Thu, 18 Feb 2010 17:12:37 +0000
HACKERS: Update
-- Prosody IM -- Copyright (C) 2008-2009 Matthew Wild -- Copyright (C) 2008-2009 Waqas Hussain -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- local hosts = hosts; local sessions = sessions; local core_process_stanza = function(a, b) core_process_stanza(a, b); end local add_task = require "util.timer".add_task; local socket = require "socket"; local format = string.format; local t_insert, t_sort = table.insert, table.sort; local get_traceback = debug.traceback; local tostring, pairs, ipairs, getmetatable, newproxy, error, tonumber = tostring, pairs, ipairs, getmetatable, newproxy, error, tonumber; local idna_to_ascii = require "util.encodings".idna.to_ascii; local connlisteners_get = require "net.connlisteners".get; local wrapclient = require "net.server".wrapclient; local modulemanager = require "core.modulemanager"; local st = require "stanza"; local stanza = st.stanza; local nameprep = require "util.encodings".stringprep.nameprep; local fire_event = require "core.eventmanager".fire_event; local uuid_gen = require "util.uuid".generate; local logger_init = require "util.logger".init; local log = logger_init("s2smanager"); local sha256_hash = require "util.hashes".sha256; local dialback_secret = uuid_gen(); local adns, dns = require "net.adns", require "net.dns"; local config = require "core.configmanager"; local connect_timeout = config.get("*", "core", "s2s_timeout") or 60; local dns_timeout = config.get("*", "core", "dns_timeout") or 60; local max_dns_depth = config.get("*", "core", "dns_max_depth") or 3; incoming_s2s = {}; _G.prosody.incoming_s2s = incoming_s2s; local incoming_s2s = incoming_s2s; module "s2smanager" function compare_srv_priorities(a,b) return a.priority < b.priority or (a.priority == b.priority and a.weight > b.weight); end local function bounce_sendq(session, reason) local sendq = session.sendq; if sendq then session.log("info", "sending error replies for "..#sendq.." queued stanzas because of failed outgoing connection to "..tostring(session.to_host)); local dummy = { type = "s2sin"; send = function(s) (session.log or log)("error", "Replying to to an s2s error reply, please report this! Traceback: %s", get_traceback()); end; dummy = true; }; for i, data in ipairs(sendq) do local reply = data[2]; local xmlns = reply.attr.xmlns; if not xmlns or xmlns == "jabber:client" or xmlns == "jabber:server" then reply.attr.type = "error"; reply:tag("error", {type = "cancel"}) :tag("remote-server-not-found", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"}):up(); if reason then reply:tag("text", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"}):text("Connection failed: "..reason):up(); end core_process_stanza(dummy, reply); end sendq[i] = nil; end session.sendq = nil; end end function send_to_host(from_host, to_host, data) if not hosts[from_host] then log("warn", "Attempt to send stanza from %s - a host we don't serve", from_host); return false; end local host = hosts[from_host].s2sout[to_host]; if host then -- We have a connection to this host already if host.type == "s2sout_unauthed" and (data.name ~= "db:verify" or not host.dialback_key) and ((not data.xmlns) or data.xmlns == "jabber:client" or data.xmlns == "jabber:server") then (host.log or log)("debug", "trying to send over unauthed s2sout to "..to_host); -- Queue stanza until we are able to send it if host.sendq then t_insert(host.sendq, {tostring(data), st.reply(data)}); else host.sendq = { {tostring(data), st.reply(data)} }; end host.log("debug", "stanza [%s] queued ", data.name); elseif host.type == "local" or host.type == "component" then log("error", "Trying to send a stanza to ourselves??") log("error", "Traceback: %s", get_traceback()); log("error", "Stanza: %s", tostring(data)); else (host.log or log)("debug", "going to send stanza to "..to_host.." from "..from_host); -- FIXME if host.from_host ~= from_host then log("error", "WARNING! This might, possibly, be a bug, but it might not..."); log("error", "We are going to send from %s instead of %s", tostring(host.from_host), tostring(from_host)); end host.sends2s(data); host.log("debug", "stanza sent over "..host.type); end else log("debug", "opening a new outgoing connection for this stanza"); local host_session = new_outgoing(from_host, to_host); -- Store in buffer host_session.sendq = { {tostring(data), st.reply(data)} }; log("debug", "stanza [%s] queued until connection complete", tostring(data.name)); if (not host_session.connecting) and (not host_session.conn) then log("warn", "Connection to %s failed already, destroying session...", to_host); destroy_session(host_session); end end end local open_sessions = 0; function new_incoming(conn) local session = { conn = conn, type = "s2sin_unauthed", direction = "incoming", hosts = {} }; if true then session.trace = newproxy(true); getmetatable(session.trace).__gc = function () open_sessions = open_sessions - 1; end; end open_sessions = open_sessions + 1; local w, log = conn.write, logger_init("s2sin"..tostring(conn):match("[a-f0-9]+$")); session.log = log; session.sends2s = function (t) log("debug", "sending: %s", tostring(t)); w(tostring(t)); end incoming_s2s[session] = true; add_task(connect_timeout, function () if session.conn ~= conn or session.type == "s2sin" then return; -- Ok, we're connect[ed|ing] end -- Not connected, need to close session and clean up (session.log or log)("warn", "Destroying incomplete session %s->%s due to inactivity", session.from_host or "(unknown)", session.to_host or "(unknown)"); session:close("connection-timeout"); end); return session; end function new_outgoing(from_host, to_host) local host_session = { to_host = to_host, from_host = from_host, host = from_host, notopen = true, type = "s2sout_unauthed", direction = "outgoing" }; hosts[from_host].s2sout[to_host] = host_session; local log; do local conn_name = "s2sout"..tostring(host_session):match("[a-f0-9]*$"); log = logger_init(conn_name); host_session.log = log; end -- Kick the connection attempting machine attempt_connection(host_session); if not host_session.sends2s then -- A sends2s which buffers data (until the stream is opened) -- note that data in this buffer will be sent before the stream is authed -- and will not be ack'd in any way, successful or otherwise local buffer; function host_session.sends2s(data) if not buffer then buffer = {}; host_session.send_buffer = buffer; end log("debug", "Buffering data on unconnected s2sout to %s", to_host); buffer[#buffer+1] = data; log("debug", "Buffered item %d: %s", #buffer, tostring(data)); end end return host_session; end function attempt_connection(host_session, err) local from_host, to_host = host_session.from_host, host_session.to_host; local connect_host, connect_port = idna_to_ascii(to_host), 5269; if not connect_host then return false; end if not err then -- This is our first attempt log("debug", "First attempt to connect to %s, starting with SRV lookup...", to_host); host_session.connecting = true; local handle; handle = adns.lookup(function (answer) handle = nil; host_session.connecting = nil; if answer then log("debug", to_host.." has SRV records, handling..."); local srv_hosts = {}; host_session.srv_hosts = srv_hosts; for _, record in ipairs(answer) do t_insert(srv_hosts, record.srv); end t_sort(srv_hosts, compare_srv_priorities); local srv_choice = srv_hosts[1]; host_session.srv_choice = 1; if srv_choice then connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port; log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port); end else log("debug", to_host.." has no SRV records, falling back to A"); end -- Try with SRV, or just the plain hostname if no SRV local ok, err = try_connect(host_session, connect_host, connect_port); if not ok then if not attempt_connection(host_session, err) then -- No more attempts will be made destroy_session(host_session, err); end end end, "_xmpp-server._tcp."..connect_host..".", "SRV"); -- Set handler for DNS timeout add_task(dns_timeout, function () if handle then adns.cancel(handle, true); end end); log("debug", "DNS lookup for %s sent, waiting for response before we can connect", to_host); return true; -- Attempt in progress elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV host_session.srv_choice = host_session.srv_choice + 1; local srv_choice = host_session.srv_hosts[host_session.srv_choice]; connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port; host_session.log("info", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port); else host_session.log("info", "Out of connection options, can't connect to %s", tostring(host_session.to_host)); -- We're out of options return false; end if not (connect_host and connect_port) then -- Likely we couldn't resolve DNS log("warn", "Hmm, we're without a host (%s) and port (%s) to connect to for %s, giving up :(", tostring(connect_host), tostring(connect_port), tostring(to_host)); return false; end return try_connect(host_session, connect_host, connect_port); end function try_connect(host_session, connect_host, connect_port) host_session.connecting = true; local handle; handle = adns.lookup(function (reply) handle = nil; host_session.connecting = nil; -- COMPAT: This is a compromise for all you CNAME-(ab)users :) if not (reply and reply[#reply] and reply[#reply].a) then local count = max_dns_depth; reply = dns.peek(connect_host, "CNAME", "IN"); while count > 0 and reply and reply[#reply] and not reply[#reply].a and reply[#reply].cname do log("debug", "Looking up %s (DNS depth is %d)", tostring(reply[#reply].cname), count); reply = dns.peek(reply[#reply].cname, "A", "IN") or dns.peek(reply[#reply].cname, "CNAME", "IN"); count = count - 1; end end -- end of CNAME resolving if reply and reply[#reply] and reply[#reply].a then log("debug", "DNS reply for %s gives us %s", connect_host, reply[#reply].a); return make_connect(host_session, reply[#reply].a, connect_port); else log("debug", "DNS lookup failed to get a response for %s", connect_host); if not attempt_connection(host_session, "name resolution failed") then -- Retry if we can log("debug", "No other records to try for %s - destroying", host_session.to_host); destroy_session(host_session, "DNS resolution failed"); -- End of the line, we can't end end end, connect_host, "A", "IN"); -- Set handler for DNS timeout add_task(dns_timeout, function () if handle then adns.cancel(handle, true); end end); return true; end function make_connect(host_session, connect_host, connect_port) host_session.log("info", "Beginning new connection attempt to %s (%s:%d)", host_session.to_host, connect_host, connect_port); -- Ok, we're going to try to connect local from_host, to_host = host_session.from_host, host_session.to_host; local conn, handler = socket.tcp() if not conn then log("warn", "Failed to create outgoing connection, system error: %s", handler); return false, handler; end conn:settimeout(0); local success, err = conn:connect(connect_host, connect_port); if not success and err ~= "timeout" then log("warn", "s2s connect() to %s (%s:%d) failed: %s", host_session.to_host, connect_host, connect_port, err); return false, err; end local cl = connlisteners_get("xmppserver"); conn = wrapclient(conn, connect_host, connect_port, cl, cl.default_mode or 1, hosts[from_host].ssl_ctx, false ); host_session.conn = conn; -- Register this outgoing connection so that xmppserver_listener knows about it -- otherwise it will assume it is a new incoming connection cl.register_outgoing(conn, host_session); local w, log = conn.write, host_session.log; host_session.sends2s = function (t) log("debug", "sending: %s", tostring(t)); w(tostring(t)); end conn.write(format([[<stream:stream xmlns='jabber:server' xmlns:db='jabber:server:dialback' xmlns:stream='http://etherx.jabber.org/streams' from='%s' to='%s' version='1.0' xml:lang='en'>]], from_host, to_host)); log("debug", "Connection attempt in progress..."); add_task(connect_timeout, function () if host_session.conn ~= conn or host_session.type == "s2sout" or host_session.connecting then return; -- Ok, we're connect[ed|ing] end -- Not connected, need to close session and clean up (host_session.log or log)("warn", "Destroying incomplete session %s->%s due to inactivity", host_session.from_host or "(unknown)", host_session.to_host or "(unknown)"); host_session:close("connection-timeout"); end); return true; end function streamopened(session, attr) local send = session.sends2s; -- TODO: #29: SASL/TLS on s2s streams session.version = tonumber(attr.version) or 0; if session.secure == false then session.secure = true; end if session.version >= 1.0 and not (attr.to and attr.from) then (session.log or log)("warn", "Remote of stream "..(session.from_host or "(unknown)").."->"..(session.to_host or "(unknown)") .." failed to specify to (%s) and/or from (%s) hostname as per RFC", tostring(attr.to), tostring(attr.from)); end if session.direction == "incoming" then -- Send a reply stream header session.to_host = attr.to and nameprep(attr.to); session.from_host = attr.from and nameprep(attr.from); session.streamid = uuid_gen(); (session.log or log)("debug", "incoming s2s received <stream:stream>"); if session.to_host and not hosts[session.to_host] then -- Attempting to connect to a host we don't serve session:close({ condition = "host-unknown"; text = "This host does not serve "..session.to_host }); return; end send("<?xml version='1.0'?>"); send(stanza("stream:stream", { xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback', ["xmlns:stream"]='http://etherx.jabber.org/streams', id=session.streamid, from=session.to_host, to=session.from_host, version=(session.version > 0 and "1.0" or nil) }):top_tag()); if session.version >= 1.0 then local features = st.stanza("stream:features"); if session.to_host then hosts[session.to_host].events.fire_event("s2s-stream-features", { session = session, features = features }); else (session.log or log)("warn", "No 'to' on stream header from %s means we can't offer any features", session.from_host or "unknown host"); end log("debug", "Sending stream features: %s", tostring(features)); send(features); end elseif session.direction == "outgoing" then -- If we are just using the connection for verifying dialback keys, we won't try and auth it if not attr.id then error("stream response did not give us a streamid!!!"); end session.streamid = attr.id; -- Send unauthed buffer -- (stanzas which are fine to send before dialback) -- Note that this is *not* the stanza queue (which -- we can only send if auth succeeds) :) local send_buffer = session.send_buffer; if send_buffer and #send_buffer > 0 then log("debug", "Sending s2s send_buffer now..."); for i, data in ipairs(send_buffer) do session.sends2s(data); send_buffer[i] = nil; end end session.send_buffer = nil; -- If server is pre-1.0, don't wait for features, just do dialback if session.version < 1.0 then if not session.dialback_verifying then log("debug", "Initiating dialback..."); initiate_dialback(session); else mark_connected(session); end end end session.notopen = nil; end function streamclosed(session) (session.log or log)("debug", "</stream:stream>"); if session.sends2s then session.sends2s("</stream:stream>"); end session.notopen = true; end function initiate_dialback(session) -- generate dialback key session.dialback_key = generate_dialback(session.streamid, session.to_host, session.from_host); session.sends2s(format("<db:result from='%s' to='%s'>%s</db:result>", session.from_host, session.to_host, session.dialback_key)); session.log("info", "sent dialback key on outgoing s2s stream"); end function generate_dialback(id, to, from) return sha256_hash(id..to..from..dialback_secret, true); end function verify_dialback(id, to, from, key) return key == generate_dialback(id, to, from); end function make_authenticated(session, host) if not session.secure then local local_host = session.direction == "incoming" and session.to_host or session.from_host; if config.get(local_host, "core", "s2s_require_encryption") then session:close({ condition = "policy-violation", text = "Encrypted server-to-server communication is required but was not " ..((session.direction == "outgoing" and "offered") or "used") }); end end if session.type == "s2sout_unauthed" then session.type = "s2sout"; elseif session.type == "s2sin_unauthed" then session.type = "s2sin"; if host then session.hosts[host].authed = true; end elseif session.type == "s2sin" and host then session.hosts[host].authed = true; else return false; end session.log("debug", "connection %s->%s is now authenticated", session.from_host or "(unknown)", session.to_host or "(unknown)"); mark_connected(session); return true; end -- Stream is authorised, and ready for normal stanzas function mark_connected(session) local sendq, send = session.sendq, session.sends2s; local from, to = session.from_host, session.to_host; session.log("info", session.direction.." s2s connection "..from.."->"..to.." complete"); local send_to_host = send_to_host; function session.send(data) send_to_host(to, from, data); end if session.direction == "outgoing" then if sendq then session.log("debug", "sending "..#sendq.." queued stanzas across new outgoing connection to "..session.to_host); for i, data in ipairs(sendq) do send(data[1]); sendq[i] = nil; end session.sendq = nil; end session.srv_hosts = nil; end end function destroy_session(session, reason) (session.log or log)("info", "Destroying "..tostring(session.direction).." session "..tostring(session.from_host).."->"..tostring(session.to_host)); if session.direction == "outgoing" then hosts[session.from_host].s2sout[session.to_host] = nil; bounce_sendq(session, reason); elseif session.direction == "incoming" then incoming_s2s[session] = nil; end for k in pairs(session) do if k ~= "trace" then session[k] = nil; end end end return _M;