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/algapi.h>
14#include <crypto/cbc.h>
15#include <crypto/internal/skcipher.h>
16#include <linux/err.h>
17#include <linux/init.h>
18#include <linux/kernel.h>
19#include <linux/log2.h>
20#include <linux/module.h>
21
22static inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm,
23 const u8 *src, u8 *dst)
24{
25 crypto_cipher_encrypt_one(skcipher_cipher_simple(tfm), dst, src);
26}
27
28static int crypto_cbc_encrypt(struct skcipher_request *req)
29{
30 return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one);
31}
32
33static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm,
34 const u8 *src, u8 *dst)
35{
36 crypto_cipher_decrypt_one(skcipher_cipher_simple(tfm), dst, src);
37}
38
39static int crypto_cbc_decrypt(struct skcipher_request *req)
40{
41 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
42 struct skcipher_walk walk;
43 int err;
44
45 err = skcipher_walk_virt(&walk, req, false);
46
47 while (walk.nbytes) {
48 err = crypto_cbc_decrypt_blocks(&walk, tfm,
49 crypto_cbc_decrypt_one);
50 err = skcipher_walk_done(&walk, err);
51 }
52
53 return err;
54}
55
56static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
57{
58 struct skcipher_instance *inst;
59 struct crypto_alg *alg;
60 int err;
61
62 inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);
63 if (IS_ERR(inst))
64 return PTR_ERR(inst);
65
66 err = -EINVAL;
67 if (!is_power_of_2(alg->cra_blocksize))
68 goto out_free_inst;
69
70 inst->alg.encrypt = crypto_cbc_encrypt;
71 inst->alg.decrypt = crypto_cbc_decrypt;
72
73 err = skcipher_register_instance(tmpl, inst);
74 if (err)
75 goto out_free_inst;
76 goto out_put_alg;
77
78out_free_inst:
79 inst->free(inst);
80out_put_alg:
81 crypto_mod_put(alg);
82 return err;
83}
84
85static struct crypto_template crypto_cbc_tmpl = {
86 .name = "cbc",
87 .create = crypto_cbc_create,
88 .module = THIS_MODULE,
89};
90
91static int __init crypto_cbc_module_init(void)
92{
93 return crypto_register_template(&crypto_cbc_tmpl);
94}
95
96static void __exit crypto_cbc_module_exit(void)
97{
98 crypto_unregister_template(&crypto_cbc_tmpl);
99}
100
101module_init(crypto_cbc_module_init);
102module_exit(crypto_cbc_module_exit);
103
104MODULE_LICENSE("GPL");
105MODULE_DESCRIPTION("CBC block cipher mode of operation");
106MODULE_ALIAS_CRYPTO("cbc");
107