diff options
| -rw-r--r-- | plugins/mod_saslauth.lua | 2 | ||||
| -rw-r--r-- | util/sasl.lua | 171 |
2 files changed, 156 insertions, 17 deletions
diff --git a/plugins/mod_saslauth.lua b/plugins/mod_saslauth.lua index 75af5eb6..b95d160d 100644 --- a/plugins/mod_saslauth.lua +++ b/plugins/mod_saslauth.lua @@ -94,7 +94,9 @@ add_event_hook("stream-features", function (session, features) if not session.username then t_insert(features, "<mechanisms xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>"); + -- TODO: Provide PLAIN only if TLS is active, this is a SHOULD from the introduction of RFC 4616. This behavior could be overridden via configuration but will issuing a warning or so. t_insert(features, "<mechanism>PLAIN</mechanism>"); + t_insert(features, "<mechanism>DIGEST-MD5</mechanism>"); t_insert(features, "</mechanisms>"); else t_insert(features, "<bind xmlns='urn:ietf:params:xml:ns:xmpp-bind'><required/></bind>"); diff --git a/util/sasl.lua b/util/sasl.lua index dbd6326a..8750ce98 100644 --- a/util/sasl.lua +++ b/util/sasl.lua @@ -1,41 +1,178 @@ 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; -module "sasl" +local gmatch = string.gmatch +local string = string +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 function new_plain(realm, password_handler) + local object = { mechanism = "PLAIN", realm = realm, password_handler = password_handler} + object.feed = function(self, message) + log("debug", "feed: "..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 self.onAuth(authentication, password) == true then - self.onWrite(st.stanza("success", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"})) - self.onSuccess(authentication) + + local password_encoding, correct_password = self.password_handler(authentication.."@"..self.realm, "PLAIN") + + local claimed_password = "" + if password_encoding == nil then claimed_password = password + else claimed_password = password_encoding(password) end + + if claimed_password == correct_password then + return "success", nil else - self.onWrite(st.stanza("failure", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):tag("temporary-auth-failure")); + return "failure", "not-authorized" end end return object end +local function new_digest_md5(onAuth, onSuccess, onFail, onWrite) + --TODO maybe 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["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["realm"] then data = data..[[realm="]]..message.realm..[[",]] end + if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end + data = data:gsub(",$", "") + return data + end + + local function parse(data) + message = {} + log("debug", "parse-message: "..data) + for k, v in gmatch(data, [[([%w%-]+)="?([%w%-%/%.%+=]+)"?,?]]) do + message[k] = v + log("debug", " "..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 = generate_uuid() + log("debug", "SASL nonce: "..object.nonce) + 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) + log("debug", "SASL step: "..self.step) + 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["nc"] then + if self.nonce_count[response["nc"]] 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 + self["username"] = response["username"] + + -- check for nonce, ... + if not response["nonce"] then + self.onFail("malformed-request") + else + -- check if it's the right nonce + if response["nonce"] ~= tostring(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 + + if response["realm"] == nil then response["realm"] = "" end + + local domain = "" + local protocol = "" + if response["digest-uri"] then + protocol, domain = 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"] + + --FIXME actual username and password here :P + local X = "tobias:"..response["realm"]..":tobias" + local Y = md5.sum(X) + local A1 = Y..":"..response["nonce"]..":"..response["cnonce"]--:authzid + local A2 = "AUTHENTICATE:"..protocol.."/"..domain + + local HA1 = md5.sumhexa(A1) + local HA2 = md5.sumhexa(A2) + + local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2 + local response_value = md5.sumhexa(KD) + + log("debug", "response_value: "..response_value); + log("debug", "response: "..response["response"]); + if response_value == response["response"] then + -- calculate rspauth + A2 = ":"..protocol.."/"..domain + + HA1 = md5.sumhexa(A1) + HA2 = md5.sumhexa(A2) + + KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2 + local rspauth = md5.sumhexa(KD) + + self.onWrite(st.stanza("challenge", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):text(base64.encode(serialize({rspauth = rspauth})))) + else + self.onWrite(st.stanza("response", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"})) + self.onFail() + end + elseif self.step == 3 then + if stanza.name == "response" then + self.onWrite(st.stanza("success", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"})) + self.onSuccess(self.username) + else + self.onFail("Third step isn't a response stanza.") + end + end + end + return object +end -function new(mechanism, onAuth, onSuccess, onFail, onWrite) +function new(mechanism, realm, password) local object - if mechanism == "PLAIN" then object = new_plain(onAuth, onSuccess, onFail, onWrite) + if mechanism == "PLAIN" then object = new_plain(realm, password) + --elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(ream, password) else log("debug", "Unsupported SASL mechanism: "..tostring(mechanism)); - onFail("unsupported-mechanism") + return nil end return object end |