plugins/mod_auth_anonymous.lua
author Jonas Schäfer <jonas@wielicki.name>
Mon, 10 Jan 2022 18:23:54 +0100
branch0.11
changeset 12185 783056b4e448
parent 8056 7d26dab7ce0d
child 11126 d60094d9b458
permissions -rw-r--r--
util.xml: Do not allow doctypes, comments or processing instructions Yes. This is as bad as it sounds. CVE pending. In Prosody itself, this only affects mod_websocket, which uses util.xml to parse the <open/> frame, thus allowing unauthenticated remote DoS using Billion Laughs. However, third-party modules using util.xml may also be affected by this. This commit installs handlers which disallow the use of doctype declarations and processing instructions without any escape hatch. It, by default, also introduces such a handler for comments, however, there is a way to enable comments nontheless. This is because util.xml is used to parse human-facing data, where comments are generally a desirable feature, and also because comments are generally harmless.

-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--
-- luacheck: ignore 212

local new_sasl = require "util.sasl".new;
local datamanager = require "util.datamanager";
local hosts = prosody.hosts;

-- define auth provider
local provider = {};

function provider.test_password(username, password)
	return nil, "Password based auth not supported.";
end

function provider.get_password(username)
	return nil, "Password not available.";
end

function provider.set_password(username, password)
	return nil, "Password based auth not supported.";
end

function provider.user_exists(username)
	return nil, "Only anonymous users are supported."; -- FIXME check if anonymous user is connected?
end

function provider.create_user(username, password)
	return nil, "Account creation/modification not supported.";
end

function provider.get_sasl_handler()
	local anonymous_authentication_profile = {
		anonymous = function(sasl, username, realm)
			return true; -- for normal usage you should always return true here
		end
	};
	return new_sasl(module.host, anonymous_authentication_profile);
end

function provider.users()
	return next, hosts[module.host].sessions, nil;
end

-- datamanager callback to disable writes
local function dm_callback(username, host, datastore, data)
	if host == module.host then
		return false;
	end
	return username, host, datastore, data;
end

if not module:get_option_boolean("allow_anonymous_s2s", false) then
	module:hook("route/remote", function (event)
		return false; -- Block outgoing s2s from anonymous users
	end, 300);
end

function module.load()
	datamanager.add_callback(dm_callback);
end
function module.unload()
	datamanager.remove_callback(dm_callback);
end

module:provides("auth", provider);