Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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#include <linux/slab.h>
22
23struct crypto_cbc_ctx {
24 struct crypto_cipher *child;
25};
26
27static int crypto_cbc_setkey(struct crypto_skcipher *parent, const u8 *key,
28 unsigned int keylen)
29{
30 struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(parent);
31 struct crypto_cipher *child = ctx->child;
32 int err;
33
34 crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
35 crypto_cipher_set_flags(child, crypto_skcipher_get_flags(parent) &
36 CRYPTO_TFM_REQ_MASK);
37 err = crypto_cipher_setkey(child, key, keylen);
38 crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &
39 CRYPTO_TFM_RES_MASK);
40 return err;
41}
42
43static inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm,
44 const u8 *src, u8 *dst)
45{
46 struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
47
48 crypto_cipher_encrypt_one(ctx->child, dst, src);
49}
50
51static int crypto_cbc_encrypt(struct skcipher_request *req)
52{
53 return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one);
54}
55
56static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm,
57 const u8 *src, u8 *dst)
58{
59 struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
60
61 crypto_cipher_decrypt_one(ctx->child, dst, src);
62}
63
64static int crypto_cbc_decrypt(struct skcipher_request *req)
65{
66 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
67 struct skcipher_walk walk;
68 int err;
69
70 err = skcipher_walk_virt(&walk, req, false);
71
72 while (walk.nbytes) {
73 err = crypto_cbc_decrypt_blocks(&walk, tfm,
74 crypto_cbc_decrypt_one);
75 err = skcipher_walk_done(&walk, err);
76 }
77
78 return err;
79}
80
81static int crypto_cbc_init_tfm(struct crypto_skcipher *tfm)
82{
83 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
84 struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
85 struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
86 struct crypto_cipher *cipher;
87
88 cipher = crypto_spawn_cipher(spawn);
89 if (IS_ERR(cipher))
90 return PTR_ERR(cipher);
91
92 ctx->child = cipher;
93 return 0;
94}
95
96static void crypto_cbc_exit_tfm(struct crypto_skcipher *tfm)
97{
98 struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
99
100 crypto_free_cipher(ctx->child);
101}
102
103static void crypto_cbc_free(struct skcipher_instance *inst)
104{
105 crypto_drop_skcipher(skcipher_instance_ctx(inst));
106 kfree(inst);
107}
108
109static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
110{
111 struct skcipher_instance *inst;
112 struct crypto_attr_type *algt;
113 struct crypto_spawn *spawn;
114 struct crypto_alg *alg;
115 u32 mask;
116 int err;
117
118 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER);
119 if (err)
120 return err;
121
122 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
123 if (!inst)
124 return -ENOMEM;
125
126 algt = crypto_get_attr_type(tb);
127 err = PTR_ERR(algt);
128 if (IS_ERR(algt))
129 goto err_free_inst;
130
131 mask = CRYPTO_ALG_TYPE_MASK |
132 crypto_requires_off(algt->type, algt->mask,
133 CRYPTO_ALG_NEED_FALLBACK);
134
135 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask);
136 err = PTR_ERR(alg);
137 if (IS_ERR(alg))
138 goto err_free_inst;
139
140 spawn = skcipher_instance_ctx(inst);
141 err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
142 CRYPTO_ALG_TYPE_MASK);
143 crypto_mod_put(alg);
144 if (err)
145 goto err_free_inst;
146
147 err = crypto_inst_setname(skcipher_crypto_instance(inst), "cbc", alg);
148 if (err)
149 goto err_drop_spawn;
150
151 err = -EINVAL;
152 if (!is_power_of_2(alg->cra_blocksize))
153 goto err_drop_spawn;
154
155 inst->alg.base.cra_priority = alg->cra_priority;
156 inst->alg.base.cra_blocksize = alg->cra_blocksize;
157 inst->alg.base.cra_alignmask = alg->cra_alignmask;
158
159 inst->alg.ivsize = alg->cra_blocksize;
160 inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize;
161 inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize;
162
163 inst->alg.base.cra_ctxsize = sizeof(struct crypto_cbc_ctx);
164
165 inst->alg.init = crypto_cbc_init_tfm;
166 inst->alg.exit = crypto_cbc_exit_tfm;
167
168 inst->alg.setkey = crypto_cbc_setkey;
169 inst->alg.encrypt = crypto_cbc_encrypt;
170 inst->alg.decrypt = crypto_cbc_decrypt;
171
172 inst->free = crypto_cbc_free;
173
174 err = skcipher_register_instance(tmpl, inst);
175 if (err)
176 goto err_drop_spawn;
177
178out:
179 return err;
180
181err_drop_spawn:
182 crypto_drop_spawn(spawn);
183err_free_inst:
184 kfree(inst);
185 goto out;
186}
187
188static struct crypto_template crypto_cbc_tmpl = {
189 .name = "cbc",
190 .create = crypto_cbc_create,
191 .module = THIS_MODULE,
192};
193
194static int __init crypto_cbc_module_init(void)
195{
196 return crypto_register_template(&crypto_cbc_tmpl);
197}
198
199static void __exit crypto_cbc_module_exit(void)
200{
201 crypto_unregister_template(&crypto_cbc_tmpl);
202}
203
204module_init(crypto_cbc_module_init);
205module_exit(crypto_cbc_module_exit);
206
207MODULE_LICENSE("GPL");
208MODULE_DESCRIPTION("CBC block cipher algorithm");
209MODULE_ALIAS_CRYPTO("cbc");