mod_http_oauth2: Implement stateless dynamic client registration Replaces previous explicit registration that required either the additional module mod_adhoc_oauth2_client or manually editing the database. That method was enough to have something to test with, but would not probably not scale easily. Dynamic client registration allows creating clients on the fly, which may be even easier in theory. In order to not allow basically unauthenticated writes to the database, we implement a stateless model here. per_host_key := HMAC(config -> oauth2_registration_key, hostname) client_id := JWT { client metadata } signed with per_host_key client_secret := HMAC(per_host_key, client_id) This should ensure everything we need to know is part of the client_id, allowing redirects etc to be validated, and the client_secret can be validated with only the client_id and the per_host_key. A nonce injected into the client_id JWT should ensure nobody can submit the same client metadata and retrieve the same client_secret

local jid = require "util.jid";
local st = require "util.stanza";

local local_rooms = module:get_option_inherited_set("muc_local_only", {});

module:hook("muc-occupant-pre-join", function (event)
	local room = event.room;
	if not local_rooms:contains(room.jid) then
		return; -- Not a protected room, ignore
	end
	local user_jid = event.occupant.bare_jid;
	local user_host = jid.host(user_jid);
	if not prosody.hosts[user_host] then
		local error_reply = st.error_reply(event.stanza, "cancel", "forbidden", "This group is only available to local users", room.jid);
		event.origin.send(error_reply);
		return true;
	end
	room:set_affiliation(true, user_jid, "member", "Granting access to local user");
end);