diff options
| -rw-r--r-- | plugins/mod_saslauth.lua | 107 | ||||
| -rw-r--r-- | util/sasl.lua | 174 |
2 files changed, 233 insertions, 48 deletions
diff --git a/plugins/mod_saslauth.lua b/plugins/mod_saslauth.lua index 24c82a1c..2a1485d0 100644 --- a/plugins/mod_saslauth.lua +++ b/plugins/mod_saslauth.lua @@ -2,10 +2,12 @@ local st = require "util.stanza"; local send = require "core.sessionmanager".send_to_session; local sm_bind_resource = require "core.sessionmanager".bind_resource; +local jid local usermanager_validate_credentials = require "core.usermanager".validate_credentials; local t_concat, t_insert = table.concat, table.insert; local tostring = tostring; +local jid_split = require "util.jid".split local log = require "util.logger".init("mod_saslauth"); @@ -15,50 +17,91 @@ local xmlns_stanzas ='urn:ietf:params:xml:ns:xmpp-stanzas'; local new_sasl = require "util.sasl".new; +local function build_reply(status, ret) + local reply = st.stanza(status, {xmlns = xmlns_sasl}); + if status == "challenge" then + reply:text(ret or ""); + elseif status == "failure" then + reply:tag(ret):up(); + elseif status == "success" then + reply:text(ret or ""); + else + error("Unknown sasl status: "..status); + end + return reply; +end + +local function handle_status(session, status) + if status == "failure" then + session.sasl_handler = nil; + elseif status == "success" then + if not session.sasl_handler.username then error("SASL succeeded but we didn't get a username!"); end -- TODO move this to sessionmanager + sessionmanager.make_authenticated(session, session.sasl_handler.username); + session.sasl_handler = nil; + session:reset_stream(); + end +end + +local function password_callback(jid, mechanism) + local node, host = jid_split(jid); + local password = (datamanager.load(node, host, "accounts") or {}).password; -- FIXME handle hashed passwords + local func = function(x) return x; end; + if password then + if mechanism == "PLAIN" then + return func, password; + elseif mechanism == "DIGEST-MD5" then + return func, require "hashes".md5(node.."::"..password); + end + end + return func, nil; +end + +function do_sasl(session, stanza) + local text = stanza[1]; + if text then + text = base64.decode(text); + if not text then + session.sasl_handler = nil; + session.send(build_reply("failure", "incorrect-encoding")); + return; + end + end + local status, ret = session.sasl_handler:feed(text); + handle_status(session, status); + local s = build_reply(status, ret); + log("debug", "sasl reply: "..tostring(s)); + session.send(s); +end + add_handler("c2s_unauthed", "auth", xmlns_sasl, function (session, stanza) if not session.sasl_handler then - session.sasl_handler = new_sasl(stanza.attr.mechanism, - function (username, password) - -- onAuth - require "core.usermanager" - if usermanager_validate_credentials(session.host, username, password) then - return true; - end - return false; - end, - function (username) - -- onSuccess - local success, err = sessionmanager.make_authenticated(session, username); - if not success then - sessionmanager.destroy_session(session); - return; - end - session.sasl_handler = nil; - session:reset_stream(); - end, - function (reason) - -- onFail - log("debug", "SASL failure, reason: %s", reason); - end, - function (stanza) - -- onWrite - log("debug", "SASL writes: %s", tostring(stanza)); - send(session, stanza); - end - ); - session.sasl_handler:feed(stanza); + session.sasl_handler = new_sasl(stanza.attr.mechanism, session.host, password_callback); + do_sasl(session, stanza); else error("Client tried to negotiate SASL again", 0); end - end); - + +add_handler("c2s_unauthed", "abort", xmlns_sasl, + function(session, stanza) + if not session.sasl_handler then error("Attempt to abort when sasl has not started"); end + do_sasl(session, stanza); + end); + +add_handler("c2s_unauthed", "response", xmlns_sasl, + function(session, stanza) + if not session.sasl_handler then error("Attempt to respond when sasl has not started"); end + do_sasl(session, stanza); + end); + 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..430bfe5c 100644 --- a/util/sasl.lua +++ b/util/sasl.lua @@ -1,41 +1,183 @@ 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 string = string +local math = require "math" +local type = type +local error = error +local print = print + module "sasl" +local function new_plain(realm, password_handler) + local object = { mechanism = "PLAIN", realm = realm, password_handler = password_handler} + object.feed = function(self, message) + --print(message:gsub("%W", function (c) return string.format("\\%d", string.byte(c)) end)); -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]) + 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]+)") - 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 + + self.username = authentication + if claimed_password == correct_password then + log("debug", "success") + return "success", nil else - self.onWrite(st.stanza("failure", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):tag("temporary-auth-failure")); + log("debug", "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 |