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
|
-- 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 format = string.format;
local hosts = _G.hosts;
local s2s_make_authenticated = require "core.s2smanager".make_authenticated;
local log = module._log;
local st = require "util.stanza";
local sha256_hash = require "util.hashes".sha256;
local nameprep = require "util.encodings".stringprep.nameprep;
local xmlns_stream = "http://etherx.jabber.org/streams";
local dialback_requests = setmetatable({}, { __mode = 'v' });
function generate_dialback(id, to, from)
return sha256_hash(id..to..from..hosts[from].dialback_secret, 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 verify_dialback(id, to, from, key)
return key == generate_dialback(id, to, from);
end
module:hook("stanza/jabber:server:dialback:verify", function(event)
local origin, stanza = event.origin, event.stanza;
if origin.type == "s2sin_unauthed" or origin.type == "s2sin" then
-- We are being asked to verify the key, to ensure it was generated by us
origin.log("debug", "verifying that dialback key is ours...");
local attr = stanza.attr;
-- COMPAT: Grr, ejabberd breaks this one too?? it is black and white in XEP-220 example 34
--if attr.from ~= origin.to_host then error("invalid-from"); end
local type;
if verify_dialback(attr.id, attr.from, attr.to, stanza[1]) then
type = "valid"
else
type = "invalid"
origin.log("warn", "Asked to verify a dialback key that was incorrect. An imposter is claiming to be %s?", attr.to);
end
origin.log("debug", "verified dialback key... it is %s", type);
origin.sends2s(st.stanza("db:verify", { from = attr.to, to = attr.from, id = attr.id, type = type }):text(stanza[1]));
return true;
end
end);
module:hook("stanza/jabber:server:dialback:result", function(event)
local origin, stanza = event.origin, event.stanza;
if origin.type == "s2sin_unauthed" or origin.type == "s2sin" then
-- he wants to be identified through dialback
-- We need to check the key with the Authoritative server
local attr = stanza.attr;
origin.hosts[attr.from] = { dialback_key = stanza[1] };
if not hosts[attr.to] then
-- Not a host that we serve
origin.log("info", "%s tried to connect to %s, which we don't serve", attr.from, attr.to);
origin:close("host-unknown");
return true;
end
dialback_requests[attr.from.."/"..origin.streamid] = origin;
if not origin.from_host then
-- Just used for friendlier logging
origin.from_host = nameprep(attr.from);
-- COMPAT: Fix ejabberd chopness by resetting the send function
if not origin.from_host then
origin.log("debug", "We need to know where to connect but remote server blindly refuses to tell us and to comply to specs, closing connection.");
origin:close("invalid-from");
else
origin.log("debug", "Remote server didn't specify a from attr, resetting session.send now that we know where to knock to.");
origin.send = function(stanza) hosts[attr.to].events.fire_event("route/remote", { from_host = origin.to_host, to_host = origin.from_host, stanza = stanza}); end
end
end
if not origin.to_host then
-- Just used for friendlier logging
origin.to_host = attr.to;
end
origin.log("debug", "asking %s if key %s belongs to them", attr.from, stanza[1]);
origin.send(st.stanza("db:verify", { from = attr.to, to = attr.from, id = origin.streamid }):text(stanza[1]));
return true;
end
end);
module:hook("stanza/jabber:server:dialback:verify", function(event)
local origin, stanza = event.origin, event.stanza;
if origin.type == "s2sout_unauthed" or origin.type == "s2sout" then
local attr = stanza.attr;
local dialback_verifying = dialback_requests[attr.from.."/"..(attr.id or "")];
module:log("debug", tostring(dialback_verifying).." "..attr.from.." "..origin.to_host);
if dialback_verifying and attr.from == origin.to_host then
local valid;
if attr.type == "valid" then
s2s_make_authenticated(dialback_verifying, attr.from);
valid = "valid";
else
-- Warn the original connection that is was not verified successfully
log("warn", "authoritative server for "..(attr.from or "(unknown)").." denied the key");
valid = "invalid";
end
if not dialback_verifying.sends2s then
log("warn", "Incoming s2s session %s was closed in the meantime, so we can't notify it of the db result", tostring(dialback_verifying):match("%w+$"));
else
dialback_verifying.sends2s(
st.stanza("db:result", { from = attr.to, to = attr.from, id = attr.id, type = valid })
:text(dialback_verifying.hosts[attr.from].dialback_key));
end
dialback_requests[attr.from.."/"..(attr.id or "")] = nil;
end
return true;
end
end);
module:hook("stanza/jabber:server:dialback:result", function(event)
local origin, stanza = event.origin, event.stanza;
if origin.type == "s2sout_unauthed" or origin.type == "s2sout" then
-- Remote server is telling us whether we passed dialback
local attr = stanza.attr;
if not hosts[attr.to] then
origin:close("host-unknown");
return true;
elseif hosts[attr.to].s2sout[attr.from] ~= origin then
-- This isn't right
origin:close("invalid-id");
return true;
end
if stanza.attr.type == "valid" then
s2s_make_authenticated(origin, attr.from);
else
origin:close("not-authorized", "dialback authentication failed");
end
return true;
end
end);
module:hook_stanza("urn:ietf:params:xml:ns:xmpp-sasl", "failure", function (origin, stanza)
if origin.external_auth == "failed" then
module:log("debug", "SASL EXTERNAL failed, falling back to dialback");
initiate_dialback(origin);
return true;
end
end, 100);
module:hook_stanza(xmlns_stream, "features", function (origin, stanza)
if not origin.external_auth or origin.external_auth == "failed" then
module:log("debug", "Initiating dialback...");
initiate_dialback(origin);
return true;
end
end, 100);
module:hook("s2s-authenticate-legacy", function (event)
module:log("debug", "Initiating dialback...");
initiate_dialback(event.origin);
return true;
end, 100);
-- Offer dialback to incoming hosts
module:hook("s2s-stream-features", function (data)
data.features:tag("dialback", { xmlns='urn:xmpp:features:dialback' }):up();
end);
|
