util/id.lua
author Matthew Wild <mwild1@gmail.com>
Mon, 31 Oct 2022 14:32:02 +0000
branch0.12
changeset 12794 24b55f0e2db9
parent 12115 f8d280215633
child 12979 d10957394a3c
permissions -rw-r--r--
mod_http: Allow disabling CORS in the http_cors_override option and by default Fixes #1779. Due to an oversight in the logic, if the user set 'enabled' to false in an override, it would disable the item's requested CORS settings, but still apply Prosody's default CORS policy. This change ensures that 'enabled = false' will now disable CORS entirely for the requested item. Due to the new structure of the code, it was necessary to have a flag to say whether CORS is to be applied at all. Rather than hard-coding 'true' here, I chose to add a new option: 'http_default_cors_enabled'. This is a boolean that allows the operator to disable Prosody's default CORS policy entirely (the one that is used when a module or config does not override it). This makes it easier to disable CORS and then selectively enable it only on services you want it on.

-- Prosody IM
-- Copyright (C) 2008-2017 Matthew Wild
-- Copyright (C) 2008-2017 Waqas Hussain
-- Copyright (C) 2008-2017 Kim Alvefur
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local s_gsub = string.gsub;
local random_bytes = require "util.random".bytes;
local base64_encode = require "util.encodings".base64.encode;

local b64url = { ["+"] = "-", ["/"] = "_", ["="] = "" };
local function b64url_random(len)
	return (s_gsub(base64_encode(random_bytes(len)), "[+/=]", b64url));
end

return {
	-- sizes divisible by 3 fit nicely into base64 without padding==

	-- for short lived things with low risk of collisions
	tiny = function() return b64url_random(3); end;

	-- close to 8 bytes, should be good enough for relatively short lived or uses
	-- scoped by host or users, half the size of an uuid
	short = function() return b64url_random(9); end;

	-- more entropy than uuid at 2/3 the size
	-- should be okay for globally scoped ids or security token
	medium = function() return b64url_random(18); end;

	-- as long as an uuid but MOAR entropy
	long = function() return b64url_random(27); end;

	-- pick your own adventure
	custom = function (size)
		return function () return b64url_random(size); end;
	end;
}