view mod_auth_token/token_auth_utils.lib.lua @ 5342:e28ba69b5307

mod_rest: Implement use of refresh tokens in rest.sh example Because having access tokens expire daily was becoming annoying. Now this is starting to be in dire need of refactoring.
author Kim Alvefur <zash@zash.se>
date Wed, 12 Apr 2023 11:24:50 +0200
parents 0fb12a4b6106
children
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local base64 = require "util.encodings".base64;
local hmac = require "openssl.hmac";
local luatz = require "luatz";
local otp = require "otp";

local DIGEST_TYPE = "SHA256";
local OTP_DEVIATION = 1;
local OTP_DIGITS = 8;
local OTP_INTERVAL = 30;

local nonce_cache = {};

local function check_nonce(jid, otp_value, nonce)
	-- We cache all nonces used per OTP, to ensure that a token cannot be used
	-- more than once.
	--
	-- We assume that the OTP is valid in the current time window. This is the
	-- case because we only call check_nonce *after* the OTP has been verified.
	--
	-- We only store one OTP per JID, so if a new OTP comes in, we wipe the
	-- previous OTP and its cached nonces.
	if nonce_cache[jid] == nil or nonce_cache[jid][otp_value] == nil then
		nonce_cache[jid] = {}
		nonce_cache[jid][otp_value] = {}
		nonce_cache[jid][otp_value][nonce] = true
		return true;
	end
	if nonce_cache[jid][otp_value][nonce] == true then
		return false;
	else
		nonce_cache[jid][otp_value][nonce] = true;
		return true;
	end
end


local function verify_token(username, password, otp_seed, token_secret, log)
	local totp = otp.new_totp_from_key(otp_seed, OTP_DIGITS, OTP_INTERVAL)
	local token = string.match(password, "(%d+) ")
	local otp_value = token:sub(1,8)
	local nonce = token:sub(9)
	local signature = base64.decode(string.match(password, " (.+)"))
	local jid = username.."@"..module.host

	if totp:verify(otp_value, OTP_DEVIATION, luatz.time()) then
		log("debug", "The TOTP was verified");
		local hmac_ctx = hmac.new(token_secret, DIGEST_TYPE)
		if signature == hmac_ctx:final(otp_value..nonce..jid) then
			log("debug", "The key was verified");
			if check_nonce(jid, otp_value, nonce) then
				log("debug", "The nonce was verified");
				return true;
			end
		end
	end
	log("debug", "Verification failed");
	return false;
end

return {
	OTP_DEVIATION = OTP_DIGITS,
	OTP_DIGITS = OTP_DIGITS,
	OTP_INTERVAL = OTP_INTERVAL,
	DIGEST_TYPE = DIGEST_TYPE,
	verify_token = verify_token;
}