[linux.git] / crypto / xcbc.c

/*
 * 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 <[email protected]>
 */

#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");
Commit	Line	Data
333b0d7e KM	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 <[email protected]>
	20	*/
	21
	22	#include <linux/crypto.h>
	23	#include <linux/err.h>
fb469840	24	#include <linux/hardirq.h>
333b0d7e KM	25	#include <linux/kernel.h>
	26	#include <linux/mm.h>
	27	#include <linux/rtnetlink.h>
	28	#include <linux/slab.h>
	29	#include <linux/scatterlist.h>
	30	#include "internal.h"
	31
5b37538a AB	32	static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
	33	0x02020202, 0x02020202, 0x02020202, 0x02020202,
	34	0x03030303, 0x03030303, 0x03030303, 0x03030303};
333b0d7e KM	35	/*
	36	* +------------------------
	37	* \| <parent tfm>
	38	* +------------------------
	39	* \| crypto_xcbc_ctx
	40	* +------------------------
	41	* \| odds (block size)
	42	* +------------------------
	43	* \| prev (block size)
	44	* +------------------------
	45	* \| key (block size)
	46	* +------------------------
	47	* \| consts (block size * 3)
	48	* +------------------------
	49	*/
	50	struct crypto_xcbc_ctx {
6b701dde	51	struct crypto_cipher *child;
333b0d7e KM	52	u8 *odds;
	53	u8 *prev;
	54	u8 *key;
	55	u8 *consts;
	56	void (xor)(u8 a, const u8 *b, unsigned int bs);
	57	unsigned int keylen;
	58	unsigned int len;
	59	};
	60
	61	static void xor_128(u8 a, const u8 b, unsigned int bs)
	62	{
	63	((u32 )a)[0] ^= ((u32 )b)[0];
	64	((u32 )a)[1] ^= ((u32 )b)[1];
	65	((u32 )a)[2] ^= ((u32 )b)[2];
	66	((u32 )a)[3] ^= ((u32 )b)[3];
	67	}
	68
	69	static int _crypto_xcbc_digest_setkey(struct crypto_hash *parent,
	70	struct crypto_xcbc_ctx *ctx)
	71	{
	72	int bs = crypto_hash_blocksize(parent);
	73	int err = 0;
	74	u8 key1[bs];
	75
	76	if ((err = crypto_cipher_setkey(ctx->child, ctx->key, ctx->keylen)))
	77	return err;
	78
6b701dde	79	crypto_cipher_encrypt_one(ctx->child, key1, ctx->consts);
333b0d7e KM	80
	81	return crypto_cipher_setkey(ctx->child, key1, bs);
	82	}
	83
	84	static int crypto_xcbc_digest_setkey(struct crypto_hash *parent,
	85	const u8 *inkey, unsigned int keylen)
	86	{
	87	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
	88
6b701dde	89	if (keylen != crypto_cipher_blocksize(ctx->child))
333b0d7e KM	90	return -EINVAL;
	91
	92	ctx->keylen = keylen;
	93	memcpy(ctx->key, inkey, keylen);
	94	ctx->consts = (u8*)ks;
	95
	96	return _crypto_xcbc_digest_setkey(parent, ctx);
	97	}
	98
5b37538a	99	static int crypto_xcbc_digest_init(struct hash_desc *pdesc)
333b0d7e KM	100	{
	101	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(pdesc->tfm);
	102	int bs = crypto_hash_blocksize(pdesc->tfm);
	103
	104	ctx->len = 0;
	105	memset(ctx->odds, 0, bs);
	106	memset(ctx->prev, 0, bs);
	107
	108	return 0;
	109	}
	110
fb469840 HX	111	static int crypto_xcbc_digest_update2(struct hash_desc *pdesc,
	112	struct scatterlist *sg,
	113	unsigned int nbytes)
333b0d7e KM	114	{
	115	struct crypto_hash *parent = pdesc->tfm;
	116	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
6b701dde	117	struct crypto_cipher *tfm = ctx->child;
333b0d7e KM	118	int bs = crypto_hash_blocksize(parent);
	119	unsigned int i = 0;
	120
	121	do {
	122
	123	struct page *pg = sg[i].page;
	124	unsigned int offset = sg[i].offset;
	125	unsigned int slen = sg[i].length;
	126
	127	while (slen > 0) {
	128	unsigned int len = min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
	129	char *p = crypto_kmap(pg, 0) + offset;
	130
	131	/* checking the data can fill the block */
	132	if ((ctx->len + len) <= bs) {
	133	memcpy(ctx->odds + ctx->len, p, len);
	134	ctx->len += len;
	135	slen -= len;
	136
	137	/* checking the rest of the page */
	138	if (len + offset >= PAGE_SIZE) {
	139	offset = 0;
	140	pg++;
	141	} else
	142	offset += len;
	143
	144	crypto_kunmap(p, 0);
6b701dde	145	crypto_yield(pdesc->flags);
333b0d7e KM	146	continue;
	147	}
	148
	149	/* filling odds with new data and encrypting it */
	150	memcpy(ctx->odds + ctx->len, p, bs - ctx->len);
	151	len -= bs - ctx->len;
	152	p += bs - ctx->len;
	153
	154	ctx->xor(ctx->prev, ctx->odds, bs);
6b701dde	155	crypto_cipher_encrypt_one(tfm, ctx->prev, ctx->prev);
333b0d7e KM	156
	157	/* clearing the length */
	158	ctx->len = 0;
	159
	160	/* encrypting the rest of data */
	161	while (len > bs) {
	162	ctx->xor(ctx->prev, p, bs);
6b701dde HX	163	crypto_cipher_encrypt_one(tfm, ctx->prev,
6b701dde HX	164	ctx->prev);
333b0d7e KM	165	p += bs;
	166	len -= bs;
	167	}
	168
	169	/* keeping the surplus of blocksize */
	170	if (len) {
	171	memcpy(ctx->odds, p, len);
	172	ctx->len = len;
	173	}
	174	crypto_kunmap(p, 0);
6b701dde	175	crypto_yield(pdesc->flags);
333b0d7e KM	176	slen -= min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
	177	offset = 0;
	178	pg++;
	179	}
	180	nbytes-=sg[i].length;
	181	i++;
	182	} while (nbytes>0);
	183
	184	return 0;
	185	}
	186
fb469840 HX	187	static int crypto_xcbc_digest_update(struct hash_desc *pdesc,
	188	struct scatterlist *sg,
	189	unsigned int nbytes)
	190	{
	191	if (WARN_ON_ONCE(in_irq()))
	192	return -EDEADLK;
	193	return crypto_xcbc_digest_update2(pdesc, sg, nbytes);
	194	}
	195
5b37538a	196	static int crypto_xcbc_digest_final(struct hash_desc pdesc, u8 out)
333b0d7e KM	197	{
	198	struct crypto_hash *parent = pdesc->tfm;
	199	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
6b701dde	200	struct crypto_cipher *tfm = ctx->child;
333b0d7e KM	201	int bs = crypto_hash_blocksize(parent);
	202	int err = 0;
	203
	204	if (ctx->len == bs) {
	205	u8 key2[bs];
	206
	207	if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
	208	return err;
	209
6b701dde HX	210	crypto_cipher_encrypt_one(tfm, key2,
6b701dde HX	211	(u8 *)(ctx->consts + bs));
333b0d7e KM	212
	213	ctx->xor(ctx->prev, ctx->odds, bs);
	214	ctx->xor(ctx->prev, key2, bs);
	215	_crypto_xcbc_digest_setkey(parent, ctx);
	216
6b701dde	217	crypto_cipher_encrypt_one(tfm, out, ctx->prev);
333b0d7e KM	218	} else {
	219	u8 key3[bs];
	220	unsigned int rlen;
	221	u8 *p = ctx->odds + ctx->len;
	222	*p = 0x80;
	223	p++;
	224
	225	rlen = bs - ctx->len -1;
	226	if (rlen)
	227	memset(p, 0, rlen);
	228
	229	if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
	230	return err;
	231
6b701dde HX	232	crypto_cipher_encrypt_one(tfm, key3,
6b701dde HX	233	(u8 )(ctx->consts + bs 2));
333b0d7e KM	234
	235	ctx->xor(ctx->prev, ctx->odds, bs);
	236	ctx->xor(ctx->prev, key3, bs);
	237
	238	_crypto_xcbc_digest_setkey(parent, ctx);
	239
6b701dde	240	crypto_cipher_encrypt_one(tfm, out, ctx->prev);
333b0d7e KM	241	}
	242
	243	return 0;
	244	}
	245
	246	static int crypto_xcbc_digest(struct hash_desc *pdesc,
	247	struct scatterlist sg, unsigned int nbytes, u8 out)
	248	{
fb469840 HX	249	if (WARN_ON_ONCE(in_irq()))
	250	return -EDEADLK;
	251
333b0d7e	252	crypto_xcbc_digest_init(pdesc);
fb469840	253	crypto_xcbc_digest_update2(pdesc, sg, nbytes);
333b0d7e KM	254	return crypto_xcbc_digest_final(pdesc, out);
	255	}
	256
	257	static int xcbc_init_tfm(struct crypto_tfm *tfm)
	258	{
2e306ee0	259	struct crypto_cipher *cipher;
333b0d7e KM	260	struct crypto_instance inst = (void )tfm->__crt_alg;
	261	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	262	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
	263	int bs = crypto_hash_blocksize(__crypto_hash_cast(tfm));
	264
2e306ee0 HX	265	cipher = crypto_spawn_cipher(spawn);
	266	if (IS_ERR(cipher))
	267	return PTR_ERR(cipher);
333b0d7e KM	268
	269	switch(bs) {
	270	case 16:
	271	ctx->xor = xor_128;
	272	break;
	273	default:
	274	return -EINVAL;
	275	}
	276
2e306ee0	277	ctx->child = cipher;
333b0d7e KM	278	ctx->odds = (u8*)(ctx+1);
	279	ctx->prev = ctx->odds + bs;
	280	ctx->key = ctx->prev + bs;
	281
	282	return 0;
	283	};
	284
	285	static void xcbc_exit_tfm(struct crypto_tfm *tfm)
	286	{
	287	struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
	288	crypto_free_cipher(ctx->child);
	289	}
	290
ebc610e5	291	static struct crypto_instance xcbc_alloc(struct rtattr *tb)
333b0d7e KM	292	{
	293	struct crypto_instance *inst;
	294	struct crypto_alg *alg;
ebc610e5 HX	295	int err;
	296
	297	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
	298	if (err)
	299	return ERR_PTR(err);
	300
	301	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
	302	CRYPTO_ALG_TYPE_MASK);
333b0d7e KM	303	if (IS_ERR(alg))
	304	return ERR_PTR(PTR_ERR(alg));
	305
	306	switch(alg->cra_blocksize) {
	307	case 16:
	308	break;
	309	default:
	310	return ERR_PTR(PTR_ERR(alg));
	311	}
	312
	313	inst = crypto_alloc_instance("xcbc", alg);
	314	if (IS_ERR(inst))
	315	goto out_put_alg;
	316
	317	inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
	318	inst->alg.cra_priority = alg->cra_priority;
	319	inst->alg.cra_blocksize = alg->cra_blocksize;
	320	inst->alg.cra_alignmask = alg->cra_alignmask;
	321	inst->alg.cra_type = &crypto_hash_type;
	322
	323	inst->alg.cra_hash.digestsize =
	324	(alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
	325	CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
	326	alg->cra_blocksize;
	327	inst->alg.cra_ctxsize = sizeof(struct crypto_xcbc_ctx) +
	328	ALIGN(inst->alg.cra_blocksize * 3, sizeof(void *));
	329	inst->alg.cra_init = xcbc_init_tfm;
	330	inst->alg.cra_exit = xcbc_exit_tfm;
	331
	332	inst->alg.cra_hash.init = crypto_xcbc_digest_init;
	333	inst->alg.cra_hash.update = crypto_xcbc_digest_update;
	334	inst->alg.cra_hash.final = crypto_xcbc_digest_final;
	335	inst->alg.cra_hash.digest = crypto_xcbc_digest;
	336	inst->alg.cra_hash.setkey = crypto_xcbc_digest_setkey;
	337
	338	out_put_alg:
	339	crypto_mod_put(alg);
	340	return inst;
	341	}
	342
	343	static void xcbc_free(struct crypto_instance *inst)
	344	{
	345	crypto_drop_spawn(crypto_instance_ctx(inst));
	346	kfree(inst);
	347	}
	348
	349	static struct crypto_template crypto_xcbc_tmpl = {
	350	.name = "xcbc",
	351	.alloc = xcbc_alloc,
	352	.free = xcbc_free,
	353	.module = THIS_MODULE,
	354	};
	355
	356	static int __init crypto_xcbc_module_init(void)
	357	{
	358	return crypto_register_template(&crypto_xcbc_tmpl);
	359	}
	360
	361	static void __exit crypto_xcbc_module_exit(void)
	362	{
	363	crypto_unregister_template(&crypto_xcbc_tmpl);
	364	}
	365
	366	module_init(crypto_xcbc_module_init);
367	module_exit(crypto_xcbc_module_exit);
368
369	MODULE_LICENSE("GPL");
370	MODULE_DESCRIPTION("XCBC keyed hash algorithm");