mod_password_policy/mod_password_policy.lua
author Kim Alvefur <zash@zash.se>
Sun, 03 Mar 2024 11:23:40 +0100
changeset 5857 97c9b76867ca
parent 5822 d3b69859553a
permissions -rw-r--r--
mod_log_ringbuffer: Detach event handlers on logging reload (thanks Menel) Otherwise the global event handlers accumulate, one added each time logging is reoladed, and each invocation of the signal or event triggers one dump of each created ringbuffer.

-- Password policy enforcement for Prosody
--
-- Copyright (C) 2012 Waqas Hussain
--
--
-- Configuration:
--    password_policy = {
--        length = 8;
--    }


local it = require "util.iterators";
local set = require "util.set";
local st = require "util.stanza";

local options = module:get_option("password_policy");

options = options or {};
options.length = options.length or 8;
if options.exclude_username == nil then
	options.exclude_username = true;
end

local builtin_policies = set.new({ "length", "exclude_username" });
local extra_policies = set.new(it.to_array(it.keys(options))) - builtin_policies;

local extra_policy_handlers = {};

module:handle_items("password-policy-provider", function (event)
	-- Password policy handler added
	local item = event.item;
	module:log("error", "Adding password policy handler '%s'", item.name);
	extra_policy_handlers[item.name] = item.check_password;
end, function (event)
	-- Password policy handler removed
	local item = event.item;
	extra_policy_handlers[item.name] = nil;
end);

function check_password(password, additional_info)
	if not password or password == "" then
		return nil, "No password provided", "no-password";
	end

	if #password < options.length then
		return nil, ("Password is too short (minimum %d characters)"):format(options.length), "length";
	end

	if additional_info then
		local username = additional_info.username;
		if username and password:lower():find(username:lower(), 1, true) then
			return nil, "Password must not include your username", "username";
		end
	end

	for policy in extra_policies do
		local handler = extra_policy_handlers[policy];
		if not handler then
			module:log("error", "No policy handler found for '%s' (typo, or module not loaded?)", policy);
			return nil, "Internal error while verifying password", "internal";
		end
		local ok, reason_text, reason_name = handler(password, options[policy], additional_info);
		if ok ~= true then
			return nil, reason_text or ("Password failed %s check"):format(policy), reason_name or policy;
		end
	end

	return true;
end

function get_policy() --luacheck: ignore 131/get_policy
	return options;
end

function handler(event)
	local origin, stanza = event.origin, event.stanza;

	if stanza.attr.type == "set" then
		local query = stanza.tags[1];

		local passwords = {};

		local dataform = query:get_child("x", "jabber:x:data");
		if dataform then
			for _,tag in ipairs(dataform.tags) do
				if tag.attr.var == "password" then
					table.insert(passwords, tag:get_child_text("value"));
				end
			end
		end

		table.insert(passwords, query:get_child_text("password"));

		local additional_info = {
			username = origin.username;
		};

		for _,password in ipairs(passwords) do
			if password then
				local pw_ok, pw_err, pw_failed_policy = check_password(password, additional_info);
				if not pw_ok then
					module:log("debug", "Password failed check against '%s' policy", pw_failed_policy);
					origin.send(st.error_reply(stanza, "modify", "not-acceptable", pw_err));
					return true;
				end
			end
		end
	end
end

module:hook("iq/self/jabber:iq:register:query", handler, 10);
module:hook("iq/host/jabber:iq:register:query", handler, 10);
module:hook("stanza/iq/jabber:iq:register:query", handler, 10);