w%-]+)="?([%w%-%/%.]+)"?,?]]) do
message[k] = v
end
return message
end
local object = { mechanism = "DIGEST-MD5", onAuth = onAuth, onSuccess = onSuccess, onFail = onFail,
onWrite = onWrite }
--TODO: something better than math.random would be nice, maybe OpenSSL's random number generator
object.nonce = math.random(0, 9)
for i = 1, 9 do object.nonce = object.nonce..math.random(0, 9) end
object.step = 1
object.nonce_count = {}
local challenge = base64.encode(serialize({ nonce = object.nonce,
qop = "auth",
charset = "utf-8",
algorithm = "md5-sess"} ));
object.onWrite(st.stanza("challenge", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):text(challenge))
object.feed = function(self, stanza)
if stanza.name ~= "response" and stanza.name ~= "auth" then self.onFail("invalid-stanza-tag") end
if stanza.attr.xmlns ~= "urn:ietf:params:xml:ns:xmpp-sasl" then self.onFail("invalid-stanza-namespace") end
if stanza.name == "auth" then return end
self.step = self.step + 1
if (self.step == 2) then
local response = parse(base64.decode(stanza[1]))
-- check for replay attack
if response["nonce-count"] then
if self.nonce_count[response["nonce-count"]] then self.onFail("not-authorized") end
end
-- check for username, it's REQUIRED by RFC 2831
if not response["username"] then
self.onFail("malformed-request")
end
-- check for nonce, ...
if not response["nonce"] then
self.onFail("malformed-request")
else
-- check if it's the right nonce
if response["nonce"] ~= self.nonce then self.onFail("malformed-request") end
end
if not response["cnonce"] then self.onFail("malformed-request") end
if not response["qop"] then response["qop"] = "auth" end
local hostname = ""
local protocol = ""
if response["digest-uri"] then
protocol, hostname = response["digest-uri"]:match("(%w+)/(.*)$")
else
error("No digest-uri")
end
-- compare response_value with own calculation
--local A1 = usermanager.get_md5(response["username"], hostname)..":"..response["nonce"]..response["cnonce"]
local A1 = H("tobias:luaetta.ath.cx:tobias")..":"..response["nonce"]..response["cnonce"]
local A2 = "AUTHENTICATE:"..response["digest-uri"]
local response_value = HEX(KD(HEX(H(A1)), response["nonce"]..":"..response["nonce-count"]..":"..response["cnonce-value"]..":"..response["qop"]..":"..HEX(H(A2))))
log("debug", "response_value: "..response_value);
if response["qop"] == "auth" then
else
end
--local response_value = HEX(KD(HEX(H(A1)), response["nonce"]..":"..response["nonce-count"]..":"..response["cnonce-value"]..":"..response["qop"]..":"..HEX(H(A2))))
end
--[[
local authorization = s_match(response, "([^&%z]+)")
local authentication = s_match(response, "%z([^&%z]+)%z")
local password = s_match(response, "%z[^&%z]+%z([^&%z]+)")
if self.onAuth(authentication, password) == true then
self.onWrite(st.stanza("success", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}))
self.onSuccess(authentication)
else
self.onWrite(st.stanza("failure", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):tag("temporary-auth-failure"));
end]]--
end
return object
end
function new(mechanism, onAuth, onSuccess, onFail, onWrite)
local object
if mechanism == "PLAIN" then object = new_plain(onAuth, onSuccess, onFail, onWrite)
elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(onAuth, onSuccess, onFail, onWrite)
else
log("debug", "Unsupported SASL mechanism: "..tostring(mechanism));
onFail("unsupported-mechanism")
end
return object
end
return _M;
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