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7a7ffe65 HX |
1 | /* |
2 | * Symmetric key cipher operations. | |
3 | * | |
4 | * Generic encrypt/decrypt wrapper for ciphers, handles operations across | |
5 | * multiple page boundaries by using temporary blocks. In user context, | |
6 | * the kernel is given a chance to schedule us once per page. | |
7 | * | |
8 | * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify it | |
11 | * under the terms of the GNU General Public License as published by the Free | |
12 | * Software Foundation; either version 2 of the License, or (at your option) | |
13 | * any later version. | |
14 | * | |
15 | */ | |
16 | ||
17 | #include <crypto/internal/skcipher.h> | |
18 | #include <linux/bug.h> | |
19 | #include <linux/module.h> | |
20 | ||
21 | #include "internal.h" | |
22 | ||
23 | static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg) | |
24 | { | |
25 | if (alg->cra_type == &crypto_blkcipher_type) | |
26 | return sizeof(struct crypto_blkcipher *); | |
27 | ||
28 | BUG_ON(alg->cra_type != &crypto_ablkcipher_type && | |
29 | alg->cra_type != &crypto_givcipher_type); | |
30 | ||
31 | return sizeof(struct crypto_ablkcipher *); | |
32 | } | |
33 | ||
34 | static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm, | |
35 | const u8 *key, unsigned int keylen) | |
36 | { | |
37 | struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm); | |
38 | struct crypto_blkcipher *blkcipher = *ctx; | |
39 | int err; | |
40 | ||
41 | crypto_blkcipher_clear_flags(blkcipher, ~0); | |
42 | crypto_blkcipher_set_flags(blkcipher, crypto_skcipher_get_flags(tfm) & | |
43 | CRYPTO_TFM_REQ_MASK); | |
44 | err = crypto_blkcipher_setkey(blkcipher, key, keylen); | |
45 | crypto_skcipher_set_flags(tfm, crypto_blkcipher_get_flags(blkcipher) & | |
46 | CRYPTO_TFM_RES_MASK); | |
47 | ||
48 | return err; | |
49 | } | |
50 | ||
51 | static int skcipher_crypt_blkcipher(struct skcipher_request *req, | |
52 | int (*crypt)(struct blkcipher_desc *, | |
53 | struct scatterlist *, | |
54 | struct scatterlist *, | |
55 | unsigned int)) | |
56 | { | |
57 | struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); | |
58 | struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm); | |
59 | struct blkcipher_desc desc = { | |
60 | .tfm = *ctx, | |
61 | .info = req->iv, | |
62 | .flags = req->base.flags, | |
63 | }; | |
64 | ||
65 | ||
66 | return crypt(&desc, req->dst, req->src, req->cryptlen); | |
67 | } | |
68 | ||
69 | static int skcipher_encrypt_blkcipher(struct skcipher_request *req) | |
70 | { | |
71 | struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req); | |
72 | struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher); | |
73 | struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; | |
74 | ||
75 | return skcipher_crypt_blkcipher(req, alg->encrypt); | |
76 | } | |
77 | ||
78 | static int skcipher_decrypt_blkcipher(struct skcipher_request *req) | |
79 | { | |
80 | struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req); | |
81 | struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher); | |
82 | struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; | |
83 | ||
84 | return skcipher_crypt_blkcipher(req, alg->decrypt); | |
85 | } | |
86 | ||
87 | static void crypto_exit_skcipher_ops_blkcipher(struct crypto_tfm *tfm) | |
88 | { | |
89 | struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm); | |
90 | ||
91 | crypto_free_blkcipher(*ctx); | |
92 | } | |
93 | ||
ecdd6bed | 94 | static int crypto_init_skcipher_ops_blkcipher(struct crypto_tfm *tfm) |
7a7ffe65 HX |
95 | { |
96 | struct crypto_alg *calg = tfm->__crt_alg; | |
97 | struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm); | |
98 | struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm); | |
99 | struct crypto_blkcipher *blkcipher; | |
100 | struct crypto_tfm *btfm; | |
101 | ||
102 | if (!crypto_mod_get(calg)) | |
103 | return -EAGAIN; | |
104 | ||
105 | btfm = __crypto_alloc_tfm(calg, CRYPTO_ALG_TYPE_BLKCIPHER, | |
106 | CRYPTO_ALG_TYPE_MASK); | |
107 | if (IS_ERR(btfm)) { | |
108 | crypto_mod_put(calg); | |
109 | return PTR_ERR(btfm); | |
110 | } | |
111 | ||
112 | blkcipher = __crypto_blkcipher_cast(btfm); | |
113 | *ctx = blkcipher; | |
114 | tfm->exit = crypto_exit_skcipher_ops_blkcipher; | |
115 | ||
116 | skcipher->setkey = skcipher_setkey_blkcipher; | |
117 | skcipher->encrypt = skcipher_encrypt_blkcipher; | |
118 | skcipher->decrypt = skcipher_decrypt_blkcipher; | |
119 | ||
120 | skcipher->ivsize = crypto_blkcipher_ivsize(blkcipher); | |
973fb3fb | 121 | skcipher->keysize = calg->cra_blkcipher.max_keysize; |
7a7ffe65 HX |
122 | |
123 | return 0; | |
124 | } | |
125 | ||
126 | static int skcipher_setkey_ablkcipher(struct crypto_skcipher *tfm, | |
127 | const u8 *key, unsigned int keylen) | |
128 | { | |
129 | struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm); | |
130 | struct crypto_ablkcipher *ablkcipher = *ctx; | |
131 | int err; | |
132 | ||
133 | crypto_ablkcipher_clear_flags(ablkcipher, ~0); | |
134 | crypto_ablkcipher_set_flags(ablkcipher, | |
135 | crypto_skcipher_get_flags(tfm) & | |
136 | CRYPTO_TFM_REQ_MASK); | |
137 | err = crypto_ablkcipher_setkey(ablkcipher, key, keylen); | |
138 | crypto_skcipher_set_flags(tfm, | |
139 | crypto_ablkcipher_get_flags(ablkcipher) & | |
140 | CRYPTO_TFM_RES_MASK); | |
141 | ||
142 | return err; | |
143 | } | |
144 | ||
145 | static int skcipher_crypt_ablkcipher(struct skcipher_request *req, | |
146 | int (*crypt)(struct ablkcipher_request *)) | |
147 | { | |
148 | struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); | |
149 | struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm); | |
150 | struct ablkcipher_request *subreq = skcipher_request_ctx(req); | |
151 | ||
152 | ablkcipher_request_set_tfm(subreq, *ctx); | |
153 | ablkcipher_request_set_callback(subreq, skcipher_request_flags(req), | |
154 | req->base.complete, req->base.data); | |
155 | ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, | |
156 | req->iv); | |
157 | ||
158 | return crypt(subreq); | |
159 | } | |
160 | ||
161 | static int skcipher_encrypt_ablkcipher(struct skcipher_request *req) | |
162 | { | |
163 | struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req); | |
164 | struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher); | |
165 | struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher; | |
166 | ||
167 | return skcipher_crypt_ablkcipher(req, alg->encrypt); | |
168 | } | |
169 | ||
170 | static int skcipher_decrypt_ablkcipher(struct skcipher_request *req) | |
171 | { | |
172 | struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req); | |
173 | struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher); | |
174 | struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher; | |
175 | ||
176 | return skcipher_crypt_ablkcipher(req, alg->decrypt); | |
177 | } | |
178 | ||
179 | static void crypto_exit_skcipher_ops_ablkcipher(struct crypto_tfm *tfm) | |
180 | { | |
181 | struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm); | |
182 | ||
183 | crypto_free_ablkcipher(*ctx); | |
184 | } | |
185 | ||
ecdd6bed | 186 | static int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm) |
7a7ffe65 HX |
187 | { |
188 | struct crypto_alg *calg = tfm->__crt_alg; | |
189 | struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm); | |
190 | struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm); | |
191 | struct crypto_ablkcipher *ablkcipher; | |
192 | struct crypto_tfm *abtfm; | |
193 | ||
194 | if (!crypto_mod_get(calg)) | |
195 | return -EAGAIN; | |
196 | ||
197 | abtfm = __crypto_alloc_tfm(calg, 0, 0); | |
198 | if (IS_ERR(abtfm)) { | |
199 | crypto_mod_put(calg); | |
200 | return PTR_ERR(abtfm); | |
201 | } | |
202 | ||
203 | ablkcipher = __crypto_ablkcipher_cast(abtfm); | |
204 | *ctx = ablkcipher; | |
205 | tfm->exit = crypto_exit_skcipher_ops_ablkcipher; | |
206 | ||
207 | skcipher->setkey = skcipher_setkey_ablkcipher; | |
208 | skcipher->encrypt = skcipher_encrypt_ablkcipher; | |
209 | skcipher->decrypt = skcipher_decrypt_ablkcipher; | |
210 | ||
211 | skcipher->ivsize = crypto_ablkcipher_ivsize(ablkcipher); | |
212 | skcipher->reqsize = crypto_ablkcipher_reqsize(ablkcipher) + | |
213 | sizeof(struct ablkcipher_request); | |
973fb3fb | 214 | skcipher->keysize = calg->cra_ablkcipher.max_keysize; |
7a7ffe65 HX |
215 | |
216 | return 0; | |
217 | } | |
218 | ||
219 | static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm) | |
220 | { | |
221 | if (tfm->__crt_alg->cra_type == &crypto_blkcipher_type) | |
222 | return crypto_init_skcipher_ops_blkcipher(tfm); | |
223 | ||
224 | BUG_ON(tfm->__crt_alg->cra_type != &crypto_ablkcipher_type && | |
225 | tfm->__crt_alg->cra_type != &crypto_givcipher_type); | |
226 | ||
227 | return crypto_init_skcipher_ops_ablkcipher(tfm); | |
228 | } | |
229 | ||
230 | static const struct crypto_type crypto_skcipher_type2 = { | |
231 | .extsize = crypto_skcipher_extsize, | |
232 | .init_tfm = crypto_skcipher_init_tfm, | |
233 | .maskclear = ~CRYPTO_ALG_TYPE_MASK, | |
234 | .maskset = CRYPTO_ALG_TYPE_BLKCIPHER_MASK, | |
235 | .type = CRYPTO_ALG_TYPE_BLKCIPHER, | |
236 | .tfmsize = offsetof(struct crypto_skcipher, base), | |
237 | }; | |
238 | ||
239 | struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name, | |
240 | u32 type, u32 mask) | |
241 | { | |
242 | return crypto_alloc_tfm(alg_name, &crypto_skcipher_type2, type, mask); | |
243 | } | |
244 | EXPORT_SYMBOL_GPL(crypto_alloc_skcipher); | |
245 | ||
246 | MODULE_LICENSE("GPL"); | |
247 | MODULE_DESCRIPTION("Symmetric key cipher type"); |