prosody/util/xmppstream.lua

312 lines
8.9 KiB
Lua

-- 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;
};