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1 | /* | |
2 | * Copyright (C)2006 USAGI/WIDE Project | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
17 | * | |
18 | * Author: | |
19 | * Kazunori Miyazawa <miyazawa@linux-ipv6.org> | |
20 | */ | |
21 | ||
22 | #include <crypto/internal/hash.h> | |
23 | #include <linux/err.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/module.h> | |
26 | ||
27 | static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101, | |
28 | 0x02020202, 0x02020202, 0x02020202, 0x02020202, | |
29 | 0x03030303, 0x03030303, 0x03030303, 0x03030303}; | |
30 | ||
31 | /* | |
32 | * +------------------------ | |
33 | * | <parent tfm> | |
34 | * +------------------------ | |
35 | * | xcbc_tfm_ctx | |
36 | * +------------------------ | |
37 | * | consts (block size * 2) | |
38 | * +------------------------ | |
39 | */ | |
40 | struct xcbc_tfm_ctx { | |
41 | struct crypto_cipher *child; | |
42 | u8 ctx[]; | |
43 | }; | |
44 | ||
45 | /* | |
46 | * +------------------------ | |
47 | * | <shash desc> | |
48 | * +------------------------ | |
49 | * | xcbc_desc_ctx | |
50 | * +------------------------ | |
51 | * | odds (block size) | |
52 | * +------------------------ | |
53 | * | prev (block size) | |
54 | * +------------------------ | |
55 | */ | |
56 | struct xcbc_desc_ctx { | |
57 | unsigned int len; | |
58 | u8 ctx[]; | |
59 | }; | |
60 | ||
61 | static int crypto_xcbc_digest_setkey(struct crypto_shash *parent, | |
62 | const u8 *inkey, unsigned int keylen) | |
63 | { | |
64 | unsigned long alignmask = crypto_shash_alignmask(parent); | |
65 | struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent); | |
66 | int bs = crypto_shash_blocksize(parent); | |
67 | u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); | |
68 | int err = 0; | |
69 | u8 key1[bs]; | |
70 | ||
71 | if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen))) | |
72 | return err; | |
73 | ||
74 | crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs); | |
75 | crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2); | |
76 | crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks); | |
77 | ||
78 | return crypto_cipher_setkey(ctx->child, key1, bs); | |
79 | ||
80 | } | |
81 | ||
82 | static int crypto_xcbc_digest_init(struct shash_desc *pdesc) | |
83 | { | |
84 | unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm); | |
85 | struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); | |
86 | int bs = crypto_shash_blocksize(pdesc->tfm); | |
87 | u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs; | |
88 | ||
89 | ctx->len = 0; | |
90 | memset(prev, 0, bs); | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p, | |
96 | unsigned int len) | |
97 | { | |
98 | struct crypto_shash *parent = pdesc->tfm; | |
99 | unsigned long alignmask = crypto_shash_alignmask(parent); | |
100 | struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent); | |
101 | struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); | |
102 | struct crypto_cipher *tfm = tctx->child; | |
103 | int bs = crypto_shash_blocksize(parent); | |
104 | u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); | |
105 | u8 *prev = odds + bs; | |
106 | ||
107 | /* checking the data can fill the block */ | |
108 | if ((ctx->len + len) <= bs) { | |
109 | memcpy(odds + ctx->len, p, len); | |
110 | ctx->len += len; | |
111 | return 0; | |
112 | } | |
113 | ||
114 | /* filling odds with new data and encrypting it */ | |
115 | memcpy(odds + ctx->len, p, bs - ctx->len); | |
116 | len -= bs - ctx->len; | |
117 | p += bs - ctx->len; | |
118 | ||
119 | crypto_xor(prev, odds, bs); | |
120 | crypto_cipher_encrypt_one(tfm, prev, prev); | |
121 | ||
122 | /* clearing the length */ | |
123 | ctx->len = 0; | |
124 | ||
125 | /* encrypting the rest of data */ | |
126 | while (len > bs) { | |
127 | crypto_xor(prev, p, bs); | |
128 | crypto_cipher_encrypt_one(tfm, prev, prev); | |
129 | p += bs; | |
130 | len -= bs; | |
131 | } | |
132 | ||
133 | /* keeping the surplus of blocksize */ | |
134 | if (len) { | |
135 | memcpy(odds, p, len); | |
136 | ctx->len = len; | |
137 | } | |
138 | ||
139 | return 0; | |
140 | } | |
141 | ||
142 | static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out) | |
143 | { | |
144 | struct crypto_shash *parent = pdesc->tfm; | |
145 | unsigned long alignmask = crypto_shash_alignmask(parent); | |
146 | struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent); | |
147 | struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); | |
148 | struct crypto_cipher *tfm = tctx->child; | |
149 | int bs = crypto_shash_blocksize(parent); | |
150 | u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1); | |
151 | u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); | |
152 | u8 *prev = odds + bs; | |
153 | unsigned int offset = 0; | |
154 | ||
155 | if (ctx->len != bs) { | |
156 | unsigned int rlen; | |
157 | u8 *p = odds + ctx->len; | |
158 | ||
159 | *p = 0x80; | |
160 | p++; | |
161 | ||
162 | rlen = bs - ctx->len -1; | |
163 | if (rlen) | |
164 | memset(p, 0, rlen); | |
165 | ||
166 | offset += bs; | |
167 | } | |
168 | ||
169 | crypto_xor(prev, odds, bs); | |
170 | crypto_xor(prev, consts + offset, bs); | |
171 | ||
172 | crypto_cipher_encrypt_one(tfm, out, prev); | |
173 | ||
174 | return 0; | |
175 | } | |
176 | ||
177 | static int xcbc_init_tfm(struct crypto_tfm *tfm) | |
178 | { | |
179 | struct crypto_cipher *cipher; | |
180 | struct crypto_instance *inst = (void *)tfm->__crt_alg; | |
181 | struct crypto_spawn *spawn = crypto_instance_ctx(inst); | |
182 | struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm); | |
183 | ||
184 | cipher = crypto_spawn_cipher(spawn); | |
185 | if (IS_ERR(cipher)) | |
186 | return PTR_ERR(cipher); | |
187 | ||
188 | ctx->child = cipher; | |
189 | ||
190 | return 0; | |
191 | }; | |
192 | ||
193 | static void xcbc_exit_tfm(struct crypto_tfm *tfm) | |
194 | { | |
195 | struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm); | |
196 | crypto_free_cipher(ctx->child); | |
197 | } | |
198 | ||
199 | static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb) | |
200 | { | |
201 | struct shash_instance *inst; | |
202 | struct crypto_alg *alg; | |
203 | unsigned long alignmask; | |
204 | int err; | |
205 | ||
206 | err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH); | |
207 | if (err) | |
208 | return err; | |
209 | ||
210 | alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, | |
211 | CRYPTO_ALG_TYPE_MASK); | |
212 | if (IS_ERR(alg)) | |
213 | return PTR_ERR(alg); | |
214 | ||
215 | switch(alg->cra_blocksize) { | |
216 | case 16: | |
217 | break; | |
218 | default: | |
219 | goto out_put_alg; | |
220 | } | |
221 | ||
222 | inst = shash_alloc_instance("xcbc", alg); | |
223 | err = PTR_ERR(inst); | |
224 | if (IS_ERR(inst)) | |
225 | goto out_put_alg; | |
226 | ||
227 | err = crypto_init_spawn(shash_instance_ctx(inst), alg, | |
228 | shash_crypto_instance(inst), | |
229 | CRYPTO_ALG_TYPE_MASK); | |
230 | if (err) | |
231 | goto out_free_inst; | |
232 | ||
233 | alignmask = alg->cra_alignmask | 3; | |
234 | inst->alg.base.cra_alignmask = alignmask; | |
235 | inst->alg.base.cra_priority = alg->cra_priority; | |
236 | inst->alg.base.cra_blocksize = alg->cra_blocksize; | |
237 | ||
238 | inst->alg.digestsize = alg->cra_blocksize; | |
239 | inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx), | |
240 | crypto_tfm_ctx_alignment()) + | |
241 | (alignmask & | |
242 | ~(crypto_tfm_ctx_alignment() - 1)) + | |
243 | alg->cra_blocksize * 2; | |
244 | ||
245 | inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx), | |
246 | alignmask + 1) + | |
247 | alg->cra_blocksize * 2; | |
248 | inst->alg.base.cra_init = xcbc_init_tfm; | |
249 | inst->alg.base.cra_exit = xcbc_exit_tfm; | |
250 | ||
251 | inst->alg.init = crypto_xcbc_digest_init; | |
252 | inst->alg.update = crypto_xcbc_digest_update; | |
253 | inst->alg.final = crypto_xcbc_digest_final; | |
254 | inst->alg.setkey = crypto_xcbc_digest_setkey; | |
255 | ||
256 | err = shash_register_instance(tmpl, inst); | |
257 | if (err) { | |
258 | out_free_inst: | |
259 | shash_free_instance(shash_crypto_instance(inst)); | |
260 | } | |
261 | ||
262 | out_put_alg: | |
263 | crypto_mod_put(alg); | |
264 | return err; | |
265 | } | |
266 | ||
267 | static struct crypto_template crypto_xcbc_tmpl = { | |
268 | .name = "xcbc", | |
269 | .create = xcbc_create, | |
270 | .free = shash_free_instance, | |
271 | .module = THIS_MODULE, | |
272 | }; | |
273 | ||
274 | static int __init crypto_xcbc_module_init(void) | |
275 | { | |
276 | return crypto_register_template(&crypto_xcbc_tmpl); | |
277 | } | |
278 | ||
279 | static void __exit crypto_xcbc_module_exit(void) | |
280 | { | |
281 | crypto_unregister_template(&crypto_xcbc_tmpl); | |
282 | } | |
283 | ||
284 | module_init(crypto_xcbc_module_init); | |
285 | module_exit(crypto_xcbc_module_exit); | |
286 | ||
287 | MODULE_LICENSE("GPL"); | |
288 | MODULE_DESCRIPTION("XCBC keyed hash algorithm"); | |
289 | MODULE_ALIAS_CRYPTO("xcbc"); |