[GitHub/mt8127/android_kernel_alcatel_ttab.git] / crypto / ctr.c

/*
 * CTR: Counter mode
 *
 * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
 *
 * 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/random.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>

struct ctr_instance_ctx {
	struct crypto_spawn alg;
	unsigned int noncesize;
	unsigned int ivsize;
	unsigned int countersize;
};

struct crypto_ctr_ctx {
	struct crypto_cipher *child;
	u8 *nonce;
};

static int crypto_ctr_setkey(struct crypto_tfm *parent, const u8 *key,
			     unsigned int keylen)
{
	struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(parent);
	struct crypto_cipher *child = ctx->child;
	struct ctr_instance_ctx *ictx =
		crypto_instance_ctx(crypto_tfm_alg_instance(parent));
	unsigned int noncelen = ictx->noncesize;
	int err = 0;

	/* the nonce is stored in bytes at end of key */
	if (keylen < noncelen)
		return  -EINVAL;

	memcpy(ctx->nonce, key + (keylen - noncelen), noncelen);

	keylen -=  noncelen;

	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_ctr_crypt_segment(struct blkcipher_walk *walk,
				    struct crypto_cipher *tfm, u8 *ctrblk,
				    unsigned int countersize)
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		   crypto_cipher_alg(tfm)->cia_encrypt;
	unsigned int bsize = crypto_cipher_blocksize(tfm);
	unsigned long alignmask = crypto_cipher_alignmask(tfm) |
				  (__alignof__(u32) - 1);
	u8 ks[bsize + alignmask];
	u8 *keystream = (u8 *)ALIGN((unsigned long)ks, alignmask + 1);
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	unsigned int nbytes = walk->nbytes;

	do {
		/* create keystream */
		fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
		crypto_xor(keystream, src, min(nbytes, bsize));

		/* copy result into dst */
		memcpy(dst, keystream, min(nbytes, bsize));

		/* increment counter in counterblock */
		crypto_inc(ctrblk + bsize - countersize, countersize);

		if (nbytes < bsize)
			break;

		src += bsize;
		dst += bsize;
		nbytes -= bsize;

	} while (nbytes);

	return 0;
}

static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
				    struct crypto_cipher *tfm, u8 *ctrblk,
				    unsigned int countersize)
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		   crypto_cipher_alg(tfm)->cia_encrypt;
	unsigned int bsize = crypto_cipher_blocksize(tfm);
	unsigned long alignmask = crypto_cipher_alignmask(tfm) |
				  (__alignof__(u32) - 1);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 ks[bsize + alignmask];
	u8 *keystream = (u8 *)ALIGN((unsigned long)ks, alignmask + 1);

	do {
		/* create keystream */
		fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
		crypto_xor(src, keystream, min(nbytes, bsize));

		/* increment counter in counterblock */
		crypto_inc(ctrblk + bsize - countersize, countersize);

		if (nbytes < bsize)
			break;

		src += bsize;
		nbytes -= bsize;

	} while (nbytes);

	return 0;
}

static int crypto_ctr_crypt(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_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm);
	struct crypto_cipher *child = ctx->child;
	unsigned int bsize = crypto_cipher_blocksize(child);
	struct ctr_instance_ctx *ictx =
		crypto_instance_ctx(crypto_tfm_alg_instance(&tfm->base));
	unsigned long alignmask = crypto_cipher_alignmask(child) |
				  (__alignof__(u32) - 1);
	u8 cblk[bsize + alignmask];
	u8 *counterblk = (u8 *)ALIGN((unsigned long)cblk, alignmask + 1);
	int err;

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

	/* set up counter block */
	memset(counterblk, 0 , bsize);
	memcpy(counterblk, ctx->nonce, ictx->noncesize);
	memcpy(counterblk + ictx->noncesize, walk.iv, ictx->ivsize);

	/* initialize counter portion of counter block */
	crypto_inc(counterblk + bsize - ictx->countersize, ictx->countersize);

	while (walk.nbytes) {
		if (walk.src.virt.addr == walk.dst.virt.addr)
			nbytes = crypto_ctr_crypt_inplace(&walk, child,
							  counterblk,
							  ictx->countersize);
		else
			nbytes = crypto_ctr_crypt_segment(&walk, child,
							  counterblk,
							  ictx->countersize);

		err = blkcipher_walk_done(desc, &walk, nbytes);
	}
	return err;
}

static int crypto_ctr_init_tfm(struct crypto_tfm *tfm)
{
	struct crypto_instance *inst = (void *)tfm->__crt_alg;
	struct ctr_instance_ctx *ictx = crypto_instance_ctx(inst);
	struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
	struct crypto_cipher *cipher;

	ctx->nonce = kzalloc(ictx->noncesize, GFP_KERNEL);
	if (!ctx->nonce)
		return -ENOMEM;

	cipher = crypto_spawn_cipher(&ictx->alg);
	if (IS_ERR(cipher))
		return PTR_ERR(cipher);

	ctx->child = cipher;

	return 0;
}

static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm)
{
	struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);

	kfree(ctx->nonce);
	crypto_free_cipher(ctx->child);
}

static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
{
	struct crypto_instance *inst;
	struct crypto_alg *alg;
	struct ctr_instance_ctx *ictx;
	unsigned int noncesize;
	unsigned int ivsize;
	unsigned int countersize;
	int err;

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

	alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
				  CRYPTO_ALG_TYPE_MASK);
	if (IS_ERR(alg))
		return ERR_PTR(PTR_ERR(alg));

	err = crypto_attr_u32(tb[2], &noncesize);
	if (err)
		goto out_put_alg;

	err = crypto_attr_u32(tb[3], &ivsize);
	if (err)
		goto out_put_alg;

	err = crypto_attr_u32(tb[4], &countersize);
	if (err)
		goto out_put_alg;

	/* verify size of nonce + iv + counter
	 * counter must be >= 4 bytes.
	 */
	err = -EINVAL;
	if (((noncesize + ivsize + countersize) < alg->cra_blocksize) ||
	    ((noncesize + ivsize) > alg->cra_blocksize) ||
	    (countersize > alg->cra_blocksize) || (countersize < 4))
		goto out_put_alg;

	/* If this is false we'd fail the alignment of crypto_inc. */
	if ((alg->cra_blocksize - countersize) % 4)
		goto out_put_alg;

	inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
	err = -ENOMEM;
	if (!inst)
		goto out_put_alg;

	err = -ENAMETOOLONG;
	if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
		     "ctr(%s,%u,%u,%u)", alg->cra_name, noncesize,
		     ivsize, countersize) >= CRYPTO_MAX_ALG_NAME) {
		goto err_free_inst;
	}

	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
		     "ctr(%s,%u,%u,%u)", alg->cra_driver_name, noncesize,
		     ivsize, countersize) >= CRYPTO_MAX_ALG_NAME) {
		goto err_free_inst;
	}

	ictx = crypto_instance_ctx(inst);
	ictx->noncesize = noncesize;
	ictx->ivsize = ivsize;
	ictx->countersize = countersize;

	err = crypto_init_spawn(&ictx->alg, alg, inst,
		CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
	if (err)
		goto err_free_inst;

	err = 0;
	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
	inst->alg.cra_priority = alg->cra_priority;
	inst->alg.cra_blocksize = 1;
	inst->alg.cra_alignmask = __alignof__(u32) - 1;
	inst->alg.cra_type = &crypto_blkcipher_type;

	inst->alg.cra_blkcipher.ivsize = ivsize;
	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize
					      + noncesize;
	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize
					      + noncesize;

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

	inst->alg.cra_init = crypto_ctr_init_tfm;
	inst->alg.cra_exit = crypto_ctr_exit_tfm;

	inst->alg.cra_blkcipher.setkey = crypto_ctr_setkey;
	inst->alg.cra_blkcipher.encrypt = crypto_ctr_crypt;
	inst->alg.cra_blkcipher.decrypt = crypto_ctr_crypt;

err_free_inst:
	if (err)
		kfree(inst);

out_put_alg:
	crypto_mod_put(alg);

	if (err)
		inst = ERR_PTR(err);

	return inst;
}

static void crypto_ctr_free(struct crypto_instance *inst)
{
	struct ctr_instance_ctx *ictx = crypto_instance_ctx(inst);

	crypto_drop_spawn(&ictx->alg);
	kfree(inst);
}

static struct crypto_template crypto_ctr_tmpl = {
	.name = "ctr",
	.alloc = crypto_ctr_alloc,
	.free = crypto_ctr_free,
	.module = THIS_MODULE,
};

static int __init crypto_ctr_module_init(void)
{
	return crypto_register_template(&crypto_ctr_tmpl);
}

static void __exit crypto_ctr_module_exit(void)
{
	crypto_unregister_template(&crypto_ctr_tmpl);
}

module_init(crypto_ctr_module_init);
module_exit(crypto_ctr_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("CTR Counter block mode");
Commit	Line	Data
23e353c8 JL	1	/*
	2	* CTR: Counter mode
	3	*
	4	* (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
	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/random.h>
	19	#include <linux/scatterlist.h>
	20	#include <linux/slab.h>
	21
	22	struct ctr_instance_ctx {
	23	struct crypto_spawn alg;
	24	unsigned int noncesize;
	25	unsigned int ivsize;
41fdab3d	26	unsigned int countersize;
23e353c8 JL	27	};
	28
	29	struct crypto_ctr_ctx {
	30	struct crypto_cipher *child;
	31	u8 *nonce;
	32	};
	33
23e353c8 JL	34	static int crypto_ctr_setkey(struct crypto_tfm parent, const u8 key,
	35	unsigned int keylen)
	36	{
	37	struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(parent);
	38	struct crypto_cipher *child = ctx->child;
	39	struct ctr_instance_ctx *ictx =
	40	crypto_instance_ctx(crypto_tfm_alg_instance(parent));
	41	unsigned int noncelen = ictx->noncesize;
	42	int err = 0;
	43
	44	/* the nonce is stored in bytes at end of key */
	45	if (keylen < noncelen)
	46	return -EINVAL;
	47
	48	memcpy(ctx->nonce, key + (keylen - noncelen), noncelen);
	49
	50	keylen -= noncelen;
	51
	52	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	53	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
	54	CRYPTO_TFM_REQ_MASK);
	55	err = crypto_cipher_setkey(child, key, keylen);
	56	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
	57	CRYPTO_TFM_RES_MASK);
	58
	59	return err;
	60	}
	61
	62	static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
	63	struct crypto_cipher tfm, u8 ctrblk,
	64	unsigned int countersize)
	65	{
	66	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	67	crypto_cipher_alg(tfm)->cia_encrypt;
	68	unsigned int bsize = crypto_cipher_blocksize(tfm);
3f8214ea HX	69	unsigned long alignmask = crypto_cipher_alignmask(tfm) \|
3f8214ea HX	70	(__alignof__(u32) - 1);
23e353c8 JL	71	u8 ks[bsize + alignmask];
	72	u8 keystream = (u8 )ALIGN((unsigned long)ks, alignmask + 1);
	73	u8 *src = walk->src.virt.addr;
	74	u8 *dst = walk->dst.virt.addr;
	75	unsigned int nbytes = walk->nbytes;
	76
	77	do {
	78	/* create keystream */
	79	fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
3f8214ea	80	crypto_xor(keystream, src, min(nbytes, bsize));
23e353c8 JL	81
	82	/* copy result into dst */
	83	memcpy(dst, keystream, min(nbytes, bsize));
	84
	85	/* increment counter in counterblock */
3f8214ea	86	crypto_inc(ctrblk + bsize - countersize, countersize);
23e353c8 JL	87
	88	if (nbytes < bsize)
	89	break;
	90
	91	src += bsize;
	92	dst += bsize;
	93	nbytes -= bsize;
	94
	95	} while (nbytes);
	96
	97	return 0;
	98	}
	99
	100	static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
	101	struct crypto_cipher tfm, u8 ctrblk,
	102	unsigned int countersize)
	103	{
	104	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	105	crypto_cipher_alg(tfm)->cia_encrypt;
	106	unsigned int bsize = crypto_cipher_blocksize(tfm);
3f8214ea HX	107	unsigned long alignmask = crypto_cipher_alignmask(tfm) \|
3f8214ea HX	108	(__alignof__(u32) - 1);
23e353c8 JL	109	unsigned int nbytes = walk->nbytes;
	110	u8 *src = walk->src.virt.addr;
	111	u8 ks[bsize + alignmask];
	112	u8 keystream = (u8 )ALIGN((unsigned long)ks, alignmask + 1);
	113
	114	do {
	115	/* create keystream */
	116	fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
3f8214ea	117	crypto_xor(src, keystream, min(nbytes, bsize));
23e353c8 JL	118
23e353c8 JL	119	/* increment counter in counterblock */
3f8214ea	120	crypto_inc(ctrblk + bsize - countersize, countersize);
23e353c8 JL	121
	122	if (nbytes < bsize)
	123	break;
	124
	125	src += bsize;
	126	nbytes -= bsize;
	127
	128	} while (nbytes);
	129
	130	return 0;
	131	}
	132
	133	static int crypto_ctr_crypt(struct blkcipher_desc *desc,
	134	struct scatterlist dst, struct scatterlist src,
	135	unsigned int nbytes)
	136	{
	137	struct blkcipher_walk walk;
	138	struct crypto_blkcipher *tfm = desc->tfm;
	139	struct crypto_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm);
	140	struct crypto_cipher *child = ctx->child;
	141	unsigned int bsize = crypto_cipher_blocksize(child);
	142	struct ctr_instance_ctx *ictx =
	143	crypto_instance_ctx(crypto_tfm_alg_instance(&tfm->base));
3f8214ea HX	144	unsigned long alignmask = crypto_cipher_alignmask(child) \|
3f8214ea HX	145	(__alignof__(u32) - 1);
23e353c8 JL	146	u8 cblk[bsize + alignmask];
23e353c8 JL	147	u8 counterblk = (u8 )ALIGN((unsigned long)cblk, alignmask + 1);
23e353c8 JL	148	int err;
	149
	150	blkcipher_walk_init(&walk, dst, src, nbytes);
	151	err = blkcipher_walk_virt_block(desc, &walk, bsize);
	152
	153	/* set up counter block */
	154	memset(counterblk, 0 , bsize);
	155	memcpy(counterblk, ctx->nonce, ictx->noncesize);
	156	memcpy(counterblk + ictx->noncesize, walk.iv, ictx->ivsize);
	157
	158	/* initialize counter portion of counter block */
3f8214ea	159	crypto_inc(counterblk + bsize - ictx->countersize, ictx->countersize);
23e353c8 JL	160
	161	while (walk.nbytes) {
	162	if (walk.src.virt.addr == walk.dst.virt.addr)
	163	nbytes = crypto_ctr_crypt_inplace(&walk, child,
	164	counterblk,
41fdab3d	165	ictx->countersize);
23e353c8 JL	166	else
	167	nbytes = crypto_ctr_crypt_segment(&walk, child,
	168	counterblk,
41fdab3d	169	ictx->countersize);
23e353c8 JL	170
	171	err = blkcipher_walk_done(desc, &walk, nbytes);
	172	}
	173	return err;
	174	}
	175
	176	static int crypto_ctr_init_tfm(struct crypto_tfm *tfm)
	177	{
	178	struct crypto_instance inst = (void )tfm->__crt_alg;
	179	struct ctr_instance_ctx *ictx = crypto_instance_ctx(inst);
	180	struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
	181	struct crypto_cipher *cipher;
	182
	183	ctx->nonce = kzalloc(ictx->noncesize, GFP_KERNEL);
	184	if (!ctx->nonce)
	185	return -ENOMEM;
	186
	187	cipher = crypto_spawn_cipher(&ictx->alg);
	188	if (IS_ERR(cipher))
	189	return PTR_ERR(cipher);
	190
	191	ctx->child = cipher;
	192
	193	return 0;
	194	}
	195
	196	static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm)
	197	{
	198	struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
	199
	200	kfree(ctx->nonce);
	201	crypto_free_cipher(ctx->child);
	202	}
	203
	204	static struct crypto_instance crypto_ctr_alloc(struct rtattr *tb)
	205	{
	206	struct crypto_instance *inst;
	207	struct crypto_alg *alg;
	208	struct ctr_instance_ctx *ictx;
	209	unsigned int noncesize;
	210	unsigned int ivsize;
41fdab3d	211	unsigned int countersize;
23e353c8 JL	212	int err;
	213
	214	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
	215	if (err)
	216	return ERR_PTR(err);
	217
	218	alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
	219	CRYPTO_ALG_TYPE_MASK);
	220	if (IS_ERR(alg))
	221	return ERR_PTR(PTR_ERR(alg));
	222
	223	err = crypto_attr_u32(tb[2], &noncesize);
	224	if (err)
	225	goto out_put_alg;
	226
	227	err = crypto_attr_u32(tb[3], &ivsize);
	228	if (err)
	229	goto out_put_alg;
	230
41fdab3d JL	231	err = crypto_attr_u32(tb[4], &countersize);
	232	if (err)
	233	goto out_put_alg;
	234
	235	/* verify size of nonce + iv + counter
	236	* counter must be >= 4 bytes.
	237	*/
23e353c8	238	err = -EINVAL;
41fdab3d JL	239	if (((noncesize + ivsize + countersize) < alg->cra_blocksize) \|\|
	240	((noncesize + ivsize) > alg->cra_blocksize) \|\|
	241	(countersize > alg->cra_blocksize) \|\| (countersize < 4))
23e353c8 JL	242	goto out_put_alg;
23e353c8 JL	243
3f8214ea HX	244	/* If this is false we'd fail the alignment of crypto_inc. */
	245	if ((alg->cra_blocksize - countersize) % 4)
	246	goto out_put_alg;
	247
23e353c8 JL	248	inst = kzalloc(sizeof(inst) + sizeof(ictx), GFP_KERNEL);
	249	err = -ENOMEM;
	250	if (!inst)
	251	goto out_put_alg;
	252
	253	err = -ENAMETOOLONG;
	254	if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
41fdab3d JL	255	"ctr(%s,%u,%u,%u)", alg->cra_name, noncesize,
41fdab3d JL	256	ivsize, countersize) >= CRYPTO_MAX_ALG_NAME) {
23e353c8 JL	257	goto err_free_inst;
	258	}
	259
	260	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
41fdab3d JL	261	"ctr(%s,%u,%u,%u)", alg->cra_driver_name, noncesize,
41fdab3d JL	262	ivsize, countersize) >= CRYPTO_MAX_ALG_NAME) {
23e353c8 JL	263	goto err_free_inst;
	264	}
	265
	266	ictx = crypto_instance_ctx(inst);
	267	ictx->noncesize = noncesize;
	268	ictx->ivsize = ivsize;
41fdab3d	269	ictx->countersize = countersize;
23e353c8 JL	270
	271	err = crypto_init_spawn(&ictx->alg, alg, inst,
	272	CRYPTO_ALG_TYPE_MASK \| CRYPTO_ALG_ASYNC);
	273	if (err)
	274	goto err_free_inst;
	275
	276	err = 0;
	277	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
	278	inst->alg.cra_priority = alg->cra_priority;
	279	inst->alg.cra_blocksize = 1;
3f8214ea	280	inst->alg.cra_alignmask = __alignof__(u32) - 1;
23e353c8 JL	281	inst->alg.cra_type = &crypto_blkcipher_type;
	282
	283	inst->alg.cra_blkcipher.ivsize = ivsize;
	284	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize
	285	+ noncesize;
	286	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize
	287	+ noncesize;
	288
	289	inst->alg.cra_ctxsize = sizeof(struct crypto_ctr_ctx);
	290
	291	inst->alg.cra_init = crypto_ctr_init_tfm;
	292	inst->alg.cra_exit = crypto_ctr_exit_tfm;
	293
	294	inst->alg.cra_blkcipher.setkey = crypto_ctr_setkey;
	295	inst->alg.cra_blkcipher.encrypt = crypto_ctr_crypt;
	296	inst->alg.cra_blkcipher.decrypt = crypto_ctr_crypt;
	297
	298	err_free_inst:
	299	if (err)
	300	kfree(inst);
	301
	302	out_put_alg:
	303	crypto_mod_put(alg);
	304
	305	if (err)
	306	inst = ERR_PTR(err);
	307
	308	return inst;
	309	}
	310
	311	static void crypto_ctr_free(struct crypto_instance *inst)
	312	{
	313	struct ctr_instance_ctx *ictx = crypto_instance_ctx(inst);
	314
	315	crypto_drop_spawn(&ictx->alg);
	316	kfree(inst);
	317	}
	318
	319	static struct crypto_template crypto_ctr_tmpl = {
	320	.name = "ctr",
	321	.alloc = crypto_ctr_alloc,
	322	.free = crypto_ctr_free,
	323	.module = THIS_MODULE,
	324	};
	325
	326	static int __init crypto_ctr_module_init(void)
	327	{
	328	return crypto_register_template(&crypto_ctr_tmpl);
	329	}
	330
	331	static void __exit crypto_ctr_module_exit(void)
	332	{
	333	crypto_unregister_template(&crypto_ctr_tmpl);
	334	}
	335
	336	module_init(crypto_ctr_module_init);
	337	module_exit(crypto_ctr_module_exit);
	338
	339	MODULE_LICENSE("GPL");
	340	MODULE_DESCRIPTION("CTR Counter block mode");