2 local md5 = require "md5"
3 local log = require "util.logger".init("sasl");
4 local tostring = tostring;
5 local st = require "util.stanza";
6 local generate_uuid = require "util.uuid".generate;
7 local s_match = string.match;
8 local gmatch = string.gmatch
10 local math = require "math"
17 local function new_plain(realm, password_handler)
18 local object = { mechanism = "PLAIN", realm = realm, password_handler = password_handler}
19 function object.feed(self, message)
21 if message == "" or message == nil then return "failure", "malformed-request" end
22 local response = message
23 local authorization = s_match(response, "([^&%z]+)")
24 local authentication = s_match(response, "%z([^&%z]+)%z")
25 local password = s_match(response, "%z[^&%z]+%z([^&%z]+)")
27 if authentication == nil or password == nil then return "failure", "malformed-request" end
29 local password_encoding, correct_password = self.password_handler(authentication, self.realm, "PLAIN")
31 if correct_password == nil then return "failure", "malformed-request" end
33 local claimed_password = ""
34 if password_encoding == nil then claimed_password = password
35 else claimed_password = password_encoding(password) end
37 self.username = authentication
38 if claimed_password == correct_password then
41 return "failure", "not-authorized"
47 local function new_digest_md5(realm, password_handler)
48 --TODO maybe support for authzid
50 local function serialize(message)
53 if type(message) ~= "table" then error("serialize needs an argument of type table.") end
55 -- testing all possible values
56 if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end
57 if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end
58 if message["charset"] then data = data..[[charset=]]..message.charset.."," end
59 if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end
60 if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end
61 if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end
62 data = data:gsub(",$", "")
66 local function parse(data)
68 for k, v in gmatch(data, [[([%w%-]+)="?([%w%-%/%.%+=]+)"?,?]]) do
74 local object = { mechanism = "DIGEST-MD5", realm = realm, password_handler = password_handler}
76 --TODO: something better than math.random would be nice, maybe OpenSSL's random number generator
77 object.nonce = generate_uuid()
79 object.nonce_count = {}
81 function object.feed(self, message)
82 self.step = self.step + 1
83 if (self.step == 1) then
84 local challenge = serialize({ nonce = object.nonce,
87 algorithm = "md5-sess",
89 return "challenge", challenge
90 elseif (self.step == 2) then
91 local response = parse(message)
92 -- check for replay attack
93 if response["nc"] then
94 if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
97 -- check for username, it's REQUIRED by RFC 2831
98 if not response["username"] then
99 return "failure", "malformed-request"
101 self["username"] = response["username"]
103 -- check for nonce, ...
104 if not response["nonce"] then
105 return "failure", "malformed-request"
107 -- check if it's the right nonce
108 if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
111 if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
112 if not response["qop"] then response["qop"] = "auth" end
114 if response["realm"] == nil then response["realm"] = "" end
118 if response["digest-uri"] then
119 protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$")
120 if protocol == nil or domain == nil then return "failure", "malformed-request" end
122 return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
125 --TODO maybe realm support
126 self.username = response["username"]
127 local password_encoding, Y = self.password_handler(response["username"], response["realm"], "DIGEST-MD5")
128 if Y == nil then return "failure", "malformed-request" end
130 local A1 = Y..":"..response["nonce"]..":"..response["cnonce"]--:authzid
131 local A2 = "AUTHENTICATE:"..protocol.."/"..domain
133 local HA1 = md5.sumhexa(A1)
134 local HA2 = md5.sumhexa(A2)
136 local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
137 local response_value = md5.sumhexa(KD)
139 if response_value == response["response"] then
141 A2 = ":"..protocol.."/"..domain
143 HA1 = md5.sumhexa(A1)
144 HA2 = md5.sumhexa(A2)
146 KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
147 local rspauth = md5.sumhexa(KD)
148 self.authenticated = true
149 return "challenge", serialize({rspauth = rspauth})
151 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
153 elseif self.step == 3 then
154 if self.authenticated ~= nil then return "success"
155 else return "failure", "malformed-request" end
161 function new(mechanism, realm, password_handler)
163 if mechanism == "PLAIN" then object = new_plain(realm, password_handler)
164 elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(realm, password_handler)
166 log("debug", "Unsupported SASL mechanism: "..tostring(mechanism));