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
|
/*
Linux loop encryption enabling module
Copyright (C) 2002 Herbert Valerio Riedel <hvr@gnu.org>
Copyright (C) 2003 Fruhwirth Clemens <clemens@endorphin.org>
This module 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 module 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 module; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/crypto.h>
#include <linux/blkdev.h>
#include <linux/loop.h>
#include <linux/scatterlist.h>
#include <asm/uaccess.h>
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("loop blockdevice transferfunction adaptor / CryptoAPI");
MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
#define LOOP_IV_SECTOR_BITS 9
#define LOOP_IV_SECTOR_SIZE (1 << LOOP_IV_SECTOR_BITS)
static int
cryptoloop_init(struct loop_device *lo, const struct loop_info64 *info)
{
int err = -EINVAL;
int cipher_len;
int mode_len;
char cms[LO_NAME_SIZE]; /* cipher-mode string */
char *cipher;
char *mode;
char *cmsp = cms; /* c-m string pointer */
struct crypto_blkcipher *tfm;
/* encryption breaks for non sector aligned offsets */
if (info->lo_offset % LOOP_IV_SECTOR_SIZE)
goto out;
strncpy(cms, info->lo_crypt_name, LO_NAME_SIZE);
cms[LO_NAME_SIZE - 1] = 0;
cipher = cmsp;
cipher_len = strcspn(cmsp, "-");
mode = cmsp + cipher_len;
mode_len = 0;
if (*mode) {
mode++;
mode_len = strcspn(mode, "-");
}
if (!mode_len) {
mode = "cbc";
mode_len = 3;
}
if (cipher_len + mode_len + 3 > LO_NAME_SIZE)
return -EINVAL;
memmove(cms, mode, mode_len);
cmsp = cms + mode_len;
*cmsp++ = '(';
memcpy(cmsp, info->lo_crypt_name, cipher_len);
cmsp += cipher_len;
*cmsp++ = ')';
*cmsp = 0;
tfm = crypto_alloc_blkcipher(cms, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
err = crypto_blkcipher_setkey(tfm, info->lo_encrypt_key,
info->lo_encrypt_key_size);
if (err != 0)
goto out_free_tfm;
lo->key_data = tfm;
return 0;
out_free_tfm:
crypto_free_blkcipher(tfm);
out:
return err;
}
typedef int (*encdec_cbc_t)(struct blkcipher_desc *desc,
struct scatterlist *sg_out,
struct scatterlist *sg_in,
unsigned int nsg);
static int
cryptoloop_transfer(struct loop_device *lo, int cmd,
struct page *raw_page, unsigned raw_off,
struct page *loop_page, unsigned loop_off,
int size, sector_t IV)
{
struct crypto_blkcipher *tfm = lo->key_data;
struct blkcipher_desc desc = {
.tfm = tfm,
.flags = CRYPTO_TFM_REQ_MAY_SLEEP,
};
struct scatterlist sg_out;
struct scatterlist sg_in;
encdec_cbc_t encdecfunc;
struct page *in_page, *out_page;
unsigned in_offs, out_offs;
int err;
sg_init_table(&sg_out, 1);
sg_init_table(&sg_in, 1);
if (cmd == READ) {
in_page = raw_page;
in_offs = raw_off;
out_page = loop_page;
out_offs = loop_off;
encdecfunc = crypto_blkcipher_crt(tfm)->decrypt;
} else {
in_page = loop_page;
in_offs = loop_off;
out_page = raw_page;
out_offs = raw_off;
encdecfunc = crypto_blkcipher_crt(tfm)->encrypt;
}
while (size > 0) {
const int sz = min(size, LOOP_IV_SECTOR_SIZE);
u32 iv[4] = { 0, };
iv[0] = cpu_to_le32(IV & 0xffffffff);
sg_set_page(&sg_in, in_page, sz, in_offs);
sg_set_page(&sg_out, out_page, sz, out_offs);
desc.info = iv;
err = encdecfunc(&desc, &sg_out, &sg_in, sz);
if (err)
return err;
IV++;
size -= sz;
in_offs += sz;
out_offs += sz;
}
return 0;
}
static int
cryptoloop_ioctl(struct loop_device *lo, int cmd, unsigned long arg)
{
return -EINVAL;
}
static int
cryptoloop_release(struct loop_device *lo)
{
struct crypto_blkcipher *tfm = lo->key_data;
if (tfm != NULL) {
crypto_free_blkcipher(tfm);
lo->key_data = NULL;
return 0;
}
printk(KERN_ERR "cryptoloop_release(): tfm == NULL?\n");
return -EINVAL;
}
static struct loop_func_table cryptoloop_funcs = {
.number = LO_CRYPT_CRYPTOAPI,
.init = cryptoloop_init,
.ioctl = cryptoloop_ioctl,
.transfer = cryptoloop_transfer,
.release = cryptoloop_release,
.owner = THIS_MODULE
};
static int __init
init_cryptoloop(void)
{
int rc = loop_register_transfer(&cryptoloop_funcs);
if (rc)
printk(KERN_ERR "cryptoloop: loop_register_transfer failed\n");
return rc;
}
static void __exit
cleanup_cryptoloop(void)
{
if (loop_unregister_transfer(LO_CRYPT_CRYPTOAPI))
printk(KERN_ERR
"cryptoloop: loop_unregister_transfer failed\n");
}
module_init(init_cryptoloop);
module_exit(cleanup_cryptoloop);
|
