prosody-modules
d0ca211e1b0e
mod_auth_token/token_auth_utils.lib.lua

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mod_auth_token/token_auth_utils.lib.lua @ 2956:d0ca211e1b0e

New HMAC token authentication module for Prosody.
author JC Brand <jc@opkode.com>
date Tue, 27 Mar 2018 10:48:04 +0200
child 3472:ac1f63cdb6d6
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2938:f000ba14d531 2956:d0ca211e1b0e
1 local base64 = require "util.encodings".base64;
2 local digest = require "openssl.digest";
3 local hmac = require "openssl.hmac";
4 local luatz = require "luatz";
5 local otp = require "otp";
6
7 local DIGEST_TYPE = "SHA256";
8 local OTP_DEVIATION = 1;
9 local OTP_DIGITS = 8;
10 local OTP_INTERVAL = 30;
11
12 local nonce_cache = {};
13
14 function check_nonce(jid, otp, nonce)
15 -- We cache all nonces used per OTP, to ensure that a token cannot be used
16 -- more than once.
17 --
18 -- We assume that the OTP is valid in the current time window. This is the
19 -- case because we only call check_nonce *after* the OTP has been verified.
20 --
21 -- We only store one OTP per JID, so if a new OTP comes in, we wipe the
22 -- previous OTP and its cached nonces.
23 if nonce_cache[jid] == nil or nonce_cache[jid][otp] == nil then
24 nonce_cache[jid] = {}
25 nonce_cache[jid][otp] = {}
26 nonce_cache[jid][otp][nonce] = true
27 return true;
28 end
29 if nonce_cache[jid][otp][nonce] == true then
30 return false;
31 else
32 nonce_cache[jid][otp][nonce] = true;
33 return true;
34 end
35 end
36
37
38 function verify_token(username, password, realm, otp_seed, token_secret, log)
39 local totp = otp.new_totp_from_key(otp_seed, OTP_DIGITS, OTP_INTERVAL)
40 local token = string.match(password, "(%d+) ")
41 local otp = token:sub(1,8)
42 local nonce = token:sub(9)
43 local signature = base64.decode(string.match(password, " (.+)"))
44 local jid = username.."@"..realm
45
46 if totp:verify(otp, OTP_DEVIATION, luatz.gmtime(luatz.time())) then
47 -- log("debug", "**** THE OTP WAS VERIFIED ****** ");
48 local hmac_ctx = hmac.new(token_secret, DIGEST_TYPE)
49 if signature == hmac_ctx:final(otp..nonce..jid) then
50 -- log("debug", "**** THE KEY WAS VERIFIED ****** ");
51 if check_nonce(jid, otp, nonce) then
52 -- log("debug", "**** THE NONCE WAS VERIFIED ****** ");
53 return true;
54 end
55 end
56 end
57 -- log("debug", "**** VERIFICATION FAILED ****** ");
58 return false;
59 end
60
61 return {
62 OTP_DEVIATION = OTP_DIGITS,
63 OTP_DIGITS = OTP_DIGITS,
64 OTP_INTERVAL = OTP_INTERVAL,
65 DIGEST_TYPE = DIGEST_TYPE,
66 verify_token = verify_token;
67 }