File

plugins/muc/members_only.lib.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 12977:74b9e05af71e
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-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
-- Copyright (C) 2014 Daurnimator
--
-- 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 muc_util = module:require "muc/util";
local valid_affiliations = muc_util.valid_affiliations;

local function get_members_only(room)
	return room._data.members_only;
end

local function set_members_only(room, members_only)
	members_only = members_only and true or nil;
	if room._data.members_only == members_only then return false; end
	room._data.members_only = members_only;
	if members_only then
		--[[
		If as a result of a change in the room configuration the room type is
		changed to members-only but there are non-members in the room,
		the service MUST remove any non-members from the room and include a
		status code of 322 in the presence unavailable stanzas sent to those users
		as well as any remaining occupants.
		]]
		local occupants_changed = {};
		for _, occupant in room:each_occupant() do
			local affiliation = room:get_affiliation(occupant.bare_jid);
			if valid_affiliations[affiliation or "none"] <= valid_affiliations.none then
				occupant.role = nil;
				room:save_occupant(occupant);
				occupants_changed[occupant] = true;
			end
		end
		local x = st.stanza("x", {xmlns = "http://jabber.org/protocol/muc#user"})
			:tag("status", {code="322"}):up();
		for occupant in pairs(occupants_changed) do
			room:publicise_occupant_status(occupant, x);
			module:fire_event("muc-occupant-left", {room = room; nick = occupant.nick; occupant = occupant;});
		end
	end
	return true;
end

local function get_allow_member_invites(room)
	return room._data.allow_member_invites;
end

-- Allows members to invite new members into a members-only room,
-- effectively creating an invite-only room
local function set_allow_member_invites(room, allow_member_invites)
	allow_member_invites = allow_member_invites and true or nil;
	if room._data.allow_member_invites == allow_member_invites then return false; end
	room._data.allow_member_invites = allow_member_invites;
	return true;
end

module:hook("muc-disco#info", function(event)
	local members_only_room = not not get_members_only(event.room);
	local members_can_invite = not not get_allow_member_invites(event.room);
	event.reply:tag("feature", {var = members_only_room and "muc_membersonly" or "muc_open"}):up();
	table.insert(event.form, {
		name = "{http://prosody.im/protocol/muc}roomconfig_allowmemberinvites";
		label = "Allow members to invite new members";
		type = "boolean";
		value = members_can_invite;
	});
	table.insert(event.form, {
		name = "muc#roomconfig_allowinvites";
		label = "Allow users to invite other users";
		type = "boolean";
		value = not members_only_room or members_can_invite;
	});
end);


module:hook("muc-config-form", function(event)
	table.insert(event.form, {
		name = "muc#roomconfig_membersonly";
		type = "boolean";
		label = "Only allow members to join";
		desc = "Enable this to only allow access for room owners, admins and members";
		value = get_members_only(event.room);
	});
	table.insert(event.form, {
		name = "{http://prosody.im/protocol/muc}roomconfig_allowmemberinvites";
		type = "boolean";
		label = "Allow members to invite new members";
		value = get_allow_member_invites(event.room);
	});
end, 90-3);

module:hook("muc-config-submitted/muc#roomconfig_membersonly", function(event)
	if set_members_only(event.room, event.value) then
		event.status_codes["104"] = true;
	end
end);

module:hook("muc-config-submitted/{http://prosody.im/protocol/muc}roomconfig_allowmemberinvites", function(event)
	if set_allow_member_invites(event.room, event.value) then
		event.status_codes["104"] = true;
	end
end);

-- No affiliation => role of "none"
module:hook("muc-get-default-role", function(event)
	if not event.affiliation and get_members_only(event.room) then
		return false;
	end
end, 2);

-- registration required for entering members-only room
module:hook("muc-occupant-pre-join", function(event)
	local room = event.room;
	if get_members_only(room) then
		local stanza = event.stanza;
		local affiliation = room:get_affiliation(stanza.attr.from);
		if valid_affiliations[affiliation or "none"] <= valid_affiliations.none then
			local reply = st.error_reply(stanza, "auth", "registration-required", nil, room.jid):up();
			event.origin.send(reply);
			return true;
		end
	end
end, -5);

-- Invitation privileges in members-only rooms SHOULD be restricted to room admins;
-- if a member without privileges to edit the member list attempts to invite another user
-- the service SHOULD return a <forbidden/> error to the occupant
module:hook("muc-pre-invite", function(event)
	local room = event.room;
	if get_members_only(room) then
		local stanza = event.stanza;
		local inviter_affiliation = room:get_affiliation(stanza.attr.from) or "none";
		local required_affiliation = room._data.allow_member_invites and "member" or "admin";
		if valid_affiliations[inviter_affiliation] < valid_affiliations[required_affiliation] then
			event.origin.send(st.error_reply(stanza, "auth", "forbidden", nil, room.jid));
			return true;
		end
	end
end);

-- When an invite is sent; add an affiliation for the invitee
module:hook("muc-invite", function(event)
	local room = event.room;
	if get_members_only(room) then
		local stanza = event.stanza;
		local invitee = stanza.attr.to;
		local affiliation = room:get_affiliation(invitee);
		local invited_unaffiliated = valid_affiliations[affiliation or "none"] <= valid_affiliations.none;
		if invited_unaffiliated then
			local from = stanza:get_child("x", "http://jabber.org/protocol/muc#user")
				:get_child("invite").attr.from;
			module:log("debug", "%s invited %s into members only room %s, granting membership",
				from, invitee, room.jid);
			-- This might fail; ignore for now
			room:set_affiliation(true, invitee, "member", "Invited by " .. from);
			room:save();
		end
	end
end);

return {
	get = get_members_only;
	set = set_members_only;
	get_allow_member_invites = get_allow_member_invites;
	set_allow_member_invites = set_allow_member_invites;
};