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
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
/*
Unix SMB/CIFS implementation.
SMB Transport encryption (sealing) code.
Copyright (C) Jeremy Allison 2007.
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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "smb_common.h"
#ifdef HAVE_KRB5
#include "lib/krb5_wrap/krb5_samba.h"
#endif
#include "auth/gensec/gensec.h"
#include "libcli/smb/smb_seal.h"
#undef malloc
/******************************************************************************
Pull out the encryption context for this packet. 0 means global context.
******************************************************************************/
NTSTATUS get_enc_ctx_num(const uint8_t *buf, uint16_t *p_enc_ctx_num)
{
if (smb_len_nbt(buf) < 8) {
return NT_STATUS_INVALID_BUFFER_SIZE;
}
if (buf[4] == 0xFF) {
if (buf[5] == 'S' && buf [6] == 'M' && buf[7] == 'B') {
/* Not an encrypted buffer. */
return NT_STATUS_NOT_FOUND;
}
if (buf[5] == 'E') {
*p_enc_ctx_num = SVAL(buf,6);
return NT_STATUS_OK;
}
}
return NT_STATUS_INVALID_NETWORK_RESPONSE;
}
/*******************************************************************
Set the length and marker of an encrypted smb packet.
********************************************************************/
static void smb_set_enclen(char *buf,int len,uint16_t enc_ctx_num)
{
_smb_setlen_tcp(buf,len);
SCVAL(buf,4,0xFF);
SCVAL(buf,5,'E');
SSVAL(buf,6,enc_ctx_num);
}
/******************************************************************************
Generic code for client and server.
Is encryption turned on ?
******************************************************************************/
bool common_encryption_on(struct smb_trans_enc_state *es)
{
return ((es != NULL) && es->enc_on);
}
/******************************************************************************
Generic code for client and server.
GENSEC decrypt an incoming buffer.
******************************************************************************/
static NTSTATUS common_gensec_decrypt_buffer(struct gensec_security *gensec,
char *buf)
{
NTSTATUS status;
size_t buf_len = smb_len_nbt(buf) + 4; /* Don't forget the 4 length bytes. */
DATA_BLOB in_buf, out_buf;
TALLOC_CTX *frame;
if (buf_len < 8) {
return NT_STATUS_BUFFER_TOO_SMALL;
}
frame = talloc_stackframe();
in_buf = data_blob_const(buf + 8, buf_len - 8);
status = gensec_unwrap(gensec, frame, &in_buf, &out_buf);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0,("common_gensec_decrypt_buffer: gensec_unwrap failed. Error %s\n",
nt_errstr(status)));
TALLOC_FREE(frame);
return status;
}
if (out_buf.length > in_buf.length) {
DEBUG(0,("common_gensec_decrypt_buffer: gensec_unwrap size (%u) too large (%u) !\n",
(unsigned int)out_buf.length,
(unsigned int)in_buf.length ));
TALLOC_FREE(frame);
return NT_STATUS_INVALID_PARAMETER;
}
memcpy(buf + 8, out_buf.data, out_buf.length);
/* Reset the length and overwrite the header. */
smb_setlen_nbt(buf, out_buf.length + 4);
TALLOC_FREE(frame);
return NT_STATUS_OK;
}
/******************************************************************************
Generic code for client and server.
NTLM encrypt an outgoing buffer. Return the encrypted pointer in ppbuf_out.
******************************************************************************/
static NTSTATUS common_gensec_encrypt_buffer(struct gensec_security *gensec,
uint16_t enc_ctx_num,
char *buf,
char **ppbuf_out)
{
NTSTATUS status;
DATA_BLOB in_buf, out_buf;
size_t buf_len = smb_len_nbt(buf) + 4; /* Don't forget the 4 length bytes. */
TALLOC_CTX *frame;
*ppbuf_out = NULL;
if (buf_len < 8) {
return NT_STATUS_BUFFER_TOO_SMALL;
}
in_buf = data_blob_const(buf + 8, buf_len - 8);
frame = talloc_stackframe();
status = gensec_wrap(gensec, frame, &in_buf, &out_buf);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0,("common_gensec_encrypt_buffer: gensec_wrap failed. Error %s\n",
nt_errstr(status)));
TALLOC_FREE(frame);
return status;
}
*ppbuf_out = (char *)malloc(out_buf.length + 8); /* We know this can't wrap. */
if (!*ppbuf_out) {
TALLOC_FREE(frame);
return NT_STATUS_NO_MEMORY;
}
memcpy(*ppbuf_out+8, out_buf.data, out_buf.length);
smb_set_enclen(*ppbuf_out, out_buf.length + 4, enc_ctx_num);
TALLOC_FREE(frame);
return NT_STATUS_OK;
}
/******************************************************************************
Generic code for client and server.
Encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out.
******************************************************************************/
NTSTATUS common_encrypt_buffer(struct smb_trans_enc_state *es, char *buffer, char **buf_out)
{
if (!common_encryption_on(es)) {
/* Not encrypting. */
*buf_out = buffer;
return NT_STATUS_OK;
}
return common_gensec_encrypt_buffer(es->gensec_security, es->enc_ctx_num, buffer, buf_out);
}
/******************************************************************************
Generic code for client and server.
Decrypt an incoming SMB buffer. Replaces the data within it.
New data must be less than or equal to the current length.
******************************************************************************/
NTSTATUS common_decrypt_buffer(struct smb_trans_enc_state *es, char *buf)
{
if (!common_encryption_on(es)) {
/* Not decrypting. */
return NT_STATUS_OK;
}
return common_gensec_decrypt_buffer(es->gensec_security, buf);
}
/******************************************************************************
Free an encryption-allocated buffer.
******************************************************************************/
void common_free_enc_buffer(struct smb_trans_enc_state *es, char *buf)
{
uint16_t enc_ctx_num;
if (!common_encryption_on(es)) {
return;
}
if (!NT_STATUS_IS_OK(get_enc_ctx_num((const uint8_t *)buf,
&enc_ctx_num))) {
return;
}
SAFE_FREE(buf);
}
|
