aboutsummaryrefslogtreecommitdiffstats
path: root/crypto/xcbc.c
blob: 9f502b86e0ea563ac04b31fbf96dcd534367e05a (plain) (blame)
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
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
/*
 * Copyright (C)2006 USAGI/WIDE Project
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author:
 * 	Kazunori Miyazawa <miyazawa@linux-ipv6.org>
 */

#include <linux/crypto.h>
#include <linux/err.h>
#include <linux/hardirq.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/scatterlist.h>
#include "internal.h"

static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
			   0x02020202, 0x02020202, 0x02020202, 0x02020202,
			   0x03030303, 0x03030303, 0x03030303, 0x03030303};
/*
 * +------------------------
 * | <parent tfm>
 * +------------------------
 * | crypto_xcbc_ctx
 * +------------------------
 * | odds (block size)
 * +------------------------
 * | prev (block size)
 * +------------------------
 * | key (block size)
 * +------------------------
 * | consts (block size * 3)
 * +------------------------
 */
struct crypto_xcbc_ctx {
	struct crypto_cipher *child;
	u8 *odds;
	u8 *prev;
	u8 *key;
	u8 *consts;
	void (*xor)(u8 *a, const u8 *b, unsigned int bs);
	unsigned int keylen;
	unsigned int len;
};

static void xor_128(u8 *a, const u8 *b, unsigned int bs)
{
	((u32 *)a)[0] ^= ((u32 *)b)[0];
	((u32 *)a)[1] ^= ((u32 *)b)[1];
	((u32 *)a)[2] ^= ((u32 *)b)[2];
	((u32 *)a)[3] ^= ((u32 *)b)[3];
}

static int _crypto_xcbc_digest_setkey(struct crypto_hash *parent,
				      struct crypto_xcbc_ctx *ctx)
{
	int bs = crypto_hash_blocksize(parent);
	int err = 0;
	u8 key1[bs];

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

	crypto_cipher_encrypt_one(ctx->child, key1, ctx->consts);

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

static int crypto_xcbc_digest_setkey(struct crypto_hash *parent,
				     const u8 *inkey, unsigned int keylen)
{
	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);

	if (keylen != crypto_cipher_blocksize(ctx->child))
		return -EINVAL;

	ctx->keylen = keylen;
	memcpy(ctx->key, inkey, keylen);
	ctx->consts = (u8*)ks;

	return _crypto_xcbc_digest_setkey(parent, ctx);
}

static int crypto_xcbc_digest_init(struct hash_desc *pdesc)
{
	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(pdesc->tfm);
	int bs = crypto_hash_blocksize(pdesc->tfm);

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

	return 0;
}

static int crypto_xcbc_digest_update2(struct hash_desc *pdesc,
				      struct scatterlist *sg,
				      unsigned int nbytes)
{
	struct crypto_hash *parent = pdesc->tfm;
	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
	struct crypto_cipher *tfm = ctx->child;
	int bs = crypto_hash_blocksize(parent);
	unsigned int i = 0;

	do {

		struct page *pg = sg[i].page;
		unsigned int offset = sg[i].offset;
		unsigned int slen = sg[i].length;

		while (slen > 0) {
			unsigned int len = min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
			char *p = crypto_kmap(pg, 0) + offset;

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

				/* checking the rest of the page */
				if (len + offset >= PAGE_SIZE) {
					offset = 0;
					pg++;
				} else
					offset += len;

				crypto_kunmap(p, 0);
				crypto_yield(pdesc->flags);
				continue;
			}

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

			ctx->xor(ctx->prev, ctx->odds, bs);
			crypto_cipher_encrypt_one(tfm, ctx->prev, ctx->prev);

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

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

			/* keeping the surplus of blocksize */
			if (len) {
				memcpy(ctx->odds, p, len);
				ctx->len = len;
			}
			crypto_kunmap(p, 0);
			crypto_yield(pdesc->flags);
			slen -= min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
			offset = 0;
			pg++;
		}
		nbytes-=sg[i].length;
		i++;
	} while (nbytes>0);

	return 0;
}

static int crypto_xcbc_digest_update(struct hash_desc *pdesc,
				     struct scatterlist *sg,
				     unsigned int nbytes)
{
	if (WARN_ON_ONCE(in_irq()))
		return -EDEADLK;
	return crypto_xcbc_digest_update2(pdesc, sg, nbytes);
}

static int crypto_xcbc_digest_final(struct hash_desc *pdesc, u8 *out)
{
	struct crypto_hash *parent = pdesc->tfm;
	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
	struct crypto_cipher *tfm = ctx->child;
	int bs = crypto_hash_blocksize(parent);
	int err = 0;

	if (ctx->len == bs) {
		u8 key2[bs];

		if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
			return err;

		crypto_cipher_encrypt_one(tfm, key2,
					  (u8 *)(ctx->consts + bs));

		ctx->xor(ctx->prev, ctx->odds, bs);
		ctx->xor(ctx->prev, key2, bs);
		_crypto_xcbc_digest_setkey(parent, ctx);

		crypto_cipher_encrypt_one(tfm, out, ctx->prev);
	} else {
		u8 key3[bs];
		unsigned int rlen;
		u8 *p = ctx->odds + ctx->len;
		*p = 0x80;
		p++;

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

		if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
			return err;

		crypto_cipher_encrypt_one(tfm, key3,
					  (u8 *)(ctx->consts + bs * 2));

		ctx->xor(ctx->prev, ctx->odds, bs);
		ctx->xor(ctx->prev, key3, bs);

		_crypto_xcbc_digest_setkey(parent, ctx);

		crypto_cipher_encrypt_one(tfm, out, ctx->prev);
	}

	return 0;
}

static int crypto_xcbc_digest(struct hash_desc *pdesc,
		  struct scatterlist *sg, unsigned int nbytes, u8 *out)
{
	if (WARN_ON_ONCE(in_irq()))
		return -EDEADLK;

	crypto_xcbc_digest_init(pdesc);
	crypto_xcbc_digest_update2(pdesc, sg, nbytes);
	return crypto_xcbc_digest_final(pdesc, out);
}

static int xcbc_init_tfm(struct crypto_tfm *tfm)
{
	struct crypto_cipher *cipher;
	struct crypto_instance *inst = (void *)tfm->__crt_alg;
	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
	int bs = crypto_hash_blocksize(__crypto_hash_cast(tfm));

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

	switch(bs) {
	case 16:
		ctx->xor = xor_128;
		break;
	default:
		return -EINVAL;
	}

	ctx->child = cipher;
	ctx->odds = (u8*)(ctx+1);
	ctx->prev = ctx->odds + bs;
	ctx->key = ctx->prev + bs;

	return 0;
};

static void xcbc_exit_tfm(struct crypto_tfm *tfm)
{
	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
	crypto_free_cipher(ctx->child);
}

static struct crypto_instance *xcbc_alloc(struct rtattr **tb)
{
	struct crypto_instance *inst;
	struct crypto_alg *alg;
	int err;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
	if (err)
		return ERR_PTR(err);

	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
				  CRYPTO_ALG_TYPE_MASK);
	if (IS_ERR(alg))
		return ERR_PTR(PTR_ERR(alg));

	switch(alg->cra_blocksize) {
	case 16:
		break;
	default:
		return ERR_PTR(PTR_ERR(alg));
	}

	inst = crypto_alloc_instance("xcbc", alg);
	if (IS_ERR(inst))
		goto out_put_alg;

	inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
	inst->alg.cra_priority = alg->cra_priority;
	inst->alg.cra_blocksize = alg->cra_blocksize;
	inst->alg.cra_alignmask = alg->cra_alignmask;
	inst->alg.cra_type = &crypto_hash_type;

	inst->alg.cra_hash.digestsize =
		(alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
		CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
				       alg->cra_blocksize;
	inst->alg.cra_ctxsize = sizeof(struct crypto_xcbc_ctx) +
				ALIGN(inst->alg.cra_blocksize * 3, sizeof(void *));
	inst->alg.cra_init = xcbc_init_tfm;
	inst->alg.cra_exit = xcbc_exit_tfm;

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

out_put_alg:
	crypto_mod_put(alg);
	return inst;
}

static void xcbc_free(struct crypto_instance *inst)
{
	crypto_drop_spawn(crypto_instance_ctx(inst));
	kfree(inst);
}

static struct crypto_template crypto_xcbc_tmpl = {
	.name = "xcbc",
	.alloc = xcbc_alloc,
	.free = xcbc_free,
	.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);
}

module_init(crypto_xcbc_module_init);
module_exit(crypto_xcbc_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("XCBC keyed hash algorithm");