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1// SPDX-License-Identifier: GPL-2.0-or-later
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>
10 */
11
12#include <crypto/algapi.h>
13#include <crypto/internal/skcipher.h>
14#include <linux/err.h>
15#include <linux/init.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18
19static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,
20 struct skcipher_walk *walk,
21 struct crypto_cipher *tfm)
22{
23 int bsize = crypto_cipher_blocksize(tfm);
24 unsigned int nbytes = walk->nbytes;
25 u8 *src = walk->src.virt.addr;
26 u8 *dst = walk->dst.virt.addr;
27 u8 * const iv = walk->iv;
28
29 do {
30 crypto_xor(iv, src, bsize);
31 crypto_cipher_encrypt_one(tfm, dst, iv);
32 crypto_xor_cpy(iv, dst, src, bsize);
33
34 src += bsize;
35 dst += bsize;
36 } while ((nbytes -= bsize) >= bsize);
37
38 return nbytes;
39}
40
41static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,
42 struct skcipher_walk *walk,
43 struct crypto_cipher *tfm)
44{
45 int bsize = crypto_cipher_blocksize(tfm);
46 unsigned int nbytes = walk->nbytes;
47 u8 *src = walk->src.virt.addr;
48 u8 * const iv = walk->iv;
49 u8 tmpbuf[MAX_CIPHER_BLOCKSIZE];
50
51 do {
52 memcpy(tmpbuf, src, bsize);
53 crypto_xor(iv, src, bsize);
54 crypto_cipher_encrypt_one(tfm, src, iv);
55 crypto_xor_cpy(iv, tmpbuf, src, bsize);
56
57 src += bsize;
58 } while ((nbytes -= bsize) >= bsize);
59
60 return nbytes;
61}
62
63static int crypto_pcbc_encrypt(struct skcipher_request *req)
64{
65 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
66 struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
67 struct skcipher_walk walk;
68 unsigned int nbytes;
69 int err;
70
71 err = skcipher_walk_virt(&walk, req, false);
72
73 while ((nbytes = walk.nbytes)) {
74 if (walk.src.virt.addr == walk.dst.virt.addr)
75 nbytes = crypto_pcbc_encrypt_inplace(req, &walk,
76 cipher);
77 else
78 nbytes = crypto_pcbc_encrypt_segment(req, &walk,
79 cipher);
80 err = skcipher_walk_done(&walk, nbytes);
81 }
82
83 return err;
84}
85
86static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,
87 struct skcipher_walk *walk,
88 struct crypto_cipher *tfm)
89{
90 int bsize = crypto_cipher_blocksize(tfm);
91 unsigned int nbytes = walk->nbytes;
92 u8 *src = walk->src.virt.addr;
93 u8 *dst = walk->dst.virt.addr;
94 u8 * const iv = walk->iv;
95
96 do {
97 crypto_cipher_decrypt_one(tfm, dst, src);
98 crypto_xor(dst, iv, bsize);
99 crypto_xor_cpy(iv, dst, src, bsize);
100
101 src += bsize;
102 dst += bsize;
103 } while ((nbytes -= bsize) >= bsize);
104
105 return nbytes;
106}
107
108static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,
109 struct skcipher_walk *walk,
110 struct crypto_cipher *tfm)
111{
112 int bsize = crypto_cipher_blocksize(tfm);
113 unsigned int nbytes = walk->nbytes;
114 u8 *src = walk->src.virt.addr;
115 u8 * const iv = walk->iv;
116 u8 tmpbuf[MAX_CIPHER_BLOCKSIZE] __aligned(__alignof__(u32));
117
118 do {
119 memcpy(tmpbuf, src, bsize);
120 crypto_cipher_decrypt_one(tfm, src, src);
121 crypto_xor(src, iv, bsize);
122 crypto_xor_cpy(iv, src, tmpbuf, bsize);
123
124 src += bsize;
125 } while ((nbytes -= bsize) >= bsize);
126
127 return nbytes;
128}
129
130static int crypto_pcbc_decrypt(struct skcipher_request *req)
131{
132 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
133 struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
134 struct skcipher_walk walk;
135 unsigned int nbytes;
136 int err;
137
138 err = skcipher_walk_virt(&walk, req, false);
139
140 while ((nbytes = walk.nbytes)) {
141 if (walk.src.virt.addr == walk.dst.virt.addr)
142 nbytes = crypto_pcbc_decrypt_inplace(req, &walk,
143 cipher);
144 else
145 nbytes = crypto_pcbc_decrypt_segment(req, &walk,
146 cipher);
147 err = skcipher_walk_done(&walk, nbytes);
148 }
149
150 return err;
151}
152
153static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
154{
155 struct skcipher_instance *inst;
156 int err;
157
158 inst = skcipher_alloc_instance_simple(tmpl, tb);
159 if (IS_ERR(inst))
160 return PTR_ERR(inst);
161
162 inst->alg.encrypt = crypto_pcbc_encrypt;
163 inst->alg.decrypt = crypto_pcbc_decrypt;
164
165 err = skcipher_register_instance(tmpl, inst);
166 if (err)
167 inst->free(inst);
168
169 return err;
170}
171
172static struct crypto_template crypto_pcbc_tmpl = {
173 .name = "pcbc",
174 .create = crypto_pcbc_create,
175 .module = THIS_MODULE,
176};
177
178static int __init crypto_pcbc_module_init(void)
179{
180 return crypto_register_template(&crypto_pcbc_tmpl);
181}
182
183static void __exit crypto_pcbc_module_exit(void)
184{
185 crypto_unregister_template(&crypto_pcbc_tmpl);
186}
187
188subsys_initcall(crypto_pcbc_module_init);
189module_exit(crypto_pcbc_module_exit);
190
191MODULE_LICENSE("GPL");
192MODULE_DESCRIPTION("PCBC block cipher mode of operation");
193MODULE_ALIAS_CRYPTO("pcbc");
1/*
2 * PCBC: Propagating Cipher Block Chaining mode
3 *
4 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 *
7 * Derived from cbc.c
8 * - Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 *
15 */
16
17#include <crypto/internal/skcipher.h>
18#include <linux/err.h>
19#include <linux/init.h>
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/slab.h>
23
24struct crypto_pcbc_ctx {
25 struct crypto_cipher *child;
26};
27
28static int crypto_pcbc_setkey(struct crypto_skcipher *parent, const u8 *key,
29 unsigned int keylen)
30{
31 struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(parent);
32 struct crypto_cipher *child = ctx->child;
33 int err;
34
35 crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
36 crypto_cipher_set_flags(child, crypto_skcipher_get_flags(parent) &
37 CRYPTO_TFM_REQ_MASK);
38 err = crypto_cipher_setkey(child, key, keylen);
39 crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &
40 CRYPTO_TFM_RES_MASK);
41 return err;
42}
43
44static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,
45 struct skcipher_walk *walk,
46 struct crypto_cipher *tfm)
47{
48 int bsize = crypto_cipher_blocksize(tfm);
49 unsigned int nbytes = walk->nbytes;
50 u8 *src = walk->src.virt.addr;
51 u8 *dst = walk->dst.virt.addr;
52 u8 *iv = walk->iv;
53
54 do {
55 crypto_xor(iv, src, bsize);
56 crypto_cipher_encrypt_one(tfm, dst, iv);
57 memcpy(iv, dst, bsize);
58 crypto_xor(iv, src, bsize);
59
60 src += bsize;
61 dst += bsize;
62 } while ((nbytes -= bsize) >= bsize);
63
64 return nbytes;
65}
66
67static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,
68 struct skcipher_walk *walk,
69 struct crypto_cipher *tfm)
70{
71 int bsize = crypto_cipher_blocksize(tfm);
72 unsigned int nbytes = walk->nbytes;
73 u8 *src = walk->src.virt.addr;
74 u8 *iv = walk->iv;
75 u8 tmpbuf[bsize];
76
77 do {
78 memcpy(tmpbuf, src, bsize);
79 crypto_xor(iv, src, bsize);
80 crypto_cipher_encrypt_one(tfm, src, iv);
81 memcpy(iv, tmpbuf, bsize);
82 crypto_xor(iv, src, bsize);
83
84 src += bsize;
85 } while ((nbytes -= bsize) >= bsize);
86
87 memcpy(walk->iv, iv, bsize);
88
89 return nbytes;
90}
91
92static int crypto_pcbc_encrypt(struct skcipher_request *req)
93{
94 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
95 struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
96 struct crypto_cipher *child = ctx->child;
97 struct skcipher_walk walk;
98 unsigned int nbytes;
99 int err;
100
101 err = skcipher_walk_virt(&walk, req, false);
102
103 while ((nbytes = walk.nbytes)) {
104 if (walk.src.virt.addr == walk.dst.virt.addr)
105 nbytes = crypto_pcbc_encrypt_inplace(req, &walk,
106 child);
107 else
108 nbytes = crypto_pcbc_encrypt_segment(req, &walk,
109 child);
110 err = skcipher_walk_done(&walk, nbytes);
111 }
112
113 return err;
114}
115
116static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,
117 struct skcipher_walk *walk,
118 struct crypto_cipher *tfm)
119{
120 int bsize = crypto_cipher_blocksize(tfm);
121 unsigned int nbytes = walk->nbytes;
122 u8 *src = walk->src.virt.addr;
123 u8 *dst = walk->dst.virt.addr;
124 u8 *iv = walk->iv;
125
126 do {
127 crypto_cipher_decrypt_one(tfm, dst, src);
128 crypto_xor(dst, iv, bsize);
129 memcpy(iv, src, bsize);
130 crypto_xor(iv, dst, bsize);
131
132 src += bsize;
133 dst += bsize;
134 } while ((nbytes -= bsize) >= bsize);
135
136 memcpy(walk->iv, iv, bsize);
137
138 return nbytes;
139}
140
141static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,
142 struct skcipher_walk *walk,
143 struct crypto_cipher *tfm)
144{
145 int bsize = crypto_cipher_blocksize(tfm);
146 unsigned int nbytes = walk->nbytes;
147 u8 *src = walk->src.virt.addr;
148 u8 *iv = walk->iv;
149 u8 tmpbuf[bsize] __attribute__ ((aligned(__alignof__(u32))));
150
151 do {
152 memcpy(tmpbuf, src, bsize);
153 crypto_cipher_decrypt_one(tfm, src, src);
154 crypto_xor(src, iv, bsize);
155 memcpy(iv, tmpbuf, bsize);
156 crypto_xor(iv, src, bsize);
157
158 src += bsize;
159 } while ((nbytes -= bsize) >= bsize);
160
161 memcpy(walk->iv, iv, bsize);
162
163 return nbytes;
164}
165
166static int crypto_pcbc_decrypt(struct skcipher_request *req)
167{
168 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
169 struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
170 struct crypto_cipher *child = ctx->child;
171 struct skcipher_walk walk;
172 unsigned int nbytes;
173 int err;
174
175 err = skcipher_walk_virt(&walk, req, false);
176
177 while ((nbytes = walk.nbytes)) {
178 if (walk.src.virt.addr == walk.dst.virt.addr)
179 nbytes = crypto_pcbc_decrypt_inplace(req, &walk,
180 child);
181 else
182 nbytes = crypto_pcbc_decrypt_segment(req, &walk,
183 child);
184 err = skcipher_walk_done(&walk, nbytes);
185 }
186
187 return err;
188}
189
190static int crypto_pcbc_init_tfm(struct crypto_skcipher *tfm)
191{
192 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
193 struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
194 struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
195 struct crypto_cipher *cipher;
196
197 cipher = crypto_spawn_cipher(spawn);
198 if (IS_ERR(cipher))
199 return PTR_ERR(cipher);
200
201 ctx->child = cipher;
202 return 0;
203}
204
205static void crypto_pcbc_exit_tfm(struct crypto_skcipher *tfm)
206{
207 struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
208
209 crypto_free_cipher(ctx->child);
210}
211
212static void crypto_pcbc_free(struct skcipher_instance *inst)
213{
214 crypto_drop_skcipher(skcipher_instance_ctx(inst));
215 kfree(inst);
216}
217
218static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
219{
220 struct skcipher_instance *inst;
221 struct crypto_attr_type *algt;
222 struct crypto_spawn *spawn;
223 struct crypto_alg *alg;
224 int err;
225
226 algt = crypto_get_attr_type(tb);
227 if (IS_ERR(algt))
228 return PTR_ERR(algt);
229
230 if (((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask) &
231 ~CRYPTO_ALG_INTERNAL)
232 return -EINVAL;
233
234 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
235 if (!inst)
236 return -ENOMEM;
237
238 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER |
239 (algt->type & CRYPTO_ALG_INTERNAL),
240 CRYPTO_ALG_TYPE_MASK |
241 (algt->mask & CRYPTO_ALG_INTERNAL));
242 err = PTR_ERR(alg);
243 if (IS_ERR(alg))
244 goto err_free_inst;
245
246 spawn = skcipher_instance_ctx(inst);
247 err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
248 CRYPTO_ALG_TYPE_MASK);
249 crypto_mod_put(alg);
250 if (err)
251 goto err_free_inst;
252
253 err = crypto_inst_setname(skcipher_crypto_instance(inst), "pcbc", alg);
254 if (err)
255 goto err_drop_spawn;
256
257 inst->alg.base.cra_flags = alg->cra_flags & CRYPTO_ALG_INTERNAL;
258 inst->alg.base.cra_priority = alg->cra_priority;
259 inst->alg.base.cra_blocksize = alg->cra_blocksize;
260 inst->alg.base.cra_alignmask = alg->cra_alignmask;
261
262 /* We access the data as u32s when xoring. */
263 inst->alg.base.cra_alignmask |= __alignof__(u32) - 1;
264
265 inst->alg.ivsize = alg->cra_blocksize;
266 inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize;
267 inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize;
268
269 inst->alg.base.cra_ctxsize = sizeof(struct crypto_pcbc_ctx);
270
271 inst->alg.init = crypto_pcbc_init_tfm;
272 inst->alg.exit = crypto_pcbc_exit_tfm;
273
274 inst->alg.setkey = crypto_pcbc_setkey;
275 inst->alg.encrypt = crypto_pcbc_encrypt;
276 inst->alg.decrypt = crypto_pcbc_decrypt;
277
278 inst->free = crypto_pcbc_free;
279
280 err = skcipher_register_instance(tmpl, inst);
281 if (err)
282 goto err_drop_spawn;
283
284out:
285 return err;
286
287err_drop_spawn:
288 crypto_drop_spawn(spawn);
289err_free_inst:
290 kfree(inst);
291 goto out;
292}
293
294static struct crypto_template crypto_pcbc_tmpl = {
295 .name = "pcbc",
296 .create = crypto_pcbc_create,
297 .module = THIS_MODULE,
298};
299
300static int __init crypto_pcbc_module_init(void)
301{
302 return crypto_register_template(&crypto_pcbc_tmpl);
303}
304
305static void __exit crypto_pcbc_module_exit(void)
306{
307 crypto_unregister_template(&crypto_pcbc_tmpl);
308}
309
310module_init(crypto_pcbc_module_init);
311module_exit(crypto_pcbc_module_exit);
312
313MODULE_LICENSE("GPL");
314MODULE_DESCRIPTION("PCBC block cipher algorithm");
315MODULE_ALIAS_CRYPTO("pcbc");