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
|
/*
Unix SMB/CIFS implementation.
Copyright (C) Andrew Tridgell 2004
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
/*
sign an outgoing packet
*/
void req_sign_packet(struct smbsrv_request *req)
{
#if 0
/* enable this when packet signing is preventing you working out why valgrind
says that data is uninitialised */
file_save("pkt.dat", req->out.buffer, req->out.size);
#endif
switch (req->smb_conn->signing.signing_state) {
case SMB_SIGNING_ENGINE_OFF:
break;
case SMB_SIGNING_ENGINE_BSRSPYL:
/* mark the packet as signed - BEFORE we sign it...*/
mark_packet_signed(&req->out);
/* I wonder what BSRSPYL stands for - but this is what MS
actually sends! */
memcpy((req->out.hdr + HDR_SS_FIELD), "BSRSPYL ", 8);
break;
case SMB_SIGNING_ENGINE_ON:
sign_outgoing_message(&req->out,
&req->smb_conn->signing.mac_key,
req->seq_num+1);
break;
}
return;
}
/*
setup the signing key for a connection. Called after authentication succeeds
in a session setup
*/
BOOL srv_setup_signing(struct smbsrv_connection *smb_conn,
DATA_BLOB *session_key,
DATA_BLOB *response)
{
if (!set_smb_signing_common(&smb_conn->signing)) {
return False;
}
return smbcli_simple_set_signing(smb_conn,
&smb_conn->signing, session_key, response);
}
void srv_signing_restart(struct smbsrv_connection *smb_conn,
DATA_BLOB *session_key,
DATA_BLOB *response)
{
if (!smb_conn->signing.seen_valid) {
DEBUG(5, ("Client did not send a valid signature on "
"SPENGO session setup - ignored, expect good next time\n"));
/* force things back on (most clients do not sign this packet)... */
srv_setup_signing(smb_conn, session_key, response);
smb_conn->signing.next_seq_num = 2;
if (smb_conn->signing.mandatory_signing) {
DEBUG(5, ("Configured for mandetory signing, 'good packet seen' forced on\n"));
/* if this is mandetory, then
* pretend we have seen a
* valid packet, so we don't
* turn it off */
smb_conn->signing.seen_valid = True;
}
}
}
BOOL srv_init_signing(struct smbsrv_connection *smb_conn)
{
smb_conn->signing.mac_key = data_blob(NULL, 0);
if (!smbcli_set_signing_off(&smb_conn->signing)) {
return False;
}
switch (lp_server_signing()) {
case SMB_SIGNING_OFF:
smb_conn->signing.allow_smb_signing = False;
break;
case SMB_SIGNING_SUPPORTED:
smb_conn->signing.allow_smb_signing = True;
break;
case SMB_SIGNING_REQUIRED:
smb_conn->signing.allow_smb_signing = True;
smb_conn->signing.mandatory_signing = True;
break;
case SMB_SIGNING_AUTO:
if (lp_domain_logons()) {
smb_conn->signing.allow_smb_signing = True;
} else {
smb_conn->signing.allow_smb_signing = False;
}
break;
}
return True;
}
/*
allocate a sequence number to a request
*/
static void req_signing_alloc_seq_num(struct smbsrv_request *req)
{
req->seq_num = req->smb_conn->signing.next_seq_num;
/* TODO: we need to handle one-way requests like NTcancel, which
only increment the sequence number by 1 */
if (req->smb_conn->signing.signing_state != SMB_SIGNING_OFF) {
req->smb_conn->signing.next_seq_num += 2;
}
}
/***********************************************************
SMB signing - Simple implementation - check a MAC sent by client
************************************************************/
/**
* Check a packet supplied by the server.
* @return False if we had an established signing connection
* which had a back checksum, True otherwise
*/
BOOL req_signing_check_incoming(struct smbsrv_request *req)
{
BOOL good;
req_signing_alloc_seq_num(req);
switch (req->smb_conn->signing.signing_state)
{
case SMB_SIGNING_ENGINE_OFF:
return True;
case SMB_SIGNING_ENGINE_BSRSPYL:
case SMB_SIGNING_ENGINE_ON:
{
if (req->in.size < (HDR_SS_FIELD + 8)) {
return False;
} else {
good = check_signed_incoming_message(&req->in,
&req->smb_conn->signing.mac_key,
req->seq_num);
return signing_good(&req->smb_conn->signing,
req->seq_num+1, good);
}
}
}
return False;
}
|
