diff options
Diffstat (limited to 'util/sasl.lua')
| -rw-r--r-- | util/sasl.lua | 228 |
1 files changed, 108 insertions, 120 deletions
diff --git a/util/sasl.lua b/util/sasl.lua index fe5b2d3c..a5657c8c 100644 --- a/util/sasl.lua +++ b/util/sasl.lua @@ -1,7 +1,5 @@ -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"; @@ -18,34 +16,33 @@ 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)); - - 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]+)") - - 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 - log("debug", "failure") - return "failure", "not-authorized" - end - end + 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]+)") + + 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" + else + log("debug", "failure") + return "failure", "not-authorized" + end + end return object end -local function new_digest_md5(onAuth, onSuccess, onFail, onWrite) +local function new_digest_md5(realm, password_handler) --TODO maybe support for authzid local function serialize(message) @@ -74,107 +71,98 @@ local function new_digest_md5(onAuth, onSuccess, onFail, onWrite) return message end - local object = { mechanism = "DIGEST-MD5", onAuth = onAuth, onSuccess = onSuccess, onFail = onFail, - onWrite = onWrite } + local object = { mechanism = "DIGEST-MD5", realm = realm, password_handler = password_handler} --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.step = 0 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 + + function object.feed(self, message) + log("debug", "SASL step: "..self.step) + 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}); + log("debug", "challenge: "..challenge) + 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 then response["realm"] = "" end + + local domain = "" + local protocol = "" + if response["digest-uri"] then + protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$") + 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.password_handler(response["username"], response["realm"], "DIGEST-MD5") + 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.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 end -function new(mechanism, realm, password) +function new(mechanism, realm, password_handler) local object - if mechanism == "PLAIN" then object = new_plain(realm, password) - --elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(ream, password) + if mechanism == "PLAIN" then object = new_plain(realm, password_handler) + elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(realm, password_handler) else log("debug", "Unsupported SASL mechanism: "..tostring(mechanism)); return nil |