plugins/adhoc/mod_adhoc.lua
author Jonas Schäfer <jonas@wielicki.name>
Mon, 10 Jan 2022 18:23:54 +0100
branch0.11
changeset 12185 783056b4e448
parent 9574 5c475f6e89a4
child 10546 f1886a48a6d4
permissions -rw-r--r--
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.

-- 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_split = require "util.jid".split;
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 username, hostname = jid_split(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 == "user") 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 username, hostname = jid_split(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 == "user") 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 username, hostname = jid_split(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;
	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);