aboutsummaryrefslogtreecommitdiffstats
path: root/util/xmppstream.lua
blob: 69e7690d3b891cfe8919e20edb75d36e2997469a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
-- 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 tostring = tostring;
local t_insert = table.insert;
local t_concat = table.concat;

local default_log = require "util.logger".init("xmppstream");

-- COMPAT: w/LuaExpat 1.1.0
local lxp_supports_doctype = pcall(lxp.new, { StartDoctypeDecl = false });

if not lxp_supports_doctype then
	default_log("warn", "The version of LuaExpat on your system leaves Prosody "
		.."vulnerable to denial-of-service attacks. You should upgrade to "
		.."LuaExpat 1.1.1 or higher as soon as possible. See "
		.."http://prosody.im/doc/depends#luaexpat for more information.");
end

local error = error;

module "xmppstream"

local new_parser = lxp.new;

local ns_prefixes = {
	["http://www.w3.org/XML/1998/namespace"] = "xml";
};

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 log = session.log or default_log;
	
	local cb_streamopened = stream_callbacks.streamopened;
	local cb_streamclosed = stream_callbacks.streamclosed;
	local cb_error = stream_callbacks.error or function(session, e) error("XML stream error: "..tostring(e)); 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 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
			stanza:text(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
		
		-- FIXME !!!!!
		for i=1,#attr do
			local k = attr[i];
			attr[i] = nil;
			local ns, nm = k:match(ns_pattern);
			if nm ~= "" then
				ns = ns_prefixes[ns];
				if ns then
					attr[ns..":"..nm] = attr[k];
					attr[k] = nil;
				end
			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 = st.stanza(name, attr);
		else -- we are inside a stanza, so add a tag
			stanza:tag(name, attr);
		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
				stanza:text(t_concat(chardata));
				chardata = {};
			end
			-- Complete stanza
			local last_add = stanza.last_add;
			if not last_add or #last_add == 0 then
				if tagname ~= stream_error_tag then
					cb_handlestanza(session, stanza);
				else
					cb_error(session, "stream-error", stanza);
				end
				stanza = nil;
			else
				stanza:up();
			end
		else
			if tagname == stream_tag then
				if cb_streamclosed then
					cb_streamclosed(session);
				end
			else
				local curr_ns,name = tagname:match(ns_pattern);
				if name == "" then
					curr_ns, name = "", curr_ns;
				end
				cb_error(session, "parse-error", "unexpected-element-close", name);
			end
			stanza, chardata = nil, {};
		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() 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, {};
	end
	
	local function set_session(stream, new_session)
		session = new_session;
		log = new_session.log or default_log;
	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;