File

util/xmppstream.lua @ 5915:e6fed1d80116

Back out 1b0ac7950129, as SSLv3 appears to still be in moderate use on the network. Also, although obsolete, SSLv3 isn't documented to have any weaknesses that TLS 1.0 (the most common version used today) doesn't also have. Get your act together clients!
author Matthew Wild <mwild1@gmail.com>
date Tue, 12 Nov 2013 02:13:01 +0000
parent 5311:86fe6e2fa5ae
child 5776:bd0ff8ae98a8
child 6042:1107d66d2ab2
line wrap: on
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-- 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 "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 });

module "xmppstream"

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.."?(.*)$";

_M.ns_separator = ns_separator;
_M.ns_pattern = ns_pattern;

function new_sax_handlers(session, stream_callbacks)
	local xml_handlers = {};
	
	local cb_streamopened = stream_callbacks.streamopened;
	local cb_streamclosed = stream_callbacks.streamclosed;
	local cb_error = stream_callbacks.error or function(session, e, stanza) error("XML stream error: "..tostring(e)..(stanza and ": "..tostring(stanza) or ""),2); end;
	local cb_handlestanza = stream_callbacks.handlestanza;
	
	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 stack = {};
	local chardata, stanza = {};
	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 session.notopen then
				if tagname == stream_tag then
					non_streamns_depth = 0;
					if cb_streamopened then
						cb_streamopened(session, attr);
					end
				else
					-- Garbage before stream?
					cb_error(session, "no-stream");
				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
			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:CharacterData(data)
		if stanza then
			t_insert(chardata, data);
		end
	end
	function xml_handlers:EndElement(tagname)
		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 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 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_doctype then
		xml_handlers.StartDoctypeDecl = restricted_handler;
	end
	xml_handlers.Comment = restricted_handler;
	xml_handlers.ProcessingInstruction = restricted_handler;
	
	local function reset()
		stanza, chardata = nil, {};
		stack = {};
	end
	
	local function set_session(stream, new_session)
		session = new_session;
	end
	
	return xml_handlers, { reset = reset, set_session = set_session };
end

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

	return {
		reset = function ()
			parser = new_parser(handlers, ns_separator);
			parse = parser.parse;
			meta.reset();
		end,
		feed = function (self, data)
			return parse(parser, data);
		end,
		set_session = meta.set_session;
	};
end

return _M;