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plugins/adhoc/adhoc.lib.lua @ 12181:783056b4e448 0.11 0.11.12
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 | 8472:d88dc6827675 |
child | 10565:421b2f8369fd |
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-- Copyright (C) 2009-2010 Florian Zeitz -- -- This file is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- local st, uuid = require "util.stanza", require "util.uuid"; local xmlns_cmd = "http://jabber.org/protocol/commands"; local states = {} local _M = {}; local function _cmdtag(desc, status, sessionid, action) local cmd = st.stanza("command", { xmlns = xmlns_cmd, node = desc.node, status = status }); if sessionid then cmd.attr.sessionid = sessionid; end if action then cmd.attr.action = action; end return cmd; end function _M.new(name, node, handler, permission) return { name = name, node = node, handler = handler, cmdtag = _cmdtag, permission = (permission or "user") }; end function _M.handle_cmd(command, origin, stanza) local cmdtag = stanza.tags[1] local sessionid = cmdtag.attr.sessionid or uuid.generate(); local dataIn = { to = stanza.attr.to; from = stanza.attr.from; action = cmdtag.attr.action or "execute"; form = cmdtag:get_child("x", "jabber:x:data"); }; local data, state = command:handler(dataIn, states[sessionid]); states[sessionid] = state; local cmdreply; if data.status == "completed" then states[sessionid] = nil; cmdreply = command:cmdtag("completed", sessionid); elseif data.status == "canceled" then states[sessionid] = nil; cmdreply = command:cmdtag("canceled", sessionid); elseif data.status == "error" then states[sessionid] = nil; local reply = st.error_reply(stanza, data.error.type, data.error.condition, data.error.message); origin.send(reply); return true; else cmdreply = command:cmdtag("executing", sessionid); data.actions = data.actions or { "complete" }; end for name, content in pairs(data) do if name == "info" then cmdreply:tag("note", {type="info"}):text(content):up(); elseif name == "warn" then cmdreply:tag("note", {type="warn"}):text(content):up(); elseif name == "error" then cmdreply:tag("note", {type="error"}):text(content.message):up(); elseif name == "actions" then local actions = st.stanza("actions", { execute = content.default }); for _, action in ipairs(content) do if (action == "prev") or (action == "next") or (action == "complete") then actions:tag(action):up(); else module:log("error", "Command %q at node %q provided an invalid action %q", command.name, command.node, action); end end cmdreply:add_child(actions); elseif name == "form" then cmdreply:add_child((content.layout or content):form(content.values)); elseif name == "result" then cmdreply:add_child((content.layout or content):form(content.values, "result")); elseif name == "other" then cmdreply:add_child(content); end end local reply = st.reply(stanza); reply:add_child(cmdreply); origin.send(reply); return true; end return _M;