aboutsummaryrefslogtreecommitdiff
path: root/crypto/xcbc.c
blob: a9e8ee9c1949cba2b20e55d0d1fd334ad7a20086 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C)2006 USAGI/WIDE Project
 *
 * Author:
 * 	Kazunori Miyazawa <miyazawa@linux-ipv6.org>
 */

#include <crypto/internal/cipher.h>
#include <crypto/internal/hash.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>

static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
			   0x02020202, 0x02020202, 0x02020202, 0x02020202,
			   0x03030303, 0x03030303, 0x03030303, 0x03030303};

/*
 * +------------------------
 * | <parent tfm>
 * +------------------------
 * | xcbc_tfm_ctx
 * +------------------------
 * | consts (block size * 2)
 * +------------------------
 */
struct xcbc_tfm_ctx {
	struct crypto_cipher *child;
	u8 consts[];
};

/*
 * +------------------------
 * | <shash desc>
 * +------------------------
 * | xcbc_desc_ctx
 * +------------------------
 * | odds (block size)
 * +------------------------
 * | prev (block size)
 * +------------------------
 */
struct xcbc_desc_ctx {
	unsigned int len;
	u8 odds[];
};

#define XCBC_BLOCKSIZE	16

static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
				     const u8 *inkey, unsigned int keylen)
{
	struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
	u8 *consts = ctx->consts;
	int err = 0;
	u8 key1[XCBC_BLOCKSIZE];
	int bs = sizeof(key1);

	if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
		return err;

	crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs);
	crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2);
	crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks);

	return crypto_cipher_setkey(ctx->child, key1, bs);

}

static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
{
	struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
	int bs = crypto_shash_blocksize(pdesc->tfm);
	u8 *prev = &ctx->odds[bs];

	ctx->len = 0;
	memset(prev, 0, bs);

	return 0;
}

static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
				     unsigned int len)
{
	struct crypto_shash *parent = pdesc->tfm;
	struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
	struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
	struct crypto_cipher *tfm = tctx->child;
	int bs = crypto_shash_blocksize(parent);
	u8 *odds = ctx->odds;
	u8 *prev = odds + bs;

	/* checking the data can fill the block */
	if ((ctx->len + len) <= bs) {
		memcpy(odds + ctx->len, p, len);
		ctx->len += len;
		return 0;
	}

	/* filling odds with new data and encrypting it */
	memcpy(odds + ctx->len, p, bs - ctx->len);
	len -= bs - ctx->len;
	p += bs - ctx->len;

	crypto_xor(prev, odds, bs);
	crypto_cipher_encrypt_one(tfm, prev, prev);

	/* clearing the length */
	ctx->len = 0;

	/* encrypting the rest of data */
	while (len > bs) {
		crypto_xor(prev, p, bs);
		crypto_cipher_encrypt_one(tfm, prev, prev);
		p += bs;
		len -= bs;
	}

	/* keeping the surplus of blocksize */
	if (len) {
		memcpy(odds, p, len);
		ctx->len = len;
	}

	return 0;
}

static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
{
	struct crypto_shash *parent = pdesc->tfm;
	struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
	struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
	struct crypto_cipher *tfm = tctx->child;
	int bs = crypto_shash_blocksize(parent);
	u8 *odds = ctx->odds;
	u8 *prev = odds + bs;
	unsigned int offset = 0;

	if (ctx->len != bs) {
		unsigned int rlen;
		u8 *p = odds + ctx->len;

		*p = 0x80;
		p++;

		rlen = bs - ctx->len -1;
		if (rlen)
			memset(p, 0, rlen);

		offset += bs;
	}

	crypto_xor(prev, odds, bs);
	crypto_xor(prev, &tctx->consts[offset], bs);

	crypto_cipher_encrypt_one(tfm, out, prev);

	return 0;
}

static int xcbc_init_tfm(struct crypto_tfm *tfm)
{
	struct crypto_cipher *cipher;
	struct crypto_instance *inst = (void *)tfm->__crt_alg;
	struct crypto_cipher_spawn *spawn = crypto_instance_ctx(inst);
	struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);

	cipher = crypto_spawn_cipher(spawn);
	if (IS_ERR(cipher))
		return PTR_ERR(cipher);

	ctx->child = cipher;

	return 0;
};

static void xcbc_exit_tfm(struct crypto_tfm *tfm)
{
	struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
	crypto_free_cipher(ctx->child);
}

static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	struct shash_instance *inst;
	struct crypto_cipher_spawn *spawn;
	struct crypto_alg *alg;
	u32 mask;
	int err;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
	if (err)
		return err;

	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
	if (!inst)
		return -ENOMEM;
	spawn = shash_instance_ctx(inst);

	err = crypto_grab_cipher(spawn, shash_crypto_instance(inst),
				 crypto_attr_alg_name(tb[1]), 0, mask);
	if (err)
		goto err_free_inst;
	alg = crypto_spawn_cipher_alg(spawn);

	err = -EINVAL;
	if (alg->cra_blocksize != XCBC_BLOCKSIZE)
		goto err_free_inst;

	err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
	if (err)
		goto err_free_inst;

	inst->alg.base.cra_priority = alg->cra_priority;
	inst->alg.base.cra_blocksize = alg->cra_blocksize;
	inst->alg.base.cra_ctxsize = sizeof(struct xcbc_tfm_ctx) +
				     alg->cra_blocksize * 2;

	inst->alg.digestsize = alg->cra_blocksize;
	inst->alg.descsize = sizeof(struct xcbc_desc_ctx) +
			     alg->cra_blocksize * 2;

	inst->alg.base.cra_init = xcbc_init_tfm;
	inst->alg.base.cra_exit = xcbc_exit_tfm;

	inst->alg.init = crypto_xcbc_digest_init;
	inst->alg.update = crypto_xcbc_digest_update;
	inst->alg.final = crypto_xcbc_digest_final;
	inst->alg.setkey = crypto_xcbc_digest_setkey;

	inst->free = shash_free_singlespawn_instance;

	err = shash_register_instance(tmpl, inst);
	if (err) {
err_free_inst:
		shash_free_singlespawn_instance(inst);
	}
	return err;
}

static struct crypto_template crypto_xcbc_tmpl = {
	.name = "xcbc",
	.create = xcbc_create,
	.module = THIS_MODULE,
};

static int __init crypto_xcbc_module_init(void)
{
	return crypto_register_template(&crypto_xcbc_tmpl);
}

static void __exit crypto_xcbc_module_exit(void)
{
	crypto_unregister_template(&crypto_xcbc_tmpl);
}

subsys_initcall(crypto_xcbc_module_init);
module_exit(crypto_xcbc_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("XCBC keyed hash algorithm");
MODULE_ALIAS_CRYPTO("xcbc");
MODULE_IMPORT_NS(CRYPTO_INTERNAL);