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
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
/*
* fs/cifs/cifs_spnego.c -- SPNEGO upcall management for CIFS
*
* Copyright (c) 2007 Red Hat, Inc.
* Author(s): Jeff Layton (jlayton@redhat.com)
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <keys/user-type.h>
#include <linux/key-type.h>
#include <linux/keyctl.h>
#include <linux/inet.h>
#include "cifsglob.h"
#include "cifs_spnego.h"
#include "cifs_debug.h"
#include "cifsproto.h"
static const struct cred *spnego_cred;
/* create a new cifs key */
static int
cifs_spnego_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
{
char *payload;
int ret;
ret = -ENOMEM;
payload = kmemdup(prep->data, prep->datalen, GFP_KERNEL);
if (!payload)
goto error;
/* attach the data */
key->payload.data[0] = payload;
ret = 0;
error:
return ret;
}
static void
cifs_spnego_key_destroy(struct key *key)
{
kfree(key->payload.data[0]);
}
/*
* keytype for CIFS spnego keys
*/
struct key_type cifs_spnego_key_type = {
.name = "cifs.spnego",
.instantiate = cifs_spnego_key_instantiate,
.destroy = cifs_spnego_key_destroy,
.describe = user_describe,
};
/* length of longest version string e.g. strlen("ver=0xFF") */
#define MAX_VER_STR_LEN 8
/* length of longest security mechanism name, eg in future could have
* strlen(";sec=ntlmsspi") */
#define MAX_MECH_STR_LEN 13
/* strlen of ";host=" */
#define HOST_KEY_LEN 6
/* strlen of ";ip4=" or ";ip6=" */
#define IP_KEY_LEN 5
/* strlen of ";uid=0x" */
#define UID_KEY_LEN 7
/* strlen of ";creduid=0x" */
#define CREDUID_KEY_LEN 11
/* strlen of ";user=" */
#define USER_KEY_LEN 6
/* strlen of ";pid=0x" */
#define PID_KEY_LEN 7
/* get a key struct with a SPNEGO security blob, suitable for session setup */
struct key *
cifs_get_spnego_key(struct cifs_ses *sesInfo)
{
struct TCP_Server_Info *server = cifs_ses_server(sesInfo);
struct sockaddr_in *sa = (struct sockaddr_in *) &server->dstaddr;
struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &server->dstaddr;
char *description, *dp;
size_t desc_len;
struct key *spnego_key;
const char *hostname = server->hostname;
const struct cred *saved_cred;
/* length of fields (with semicolons): ver=0xyz ip4=ipaddress
host=hostname sec=mechanism uid=0xFF user=username */
desc_len = MAX_VER_STR_LEN +
HOST_KEY_LEN + strlen(hostname) +
IP_KEY_LEN + INET6_ADDRSTRLEN +
MAX_MECH_STR_LEN +
UID_KEY_LEN + (sizeof(uid_t) * 2) +
CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
if (sesInfo->user_name)
desc_len += USER_KEY_LEN + strlen(sesInfo->user_name);
spnego_key = ERR_PTR(-ENOMEM);
description = kzalloc(desc_len, GFP_KERNEL);
if (description == NULL)
goto out;
dp = description;
/* start with version and hostname portion of UNC string */
spnego_key = ERR_PTR(-EINVAL);
sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
hostname);
dp = description + strlen(description);
/* add the server address */
if (server->dstaddr.ss_family == AF_INET)
sprintf(dp, "ip4=%pI4", &sa->sin_addr);
else if (server->dstaddr.ss_family == AF_INET6)
sprintf(dp, "ip6=%pI6", &sa6->sin6_addr);
else
goto out;
dp = description + strlen(description);
/* for now, only sec=krb5 and sec=mskrb5 are valid */
if (server->sec_kerberos)
sprintf(dp, ";sec=krb5");
else if (server->sec_mskerberos)
sprintf(dp, ";sec=mskrb5");
else {
cifs_dbg(VFS, "unknown or missing server auth type, use krb5\n");
sprintf(dp, ";sec=krb5");
}
dp = description + strlen(description);
sprintf(dp, ";uid=0x%x",
from_kuid_munged(&init_user_ns, sesInfo->linux_uid));
dp = description + strlen(description);
sprintf(dp, ";creduid=0x%x",
from_kuid_munged(&init_user_ns, sesInfo->cred_uid));
if (sesInfo->user_name) {
dp = description + strlen(description);
sprintf(dp, ";user=%s", sesInfo->user_name);
}
dp = description + strlen(description);
sprintf(dp, ";pid=0x%x", current->pid);
cifs_dbg(FYI, "key description = %s\n", description);
saved_cred = override_creds(spnego_cred);
spnego_key = request_key(&cifs_spnego_key_type, description, "");
revert_creds(saved_cred);
#ifdef CONFIG_CIFS_DEBUG2
if (cifsFYI && !IS_ERR(spnego_key)) {
struct cifs_spnego_msg *msg = spnego_key->payload.data[0];
cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
msg->secblob_len + msg->sesskey_len));
}
#endif /* CONFIG_CIFS_DEBUG2 */
out:
kfree(description);
return spnego_key;
}
int
init_cifs_spnego(void)
{
struct cred *cred;
struct key *keyring;
int ret;
cifs_dbg(FYI, "Registering the %s key type\n",
cifs_spnego_key_type.name);
/*
* Create an override credential set with special thread keyring for
* spnego upcalls.
*/
cred = prepare_kernel_cred(NULL);
if (!cred)
return -ENOMEM;
keyring = keyring_alloc(".cifs_spnego",
GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
(KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW | KEY_USR_READ,
KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto failed_put_cred;
}
ret = register_key_type(&cifs_spnego_key_type);
if (ret < 0)
goto failed_put_key;
/*
* instruct request_key() to use this special keyring as a cache for
* the results it looks up
*/
set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
cred->thread_keyring = keyring;
cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
spnego_cred = cred;
cifs_dbg(FYI, "cifs spnego keyring: %d\n", key_serial(keyring));
return 0;
failed_put_key:
key_put(keyring);
failed_put_cred:
put_cred(cred);
return ret;
}
void
exit_cifs_spnego(void)
{
key_revoke(spnego_cred->thread_keyring);
unregister_key_type(&cifs_spnego_key_type);
put_cred(spnego_cred);
cifs_dbg(FYI, "Unregistered %s key type\n", cifs_spnego_key_type.name);
}
|
