Merge tag 'ras_core_for_v6.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-block.git] / crypto / pcbc.c
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2874c5fd 1// SPDX-License-Identifier: GPL-2.0-or-later
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2/*
3 * PCBC: Propagating Cipher Block Chaining mode
4 *
5 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
6 * Written by David Howells (dhowells@redhat.com)
7 *
8 * Derived from cbc.c
9 * - Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
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10 */
11
6650c4de 12#include <crypto/algapi.h>
0eb76ba2 13#include <crypto/internal/cipher.h>
043a4400 14#include <crypto/internal/skcipher.h>
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15#include <linux/err.h>
16#include <linux/init.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
91652be5 19
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20static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,
21 struct skcipher_walk *walk,
d0b9007a 22 struct crypto_cipher *tfm)
91652be5 23{
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24 int bsize = crypto_cipher_blocksize(tfm);
25 unsigned int nbytes = walk->nbytes;
26 u8 *src = walk->src.virt.addr;
27 u8 *dst = walk->dst.virt.addr;
251b7aea 28 u8 * const iv = walk->iv;
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29
30 do {
d0b9007a 31 crypto_xor(iv, src, bsize);
043a4400 32 crypto_cipher_encrypt_one(tfm, dst, iv);
45fe93df 33 crypto_xor_cpy(iv, dst, src, bsize);
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34
35 src += bsize;
36 dst += bsize;
37 } while ((nbytes -= bsize) >= bsize);
38
39 return nbytes;
40}
41
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42static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,
43 struct skcipher_walk *walk,
d0b9007a 44 struct crypto_cipher *tfm)
91652be5 45{
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46 int bsize = crypto_cipher_blocksize(tfm);
47 unsigned int nbytes = walk->nbytes;
48 u8 *src = walk->src.virt.addr;
251b7aea 49 u8 * const iv = walk->iv;
6650c4de 50 u8 tmpbuf[MAX_CIPHER_BLOCKSIZE];
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51
52 do {
53 memcpy(tmpbuf, src, bsize);
d0b9007a 54 crypto_xor(iv, src, bsize);
043a4400 55 crypto_cipher_encrypt_one(tfm, src, iv);
45fe93df 56 crypto_xor_cpy(iv, tmpbuf, src, bsize);
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57
58 src += bsize;
59 } while ((nbytes -= bsize) >= bsize);
60
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61 return nbytes;
62}
63
043a4400 64static int crypto_pcbc_encrypt(struct skcipher_request *req)
91652be5 65{
043a4400 66 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
0be487ba 67 struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
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68 struct skcipher_walk walk;
69 unsigned int nbytes;
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70 int err;
71
043a4400 72 err = skcipher_walk_virt(&walk, req, false);
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73
74 while ((nbytes = walk.nbytes)) {
75 if (walk.src.virt.addr == walk.dst.virt.addr)
043a4400 76 nbytes = crypto_pcbc_encrypt_inplace(req, &walk,
0be487ba 77 cipher);
91652be5 78 else
043a4400 79 nbytes = crypto_pcbc_encrypt_segment(req, &walk,
0be487ba 80 cipher);
043a4400 81 err = skcipher_walk_done(&walk, nbytes);
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82 }
83
84 return err;
85}
86
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87static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,
88 struct skcipher_walk *walk,
d0b9007a 89 struct crypto_cipher *tfm)
91652be5 90{
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91 int bsize = crypto_cipher_blocksize(tfm);
92 unsigned int nbytes = walk->nbytes;
93 u8 *src = walk->src.virt.addr;
94 u8 *dst = walk->dst.virt.addr;
251b7aea 95 u8 * const iv = walk->iv;
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96
97 do {
043a4400 98 crypto_cipher_decrypt_one(tfm, dst, src);
d0b9007a 99 crypto_xor(dst, iv, bsize);
45fe93df 100 crypto_xor_cpy(iv, dst, src, bsize);
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101
102 src += bsize;
103 dst += bsize;
104 } while ((nbytes -= bsize) >= bsize);
105
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106 return nbytes;
107}
108
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109static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,
110 struct skcipher_walk *walk,
d0b9007a 111 struct crypto_cipher *tfm)
91652be5 112{
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113 int bsize = crypto_cipher_blocksize(tfm);
114 unsigned int nbytes = walk->nbytes;
115 u8 *src = walk->src.virt.addr;
251b7aea 116 u8 * const iv = walk->iv;
6650c4de 117 u8 tmpbuf[MAX_CIPHER_BLOCKSIZE] __aligned(__alignof__(u32));
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118
119 do {
120 memcpy(tmpbuf, src, bsize);
043a4400 121 crypto_cipher_decrypt_one(tfm, src, src);
d0b9007a 122 crypto_xor(src, iv, bsize);
45fe93df 123 crypto_xor_cpy(iv, src, tmpbuf, bsize);
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124
125 src += bsize;
126 } while ((nbytes -= bsize) >= bsize);
127
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128 return nbytes;
129}
130
043a4400 131static int crypto_pcbc_decrypt(struct skcipher_request *req)
91652be5 132{
043a4400 133 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
0be487ba 134 struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
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135 struct skcipher_walk walk;
136 unsigned int nbytes;
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137 int err;
138
043a4400 139 err = skcipher_walk_virt(&walk, req, false);
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140
141 while ((nbytes = walk.nbytes)) {
142 if (walk.src.virt.addr == walk.dst.virt.addr)
043a4400 143 nbytes = crypto_pcbc_decrypt_inplace(req, &walk,
0be487ba 144 cipher);
91652be5 145 else
043a4400 146 nbytes = crypto_pcbc_decrypt_segment(req, &walk,
0be487ba 147 cipher);
043a4400 148 err = skcipher_walk_done(&walk, nbytes);
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149 }
150
151 return err;
152}
153
043a4400 154static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
91652be5 155{
043a4400 156 struct skcipher_instance *inst;
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157 int err;
158
b3c16bfc 159 inst = skcipher_alloc_instance_simple(tmpl, tb);
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160 if (IS_ERR(inst))
161 return PTR_ERR(inst);
91652be5 162
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163 inst->alg.encrypt = crypto_pcbc_encrypt;
164 inst->alg.decrypt = crypto_pcbc_decrypt;
91652be5 165
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166 err = skcipher_register_instance(tmpl, inst);
167 if (err)
0be487ba 168 inst->free(inst);
b3c16bfc 169
043a4400 170 return err;
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171}
172
173static struct crypto_template crypto_pcbc_tmpl = {
174 .name = "pcbc",
043a4400 175 .create = crypto_pcbc_create,
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176 .module = THIS_MODULE,
177};
178
179static int __init crypto_pcbc_module_init(void)
180{
181 return crypto_register_template(&crypto_pcbc_tmpl);
182}
183
184static void __exit crypto_pcbc_module_exit(void)
185{
186 crypto_unregister_template(&crypto_pcbc_tmpl);
187}
188
c4741b23 189subsys_initcall(crypto_pcbc_module_init);
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190module_exit(crypto_pcbc_module_exit);
191
192MODULE_LICENSE("GPL");
0be487ba 193MODULE_DESCRIPTION("PCBC block cipher mode of operation");
4943ba16 194MODULE_ALIAS_CRYPTO("pcbc");
0eb76ba2 195MODULE_IMPORT_NS(CRYPTO_INTERNAL);