[linux.git] / crypto / cbc.c

/*
 * CBC: Cipher Block Chaining mode
 *
 * Copyright (c) 2006 Herbert Xu <[email protected]>
 *
 * 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.
 *
 */

#include <crypto/algapi.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>

struct crypto_cbc_ctx {
	struct crypto_cipher *child;
	void (*xor)(u8 *dst, const u8 *src, unsigned int bs);
};

static int crypto_cbc_setkey(struct crypto_tfm *parent, const u8 *key,
			     unsigned int keylen)
{
	struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(parent);
	struct crypto_cipher *child = ctx->child;
	int err;

	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
				       CRYPTO_TFM_REQ_MASK);
	err = crypto_cipher_setkey(child, key, keylen);
	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
				     CRYPTO_TFM_RES_MASK);
	return err;
}

static int crypto_cbc_encrypt_segment(struct blkcipher_desc *desc,
				      struct blkcipher_walk *walk,
				      struct crypto_cipher *tfm,
				      void (*xor)(u8 *, const u8 *,
						  unsigned int))
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		crypto_cipher_alg(tfm)->cia_encrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	u8 *iv = walk->iv;

	do {
		xor(iv, src, bsize);
		fn(crypto_cipher_tfm(tfm), dst, iv);
		memcpy(iv, dst, bsize);

		src += bsize;
		dst += bsize;
	} while ((nbytes -= bsize) >= bsize);

	return nbytes;
}

static int crypto_cbc_encrypt_inplace(struct blkcipher_desc *desc,
				      struct blkcipher_walk *walk,
				      struct crypto_cipher *tfm,
				      void (*xor)(u8 *, const u8 *,
						  unsigned int))
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		crypto_cipher_alg(tfm)->cia_encrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *iv = walk->iv;

	do {
		xor(src, iv, bsize);
		fn(crypto_cipher_tfm(tfm), src, src);
		iv = src;

		src += bsize;
	} while ((nbytes -= bsize) >= bsize);

	memcpy(walk->iv, iv, bsize);

	return nbytes;
}

static int crypto_cbc_encrypt(struct blkcipher_desc *desc,
			      struct scatterlist *dst, struct scatterlist *src,
			      unsigned int nbytes)
{
	struct blkcipher_walk walk;
	struct crypto_blkcipher *tfm = desc->tfm;
	struct crypto_cbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
	struct crypto_cipher *child = ctx->child;
	void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
		if (walk.src.virt.addr == walk.dst.virt.addr)
			nbytes = crypto_cbc_encrypt_inplace(desc, &walk, child,
							    xor);
		else
			nbytes = crypto_cbc_encrypt_segment(desc, &walk, child,
							    xor);
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
}

static int crypto_cbc_decrypt_segment(struct blkcipher_desc *desc,
				      struct blkcipher_walk *walk,
				      struct crypto_cipher *tfm,
				      void (*xor)(u8 *, const u8 *,
						  unsigned int))
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		crypto_cipher_alg(tfm)->cia_decrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	u8 *iv = walk->iv;

	do {
		fn(crypto_cipher_tfm(tfm), dst, src);
		xor(dst, iv, bsize);
		iv = src;

		src += bsize;
		dst += bsize;
	} while ((nbytes -= bsize) >= bsize);

	memcpy(walk->iv, iv, bsize);

	return nbytes;
}

static int crypto_cbc_decrypt_inplace(struct blkcipher_desc *desc,
				      struct blkcipher_walk *walk,
				      struct crypto_cipher *tfm,
				      void (*xor)(u8 *, const u8 *,
						  unsigned int))
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		crypto_cipher_alg(tfm)->cia_decrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned long alignmask = crypto_cipher_alignmask(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 stack[bsize + alignmask];
	u8 *first_iv = (u8 *)ALIGN((unsigned long)stack, alignmask + 1);

	memcpy(first_iv, walk->iv, bsize);

	/* Start of the last block. */
	src += nbytes - nbytes % bsize - bsize;
	memcpy(walk->iv, src, bsize);

	for (;;) {
		fn(crypto_cipher_tfm(tfm), src, src);
		if ((nbytes -= bsize) < bsize)
			break;
		xor(src, src - bsize, bsize);
		src -= bsize;
	}

	xor(src, first_iv, bsize);

	return nbytes;
}

static int crypto_cbc_decrypt(struct blkcipher_desc *desc,
			      struct scatterlist *dst, struct scatterlist *src,
			      unsigned int nbytes)
{
	struct blkcipher_walk walk;
	struct crypto_blkcipher *tfm = desc->tfm;
	struct crypto_cbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
	struct crypto_cipher *child = ctx->child;
	void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
		if (walk.src.virt.addr == walk.dst.virt.addr)
			nbytes = crypto_cbc_decrypt_inplace(desc, &walk, child,
							    xor);
		else
			nbytes = crypto_cbc_decrypt_segment(desc, &walk, child,
							    xor);
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
}

static void xor_byte(u8 *a, const u8 *b, unsigned int bs)
{
	do {
		*a++ ^= *b++;
	} while (--bs);
}

static void xor_quad(u8 *dst, const u8 *src, unsigned int bs)
{
	u32 *a = (u32 *)dst;
	u32 *b = (u32 *)src;

	do {
		*a++ ^= *b++;
	} while ((bs -= 4));
}

static void xor_64(u8 *a, const u8 *b, unsigned int bs)
{
	((u32 *)a)[0] ^= ((u32 *)b)[0];
	((u32 *)a)[1] ^= ((u32 *)b)[1];
}

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_cbc_init_tfm(struct crypto_tfm *tfm)
{
	struct crypto_instance *inst = (void *)tfm->__crt_alg;
	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
	struct crypto_cipher *cipher;

	switch (crypto_tfm_alg_blocksize(tfm)) {
	case 8:
		ctx->xor = xor_64;
		break;

	case 16:
		ctx->xor = xor_128;
		break;

	default:
		if (crypto_tfm_alg_blocksize(tfm) % 4)
			ctx->xor = xor_byte;
		else
			ctx->xor = xor_quad;
	}

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

	ctx->child = cipher;
	return 0;
}

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

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

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
	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));

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

	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
	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_blkcipher_type;

	if (!(alg->cra_blocksize % 4))
		inst->alg.cra_alignmask |= 3;
	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;

	inst->alg.cra_ctxsize = sizeof(struct crypto_cbc_ctx);

	inst->alg.cra_init = crypto_cbc_init_tfm;
	inst->alg.cra_exit = crypto_cbc_exit_tfm;

	inst->alg.cra_blkcipher.setkey = crypto_cbc_setkey;
	inst->alg.cra_blkcipher.encrypt = crypto_cbc_encrypt;
	inst->alg.cra_blkcipher.decrypt = crypto_cbc_decrypt;

out_put_alg:
	crypto_mod_put(alg);
	return inst;
}

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

static struct crypto_template crypto_cbc_tmpl = {
	.name = "cbc",
	.alloc = crypto_cbc_alloc,
	.free = crypto_cbc_free,
	.module = THIS_MODULE,
};

static int __init crypto_cbc_module_init(void)
{
	return crypto_register_template(&crypto_cbc_tmpl);
}

static void __exit crypto_cbc_module_exit(void)
{
	crypto_unregister_template(&crypto_cbc_tmpl);
}

module_init(crypto_cbc_module_init);
module_exit(crypto_cbc_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("CBC block cipher algorithm");
Commit	Line	Data
db131ef9 HX	1	/*
	2	* CBC: Cipher Block Chaining mode
	3	*
	4	* Copyright (c) 2006 Herbert Xu <[email protected]>
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License as published by the Free
	8	* Software Foundation; either version 2 of the License, or (at your option)
	9	* any later version.
	10	*
	11	*/
	12
	13	#include <crypto/algapi.h>
	14	#include <linux/err.h>
	15	#include <linux/init.h>
	16	#include <linux/kernel.h>
	17	#include <linux/module.h>
	18	#include <linux/scatterlist.h>
	19	#include <linux/slab.h>
	20
	21	struct crypto_cbc_ctx {
	22	struct crypto_cipher *child;
	23	void (xor)(u8 dst, const u8 *src, unsigned int bs);
	24	};
	25
	26	static int crypto_cbc_setkey(struct crypto_tfm parent, const u8 key,
	27	unsigned int keylen)
	28	{
	29	struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(parent);
	30	struct crypto_cipher *child = ctx->child;
	31	int err;
	32
	33	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	34	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
	35	CRYPTO_TFM_REQ_MASK);
	36	err = crypto_cipher_setkey(child, key, keylen);
	37	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
	38	CRYPTO_TFM_RES_MASK);
	39	return err;
	40	}
	41
	42	static int crypto_cbc_encrypt_segment(struct blkcipher_desc *desc,
	43	struct blkcipher_walk *walk,
	44	struct crypto_cipher *tfm,
	45	void (xor)(u8 , const u8 *,
	46	unsigned int))
	47	{
	48	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	49	crypto_cipher_alg(tfm)->cia_encrypt;
	50	int bsize = crypto_cipher_blocksize(tfm);
	51	unsigned int nbytes = walk->nbytes;
	52	u8 *src = walk->src.virt.addr;
	53	u8 *dst = walk->dst.virt.addr;
	54	u8 *iv = walk->iv;
	55
	56	do {
	57	xor(iv, src, bsize);
	58	fn(crypto_cipher_tfm(tfm), dst, iv);
	59	memcpy(iv, dst, bsize);
	60
	61	src += bsize;
	62	dst += bsize;
	63	} while ((nbytes -= bsize) >= bsize);
	64
65	return nbytes;
66	}
67
68	static int crypto_cbc_encrypt_inplace(struct blkcipher_desc *desc,
69	struct blkcipher_walk *walk,
70	struct crypto_cipher *tfm,
71	void (xor)(u8 , const u8 *,
72	unsigned int))
73	{
74	void (fn)(struct crypto_tfm , u8 , const u8 ) =
75	crypto_cipher_alg(tfm)->cia_encrypt;
76	int bsize = crypto_cipher_blocksize(tfm);
77	unsigned int nbytes = walk->nbytes;
78	u8 *src = walk->src.virt.addr;
79	u8 *iv = walk->iv;
80
81	do {
82	xor(src, iv, bsize);
83	fn(crypto_cipher_tfm(tfm), src, src);
84	iv = src;
85
86	src += bsize;
87	} while ((nbytes -= bsize) >= bsize);
88
89	memcpy(walk->iv, iv, bsize);
90
91	return nbytes;
92	}
93
94	static int crypto_cbc_encrypt(struct blkcipher_desc *desc,
95	struct scatterlist dst, struct scatterlist src,
96	unsigned int nbytes)
97	{
98	struct blkcipher_walk walk;
99	struct crypto_blkcipher *tfm = desc->tfm;
100	struct crypto_cbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
101	struct crypto_cipher *child = ctx->child;
102	void (xor)(u8 , const u8 *, unsigned int bs) = ctx->xor;
103	int err;
104
105	blkcipher_walk_init(&walk, dst, src, nbytes);
106	err = blkcipher_walk_virt(desc, &walk);
107
108	while ((nbytes = walk.nbytes)) {
109	if (walk.src.virt.addr == walk.dst.virt.addr)
110	nbytes = crypto_cbc_encrypt_inplace(desc, &walk, child,
111	xor);
112	else
113	nbytes = crypto_cbc_encrypt_segment(desc, &walk, child,
114	xor);
115	err = blkcipher_walk_done(desc, &walk, nbytes);
116	}
117
118	return err;
119	}
120
121	static int crypto_cbc_decrypt_segment(struct blkcipher_desc *desc,
122	struct blkcipher_walk *walk,
123	struct crypto_cipher *tfm,
124	void (xor)(u8 , const u8 *,
125	unsigned int))
126	{
127	void (fn)(struct crypto_tfm , u8 , const u8 ) =
128	crypto_cipher_alg(tfm)->cia_decrypt;
129	int bsize = crypto_cipher_blocksize(tfm);
130	unsigned int nbytes = walk->nbytes;
131	u8 *src = walk->src.virt.addr;
132	u8 *dst = walk->dst.virt.addr;
133	u8 *iv = walk->iv;
134
135	do {
136	fn(crypto_cipher_tfm(tfm), dst, src);
137	xor(dst, iv, bsize);
138	iv = src;
139
140	src += bsize;
141	dst += bsize;
142	} while ((nbytes -= bsize) >= bsize);
143
144	memcpy(walk->iv, iv, bsize);
145
146	return nbytes;
147	}
148
149	static int crypto_cbc_decrypt_inplace(struct blkcipher_desc *desc,
150	struct blkcipher_walk *walk,
151	struct crypto_cipher *tfm,
152	void (xor)(u8 , const u8 *,
153	unsigned int))
154	{
155	void (fn)(struct crypto_tfm , u8 , const u8 ) =
156	crypto_cipher_alg(tfm)->cia_decrypt;
157	int bsize = crypto_cipher_blocksize(tfm);
158	unsigned long alignmask = crypto_cipher_alignmask(tfm);
159	unsigned int nbytes = walk->nbytes;
160	u8 *src = walk->src.virt.addr;
161	u8 stack[bsize + alignmask];
162	u8 first_iv = (u8 )ALIGN((unsigned long)stack, alignmask + 1);
163
164	memcpy(first_iv, walk->iv, bsize);
165
166	/* Start of the last block. */
167	src += nbytes - nbytes % bsize - bsize;
168	memcpy(walk->iv, src, bsize);
169
170	for (;;) {
171	fn(crypto_cipher_tfm(tfm), src, src);
172	if ((nbytes -= bsize) < bsize)
173	break;
174	xor(src, src - bsize, bsize);
175	src -= bsize;
176	}
177
178	xor(src, first_iv, bsize);
179
180	return nbytes;
181	}
182
183	static int crypto_cbc_decrypt(struct blkcipher_desc *desc,
184	struct scatterlist dst, struct scatterlist src,
185	unsigned int nbytes)
186	{
187	struct blkcipher_walk walk;
188	struct crypto_blkcipher *tfm = desc->tfm;
189	struct crypto_cbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
190	struct crypto_cipher *child = ctx->child;
191	void (xor)(u8 , const u8 *, unsigned int bs) = ctx->xor;
192	int err;
193
194	blkcipher_walk_init(&walk, dst, src, nbytes);
195	err = blkcipher_walk_virt(desc, &walk);
196
197	while ((nbytes = walk.nbytes)) {
198	if (walk.src.virt.addr == walk.dst.virt.addr)
199	nbytes = crypto_cbc_decrypt_inplace(desc, &walk, child,
200	xor);
201	else
202	nbytes = crypto_cbc_decrypt_segment(desc, &walk, child,
203	xor);
204	err = blkcipher_walk_done(desc, &walk, nbytes);
205	}
206
207	return err;
208	}
209
210	static void xor_byte(u8 a, const u8 b, unsigned int bs)
211	{
212	do {
213	a++ ^= b++;
214	} while (--bs);
215	}
216
217	static void xor_quad(u8 dst, const u8 src, unsigned int bs)
218	{
219	u32 a = (u32 )dst;
220	u32 b = (u32 )src;
221
222	do {
223	a++ ^= b++;
224	} while ((bs -= 4));
225	}
226
227	static void xor_64(u8 a, const u8 b, unsigned int bs)
228	{
229	((u32 )a)[0] ^= ((u32 )b)[0];
230	((u32 )a)[1] ^= ((u32 )b)[1];
231	}
232
233	static void xor_128(u8 a, const u8 b, unsigned int bs)
234	{
235	((u32 )a)[0] ^= ((u32 )b)[0];
236	((u32 )a)[1] ^= ((u32 )b)[1];
237	((u32 )a)[2] ^= ((u32 )b)[2];
238	((u32 )a)[3] ^= ((u32 )b)[3];
239	}
240
241	static int crypto_cbc_init_tfm(struct crypto_tfm *tfm)
242	{
243	struct crypto_instance inst = (void )tfm->__crt_alg;
244	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
245	struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
2e306ee0	246	struct crypto_cipher *cipher;
db131ef9 HX	247
	248	switch (crypto_tfm_alg_blocksize(tfm)) {
	249	case 8:
	250	ctx->xor = xor_64;
	251	break;
	252
	253	case 16:
	254	ctx->xor = xor_128;
	255	break;
	256
	257	default:
	258	if (crypto_tfm_alg_blocksize(tfm) % 4)
	259	ctx->xor = xor_byte;
	260	else
	261	ctx->xor = xor_quad;
	262	}
	263
2e306ee0 HX	264	cipher = crypto_spawn_cipher(spawn);
	265	if (IS_ERR(cipher))
	266	return PTR_ERR(cipher);
db131ef9	267
2e306ee0	268	ctx->child = cipher;
db131ef9 HX	269	return 0;
	270	}
	271
	272	static void crypto_cbc_exit_tfm(struct crypto_tfm *tfm)
	273	{
	274	struct crypto_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
	275	crypto_free_cipher(ctx->child);
	276	}
	277
ebc610e5	278	static struct crypto_instance crypto_cbc_alloc(struct rtattr *tb)
db131ef9 HX	279	{
	280	struct crypto_instance *inst;
	281	struct crypto_alg *alg;
ebc610e5 HX	282	int err;
	283
	284	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
	285	if (err)
	286	return ERR_PTR(err);
db131ef9	287
ebc610e5 HX	288	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
ebc610e5 HX	289	CRYPTO_ALG_TYPE_MASK);
db131ef9 HX	290	if (IS_ERR(alg))
	291	return ERR_PTR(PTR_ERR(alg));
	292
	293	inst = crypto_alloc_instance("cbc", alg);
	294	if (IS_ERR(inst))
	295	goto out_put_alg;
	296
	297	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
	298	inst->alg.cra_priority = alg->cra_priority;
	299	inst->alg.cra_blocksize = alg->cra_blocksize;
	300	inst->alg.cra_alignmask = alg->cra_alignmask;
	301	inst->alg.cra_type = &crypto_blkcipher_type;
	302
	303	if (!(alg->cra_blocksize % 4))
	304	inst->alg.cra_alignmask \|= 3;
	305	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
	306	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
	307	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
	308
	309	inst->alg.cra_ctxsize = sizeof(struct crypto_cbc_ctx);
	310
	311	inst->alg.cra_init = crypto_cbc_init_tfm;
	312	inst->alg.cra_exit = crypto_cbc_exit_tfm;
	313
	314	inst->alg.cra_blkcipher.setkey = crypto_cbc_setkey;
	315	inst->alg.cra_blkcipher.encrypt = crypto_cbc_encrypt;
	316	inst->alg.cra_blkcipher.decrypt = crypto_cbc_decrypt;
	317
	318	out_put_alg:
	319	crypto_mod_put(alg);
	320	return inst;
	321	}
	322
	323	static void crypto_cbc_free(struct crypto_instance *inst)
	324	{
	325	crypto_drop_spawn(crypto_instance_ctx(inst));
	326	kfree(inst);
	327	}
	328
	329	static struct crypto_template crypto_cbc_tmpl = {
	330	.name = "cbc",
	331	.alloc = crypto_cbc_alloc,
	332	.free = crypto_cbc_free,
	333	.module = THIS_MODULE,
	334	};
	335
	336	static int __init crypto_cbc_module_init(void)
	337	{
	338	return crypto_register_template(&crypto_cbc_tmpl);
	339	}
	340
	341	static void __exit crypto_cbc_module_exit(void)
	342	{
	343	crypto_unregister_template(&crypto_cbc_tmpl);
	344	}
	345
	346	module_init(crypto_cbc_module_init);
	347	module_exit(crypto_cbc_module_exit);
	348
	349	MODULE_LICENSE("GPL");
	350	MODULE_DESCRIPTION("CBC block cipher algorithm");