mod_http_oauth2: Advertise the currently supported id_token signing algorithm This field is REQUIRED. The algorithm RS256 MUST be included, but isn't because we don't implement it, as that would require implementing a pile of additional cryptography and JWT stuff. Instead the id_token is signed using the client secret, which allows verification by the client, since it's a shared secret per OpenID Connect Core 1.0 § 10.1 under Symmetric Signatures. OpenID Connect Discovery 1.0 has a lot of REQUIRED and MUST clauses that are not supported here, but that's okay because this is served from the RFC 8414 OAuth 2.0 Authorization Server Metadata .well-known endpoint!

local st = require "util.stanza";

local omemo_namespace_prefix = "eu.siacs.conversations.axolotl."

module:hook("iq/bare/http://jabber.org/protocol/pubsub:pubsub", function (event)
	local origin, stanza = event.origin, event.stanza;

	local node = stanza.tags[1].tags[1].attr.node;
	if node and node:sub(1, #omemo_namespace_prefix) == omemo_namespace_prefix then
		origin.send(st.error_reply(stanza, "cancel", "item-not-found", "OMEMO is disabled"));
		return true;
	end
end, 10);