1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * CBC: Cipher Block Chaining mode
4 *
5 * Copyright (c) 2006-2016 Herbert Xu <herbert@gondor.apana.org.au>
6 */
7
8 #include <crypto/algapi.h>
9 #include <crypto/cbc.h>
10 #include <crypto/internal/skcipher.h>
11 #include <linux/err.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/log2.h>
15 #include <linux/module.h>
16
crypto_cbc_encrypt_one(struct crypto_skcipher * tfm,const u8 * src,u8 * dst)17 static inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm,
18 const u8 *src, u8 *dst)
19 {
20 crypto_cipher_encrypt_one(skcipher_cipher_simple(tfm), dst, src);
21 }
22
crypto_cbc_encrypt(struct skcipher_request * req)23 static int crypto_cbc_encrypt(struct skcipher_request *req)
24 {
25 return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one);
26 }
27
crypto_cbc_decrypt_one(struct crypto_skcipher * tfm,const u8 * src,u8 * dst)28 static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm,
29 const u8 *src, u8 *dst)
30 {
31 crypto_cipher_decrypt_one(skcipher_cipher_simple(tfm), dst, src);
32 }
33
crypto_cbc_decrypt(struct skcipher_request * req)34 static int crypto_cbc_decrypt(struct skcipher_request *req)
35 {
36 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
37 struct skcipher_walk walk;
38 int err;
39
40 err = skcipher_walk_virt(&walk, req, false);
41
42 while (walk.nbytes) {
43 err = crypto_cbc_decrypt_blocks(&walk, tfm,
44 crypto_cbc_decrypt_one);
45 err = skcipher_walk_done(&walk, err);
46 }
47
48 return err;
49 }
50
crypto_cbc_create(struct crypto_template * tmpl,struct rtattr ** tb)51 static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
52 {
53 struct skcipher_instance *inst;
54 struct crypto_alg *alg;
55 int err;
56
57 inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);
58 if (IS_ERR(inst))
59 return PTR_ERR(inst);
60
61 err = -EINVAL;
62 if (!is_power_of_2(alg->cra_blocksize))
63 goto out_free_inst;
64
65 inst->alg.encrypt = crypto_cbc_encrypt;
66 inst->alg.decrypt = crypto_cbc_decrypt;
67
68 err = skcipher_register_instance(tmpl, inst);
69 if (err)
70 goto out_free_inst;
71 goto out_put_alg;
72
73 out_free_inst:
74 inst->free(inst);
75 out_put_alg:
76 crypto_mod_put(alg);
77 return err;
78 }
79
80 static struct crypto_template crypto_cbc_tmpl = {
81 .name = "cbc",
82 .create = crypto_cbc_create,
83 .module = THIS_MODULE,
84 };
85
crypto_cbc_module_init(void)86 static int __init crypto_cbc_module_init(void)
87 {
88 return crypto_register_template(&crypto_cbc_tmpl);
89 }
90
crypto_cbc_module_exit(void)91 static void __exit crypto_cbc_module_exit(void)
92 {
93 crypto_unregister_template(&crypto_cbc_tmpl);
94 }
95
96 subsys_initcall(crypto_cbc_module_init);
97 module_exit(crypto_cbc_module_exit);
98
99 MODULE_LICENSE("GPL");
100 MODULE_DESCRIPTION("CBC block cipher mode of operation");
101 MODULE_ALIAS_CRYPTO("cbc");
102
