view mod_muc_occupant_id/mod_muc_occupant_id.lua @ 5243:d5dc8edb2695

mod_http_oauth2: Use more compact IDs UUIDs are nice but so verbose! The reduction in entropy for the nonce should be fine since the timestamp is also counts towards this, and it changes every second (modulo clock shenanigans), so the chances of someone managing to get the same client_secret by registering with the same information at the same time as another entity should be negligible.
author Kim Alvefur <zash@zash.se>
date Sat, 11 Mar 2023 22:46:27 +0100
parents ae27f3359df8
children
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-- Implementation of https://xmpp.org/extensions/inbox/occupant-id.html
-- XEP-0421: Anonymous unique occupant identifiers for MUCs

module:depends("muc");

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 generate_id(occupant, room)
	local bare = occupant.bare_jid;

	if room._data.occupant_id_salt == nil then
		room._data.occupant_id_salt = uuid.generate();
	end

	-- XXX: Temporary not-so-important migration measure. Remove this next time
	-- somebody looks at it. This module used to store every participant's
	-- occupant-id all the time forever.
	room._data.occupant_ids = nil;

	return b64encode(hmac_sha256(bare, room._data.occupant_id_salt));
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 = generate_id(occupant, room);
	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

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);