prosody
53e0ae770917
plugins/mod_vcard4.lua

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plugins/mod_vcard4.lua @ 12180:53e0ae770917

util.xml: Do not allow doctypes, comments or processing instructions Yes. This is as bad as it sounds. CVE pending. In Prosody itself, this only affects mod_websocket, which uses util.xml to parse the <open/> frame, thus allowing unauthenticated remote DoS using Billion Laughs. However, third-party modules using util.xml may also be affected by this. This commit installs handlers which disallow the use of doctype declarations and processing instructions without any escape hatch. It, by default, also introduces such a handler for comments, however, there is a way to enable comments nontheless. This is because util.xml is used to parse human-facing data, where comments are generally a desirable feature, and also because comments are generally harmless.
author Jonas Schäfer <jonas@wielicki.name>
date Mon, 10 Jan 2022 18:23:54 +0100
parent 10707:c4b49939b471
child 12977:74b9e05af71e
line wrap: on
line source

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

local mod_pep = module:depends("pep");

module:hook("account-disco-info", function (event)
	event.reply:tag("feature", { var = "urn:ietf:params:xml:ns:vcard-4.0" }):up();
end);

module:hook("iq-get/bare/urn:ietf:params:xml:ns:vcard-4.0:vcard", function (event)
	local origin, stanza = event.origin, event.stanza;

	local pep_service = mod_pep.get_pep_service(jid_split(stanza.attr.to) or origin.username);
	local ok, id, item = pep_service:get_last_item("urn:xmpp:vcard4", stanza.attr.from);
	if ok and item then
		origin.send(st.reply(stanza):add_child(item.tags[1]));
	elseif id == "item-not-found" or not id then
		origin.send(st.error_reply(stanza, "cancel", "item-not-found"));
	elseif id == "forbidden" then
		origin.send(st.error_reply(stanza, "auth", "forbidden"));
	else
		origin.send(st.error_reply(stanza, "modify", "undefined-condition"));
	end
	return true;
end);

module:hook("iq-set/self/urn:ietf:params:xml:ns:vcard-4.0:vcard", function (event)
	local origin, stanza = event.origin, event.stanza;

	local vcard4 = st.stanza("item", { xmlns = "http://jabber.org/protocol/pubsub", id = "current" })
		:add_child(stanza.tags[1]);

	local pep_service = mod_pep.get_pep_service(origin.username);

	local ok, err = pep_service:publish("urn:xmpp:vcard4", origin.full_jid, "current", vcard4);
	if ok then
		origin.send(st.reply(stanza));
	elseif err == "forbidden" then
		origin.send(st.error_reply(stanza, "auth", "forbidden"));
	else
		origin.send(st.error_reply(stanza, "modify", "undefined-condition", err));
	end
	return true;
end);