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prosody
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plugins/mod_admin_socket.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 | 10866:5265f7fe11dd |
child | 12392:5373724e08a5 |
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module:set_global(); local have_unix, unix = pcall(require, "socket.unix"); if not have_unix or type(unix) ~= "table" then module:log_status("error", "LuaSocket unix socket support not available or incompatible, ensure it is up to date"); return; end local server = require "net.server"; local adminstream = require "util.adminstream"; local socket_path = module:get_option_path("admin_socket", "prosody.sock", "data"); local sessions = module:shared("sessions"); local function fire_admin_event(session, stanza) local event_data = { origin = session, stanza = stanza; }; local event_name; if stanza.attr.xmlns then event_name = "admin/"..stanza.attr.xmlns..":"..stanza.name; else event_name = "admin/"..stanza.name; end module:log("debug", "Firing %s", event_name); return module:fire_event(event_name, event_data); end module:hook("server-stopping", function () for _, session in pairs(sessions) do session:close("system-shutdown"); end os.remove(socket_path); end); --- Unix domain socket management local conn, sock; local listeners = adminstream.server(sessions, fire_admin_event).listeners; local function accept_connection() module:log("debug", "accepting..."); local client = sock:accept(); if not client then return; end server.wrapclient(client, "unix", 0, listeners, "*a"); end function module.load() sock = unix.stream(); sock:settimeout(0); os.remove(socket_path); assert(sock:bind(socket_path)); assert(sock:listen()); if server.wrapserver then conn = server.wrapserver(sock, socket_path, 0, listeners); else conn = server.watchfd(sock:getfd(), accept_connection); end end function module.unload() if conn then conn:close(); end if sock then sock:close(); end os.remove(socket_path); end