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
|
/*
* CBC: Cipher Block Chaining mode
*
* Copyright (c) 2016 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.
*
*/
#ifndef _CRYPTO_CBC_H
#define _CRYPTO_CBC_H
#include <crypto/internal/skcipher.h>
#include <linux/string.h>
#include <linux/types.h>
static inline int crypto_cbc_encrypt_segment(
struct skcipher_walk *walk, struct crypto_skcipher *tfm,
void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
unsigned int bsize = crypto_skcipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
u8 *iv = walk->iv;
do {
crypto_xor(iv, src, bsize);
fn(tfm, iv, dst);
memcpy(iv, dst, bsize);
src += bsize;
dst += bsize;
} while ((nbytes -= bsize) >= bsize);
return nbytes;
}
static inline int crypto_cbc_encrypt_inplace(
struct skcipher_walk *walk, struct crypto_skcipher *tfm,
void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
unsigned int bsize = crypto_skcipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *iv = walk->iv;
do {
crypto_xor(src, iv, bsize);
fn(tfm, src, src);
iv = src;
src += bsize;
} while ((nbytes -= bsize) >= bsize);
memcpy(walk->iv, iv, bsize);
return nbytes;
}
static inline int crypto_cbc_encrypt_walk(struct skcipher_request *req,
void (*fn)(struct crypto_skcipher *,
const u8 *, u8 *))
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct skcipher_walk walk;
int err;
err = skcipher_walk_virt(&walk, req, false);
while (walk.nbytes) {
if (walk.src.virt.addr == walk.dst.virt.addr)
err = crypto_cbc_encrypt_inplace(&walk, tfm, fn);
else
err = crypto_cbc_encrypt_segment(&walk, tfm, fn);
err = skcipher_walk_done(&walk, err);
}
return err;
}
static inline int crypto_cbc_decrypt_segment(
struct skcipher_walk *walk, struct crypto_skcipher *tfm,
void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
unsigned int bsize = crypto_skcipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
u8 *iv = walk->iv;
do {
fn(tfm, src, dst);
crypto_xor(dst, iv, bsize);
iv = src;
src += bsize;
dst += bsize;
} while ((nbytes -= bsize) >= bsize);
memcpy(walk->iv, iv, bsize);
return nbytes;
}
static inline int crypto_cbc_decrypt_inplace(
struct skcipher_walk *walk, struct crypto_skcipher *tfm,
void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
unsigned int bsize = crypto_skcipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
u8 last_iv[MAX_CIPHER_BLOCKSIZE];
/* Start of the last block. */
src += nbytes - (nbytes & (bsize - 1)) - bsize;
memcpy(last_iv, src, bsize);
for (;;) {
fn(tfm, src, src);
if ((nbytes -= bsize) < bsize)
break;
crypto_xor(src, src - bsize, bsize);
src -= bsize;
}
crypto_xor(src, walk->iv, bsize);
memcpy(walk->iv, last_iv, bsize);
return nbytes;
}
static inline int crypto_cbc_decrypt_blocks(
struct skcipher_walk *walk, struct crypto_skcipher *tfm,
void (*fn)(struct crypto_skcipher *, const u8 *, u8 *))
{
if (walk->src.virt.addr == walk->dst.virt.addr)
return crypto_cbc_decrypt_inplace(walk, tfm, fn);
else
return crypto_cbc_decrypt_segment(walk, tfm, fn);
}
#endif /* _CRYPTO_CBC_H */
|
