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1/*
2 * CBC: Cipher Block Chaining mode
3 *
4 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 *
11 */
12
13#include <crypto/algapi.h>
14#include <linux/err.h>
15#include <linux/init.h>
16#include <linux/kernel.h>
17#include <linux/log2.h>
18#include <linux/module.h>
19#include <linux/scatterlist.h>
20#include <linux/slab.h>
21
22struct crypto_cbc_ctx {
23 struct crypto_cipher *child;
24};
25
26static int crypto_cbc_setkey(struct crypto_tfm *parent, const u8 *key,
27 unsigned int keylen)
28{
29 struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(parent);
30 struct crypto_cipher *child = ctx->child;
31 int err;
32
33 crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
34 crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
35 CRYPTO_TFM_REQ_MASK);
36 err = crypto_cipher_setkey(child, key, keylen);
37 crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
38 CRYPTO_TFM_RES_MASK);
39 return err;
40}
41
42static int crypto_cbc_encrypt_segment(struct blkcipher_desc *desc,
43 struct blkcipher_walk *walk,
44 struct crypto_cipher *tfm)
45{
46 void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
47 crypto_cipher_alg(tfm)->cia_encrypt;
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 fn(crypto_cipher_tfm(tfm), dst, iv);
57 memcpy(iv, dst, bsize);
58
59 src += bsize;
60 dst += bsize;
61 } while ((nbytes -= bsize) >= bsize);
62
63 return nbytes;
64}
65
66static int crypto_cbc_encrypt_inplace(struct blkcipher_desc *desc,
67 struct blkcipher_walk *walk,
68 struct crypto_cipher *tfm)
69{
70 void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
71 crypto_cipher_alg(tfm)->cia_encrypt;
72 int bsize = crypto_cipher_blocksize(tfm);
73 unsigned int nbytes = walk->nbytes;
74 u8 *src = walk->src.virt.addr;
75 u8 *iv = walk->iv;
76
77 do {
78 crypto_xor(src, iv, bsize);
79 fn(crypto_cipher_tfm(tfm), src, src);
80 iv = src;
81
82 src += bsize;
83 } while ((nbytes -= bsize) >= bsize);
84
85 memcpy(walk->iv, iv, bsize);
86
87 return nbytes;
88}
89
90static int crypto_cbc_encrypt(struct blkcipher_desc *desc,
91 struct scatterlist *dst, struct scatterlist *src,
92 unsigned int nbytes)
93{
94 struct blkcipher_walk walk;
95 struct crypto_blkcipher *tfm = desc->tfm;
96 struct crypto_cbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
97 struct crypto_cipher *child = ctx->child;
98 int err;
99
100 blkcipher_walk_init(&walk, dst, src, nbytes);
101 err = blkcipher_walk_virt(desc, &walk);
102
103 while ((nbytes = walk.nbytes)) {
104 if (walk.src.virt.addr == walk.dst.virt.addr)
105 nbytes = crypto_cbc_encrypt_inplace(desc, &walk, child);
106 else
107 nbytes = crypto_cbc_encrypt_segment(desc, &walk, child);
108 err = blkcipher_walk_done(desc, &walk, nbytes);
109 }
110
111 return err;
112}
113
114static int crypto_cbc_decrypt_segment(struct blkcipher_desc *desc,
115 struct blkcipher_walk *walk,
116 struct crypto_cipher *tfm)
117{
118 void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
119 crypto_cipher_alg(tfm)->cia_decrypt;
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 fn(crypto_cipher_tfm(tfm), dst, src);
128 crypto_xor(dst, iv, bsize);
129 iv = src;
130
131 src += bsize;
132 dst += bsize;
133 } while ((nbytes -= bsize) >= bsize);
134
135 memcpy(walk->iv, iv, bsize);
136
137 return nbytes;
138}
139
140static int crypto_cbc_decrypt_inplace(struct blkcipher_desc *desc,
141 struct blkcipher_walk *walk,
142 struct crypto_cipher *tfm)
143{
144 void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
145 crypto_cipher_alg(tfm)->cia_decrypt;
146 int bsize = crypto_cipher_blocksize(tfm);
147 unsigned int nbytes = walk->nbytes;
148 u8 *src = walk->src.virt.addr;
149 u8 last_iv[bsize];
150
151 /* Start of the last block. */
152 src += nbytes - (nbytes & (bsize - 1)) - bsize;
153 memcpy(last_iv, src, bsize);
154
155 for (;;) {
156 fn(crypto_cipher_tfm(tfm), src, src);
157 if ((nbytes -= bsize) < bsize)
158 break;
159 crypto_xor(src, src - bsize, bsize);
160 src -= bsize;
161 }
162
163 crypto_xor(src, walk->iv, bsize);
164 memcpy(walk->iv, last_iv, bsize);
165
166 return nbytes;
167}
168
169static int crypto_cbc_decrypt(struct blkcipher_desc *desc,
170 struct scatterlist *dst, struct scatterlist *src,
171 unsigned int nbytes)
172{
173 struct blkcipher_walk walk;
174 struct crypto_blkcipher *tfm = desc->tfm;
175 struct crypto_cbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
176 struct crypto_cipher *child = ctx->child;
177 int err;
178
179 blkcipher_walk_init(&walk, dst, src, nbytes);
180 err = blkcipher_walk_virt(desc, &walk);
181
182 while ((nbytes = walk.nbytes)) {
183 if (walk.src.virt.addr == walk.dst.virt.addr)
184 nbytes = crypto_cbc_decrypt_inplace(desc, &walk, child);
185 else
186 nbytes = crypto_cbc_decrypt_segment(desc, &walk, child);
187 err = blkcipher_walk_done(desc, &walk, nbytes);
188 }
189
190 return err;
191}
192
193static int crypto_cbc_init_tfm(struct crypto_tfm *tfm)
194{
195 struct crypto_instance *inst = (void *)tfm->__crt_alg;
196 struct crypto_spawn *spawn = crypto_instance_ctx(inst);
197 struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
198 struct crypto_cipher *cipher;
199
200 cipher = crypto_spawn_cipher(spawn);
201 if (IS_ERR(cipher))
202 return PTR_ERR(cipher);
203
204 ctx->child = cipher;
205 return 0;
206}
207
208static void crypto_cbc_exit_tfm(struct crypto_tfm *tfm)
209{
210 struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
211 crypto_free_cipher(ctx->child);
212}
213
214static struct crypto_instance *crypto_cbc_alloc(struct rtattr **tb)
215{
216 struct crypto_instance *inst;
217 struct crypto_alg *alg;
218 int err;
219
220 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
221 if (err)
222 return ERR_PTR(err);
223
224 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
225 CRYPTO_ALG_TYPE_MASK);
226 if (IS_ERR(alg))
227 return ERR_CAST(alg);
228
229 inst = ERR_PTR(-EINVAL);
230 if (!is_power_of_2(alg->cra_blocksize))
231 goto out_put_alg;
232
233 inst = crypto_alloc_instance("cbc", alg);
234 if (IS_ERR(inst))
235 goto out_put_alg;
236
237 inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
238 inst->alg.cra_priority = alg->cra_priority;
239 inst->alg.cra_blocksize = alg->cra_blocksize;
240 inst->alg.cra_alignmask = alg->cra_alignmask;
241 inst->alg.cra_type = &crypto_blkcipher_type;
242
243 /* We access the data as u32s when xoring. */
244 inst->alg.cra_alignmask |= __alignof__(u32) - 1;
245
246 inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
247 inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
248 inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
249
250 inst->alg.cra_ctxsize = sizeof(struct crypto_cbc_ctx);
251
252 inst->alg.cra_init = crypto_cbc_init_tfm;
253 inst->alg.cra_exit = crypto_cbc_exit_tfm;
254
255 inst->alg.cra_blkcipher.setkey = crypto_cbc_setkey;
256 inst->alg.cra_blkcipher.encrypt = crypto_cbc_encrypt;
257 inst->alg.cra_blkcipher.decrypt = crypto_cbc_decrypt;
258
259out_put_alg:
260 crypto_mod_put(alg);
261 return inst;
262}
263
264static void crypto_cbc_free(struct crypto_instance *inst)
265{
266 crypto_drop_spawn(crypto_instance_ctx(inst));
267 kfree(inst);
268}
269
270static struct crypto_template crypto_cbc_tmpl = {
271 .name = "cbc",
272 .alloc = crypto_cbc_alloc,
273 .free = crypto_cbc_free,
274 .module = THIS_MODULE,
275};
276
277static int __init crypto_cbc_module_init(void)
278{
279 return crypto_register_template(&crypto_cbc_tmpl);
280}
281
282static void __exit crypto_cbc_module_exit(void)
283{
284 crypto_unregister_template(&crypto_cbc_tmpl);
285}
286
287module_init(crypto_cbc_module_init);
288module_exit(crypto_cbc_module_exit);
289
290MODULE_LICENSE("GPL");
291MODULE_DESCRIPTION("CBC block cipher algorithm");
1/*
2 * CBC: Cipher Block Chaining mode
3 *
4 * Copyright (c) 2006-2016 Herbert Xu <herbert@gondor.apana.org.au>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 *
11 */
12
13#include <crypto/cbc.h>
14#include <crypto/internal/skcipher.h>
15#include <linux/err.h>
16#include <linux/init.h>
17#include <linux/kernel.h>
18#include <linux/log2.h>
19#include <linux/module.h>
20#include <linux/slab.h>
21
22struct crypto_cbc_ctx {
23 struct crypto_cipher *child;
24};
25
26static int crypto_cbc_setkey(struct crypto_skcipher *parent, const u8 *key,
27 unsigned int keylen)
28{
29 struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(parent);
30 struct crypto_cipher *child = ctx->child;
31 int err;
32
33 crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
34 crypto_cipher_set_flags(child, crypto_skcipher_get_flags(parent) &
35 CRYPTO_TFM_REQ_MASK);
36 err = crypto_cipher_setkey(child, key, keylen);
37 crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &
38 CRYPTO_TFM_RES_MASK);
39 return err;
40}
41
42static inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm,
43 const u8 *src, u8 *dst)
44{
45 struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
46
47 crypto_cipher_encrypt_one(ctx->child, dst, src);
48}
49
50static int crypto_cbc_encrypt(struct skcipher_request *req)
51{
52 return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one);
53}
54
55static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm,
56 const u8 *src, u8 *dst)
57{
58 struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
59
60 crypto_cipher_decrypt_one(ctx->child, dst, src);
61}
62
63static int crypto_cbc_decrypt(struct skcipher_request *req)
64{
65 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
66 struct skcipher_walk walk;
67 int err;
68
69 err = skcipher_walk_virt(&walk, req, false);
70
71 while (walk.nbytes) {
72 err = crypto_cbc_decrypt_blocks(&walk, tfm,
73 crypto_cbc_decrypt_one);
74 err = skcipher_walk_done(&walk, err);
75 }
76
77 return err;
78}
79
80static int crypto_cbc_init_tfm(struct crypto_skcipher *tfm)
81{
82 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
83 struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
84 struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
85 struct crypto_cipher *cipher;
86
87 cipher = crypto_spawn_cipher(spawn);
88 if (IS_ERR(cipher))
89 return PTR_ERR(cipher);
90
91 ctx->child = cipher;
92 return 0;
93}
94
95static void crypto_cbc_exit_tfm(struct crypto_skcipher *tfm)
96{
97 struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
98
99 crypto_free_cipher(ctx->child);
100}
101
102static void crypto_cbc_free(struct skcipher_instance *inst)
103{
104 crypto_drop_skcipher(skcipher_instance_ctx(inst));
105 kfree(inst);
106}
107
108static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
109{
110 struct skcipher_instance *inst;
111 struct crypto_spawn *spawn;
112 struct crypto_alg *alg;
113 int err;
114
115 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER);
116 if (err)
117 return err;
118
119 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
120 if (!inst)
121 return -ENOMEM;
122
123 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
124 CRYPTO_ALG_TYPE_MASK);
125 err = PTR_ERR(alg);
126 if (IS_ERR(alg))
127 goto err_free_inst;
128
129 spawn = skcipher_instance_ctx(inst);
130 err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
131 CRYPTO_ALG_TYPE_MASK);
132 crypto_mod_put(alg);
133 if (err)
134 goto err_free_inst;
135
136 err = crypto_inst_setname(skcipher_crypto_instance(inst), "cbc", alg);
137 if (err)
138 goto err_drop_spawn;
139
140 err = -EINVAL;
141 if (!is_power_of_2(alg->cra_blocksize))
142 goto err_drop_spawn;
143
144 inst->alg.base.cra_priority = alg->cra_priority;
145 inst->alg.base.cra_blocksize = alg->cra_blocksize;
146 inst->alg.base.cra_alignmask = alg->cra_alignmask;
147
148 /* We access the data as u32s when xoring. */
149 inst->alg.base.cra_alignmask |= __alignof__(u32) - 1;
150
151 inst->alg.ivsize = alg->cra_blocksize;
152 inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize;
153 inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize;
154
155 inst->alg.base.cra_ctxsize = sizeof(struct crypto_cbc_ctx);
156
157 inst->alg.init = crypto_cbc_init_tfm;
158 inst->alg.exit = crypto_cbc_exit_tfm;
159
160 inst->alg.setkey = crypto_cbc_setkey;
161 inst->alg.encrypt = crypto_cbc_encrypt;
162 inst->alg.decrypt = crypto_cbc_decrypt;
163
164 inst->free = crypto_cbc_free;
165
166 err = skcipher_register_instance(tmpl, inst);
167 if (err)
168 goto err_drop_spawn;
169
170out:
171 return err;
172
173err_drop_spawn:
174 crypto_drop_spawn(spawn);
175err_free_inst:
176 kfree(inst);
177 goto out;
178}
179
180static struct crypto_template crypto_cbc_tmpl = {
181 .name = "cbc",
182 .create = crypto_cbc_create,
183 .module = THIS_MODULE,
184};
185
186static int __init crypto_cbc_module_init(void)
187{
188 return crypto_register_template(&crypto_cbc_tmpl);
189}
190
191static void __exit crypto_cbc_module_exit(void)
192{
193 crypto_unregister_template(&crypto_cbc_tmpl);
194}
195
196module_init(crypto_cbc_module_init);
197module_exit(crypto_cbc_module_exit);
198
199MODULE_LICENSE("GPL");
200MODULE_DESCRIPTION("CBC block cipher algorithm");
201MODULE_ALIAS_CRYPTO("cbc");