File

plugins/muc/lock.lib.lua @ 11665:148075532021

net.server_epoll: Prevent stack overflow of opportunistic writes net.http.files serving a big enough file on a fast enough connection with opportunistic_writes enabled could trigger a stack overflow through repeatedly serving more data that immediately gets sent, draining the buffer and triggering more data to be sent. This also blocked the server on a single task until completion or an error. This change prevents nested opportunistic writes, which should prevent the stack overflow, at the cost of reduced download speed, but this is unlikely to be noticeable outside of Gbit networks. Speed at the cost of blocking other processing is not worth it, especially with the risk of stack overflow.
author Kim Alvefur <zash@zash.se>
date Sun, 11 Jul 2021 09:39:21 +0200
parent 10450:c1edeb9fe337
child 12977:74b9e05af71e
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-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
-- Copyright (C) 2014 Daurnimator
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local st = require "util.stanza";

local lock_rooms = module:get_option_boolean("muc_room_locking", true);
local lock_room_timeout = module:get_option_number("muc_room_lock_timeout", 300);

local function lock(room)
	module:fire_event("muc-room-locked", {room = room;});
	room._data.locked = os.time() + lock_room_timeout;
end
local function unlock(room)
	module:fire_event("muc-room-unlocked", {room = room;});
	room._data.locked = nil;
end
local function is_locked(room)
	local ts = room._data.locked;
	if ts then
		if os.time() < ts then return true; end
		unlock(room);
	end
	return false;
end

if lock_rooms then
	module:hook("muc-room-pre-create", function(event)
		-- Older groupchat protocol doesn't lock
		if not event.stanza:get_child("x", "http://jabber.org/protocol/muc") then return end
		-- Lock room at creation
		local room = event.room;
		lock(room);
	end, 10);
end

-- Don't let users into room while it is locked
module:hook("muc-occupant-pre-join", function(event)
	if not event.is_new_room and is_locked(event.room) then -- Deny entry
		module:log("debug", "Room is locked, denying entry");
		event.origin.send(st.error_reply(event.stanza, "cancel", "item-not-found", nil, module.host));
		return true;
	end
end, -30);

-- When config is submitted; unlock the room
module:hook("muc-config-submitted", function(event)
	if is_locked(event.room) then
		unlock(event.room);
	end
end, -1);

return {
	lock = lock;
	unlock = unlock;
	is_locked = is_locked;
};