prosody
9e5802b45b9e
util/xmppstream.lua

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util/xmppstream.lua @ 13073:9e5802b45b9e

mod_tokenauth: Only check if expiry of expiring tokens Some tokens, e.g. OAuth2 refresh tokens, might not have their lifetime explicitly bounded here, but rather be bounded by the lifetime of something else, like the OAuth2 client. Open question: Would it be better to enforce a lifetime on all tokens?
author Kim Alvefur <zash@zash.se>
date Wed, 12 Apr 2023 10:21:32 +0200
parent 12975:d10957394a3c
line wrap: on
line source

-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local lxp = require "lxp";
local st = require "prosody.util.stanza";
local stanza_mt = st.stanza_mt;

local error = error;
local tostring = tostring;
local t_insert = table.insert;
local t_concat = table.concat;
local t_remove = table.remove;
local setmetatable = setmetatable;

-- COMPAT: w/LuaExpat 1.1.0
local lxp_supports_doctype = pcall(lxp.new, { StartDoctypeDecl = false });
local lxp_supports_xmldecl = pcall(lxp.new, { XmlDecl = false });
local lxp_supports_bytecount = not not lxp.new({}).getcurrentbytecount;

local default_stanza_size_limit = 1024*1024*1; -- 1MB

local _ENV = nil;
-- luacheck: std none

local new_parser = lxp.new;

local xml_namespace = {
	["http://www.w3.org/XML/1998/namespace\1lang"] = "xml:lang";
	["http://www.w3.org/XML/1998/namespace\1space"] = "xml:space";
	["http://www.w3.org/XML/1998/namespace\1base"] = "xml:base";
	["http://www.w3.org/XML/1998/namespace\1id"] = "xml:id";
};

local xmlns_streams = "http://etherx.jabber.org/streams";

local ns_separator = "\1";
local ns_pattern = "^([^"..ns_separator.."]*)"..ns_separator.."?(.*)$";

local function dummy_cb() end

local function new_sax_handlers(session, stream_callbacks, cb_handleprogress)
	local xml_handlers = {};

	local cb_streamopened = stream_callbacks.streamopened;
	local cb_streamclosed = stream_callbacks.streamclosed;
	local cb_error = stream_callbacks.error or
		function(_, e, stanza)
			error("XML stream error: "..tostring(e)..(stanza and ": "..tostring(stanza) or ""),2);
		end;
	local cb_handlestanza = stream_callbacks.handlestanza;
	cb_handleprogress = cb_handleprogress or dummy_cb;

	local stream_ns = stream_callbacks.stream_ns or xmlns_streams;
	local stream_tag = stream_callbacks.stream_tag or "stream";
	if stream_ns ~= "" then
		stream_tag = stream_ns..ns_separator..stream_tag;
	end
	local stream_error_tag = stream_ns..ns_separator..(stream_callbacks.error_tag or "error");

	local stream_default_ns = stream_callbacks.default_ns;

	local stream_lang = "en";

	local stack = {};
	local chardata, stanza = {};
	local stanza_size = 0;
	local non_streamns_depth = 0;
	function xml_handlers:StartElement(tagname, attr)
		if stanza and #chardata > 0 then
			-- We have some character data in the buffer
			t_insert(stanza, t_concat(chardata));
			chardata = {};
		end
		local curr_ns,name = tagname:match(ns_pattern);
		if name == "" then
			curr_ns, name = "", curr_ns;
		end

		if curr_ns ~= stream_default_ns or non_streamns_depth > 0 then
			attr.xmlns = curr_ns;
			non_streamns_depth = non_streamns_depth + 1;
		end

		for i=1,#attr do
			local k = attr[i];
			attr[i] = nil;
			local xmlk = xml_namespace[k];
			if xmlk then
				attr[xmlk] = attr[k];
				attr[k] = nil;
			end
		end

		if not stanza then --if we are not currently inside a stanza
			if lxp_supports_bytecount then
				stanza_size = self:getcurrentbytecount();
			end
			if session.notopen then
				if tagname == stream_tag then
					non_streamns_depth = 0;
					stream_lang = attr["xml:lang"] or stream_lang;
					if cb_streamopened then
						if lxp_supports_bytecount then
							cb_handleprogress(stanza_size);
							stanza_size = 0;
						end
						cb_streamopened(session, attr);
					end
				else
					-- Garbage before stream?
					cb_error(session, "no-stream", tagname);
				end
				return;
			end
			if curr_ns == "jabber:client" and name ~= "iq" and name ~= "presence" and name ~= "message" then
				cb_error(session, "invalid-top-level-element");
			end

			stanza = setmetatable({ name = name, attr = attr, tags = {} }, stanza_mt);
		else -- we are inside a stanza, so add a tag
			if lxp_supports_bytecount then
				stanza_size = stanza_size + self:getcurrentbytecount();
			end
			t_insert(stack, stanza);
			local oldstanza = stanza;
			stanza = setmetatable({ name = name, attr = attr, tags = {} }, stanza_mt);
			t_insert(oldstanza, stanza);
			t_insert(oldstanza.tags, stanza);
		end
	end

	function xml_handlers:StartCdataSection()
		if lxp_supports_bytecount then
			if stanza then
				stanza_size = stanza_size + self:getcurrentbytecount();
			else
				cb_handleprogress(self:getcurrentbytecount());
			end
		end
	end
	function xml_handlers:EndCdataSection()
		if lxp_supports_bytecount then
			if stanza then
				stanza_size = stanza_size + self:getcurrentbytecount();
			else
				cb_handleprogress(self:getcurrentbytecount());
			end
		end
	end
	function xml_handlers:CharacterData(data)
		if stanza then
			if lxp_supports_bytecount then
				stanza_size = stanza_size + self:getcurrentbytecount();
			end
			t_insert(chardata, data);
		elseif lxp_supports_bytecount then
			cb_handleprogress(self:getcurrentbytecount());
		end
	end
	function xml_handlers:EndElement(tagname)
		if lxp_supports_bytecount then
			stanza_size = stanza_size + self:getcurrentbytecount()
		end
		if non_streamns_depth > 0 then
			non_streamns_depth = non_streamns_depth - 1;
		end
		if stanza then
			if #chardata > 0 then
				-- We have some character data in the buffer
				t_insert(stanza, t_concat(chardata));
				chardata = {};
			end
			-- Complete stanza
			if #stack == 0 then
				if lxp_supports_bytecount then
					cb_handleprogress(stanza_size);
				end
				stanza_size = 0;
				if stanza.attr["xml:lang"] == nil then
					stanza.attr["xml:lang"] = stream_lang;
				end
				if tagname ~= stream_error_tag then
					cb_handlestanza(session, stanza);
				else
					cb_error(session, "stream-error", stanza);
				end
				stanza = nil;
			else
				stanza = t_remove(stack);
			end
		else
			if lxp_supports_bytecount then
				cb_handleprogress(stanza_size);
			end
			if cb_streamclosed then
				cb_streamclosed(session);
			end
		end
	end

	local function restricted_handler(parser)
		cb_error(session, "parse-error", "restricted-xml", "Restricted XML, see RFC 6120 section 11.1.");
		if not parser.stop or not parser:stop() then
			error("Failed to abort parsing");
		end
	end

	if lxp_supports_xmldecl then
		function xml_handlers:XmlDecl(version, encoding, standalone)
			if lxp_supports_bytecount then
				cb_handleprogress(self:getcurrentbytecount());
			end
			if (encoding and encoding:lower() ~= "utf-8")
			or (standalone == "no")
			or (version and version ~= "1.0") then
				return restricted_handler(self);
			end
		end
	end
	if lxp_supports_doctype then
		xml_handlers.StartDoctypeDecl = restricted_handler;
	end
	xml_handlers.Comment = restricted_handler;
	xml_handlers.ProcessingInstruction = restricted_handler;

	local function reset()
		stanza, chardata, stanza_size = nil, {}, 0;
		stack = {};
	end

	local function set_session(stream, new_session) -- luacheck: ignore 212/stream
		session = new_session;
	end

	return xml_handlers, { reset = reset, set_session = set_session };
end

local function new(session, stream_callbacks, stanza_size_limit)
	-- Used to track parser progress (e.g. to enforce size limits)
	local n_outstanding_bytes = 0;
	local handle_progress;
	if lxp_supports_bytecount then
		function handle_progress(n_parsed_bytes)
			n_outstanding_bytes = n_outstanding_bytes - n_parsed_bytes;
		end
		stanza_size_limit = stanza_size_limit or default_stanza_size_limit;
	elseif stanza_size_limit then
		error("Stanza size limits are not supported on this version of LuaExpat")
	end

	local handlers, meta = new_sax_handlers(session, stream_callbacks, handle_progress);
	local parser = new_parser(handlers, ns_separator, false);
	local parse = parser.parse;

	function session.open_stream(session, from, to) -- luacheck: ignore 432/session
		local send = session.sends2s or session.send;

		local attr = {
			["xmlns:stream"] = "http://etherx.jabber.org/streams",
			["xml:lang"] = "en",
			xmlns = stream_callbacks.default_ns,
			version = session.version and (session.version > 0 and "1.0" or nil),
			id = session.streamid or "",
			from = from or session.host, to = to,
		};
		if session.stream_attrs then
			session:stream_attrs(from, to, attr)
		end
		send("<?xml version='1.0'?>"..st.stanza("stream:stream", attr):top_tag());
		return true;
	end

	return {
		reset = function ()
			parser = new_parser(handlers, ns_separator, false);
			parse = parser.parse;
			n_outstanding_bytes = 0;
			meta.reset();
		end,
		feed = function (self, data) -- luacheck: ignore 212/self
			if lxp_supports_bytecount then
				n_outstanding_bytes = n_outstanding_bytes + #data;
			end
			local _parser = parser;
			local ok, err = parse(_parser, data);
			if lxp_supports_bytecount and n_outstanding_bytes > stanza_size_limit then
				return nil, "stanza-too-large";
			end
			if parser ~= _parser then
				_parser:parse();
				_parser:close();
			end
			return ok, err;
		end,
		set_session = meta.set_session;
		set_stanza_size_limit = function (_, new_stanza_size_limit)
			stanza_size_limit = new_stanza_size_limit;
		end;
	};
end

return {
	ns_separator = ns_separator;
	ns_pattern = ns_pattern;
	new_sax_handlers = new_sax_handlers;
	new = new;
};