File

plugins/muc/occupant_id.lib.lua @ 12493:e9ea5c88def0

mod_s2s: Don't bounce queued error stanzas (thanks Martin) The check for the type attr was lost in 11765f0605ec leading to attempts to create error replies for error stanzas, which util.stanza rejects. Tested by sending <message to="reject.badxmpp.eu" type="error"><error/></message> which produced a traceback previously.
author Kim Alvefur <zash@zash.se>
date Sat, 07 May 2022 13:01:49 +0200
parent 12108:e9882c4c397f
child 12977:74b9e05af71e
line wrap: on
line source

-- Implementation of https://xmpp.org/extensions/inbox/occupant-id.html
-- XEP-0421: Anonymous unique occupant identifiers for MUCs

-- (C) 2020 Maxime “pep” Buquet <pep@bouah.net>
-- (C) 2020 Matthew Wild <mwild1@gmail.com>

local uuid = require "util.uuid";
local hmac_sha256 = require "util.hashes".hmac_sha256;
local b64encode = require "util.encodings".base64.encode;

local xmlns_occupant_id = "urn:xmpp:occupant-id:0";

local function get_room_salt(room)
	local salt = room._data.occupant_id_salt;
	if not salt then
		salt = uuid.generate();
		room._data.occupant_id_salt = salt;
	end
	return salt;
end

local function get_occupant_id(room, occupant)
	if occupant.stable_id then
		return occupant.stable_id;
	end

	local salt = get_room_salt(room)

	occupant.stable_id = b64encode(hmac_sha256(occupant.bare_jid, salt));

	return occupant.stable_id;
end

local function update_occupant(event)
	local stanza, room, occupant, dest_occupant = event.stanza, event.room, event.occupant, event.dest_occupant;

	-- "muc-occupant-pre-change" provides "dest_occupant" but not "occupant".
	if dest_occupant ~= nil then
		occupant = dest_occupant;
	end

	-- strip any existing <occupant-id/> tags to avoid forgery
	stanza:remove_children("occupant-id", xmlns_occupant_id);

	local unique_id = get_occupant_id(room, occupant);
	stanza:tag("occupant-id", { xmlns = xmlns_occupant_id, id = unique_id }):up();
end

local function muc_private(event)
	local stanza, room = event.stanza, event.room;
	local occupant = room._occupants[stanza.attr.from];

	update_occupant({
		stanza = stanza,
		room = room,
		occupant = occupant,
	});
end

if module:get_option_boolean("muc_occupant_id", true) then
	module:add_feature(xmlns_occupant_id);
	module:hook("muc-disco#info", function (event)
		event.reply:tag("feature", { var = xmlns_occupant_id }):up();
	end);

	module:hook("muc-broadcast-presence", update_occupant);
	module:hook("muc-occupant-pre-join", update_occupant);
	module:hook("muc-occupant-pre-change", update_occupant);
	module:hook("muc-occupant-groupchat", update_occupant);
	module:hook("muc-private-message", muc_private);
end

return {
	get_room_salt = get_room_salt;
	get_occupant_id = get_occupant_id;
};