File

plugins/mod_register_ibr.lua @ 13801:a5d5fefb8b68 13.0

mod_tls: Enable Prosody's certificate checking for incoming s2s connections (fixes #1916) (thanks Damian, Zash) Various options in Prosody allow control over the behaviour of the certificate verification process For example, some deployments choose to allow falling back to traditional "dialback" authentication (XEP-0220), while others verify via DANE, hard-coded fingerprints, or other custom plugins. Implementing this flexibility requires us to override OpenSSL's default certificate verification, to allow Prosody to verify the certificate itself, apply custom policies and make decisions based on the outcome. To enable our custom logic, we have to suppress OpenSSL's default behaviour of aborting the connection with a TLS alert message. With LuaSec, this can be achieved by using the verifyext "lsec_continue" flag. We also need to use the lsec_ignore_purpose flag, because XMPP s2s uses server certificates as "client" certificates (for mutual TLS verification in outgoing s2s connections). Commit 99d2100d2918 moved these settings out of the defaults and into mod_s2s, because we only really need these changes for s2s, and they should be opt-in, rather than automatically applied to all TLS services we offer. That commit was incomplete, because it only added the flags for incoming direct TLS connections. StartTLS connections are handled by mod_tls, which was not applying the lsec_* flags. It previously worked because they were already in the defaults. This resulted in incoming s2s connections with "invalid" certificates being aborted early by OpenSSL, even if settings such as `s2s_secure_auth = false` or DANE were present in the config. Outgoing s2s connections inherit verify "none" from the defaults, which means OpenSSL will receive the cert but will not terminate the connection when it is deemed invalid. This means we don't need lsec_continue there, and we also don't need lsec_ignore_purpose (because the remote peer is a "server"). Wondering why we can't just use verify "none" for incoming s2s? It's because in that mode, OpenSSL won't request a certificate from the peer for incoming connections. Setting verify "peer" is how you ask OpenSSL to request a certificate from the client, but also what triggers its built-in verification.
author Matthew Wild <mwild1@gmail.com>
date Tue, 01 Apr 2025 17:26:56 +0100
parent 13232:e0ab20519ce5
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-- 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.
--


local st = require "prosody.util.stanza";
local dataform_new = require "prosody.util.dataforms".new;
local usermanager_user_exists  = require "prosody.core.usermanager".user_exists;
local usermanager_create_user_with_role  = require "prosody.core.usermanager".create_user_with_role;
local usermanager_set_password = require "prosody.core.usermanager".create_user;
local usermanager_delete_user  = require "prosody.core.usermanager".delete_user;
local nodeprep = require "prosody.util.encodings".stringprep.nodeprep;
local util_error = require "prosody.util.error";

local additional_fields = module:get_option_array("additional_registration_fields", {});
local require_encryption = module:get_option_boolean("c2s_require_encryption",
	module:get_option_boolean("require_encryption", true));

local default_role = module:get_option_string("register_ibr_default_role", "prosody:registered");

pcall(function ()
	module:depends("register_limits");
end);

local account_details = module:open_store("account_details");

local field_map = {
	FORM_TYPE = { name = "FORM_TYPE", type = "hidden", value = "jabber:iq:register" };
	username = { name = "username", type = "text-single", label = "Username", required = true };
	password = { name = "password", type = "text-private", label = "Password", required = true };
	nick = { name = "nick", type = "text-single", label = "Nickname" };
	name = { name = "name", type = "text-single", label = "Full Name" };
	first = { name = "first", type = "text-single", label = "Given Name" };
	last = { name = "last", type = "text-single", label = "Family Name" };
	email = { name = "email", type = "text-single", label = "Email" };
	address = { name = "address", type = "text-single", label = "Street" };
	city = { name = "city", type = "text-single", label = "City" };
	state = { name = "state", type = "text-single", label = "State" };
	zip = { name = "zip", type = "text-single", label = "Postal code" };
	phone = { name = "phone", type = "text-single", label = "Telephone number" };
	url = { name = "url", type = "text-single", label = "Webpage" };
	date = { name = "date", type = "text-single", label = "Birth date" };
};

local title = module:get_option_string("registration_title",
	"Creating a new account");
local instructions = module:get_option_string("registration_instructions",
	"Choose a username and password for use with this service.");

local registration_form = dataform_new{
	title = title;
	instructions = instructions;

	field_map.FORM_TYPE;
	field_map.username;
	field_map.password;
};

local registration_query = st.stanza("query", {xmlns = "jabber:iq:register"})
	:tag("instructions"):text(instructions):up()
	:tag("username"):up()
	:tag("password"):up();

for _, field in ipairs(additional_fields) do
	if type(field) == "table" then
		registration_form[#registration_form + 1] = field;
	elseif field_map[field] or field_map[field:sub(1, -2)] then
		if field:match("%+$") then
			field = field:sub(1, -2);
			field_map[field].required = true;
		end

		registration_form[#registration_form + 1] = field_map[field];
		registration_query:tag(field):up();
	else
		module:log("error", "Unknown field %q", field);
	end
end
registration_query:add_child(registration_form:form());

local register_stream_feature = st.stanza("register", {xmlns="http://jabber.org/features/iq-register"}):up();
module:hook("stream-features", function(event)
	local session, features = event.origin, event.features;

	-- Advertise registration to unauthorized clients only.
	if session.type ~= "c2s_unauthed" or (require_encryption and not session.secure) then
		return
	end

	features:add_child(register_stream_feature);
end);

local function parse_response(query)
	local form = query:get_child("x", "jabber:x:data");
	if form then
		return registration_form:data(form);
	else
		local data = {};
		local errors = {};
		for _, field in ipairs(registration_form) do
			local name, required = field.name, field.required;
			if field_map[name] then
				data[name] = query:get_child_text(name);
				if (not data[name] or #data[name] == 0) and required then
					errors[name] = "Required value missing";
				end
			end
		end
		if next(errors) then
			return data, errors;
		end
		return data;
	end
end

-- In-band registration
module:hook("stanza/iq/jabber:iq:register:query", function(event)
	local session, stanza = event.origin, event.stanza;
	local log = session.log or module._log;

	if session.type ~= "c2s_unauthed" then
		log("debug", "Attempted registration when disabled or already authenticated");
		session.send(st.error_reply(stanza, "cancel", "service-unavailable"));
		return true;
	end

	if require_encryption and not session.secure then
		session.send(st.error_reply(stanza, "modify", "policy-violation", "Encryption is required"));
		return true;
	end

	local query = stanza.tags[1];
	if stanza.attr.type == "get" then
		local reply = st.reply(stanza);
		reply:add_child(registration_query);
		session.send(reply);
		return true;
	end

	-- stanza.attr.type == "set"
	if query.tags[1] and query.tags[1].name == "remove" then
		session.send(st.error_reply(stanza, "auth", "registration-required"));
		return true;
	end

	local data, errors = parse_response(query);
	if errors then
		log("debug", "Error parsing registration form:");
		local textual_errors = {};
		for field, err in pairs(errors) do
			log("debug", "Field %q: %s", field, err);
			table.insert(textual_errors, ("%s: %s"):format(field:gsub("^%a", string.upper), err));
		end
		session.send(st.error_reply(stanza, "modify", "not-acceptable", table.concat(textual_errors, "\n")));
		return true;
	end

	local username, password = nodeprep(data.username, true), data.password;
	data.username, data.password = nil, nil;
	local host = module.host;
	if not username or username == "" then
		log("debug", "The requested username is invalid.");
		session.send(st.error_reply(stanza, "modify", "not-acceptable", "The requested username is invalid."));
		return true;
	end

	local user = {
		username = username, password = password, host = host;
		additional = data, ip = session.ip, session = session;
		role = default_role;
		allowed = true;
	};
	module:fire_event("user-registering", user);
	if not user.allowed then
		local error_type, error_condition, reason;
		local err = user.error;
		if err then
			error_type, error_condition, reason = err.type, err.condition, err.text;
		else
			-- COMPAT pre-util.error
			error_type, error_condition, reason = user.error_type, user.error_condition, user.reason;
		end
		log("debug", "Registration disallowed by module: %s", reason or "no reason given");
		session.send(st.error_reply(stanza, error_type or "modify", error_condition or "not-acceptable", reason));
		return true;
	end

	if usermanager_user_exists(username, host) then
		if user.allow_reset == username then
			local ok, err = util_error.coerce(usermanager_set_password(username, password, host));
			if ok then
				module:fire_event("user-password-reset", user);
				session.send(st.reply(stanza)); -- reset ok!
			else
				session.log("error", "Unable to reset password for %s@%s: %s", username, host, err);
				session.send(st.error_reply(stanza, err.type, err.condition, err.text));
			end
			return true;
		else
			log("debug", "Attempt to register with existing username");
			session.send(st.error_reply(stanza, "cancel", "conflict", "The requested username already exists."));
			return true;
		end
	end

	local created, err = usermanager_create_user_with_role(username, password, host, user.role);
	if created then
		data.registered = os.time();
		if not account_details:set(username, data) then
			log("debug", "Could not store extra details");
			usermanager_delete_user(username, host);
			session.send(st.error_reply(stanza, "wait", "internal-server-error", "Failed to write data to disk."));
			return true;
		end
		session.send(st.reply(stanza)); -- user created!
		log("info", "User account created: %s@%s", username, host);
		module:fire_event("user-registered", {
			username = username, host = host, source = "mod_register",
			session = session });
	else
		log("debug", "Could not create user", err);
		session.send(st.error_reply(stanza, "cancel", "feature-not-implemented", err));
	end
	return true;
end);