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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
3106caab 22#include <crypto/internal/hash.h>
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23#include <linux/err.h>
24#include <linux/kernel.h>
333b0d7e 25
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26static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
27 0x02020202, 0x02020202, 0x02020202, 0x02020202,
28 0x03030303, 0x03030303, 0x03030303, 0x03030303};
ac95301f 29
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30/*
31 * +------------------------
32 * | <parent tfm>
33 * +------------------------
ac95301f 34 * | xcbc_tfm_ctx
333b0d7e 35 * +------------------------
ac95301f 36 * | consts (block size * 2)
333b0d7e 37 * +------------------------
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38 */
39struct xcbc_tfm_ctx {
40 struct crypto_cipher *child;
41 u8 ctx[];
42};
43
44/*
333b0d7e 45 * +------------------------
ac95301f 46 * | <shash desc>
333b0d7e 47 * +------------------------
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48 * | xcbc_desc_ctx
49 * +------------------------
50 * | odds (block size)
51 * +------------------------
52 * | prev (block size)
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53 * +------------------------
54 */
ac95301f 55struct xcbc_desc_ctx {
333b0d7e 56 unsigned int len;
ac95301f 57 u8 ctx[];
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58};
59
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60static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
61 const u8 *inkey, unsigned int keylen)
333b0d7e 62{
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63 unsigned long alignmask = crypto_shash_alignmask(parent);
64 struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
3106caab 65 int bs = crypto_shash_blocksize(parent);
ac95301f 66 u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
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67 int err = 0;
68 u8 key1[bs];
69
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70 if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
71 return err;
333b0d7e 72
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73 crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs);
74 crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2);
75 crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks);
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76
77 return crypto_cipher_setkey(ctx->child, key1, bs);
333b0d7e 78
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79}
80
3106caab 81static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
333b0d7e 82{
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83 unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm);
84 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
3106caab 85 int bs = crypto_shash_blocksize(pdesc->tfm);
ac95301f 86 u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs;
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87
88 ctx->len = 0;
ac95301f 89 memset(prev, 0, bs);
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90
91 return 0;
92}
93
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94static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
95 unsigned int len)
333b0d7e 96{
3106caab 97 struct crypto_shash *parent = pdesc->tfm;
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98 unsigned long alignmask = crypto_shash_alignmask(parent);
99 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
100 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
101 struct crypto_cipher *tfm = tctx->child;
3106caab 102 int bs = crypto_shash_blocksize(parent);
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103 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
104 u8 *prev = odds + bs;
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105
106 /* checking the data can fill the block */
107 if ((ctx->len + len) <= bs) {
ac95301f 108 memcpy(odds + ctx->len, p, len);
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109 ctx->len += len;
110 return 0;
1edcf2e1 111 }
333b0d7e 112
3106caab 113 /* filling odds with new data and encrypting it */
ac95301f 114 memcpy(odds + ctx->len, p, bs - ctx->len);
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115 len -= bs - ctx->len;
116 p += bs - ctx->len;
333b0d7e 117
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118 crypto_xor(prev, odds, bs);
119 crypto_cipher_encrypt_one(tfm, prev, prev);
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120
121 /* clearing the length */
122 ctx->len = 0;
123
124 /* encrypting the rest of data */
125 while (len > bs) {
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126 crypto_xor(prev, p, bs);
127 crypto_cipher_encrypt_one(tfm, prev, prev);
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128 p += bs;
129 len -= bs;
130 }
131
132 /* keeping the surplus of blocksize */
133 if (len) {
ac95301f 134 memcpy(odds, p, len);
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135 ctx->len = len;
136 }
137
138 return 0;
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139}
140
3106caab 141static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
333b0d7e 142{
3106caab 143 struct crypto_shash *parent = pdesc->tfm;
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144 unsigned long alignmask = crypto_shash_alignmask(parent);
145 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
146 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
147 struct crypto_cipher *tfm = tctx->child;
3106caab 148 int bs = crypto_shash_blocksize(parent);
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149 u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1);
150 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
151 u8 *prev = odds + bs;
152 unsigned int offset = 0;
333b0d7e 153
ac95301f 154 if (ctx->len != bs) {
333b0d7e 155 unsigned int rlen;
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156 u8 *p = odds + ctx->len;
157
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158 *p = 0x80;
159 p++;
160
161 rlen = bs - ctx->len -1;
162 if (rlen)
163 memset(p, 0, rlen);
164
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165 offset += bs;
166 }
333b0d7e 167
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168 crypto_xor(prev, odds, bs);
169 crypto_xor(prev, consts + offset, bs);
333b0d7e 170
ac95301f 171 crypto_cipher_encrypt_one(tfm, out, prev);
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172
173 return 0;
174}
175
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176static int xcbc_init_tfm(struct crypto_tfm *tfm)
177{
2e306ee0 178 struct crypto_cipher *cipher;
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179 struct crypto_instance *inst = (void *)tfm->__crt_alg;
180 struct crypto_spawn *spawn = crypto_instance_ctx(inst);
ac95301f 181 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
333b0d7e 182
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183 cipher = crypto_spawn_cipher(spawn);
184 if (IS_ERR(cipher))
185 return PTR_ERR(cipher);
333b0d7e 186
2e306ee0 187 ctx->child = cipher;
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188
189 return 0;
190};
191
192static void xcbc_exit_tfm(struct crypto_tfm *tfm)
193{
ac95301f 194 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
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195 crypto_free_cipher(ctx->child);
196}
197
3106caab 198static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
333b0d7e 199{
3106caab 200 struct shash_instance *inst;
333b0d7e 201 struct crypto_alg *alg;
36f87a4a 202 unsigned long alignmask;
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203 int err;
204
3106caab 205 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
ebc610e5 206 if (err)
3106caab 207 return err;
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208
209 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
210 CRYPTO_ALG_TYPE_MASK);
333b0d7e 211 if (IS_ERR(alg))
3106caab 212 return PTR_ERR(alg);
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213
214 switch(alg->cra_blocksize) {
215 case 16:
216 break;
217 default:
1b87887d 218 goto out_put_alg;
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219 }
220
3106caab 221 inst = shash_alloc_instance("xcbc", alg);
b5ebd44e 222 err = PTR_ERR(inst);
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223 if (IS_ERR(inst))
224 goto out_put_alg;
225
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226 err = crypto_init_spawn(shash_instance_ctx(inst), alg,
227 shash_crypto_instance(inst),
228 CRYPTO_ALG_TYPE_MASK);
229 if (err)
230 goto out_free_inst;
231
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232 alignmask = alg->cra_alignmask | 3;
233 inst->alg.base.cra_alignmask = alignmask;
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234 inst->alg.base.cra_priority = alg->cra_priority;
235 inst->alg.base.cra_blocksize = alg->cra_blocksize;
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236
237 inst->alg.digestsize = alg->cra_blocksize;
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238 inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx),
239 crypto_tfm_ctx_alignment()) +
36f87a4a 240 (alignmask &
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241 ~(crypto_tfm_ctx_alignment() - 1)) +
242 alg->cra_blocksize * 2;
243
244 inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx),
36f87a4a 245 alignmask + 1) +
ac95301f 246 alg->cra_blocksize * 2;
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247 inst->alg.base.cra_init = xcbc_init_tfm;
248 inst->alg.base.cra_exit = xcbc_exit_tfm;
249
250 inst->alg.init = crypto_xcbc_digest_init;
251 inst->alg.update = crypto_xcbc_digest_update;
252 inst->alg.final = crypto_xcbc_digest_final;
253 inst->alg.setkey = crypto_xcbc_digest_setkey;
254
255 err = shash_register_instance(tmpl, inst);
256 if (err) {
257out_free_inst:
258 shash_free_instance(shash_crypto_instance(inst));
259 }
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260
261out_put_alg:
262 crypto_mod_put(alg);
3106caab 263 return err;
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264}
265
266static struct crypto_template crypto_xcbc_tmpl = {
267 .name = "xcbc",
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268 .create = xcbc_create,
269 .free = shash_free_instance,
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270 .module = THIS_MODULE,
271};
272
273static int __init crypto_xcbc_module_init(void)
274{
275 return crypto_register_template(&crypto_xcbc_tmpl);
276}
277
278static void __exit crypto_xcbc_module_exit(void)
279{
280 crypto_unregister_template(&crypto_xcbc_tmpl);
281}
282
283module_init(crypto_xcbc_module_init);
284module_exit(crypto_xcbc_module_exit);
285
286MODULE_LICENSE("GPL");
287MODULE_DESCRIPTION("XCBC keyed hash algorithm");