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
|
/*
* PCBC: Propagating Cipher Block Chaining mode
*
* Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* Derived from cbc.c
* - Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
*
* 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.
*
*/
#include <crypto/algapi.h>
#include <crypto/internal/skcipher.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,
struct skcipher_walk *walk,
struct crypto_cipher *tfm)
{
int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
u8 * const iv = walk->iv;
do {
crypto_xor(iv, src, bsize);
crypto_cipher_encrypt_one(tfm, dst, iv);
crypto_xor_cpy(iv, dst, src, bsize);
src += bsize;
dst += bsize;
} while ((nbytes -= bsize) >= bsize);
return nbytes;
}
static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,
struct skcipher_walk *walk,
struct crypto_cipher *tfm)
{
int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 * const iv = walk->iv;
u8 tmpbuf[MAX_CIPHER_BLOCKSIZE];
do {
memcpy(tmpbuf, src, bsize);
crypto_xor(iv, src, bsize);
crypto_cipher_encrypt_one(tfm, src, iv);
crypto_xor_cpy(iv, tmpbuf, src, bsize);
src += bsize;
} while ((nbytes -= bsize) >= bsize);
return nbytes;
}
static int crypto_pcbc_encrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
struct skcipher_walk walk;
unsigned int nbytes;
int err;
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes)) {
if (walk.src.virt.addr == walk.dst.virt.addr)
nbytes = crypto_pcbc_encrypt_inplace(req, &walk,
cipher);
else
nbytes = crypto_pcbc_encrypt_segment(req, &walk,
cipher);
err = skcipher_walk_done(&walk, nbytes);
}
return err;
}
static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,
struct skcipher_walk *walk,
struct crypto_cipher *tfm)
{
int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
u8 * const iv = walk->iv;
do {
crypto_cipher_decrypt_one(tfm, dst, src);
crypto_xor(dst, iv, bsize);
crypto_xor_cpy(iv, dst, src, bsize);
src += bsize;
dst += bsize;
} while ((nbytes -= bsize) >= bsize);
return nbytes;
}
static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,
struct skcipher_walk *walk,
struct crypto_cipher *tfm)
{
int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 * const iv = walk->iv;
u8 tmpbuf[MAX_CIPHER_BLOCKSIZE] __aligned(__alignof__(u32));
do {
memcpy(tmpbuf, src, bsize);
crypto_cipher_decrypt_one(tfm, src, src);
crypto_xor(src, iv, bsize);
crypto_xor_cpy(iv, src, tmpbuf, bsize);
src += bsize;
} while ((nbytes -= bsize) >= bsize);
return nbytes;
}
static int crypto_pcbc_decrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
struct skcipher_walk walk;
unsigned int nbytes;
int err;
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes)) {
if (walk.src.virt.addr == walk.dst.virt.addr)
nbytes = crypto_pcbc_decrypt_inplace(req, &walk,
cipher);
else
nbytes = crypto_pcbc_decrypt_segment(req, &walk,
cipher);
err = skcipher_walk_done(&walk, nbytes);
}
return err;
}
static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
{
struct skcipher_instance *inst;
struct crypto_alg *alg;
int err;
inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);
if (IS_ERR(inst))
return PTR_ERR(inst);
inst->alg.encrypt = crypto_pcbc_encrypt;
inst->alg.decrypt = crypto_pcbc_decrypt;
err = skcipher_register_instance(tmpl, inst);
if (err)
inst->free(inst);
crypto_mod_put(alg);
return err;
}
static struct crypto_template crypto_pcbc_tmpl = {
.name = "pcbc",
.create = crypto_pcbc_create,
.module = THIS_MODULE,
};
static int __init crypto_pcbc_module_init(void)
{
return crypto_register_template(&crypto_pcbc_tmpl);
}
static void __exit crypto_pcbc_module_exit(void)
{
crypto_unregister_template(&crypto_pcbc_tmpl);
}
module_init(crypto_pcbc_module_init);
module_exit(crypto_pcbc_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("PCBC block cipher mode of operation");
MODULE_ALIAS_CRYPTO("pcbc");
|
