File

plugins/adhoc/mod_adhoc.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 11209:f6661fac7e9a
child 12387:05c250fa335a
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line source

-- Copyright (C) 2009 Thilo Cestonaro
-- Copyright (C) 2009-2011 Florian Zeitz
--
-- This file is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local it = require "util.iterators";
local st = require "util.stanza";
local is_admin = require "core.usermanager".is_admin;
local jid_host = require "util.jid".host;
local adhoc_handle_cmd = module:require "adhoc".handle_cmd;
local xmlns_cmd = "http://jabber.org/protocol/commands";
local commands = {};

module:add_feature(xmlns_cmd);

module:hook("host-disco-info-node", function (event)
	local stanza, origin, reply, node = event.stanza, event.origin, event.reply, event.node;
	if commands[node] then
		local from = stanza.attr.from;
		local privileged = is_admin(from, stanza.attr.to);
		local global_admin = is_admin(from);
		local hostname = jid_host(from);
		local command = commands[node];
		if (command.permission == "admin" and privileged)
		    or (command.permission == "global_admin" and global_admin)
		    or (command.permission == "local_user" and hostname == module.host)
		    or (command.permission == "any") then
			reply:tag("identity", { name = command.name,
			    category = "automation", type = "command-node" }):up();
			reply:tag("feature", { var = xmlns_cmd }):up();
			reply:tag("feature", { var = "jabber:x:data" }):up();
			event.exists = true;
		else
			origin.send(st.error_reply(stanza, "auth", "forbidden", "This item is not available to you"));
			return true;
		end
	elseif node == xmlns_cmd then
		reply:tag("identity", { name = "Ad-Hoc Commands",
		    category = "automation", type = "command-list" }):up();
		    event.exists = true;
	end
end);

module:hook("host-disco-items-node", function (event)
	local stanza, reply, disco_node = event.stanza, event.reply, event.node;
	if disco_node ~= xmlns_cmd then
		return;
	end

	local from = stanza.attr.from;
	local admin = is_admin(from, stanza.attr.to);
	local global_admin = is_admin(from);
	local hostname = jid_host(from);
	for node, command in it.sorted_pairs(commands) do
		if (command.permission == "admin" and admin)
		    or (command.permission == "global_admin" and global_admin)
		    or (command.permission == "local_user" and hostname == module.host)
		    or (command.permission == "any") then
			reply:tag("item", { name = command.name,
			    node = node, jid = module:get_host() });
			reply:up();
		end
	end
	event.exists = true;
end);

module:hook("iq-set/host/"..xmlns_cmd..":command", function (event)
	local origin, stanza = event.origin, event.stanza;
	local node = stanza.tags[1].attr.node
	local command = commands[node];
	if command then
		local from = stanza.attr.from;
		local admin = is_admin(from, stanza.attr.to);
		local global_admin = is_admin(from);
		local hostname = jid_host(from);
		if (command.permission == "admin" and not admin)
		    or (command.permission == "global_admin" and not global_admin)
		    or (command.permission == "local_user" and hostname ~= module.host) then
			origin.send(st.error_reply(stanza, "auth", "forbidden", "You don't have permission to execute this command"):up()
			    :add_child(commands[node]:cmdtag("canceled")
				:tag("note", {type="error"}):text("You don't have permission to execute this command")));
			return true
		end
		-- User has permission now execute the command
		adhoc_handle_cmd(commands[node], origin, stanza);
		return true;
	end
end, 500);

local function adhoc_added(event)
	local item = event.item;
	-- Dang this was noicy
	module:log("debug", "Command added by mod_%s: %q, %q", item._provided_by or "<unknown module>", item.name, item.node);
	commands[item.node] = item;
end

local function adhoc_removed(event)
	commands[event.item.node] = nil;
end

module:handle_items("adhoc", adhoc_added, adhoc_removed); -- COMPAT pre module:provides() introduced in 0.9
module:handle_items("adhoc-provider", adhoc_added, adhoc_removed);