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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 | ||
23 | struct crypto_cbc_ctx { | |
24 | struct crypto_cipher *child; | |
25 | }; | |
26 | ||
27 | static 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 | ||
43 | static 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 | ||
51 | static int crypto_cbc_encrypt(struct skcipher_request *req) | |
52 | { | |
53 | return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one); | |
54 | } | |
55 | ||
56 | static 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 | ||
64 | static 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 | ||
81 | static 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 | ||
96 | static 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 | ||
103 | static void crypto_cbc_free(struct skcipher_instance *inst) | |
104 | { | |
105 | crypto_drop_skcipher(skcipher_instance_ctx(inst)); | |
106 | kfree(inst); | |
107 | } | |
108 | ||
109 | static 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 | ||
178 | out: | |
179 | return err; | |
180 | ||
181 | err_drop_spawn: | |
182 | crypto_drop_spawn(spawn); | |
183 | err_free_inst: | |
184 | kfree(inst); | |
185 | goto out; | |
186 | } | |
187 | ||
188 | static struct crypto_template crypto_cbc_tmpl = { | |
189 | .name = "cbc", | |
190 | .create = crypto_cbc_create, | |
191 | .module = THIS_MODULE, | |
192 | }; | |
193 | ||
194 | static int __init crypto_cbc_module_init(void) | |
195 | { | |
196 | return crypto_register_template(&crypto_cbc_tmpl); | |
197 | } | |
198 | ||
199 | static void __exit crypto_cbc_module_exit(void) | |
200 | { | |
201 | crypto_unregister_template(&crypto_cbc_tmpl); | |
202 | } | |
203 | ||
204 | module_init(crypto_cbc_module_init); | |
205 | module_exit(crypto_cbc_module_exit); | |
206 | ||
207 | MODULE_LICENSE("GPL"); | |
208 | MODULE_DESCRIPTION("CBC block cipher algorithm"); | |
209 | MODULE_ALIAS_CRYPTO("cbc"); |