prosody
8fbbdb11a520
util/sasl.lua

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util/sasl.lua @ 2193:8fbbdb11a520

Merge with sasl branch.
author Tobias Markmann <tm@ayena.de>
date Mon, 16 Nov 2009 21:43:57 +0100
parent 2080:ca419b92a8c7
parent 2191:e79c0ce6cf54
child 2198:d18b4d22b8da
comparison
equal deleted inserted replaced
2080:ca419b92a8c7 2193:8fbbdb11a520
14 14
15 local md5 = require "util.hashes".md5; 15 local md5 = require "util.hashes".md5;
16 local log = require "util.logger".init("sasl"); 16 local log = require "util.logger".init("sasl");
17 local tostring = tostring; 17 local tostring = tostring;
18 local st = require "util.stanza"; 18 local st = require "util.stanza";
19 local generate_uuid = require "util.uuid".generate; 19 local pairs, ipairs = pairs, ipairs;
20 local t_insert, t_concat = table.insert, table.concat; 20 local t_insert, t_concat = table.insert, table.concat;
21 local to_byte, to_char = string.byte, string.char;
22 local to_unicode = require "util.encodings".idna.to_unicode; 21 local to_unicode = require "util.encodings".idna.to_unicode;
23 local s_match = string.match; 22 local s_match = string.match;
24 local gmatch = string.gmatch 23 local gmatch = string.gmatch
25 local string = string 24 local string = string
26 local math = require "math" 25 local math = require "math"
27 local type = type 26 local type = type
28 local error = error 27 local error = error
29 local print = print 28 local print = print
29 local setmetatable = setmetatable;
30 local assert = assert;
31 local dofile = dofile;
32 local require = require;
30 33
34 require "util.iterators"
35 local keys = keys
36
37 local array = require "util.array"
31 module "sasl" 38 module "sasl"
32 39
33 -- Credentials handler: 40 --[[
34 -- Arguments: ("PLAIN", user, host, password) 41 Authentication Backend Prototypes:
35 -- Returns: true (success) | false (fail) | nil (user unknown)
36 local function new_plain(realm, credentials_handler)
37 local object = { mechanism = "PLAIN", realm = realm, credentials_handler = credentials_handler}
38 function object.feed(self, message)
39 if message == "" or message == nil then return "failure", "malformed-request" end
40 local response = message
41 local authorization = s_match(response, "([^%z]+)")
42 local authentication = s_match(response, "%z([^%z]+)%z")
43 local password = s_match(response, "%z[^%z]+%z([^%z]+)")
44 42
45 if authentication == nil or password == nil then return "failure", "malformed-request" end 43 state = false : disabled
46 self.username = authentication 44 state = true : enabled
47 local auth_success = self.credentials_handler("PLAIN", self.username, self.realm, password) 45 state = nil : non-existant
48 46
49 if auth_success then 47 plain:
50 return "success" 48 function(username, realm)
51 elseif auth_success == nil then 49 return password, state;
52 return "failure", "account-disabled" 50 end
53 else 51
54 return "failure", "not-authorized" 52 plain-test:
55 end 53 function(username, realm, password)
56 end 54 return true or false, state;
57 return object 55 end
56
57 digest-md5:
58 function(username, domain, realm, encoding) -- domain and realm are usually the same; for some broken
59 -- implementations it's not
60 return digesthash, state;
61 end
62
63 digest-md5-test:
64 function(username, domain, realm, encoding, digesthash)
65 return true or false, state;
66 end
67 ]]
68
69 local method = {};
70 method.__index = method;
71 local mechanisms = {};
72 local backend_mechanism = {};
73
74 -- register a new SASL mechanims
75 local function registerMechanism(name, backends, f)
76 assert(type(name) == "string", "Parameter name MUST be a string.");
77 assert(type(backends) == "string" or type(backends) == "table", "Parameter backends MUST be either a string or a table.");
78 assert(type(f) == "function", "Parameter f MUST be a function.");
79 mechanisms[name] = f
80 for _, backend_name in ipairs(backends) do
81 if backend_mechanism[backend_name] == nil then backend_mechanism[backend_name] = {}; end
82 t_insert(backend_mechanism[backend_name], name);
83 end
58 end 84 end
59 85
60 -- credentials_handler: 86 -- create a new SASL object which can be used to authenticate clients
61 -- Arguments: (mechanism, node, domain, realm, decoder) 87 function new(realm, profile)
62 -- Returns: Password encoding, (plaintext) password 88 sasl_i = {profile = profile};
63 -- implementing RFC 2831 89 sasl_i.realm = realm;
64 local function new_digest_md5(realm, credentials_handler) 90 return setmetatable(sasl_i, method);
65 --TODO complete support for authzid 91 end
66 92
67 local function serialize(message) 93 -- get a list of possible SASL mechanims to use
68 local data = "" 94 function method:mechanisms()
69 95 local mechanisms = {}
70 if type(message) ~= "table" then error("serialize needs an argument of type table.") end 96 for backend, f in pairs(self.profile) do
71 97 print(backend)
72 -- testing all possible values 98 if backend_mechanism[backend] then
73 if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end 99 for _, mechanism in ipairs(backend_mechanism[backend]) do
74 if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end 100 mechanisms[mechanism] = true;
75 if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end
76 if message["charset"] then data = data..[[charset=]]..message.charset.."," end
77 if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end
78 if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end
79 data = data:gsub(",$", "")
80 return data
81 end
82
83 local function utf8tolatin1ifpossible(passwd)
84 local i = 1;
85 while i <= #passwd do
86 local passwd_i = to_byte(passwd:sub(i, i));
87 if passwd_i > 0x7F then
88 if passwd_i < 0xC0 or passwd_i > 0xC3 then
89 return passwd;
90 end
91 i = i + 1;
92 passwd_i = to_byte(passwd:sub(i, i));
93 if passwd_i < 0x80 or passwd_i > 0xBF then
94 return passwd;
95 end
96 end
97 i = i + 1;
98 end
99
100 local p = {};
101 local j = 0;
102 i = 1;
103 while (i <= #passwd) do
104 local passwd_i = to_byte(passwd:sub(i, i));
105 if passwd_i > 0x7F then
106 i = i + 1;
107 local passwd_i_1 = to_byte(passwd:sub(i, i));
108 t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever
109 else
110 t_insert(p, to_char(passwd_i));
111 end
112 i = i + 1;
113 end
114 return t_concat(p);
115 end
116 local function latin1toutf8(str)
117 local p = {};
118 for ch in gmatch(str, ".") do
119 ch = to_byte(ch);
120 if (ch < 0x80) then
121 t_insert(p, to_char(ch));
122 elseif (ch < 0xC0) then
123 t_insert(p, to_char(0xC2, ch));
124 else
125 t_insert(p, to_char(0xC3, ch - 64));
126 end 101 end
127 end 102 end
128 return t_concat(p);
129 end 103 end
130 local function parse(data) 104 self["possible_mechanisms"] = mechanisms;
131 local message = {} 105 return array.collect(keys(mechanisms));
132 for k, v in gmatch(data, [[([%w%-]+)="?([^",]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
133 message[k] = v;
134 end
135 return message;
136 end
137
138 local object = { mechanism = "DIGEST-MD5", realm = realm, credentials_handler = credentials_handler};
139
140 object.nonce = generate_uuid();
141 object.step = 0;
142 object.nonce_count = {};
143
144 function object.feed(self, message)
145 self.step = self.step + 1;
146 if (self.step == 1) then
147 local challenge = serialize({ nonce = object.nonce,
148 qop = "auth",
149 charset = "utf-8",
150 algorithm = "md5-sess",
151 realm = self.realm});
152 return "challenge", challenge;
153 elseif (self.step == 2) then
154 local response = parse(message);
155 -- check for replay attack
156 if response["nc"] then
157 if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
158 end
159
160 -- check for username, it's REQUIRED by RFC 2831
161 if not response["username"] then
162 return "failure", "malformed-request";
163 end
164 self["username"] = response["username"];
165
166 -- check for nonce, ...
167 if not response["nonce"] then
168 return "failure", "malformed-request";
169 else
170 -- check if it's the right nonce
171 if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
172 end
173
174 if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
175 if not response["qop"] then response["qop"] = "auth" end
176
177 if response["realm"] == nil or response["realm"] == "" then
178 response["realm"] = "";
179 elseif response["realm"] ~= self.realm then
180 return "failure", "not-authorized", "Incorrect realm value";
181 end
182
183 local decoder;
184 if response["charset"] == nil then
185 decoder = utf8tolatin1ifpossible;
186 elseif response["charset"] ~= "utf-8" then
187 return "failure", "incorrect-encoding", "The client's response uses "..response["charset"].." for encoding with isn't supported by sasl.lua. Supported encodings are latin or utf-8.";
188 end
189
190 local domain = "";
191 local protocol = "";
192 if response["digest-uri"] then
193 protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$");
194 if protocol == nil or domain == nil then return "failure", "malformed-request" end
195 else
196 return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
197 end
198
199 --TODO maybe realm support
200 self.username = response["username"];
201 local password_encoding, Y = self.credentials_handler("DIGEST-MD5", response["username"], self.realm, response["realm"], decoder);
202 if Y == nil then return "failure", "not-authorized"
203 elseif Y == false then return "failure", "account-disabled" end
204 local A1 = "";
205 if response.authzid then
206 if response.authzid == self.username or response.authzid == self.username.."@"..self.realm then
207 -- COMPAT
208 log("warn", "Client is violating RFC 3920 (section 6.1, point 7).");
209 A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
210 else
211 return "failure", "invalid-authzid";
212 end
213 else
214 A1 = Y..":"..response["nonce"]..":"..response["cnonce"];
215 end
216 local A2 = "AUTHENTICATE:"..protocol.."/"..domain;
217
218 local HA1 = md5(A1, true);
219 local HA2 = md5(A2, true);
220
221 local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2;
222 local response_value = md5(KD, true);
223
224 if response_value == response["response"] then
225 -- calculate rspauth
226 A2 = ":"..protocol.."/"..domain;
227
228 HA1 = md5(A1, true);
229 HA2 = md5(A2, true);
230
231 KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
232 local rspauth = md5(KD, true);
233 self.authenticated = true;
234 return "challenge", serialize({rspauth = rspauth});
235 else
236 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
237 end
238 elseif self.step == 3 then
239 if self.authenticated ~= nil then return "success"
240 else return "failure", "malformed-request" end
241 end
242 end
243 return object;
244 end 106 end
245 107
246 -- Credentials handler: Can be nil. If specified, should take the mechanism as 108 -- select a mechanism to use
247 -- the only argument, and return true for OK, or false for not-OK (TODO) 109 function method:select(mechanism)
248 local function new_anonymous(realm, credentials_handler) 110 if self.mech_i then
249 local object = { mechanism = "ANONYMOUS", realm = realm, credentials_handler = credentials_handler} 111 return false;
250 function object.feed(self, message) 112 end
251 return "success" 113
252 end 114 self.mech_i = mechanisms[mechanism]
253 object["username"] = generate_uuid() 115 if self.mech_i == nil then
254 return object 116 return false;
117 end
118 return true;
255 end 119 end
256 120
121 -- feed new messages to process into the library
122 function method:process(message)
123 --if message == "" or message == nil then return "failure", "malformed-request" end
124 return self.mech_i(self, message);
125 end
257 126
258 function new(mechanism, realm, credentials_handler) 127 -- load the mechanisms
259 local object 128 load_mechs = {"plain", "digest-md5", "anonymous"}
260 if mechanism == "PLAIN" then object = new_plain(realm, credentials_handler) 129 for _, mech in ipairs(load_mechs) do
261 elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(realm, credentials_handler) 130 local name = "util.sasl."..mech;
262 elseif mechanism == "ANONYMOUS" then object = new_anonymous(realm, credentials_handler) 131 local m = require(name);
263 else 132 m.init(registerMechanism)
264 log("debug", "Unsupported SASL mechanism: "..tostring(mechanism));
265 return nil
266 end
267 return object
268 end 133 end
269 134
270 return _M; 135 return _M;