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
|
%%%----------------------------------------------------------------------
%%% File : cyrsasl_digest.erl
%%% Author : Alexey Shchepin <alexey@sevcom.net>
%%% Purpose : DIGEST-MD5 SASL mechanism
%%% Created : 11 Mar 2003 by Alexey Shchepin <alexey@sevcom.net>
%%% Id : $Id$
%%%----------------------------------------------------------------------
-module(cyrsasl_digest).
-author('alexey@sevcom.net').
-export([start/1,
stop/0,
mech_new/3,
mech_step/2]).
-include("ejabberd.hrl").
-behaviour(cyrsasl).
-record(state, {step, nonce, username, authzid, get_password, auth_module,
host}).
start(_Opts) ->
cyrsasl:register_mechanism("DIGEST-MD5", ?MODULE, true).
stop() ->
ok.
mech_new(Host, GetPassword, _CheckPassword) ->
{ok, #state{step = 1,
nonce = randoms:get_string(),
host = Host,
get_password = GetPassword}}.
mech_step(#state{step = 1, nonce = Nonce} = State, _) ->
{continue,
"nonce=\"" ++ Nonce ++
"\",qop=\"auth\",charset=utf-8,algorithm=md5-sess",
State#state{step = 3}};
mech_step(#state{step = 3, nonce = Nonce} = State, ClientIn) ->
case parse(ClientIn) of
bad ->
{error, "bad-protocol"};
KeyVals ->
DigestURI = xml:get_attr_s("digest-uri", KeyVals),
UserName = xml:get_attr_s("username", KeyVals),
case is_digesturi_valid(DigestURI, State#state.host) of
false ->
?DEBUG("User login not authorized because digest-uri "
"seems invalid: ~p", [DigestURI]),
{error, "not-authorized", UserName};
true ->
AuthzId = xml:get_attr_s("authzid", KeyVals),
case (State#state.get_password)(UserName) of
{false, _} ->
{error, "not-authorized", UserName};
{Passwd, AuthModule} ->
Response = response(KeyVals, UserName, Passwd,
Nonce, AuthzId, "AUTHENTICATE"),
case xml:get_attr_s("response", KeyVals) of
Response ->
RspAuth = response(KeyVals,
UserName, Passwd,
Nonce, AuthzId, ""),
{continue,
"rspauth=" ++ RspAuth,
State#state{step = 5,
auth_module = AuthModule,
username = UserName,
authzid = AuthzId}};
_ ->
{error, "not-authorized", UserName}
end
end
end
end;
mech_step(#state{step = 5,
auth_module = AuthModule,
username = UserName,
authzid = AuthzId}, "") ->
{ok, [{username, UserName}, {authzid, AuthzId},
{auth_module, AuthModule}]};
mech_step(A, B) ->
?DEBUG("SASL DIGEST: A ~p B ~p", [A,B]),
{error, "bad-protocol"}.
parse(S) ->
parse1(S, "", []).
parse1([$= | Cs], S, Ts) ->
parse2(Cs, lists:reverse(S), "", Ts);
parse1([$, | Cs], [], Ts) ->
parse1(Cs, [], Ts);
parse1([$\s | Cs], [], Ts) ->
parse1(Cs, [], Ts);
parse1([C | Cs], S, Ts) ->
parse1(Cs, [C | S], Ts);
parse1([], [], T) ->
lists:reverse(T);
parse1([], _S, _T) ->
bad.
parse2([$\" | Cs], Key, Val, Ts) ->
parse3(Cs, Key, Val, Ts);
parse2([C | Cs], Key, Val, Ts) ->
parse4(Cs, Key, [C | Val], Ts);
parse2([], _, _, _) ->
bad.
parse3([$\" | Cs], Key, Val, Ts) ->
parse4(Cs, Key, Val, Ts);
parse3([$\\, C | Cs], Key, Val, Ts) ->
parse3(Cs, Key, [C | Val], Ts);
parse3([C | Cs], Key, Val, Ts) ->
parse3(Cs, Key, [C | Val], Ts);
parse3([], _, _, _) ->
bad.
parse4([$, | Cs], Key, Val, Ts) ->
parse1(Cs, "", [{Key, lists:reverse(Val)} | Ts]);
parse4([$\s | Cs], Key, Val, Ts) ->
parse4(Cs, Key, Val, Ts);
parse4([C | Cs], Key, Val, Ts) ->
parse4(Cs, Key, [C | Val], Ts);
parse4([], Key, Val, Ts) ->
parse1([], "", [{Key, lists:reverse(Val)} | Ts]).
%% @doc Check if the digest-uri is valid.
%% RFC-2831 allows to provide the IP address in Host,
%% however ejabberd doesn't allow that.
%% If the service (for example jabber.example.org)
%% is provided by several hosts (being one of them server3.example.org),
%% then digest-uri can be like xmpp/server3.example.org/jabber.example.org
%% In that case, ejabberd only checks the service name, not the host.
is_digesturi_valid(DigestURICase, JabberHost) ->
DigestURI = stringprep:tolower(DigestURICase),
case catch string:tokens(DigestURI, "/") of
["xmpp", Host] when Host == JabberHost ->
true;
["xmpp", _Host, ServName] when ServName == JabberHost ->
true;
_ ->
false
end.
digit_to_xchar(D) when (D >= 0) and (D < 10) ->
D + 48;
digit_to_xchar(D) ->
D + 87.
hex(S) ->
hex(S, []).
hex([], Res) ->
lists:reverse(Res);
hex([N | Ns], Res) ->
hex(Ns, [digit_to_xchar(N rem 16),
digit_to_xchar(N div 16) | Res]).
response(KeyVals, User, Passwd, Nonce, AuthzId, A2Prefix) ->
Realm = xml:get_attr_s("realm", KeyVals),
CNonce = xml:get_attr_s("cnonce", KeyVals),
DigestURI = xml:get_attr_s("digest-uri", KeyVals),
NC = xml:get_attr_s("nc", KeyVals),
QOP = xml:get_attr_s("qop", KeyVals),
A1 = case AuthzId of
"" ->
binary_to_list(
crypto:md5(User ++ ":" ++ Realm ++ ":" ++ Passwd)) ++
":" ++ Nonce ++ ":" ++ CNonce;
_ ->
binary_to_list(
crypto:md5(User ++ ":" ++ Realm ++ ":" ++ Passwd)) ++
":" ++ Nonce ++ ":" ++ CNonce ++ ":" ++ AuthzId
end,
A2 = case QOP of
"auth" ->
A2Prefix ++ ":" ++ DigestURI;
_ ->
A2Prefix ++ ":" ++ DigestURI ++
":00000000000000000000000000000000"
end,
T = hex(binary_to_list(crypto:md5(A1))) ++ ":" ++ Nonce ++ ":" ++
NC ++ ":" ++ CNonce ++ ":" ++ QOP ++ ":" ++
hex(binary_to_list(crypto:md5(A2))),
hex(binary_to_list(crypto:md5(T))).
|
