[linux-2.6-block.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 <crypto/ctr.h>
#include <crypto/internal/skcipher.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

struct crypto_rfc3686_ctx {
	struct crypto_skcipher *child;
	u8 nonce[CTR_RFC3686_NONCE_SIZE];
};

struct crypto_rfc3686_req_ctx {
	u8 iv[CTR_RFC3686_BLOCK_SIZE];
	struct skcipher_request subreq CRYPTO_MINALIGN_ATTR;
};

static void crypto_ctr_crypt_final(struct skcipher_walk *walk,
				   struct crypto_cipher *tfm)
{
	unsigned int bsize = crypto_cipher_blocksize(tfm);
	unsigned long alignmask = crypto_cipher_alignmask(tfm);
	u8 *ctrblk = walk->iv;
	u8 tmp[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
	u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	unsigned int nbytes = walk->nbytes;

	crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
	crypto_xor_cpy(dst, keystream, src, nbytes);

	crypto_inc(ctrblk, bsize);
}

static int crypto_ctr_crypt_segment(struct skcipher_walk *walk,
				    struct crypto_cipher *tfm)
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		   crypto_cipher_alg(tfm)->cia_encrypt;
	unsigned int bsize = crypto_cipher_blocksize(tfm);
	u8 *ctrblk = walk->iv;
	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), dst, ctrblk);
		crypto_xor(dst, src, bsize);

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

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

	return nbytes;
}

static int crypto_ctr_crypt_inplace(struct skcipher_walk *walk,
				    struct crypto_cipher *tfm)
{
	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);
	unsigned int nbytes = walk->nbytes;
	u8 *ctrblk = walk->iv;
	u8 *src = walk->src.virt.addr;
	u8 tmp[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
	u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);

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

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

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

	return nbytes;
}

static int crypto_ctr_crypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
	const unsigned int bsize = crypto_cipher_blocksize(cipher);
	struct skcipher_walk walk;
	unsigned int nbytes;
	int err;

	err = skcipher_walk_virt(&walk, req, false);

	while (walk.nbytes >= bsize) {
		if (walk.src.virt.addr == walk.dst.virt.addr)
			nbytes = crypto_ctr_crypt_inplace(&walk, cipher);
		else
			nbytes = crypto_ctr_crypt_segment(&walk, cipher);

		err = skcipher_walk_done(&walk, nbytes);
	}

	if (walk.nbytes) {
		crypto_ctr_crypt_final(&walk, cipher);
		err = skcipher_walk_done(&walk, 0);
	}

	return err;
}

static int crypto_ctr_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	struct skcipher_instance *inst;
	struct crypto_alg *alg;
	int err;

	inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);
	if (IS_ERR(inst))
		return PTR_ERR(inst);

	/* Block size must be >= 4 bytes. */
	err = -EINVAL;
	if (alg->cra_blocksize < 4)
		goto out_free_inst;

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

	/* CTR mode is a stream cipher. */
	inst->alg.base.cra_blocksize = 1;

	/*
	 * To simplify the implementation, configure the skcipher walk to only
	 * give a partial block at the very end, never earlier.
	 */
	inst->alg.chunksize = alg->cra_blocksize;

	inst->alg.encrypt = crypto_ctr_crypt;
	inst->alg.decrypt = crypto_ctr_crypt;

	err = skcipher_register_instance(tmpl, inst);
	if (err)
		goto out_free_inst;
	goto out_put_alg;

out_free_inst:
	inst->free(inst);
out_put_alg:
	crypto_mod_put(alg);
	return err;
}

static int crypto_rfc3686_setkey(struct crypto_skcipher *parent,
				 const u8 *key, unsigned int keylen)
{
	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(parent);
	struct crypto_skcipher *child = ctx->child;
	int err;

	/* the nonce is stored in bytes at end of key */
	if (keylen < CTR_RFC3686_NONCE_SIZE)
		return -EINVAL;

	memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
	       CTR_RFC3686_NONCE_SIZE);

	keylen -= CTR_RFC3686_NONCE_SIZE;

	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
					 CRYPTO_TFM_REQ_MASK);
	err = crypto_skcipher_setkey(child, key, keylen);
	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
					  CRYPTO_TFM_RES_MASK);

	return err;
}

static int crypto_rfc3686_crypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_skcipher *child = ctx->child;
	unsigned long align = crypto_skcipher_alignmask(tfm);
	struct crypto_rfc3686_req_ctx *rctx =
		(void *)PTR_ALIGN((u8 *)skcipher_request_ctx(req), align + 1);
	struct skcipher_request *subreq = &rctx->subreq;
	u8 *iv = rctx->iv;

	/* set up counter block */
	memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
	memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->iv, CTR_RFC3686_IV_SIZE);

	/* initialize counter portion of counter block */
	*(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
		cpu_to_be32(1);

	skcipher_request_set_tfm(subreq, child);
	skcipher_request_set_callback(subreq, req->base.flags,
				      req->base.complete, req->base.data);
	skcipher_request_set_crypt(subreq, req->src, req->dst,
				   req->cryptlen, iv);

	return crypto_skcipher_encrypt(subreq);
}

static int crypto_rfc3686_init_tfm(struct crypto_skcipher *tfm)
{
	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_skcipher *cipher;
	unsigned long align;
	unsigned int reqsize;

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

	ctx->child = cipher;

	align = crypto_skcipher_alignmask(tfm);
	align &= ~(crypto_tfm_ctx_alignment() - 1);
	reqsize = align + sizeof(struct crypto_rfc3686_req_ctx) +
		  crypto_skcipher_reqsize(cipher);
	crypto_skcipher_set_reqsize(tfm, reqsize);

	return 0;
}

static void crypto_rfc3686_exit_tfm(struct crypto_skcipher *tfm)
{
	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);

	crypto_free_skcipher(ctx->child);
}

static void crypto_rfc3686_free(struct skcipher_instance *inst)
{
	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);

	crypto_drop_skcipher(spawn);
	kfree(inst);
}

static int crypto_rfc3686_create(struct crypto_template *tmpl,
				 struct rtattr **tb)
{
	struct crypto_attr_type *algt;
	struct skcipher_instance *inst;
	struct skcipher_alg *alg;
	struct crypto_skcipher_spawn *spawn;
	const char *cipher_name;
	u32 mask;

	int err;

	algt = crypto_get_attr_type(tb);
	if (IS_ERR(algt))
		return PTR_ERR(algt);

	if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
		return -EINVAL;

	cipher_name = crypto_attr_alg_name(tb[1]);
	if (IS_ERR(cipher_name))
		return PTR_ERR(cipher_name);

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

	mask = crypto_requires_sync(algt->type, algt->mask) |
		crypto_requires_off(algt->type, algt->mask,
				    CRYPTO_ALG_NEED_FALLBACK);

	spawn = skcipher_instance_ctx(inst);

	crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
	err = crypto_grab_skcipher(spawn, cipher_name, 0, mask);
	if (err)
		goto err_free_inst;

	alg = crypto_spawn_skcipher_alg(spawn);

	/* We only support 16-byte blocks. */
	err = -EINVAL;
	if (crypto_skcipher_alg_ivsize(alg) != CTR_RFC3686_BLOCK_SIZE)
		goto err_drop_spawn;

	/* Not a stream cipher? */
	if (alg->base.cra_blocksize != 1)
		goto err_drop_spawn;

	err = -ENAMETOOLONG;
	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
		     "rfc3686(%s)", alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
		goto err_drop_spawn;
	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
		     "rfc3686(%s)", alg->base.cra_driver_name) >=
	    CRYPTO_MAX_ALG_NAME)
		goto err_drop_spawn;

	inst->alg.base.cra_priority = alg->base.cra_priority;
	inst->alg.base.cra_blocksize = 1;
	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;

	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;

	inst->alg.ivsize = CTR_RFC3686_IV_SIZE;
	inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
				CTR_RFC3686_NONCE_SIZE;
	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
				CTR_RFC3686_NONCE_SIZE;

	inst->alg.setkey = crypto_rfc3686_setkey;
	inst->alg.encrypt = crypto_rfc3686_crypt;
	inst->alg.decrypt = crypto_rfc3686_crypt;

	inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);

	inst->alg.init = crypto_rfc3686_init_tfm;
	inst->alg.exit = crypto_rfc3686_exit_tfm;

	inst->free = crypto_rfc3686_free;

	err = skcipher_register_instance(tmpl, inst);
	if (err)
		goto err_drop_spawn;

out:
	return err;

err_drop_spawn:
	crypto_drop_skcipher(spawn);
err_free_inst:
	kfree(inst);
	goto out;
}

static struct crypto_template crypto_ctr_tmpls[] = {
	{
		.name = "ctr",
		.create = crypto_ctr_create,
		.module = THIS_MODULE,
	}, {
		.name = "rfc3686",
		.create = crypto_rfc3686_create,
		.module = THIS_MODULE,
	},
};

static int __init crypto_ctr_module_init(void)
{
	return crypto_register_templates(crypto_ctr_tmpls,
					 ARRAY_SIZE(crypto_ctr_tmpls));
}

static void __exit crypto_ctr_module_exit(void)
{
	crypto_unregister_templates(crypto_ctr_tmpls,
				    ARRAY_SIZE(crypto_ctr_tmpls));
}

module_init(crypto_ctr_module_init);
module_exit(crypto_ctr_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("CTR block cipher mode of operation");
MODULE_ALIAS_CRYPTO("rfc3686");
MODULE_ALIAS_CRYPTO("ctr");
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>
5311f248	14	#include <crypto/ctr.h>
69d3150c	15	#include <crypto/internal/skcipher.h>
23e353c8 JL	16	#include <linux/err.h>
	17	#include <linux/init.h>
	18	#include <linux/kernel.h>
	19	#include <linux/module.h>
23e353c8 JL	20	#include <linux/slab.h>
23e353c8 JL	21
5311f248	22	struct crypto_rfc3686_ctx {
b2b39c2f	23	struct crypto_skcipher *child;
5311f248	24	u8 nonce[CTR_RFC3686_NONCE_SIZE];
23e353c8 JL	25	};
23e353c8 JL	26
69d3150c JK	27	struct crypto_rfc3686_req_ctx {
69d3150c JK	28	u8 iv[CTR_RFC3686_BLOCK_SIZE];
b2b39c2f	29	struct skcipher_request subreq CRYPTO_MINALIGN_ATTR;
69d3150c JK	30	};
69d3150c JK	31
11f14630	32	static void crypto_ctr_crypt_final(struct skcipher_walk *walk,
5311f248	33	struct crypto_cipher *tfm)
0971eb0d HX	34	{
0971eb0d HX	35	unsigned int bsize = crypto_cipher_blocksize(tfm);
5311f248 HX	36	unsigned long alignmask = crypto_cipher_alignmask(tfm);
5311f248 HX	37	u8 *ctrblk = walk->iv;
6650c4de	38	u8 tmp[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
5311f248	39	u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
0971eb0d HX	40	u8 *src = walk->src.virt.addr;
	41	u8 *dst = walk->dst.virt.addr;
	42	unsigned int nbytes = walk->nbytes;
	43
	44	crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
45fe93df	45	crypto_xor_cpy(dst, keystream, src, nbytes);
5311f248 HX	46
5311f248 HX	47	crypto_inc(ctrblk, bsize);
0971eb0d HX	48	}
0971eb0d HX	49
11f14630	50	static int crypto_ctr_crypt_segment(struct skcipher_walk *walk,
5311f248	51	struct crypto_cipher *tfm)
23e353c8 JL	52	{
	53	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	54	crypto_cipher_alg(tfm)->cia_encrypt;
	55	unsigned int bsize = crypto_cipher_blocksize(tfm);
5311f248	56	u8 *ctrblk = walk->iv;
23e353c8 JL	57	u8 *src = walk->src.virt.addr;
	58	u8 *dst = walk->dst.virt.addr;
	59	unsigned int nbytes = walk->nbytes;
	60
	61	do {
	62	/* create keystream */
0971eb0d HX	63	fn(crypto_cipher_tfm(tfm), dst, ctrblk);
0971eb0d HX	64	crypto_xor(dst, src, bsize);
23e353c8 JL	65
23e353c8 JL	66	/* increment counter in counterblock */
5311f248	67	crypto_inc(ctrblk, bsize);
23e353c8	68
23e353c8 JL	69	src += bsize;
23e353c8 JL	70	dst += bsize;
0971eb0d	71	} while ((nbytes -= bsize) >= bsize);
23e353c8	72
0971eb0d	73	return nbytes;
23e353c8 JL	74	}
23e353c8 JL	75
11f14630	76	static int crypto_ctr_crypt_inplace(struct skcipher_walk *walk,
5311f248	77	struct crypto_cipher *tfm)
23e353c8 JL	78	{
	79	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	80	crypto_cipher_alg(tfm)->cia_encrypt;
	81	unsigned int bsize = crypto_cipher_blocksize(tfm);
5311f248	82	unsigned long alignmask = crypto_cipher_alignmask(tfm);
23e353c8	83	unsigned int nbytes = walk->nbytes;
5311f248	84	u8 *ctrblk = walk->iv;
23e353c8	85	u8 *src = walk->src.virt.addr;
6650c4de	86	u8 tmp[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
5311f248	87	u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
23e353c8 JL	88
	89	do {
	90	/* create keystream */
	91	fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
0971eb0d	92	crypto_xor(src, keystream, bsize);
23e353c8 JL	93
23e353c8 JL	94	/* increment counter in counterblock */
5311f248	95	crypto_inc(ctrblk, bsize);
23e353c8	96
23e353c8	97	src += bsize;
0971eb0d	98	} while ((nbytes -= bsize) >= bsize);
23e353c8	99
0971eb0d	100	return nbytes;
23e353c8 JL	101	}
23e353c8 JL	102
11f14630	103	static int crypto_ctr_crypt(struct skcipher_request *req)
23e353c8	104	{
11f14630 EB	105	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	106	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
	107	const unsigned int bsize = crypto_cipher_blocksize(cipher);
	108	struct skcipher_walk walk;
	109	unsigned int nbytes;
23e353c8 JL	110	int err;
23e353c8 JL	111
11f14630	112	err = skcipher_walk_virt(&walk, req, false);
23e353c8	113
0971eb0d	114	while (walk.nbytes >= bsize) {
23e353c8	115	if (walk.src.virt.addr == walk.dst.virt.addr)
11f14630	116	nbytes = crypto_ctr_crypt_inplace(&walk, cipher);
23e353c8	117	else
11f14630	118	nbytes = crypto_ctr_crypt_segment(&walk, cipher);
23e353c8	119
11f14630	120	err = skcipher_walk_done(&walk, nbytes);
23e353c8	121	}
0971eb0d HX	122
0971eb0d HX	123	if (walk.nbytes) {
11f14630 EB	124	crypto_ctr_crypt_final(&walk, cipher);
11f14630 EB	125	err = skcipher_walk_done(&walk, 0);
0971eb0d HX	126	}
0971eb0d HX	127
23e353c8 JL	128	return err;
	129	}
	130
11f14630	131	static int crypto_ctr_create(struct crypto_template tmpl, struct rtattr *tb)
23e353c8	132	{
11f14630	133	struct skcipher_instance *inst;
23e353c8	134	struct crypto_alg *alg;
23e353c8 JL	135	int err;
23e353c8 JL	136
11f14630 EB	137	inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);
	138	if (IS_ERR(inst))
	139	return PTR_ERR(inst);
23e353c8	140
5311f248	141	/* Block size must be >= 4 bytes. */
23e353c8	142	err = -EINVAL;
5311f248	143	if (alg->cra_blocksize < 4)
11f14630	144	goto out_free_inst;
23e353c8	145
3f8214ea	146	/* If this is false we'd fail the alignment of crypto_inc. */
5311f248	147	if (alg->cra_blocksize % 4)
11f14630	148	goto out_free_inst;
23e353c8	149
11f14630 EB	150	/* CTR mode is a stream cipher. */
11f14630 EB	151	inst->alg.base.cra_blocksize = 1;
23e353c8	152
11f14630 EB	153	/*
	154	* To simplify the implementation, configure the skcipher walk to only
	155	* give a partial block at the very end, never earlier.
	156	*/
	157	inst->alg.chunksize = alg->cra_blocksize;
23e353c8	158
11f14630 EB	159	inst->alg.encrypt = crypto_ctr_crypt;
11f14630 EB	160	inst->alg.decrypt = crypto_ctr_crypt;
23e353c8	161
11f14630 EB	162	err = skcipher_register_instance(tmpl, inst);
	163	if (err)
	164	goto out_free_inst;
	165	goto out_put_alg;
5311f248	166
11f14630 EB	167	out_free_inst:
11f14630 EB	168	inst->free(inst);
5311f248	169	out_put_alg:
11f14630 EB	170	crypto_mod_put(alg);
11f14630 EB	171	return err;
23e353c8 JL	172	}
23e353c8 JL	173
b2b39c2f	174	static int crypto_rfc3686_setkey(struct crypto_skcipher *parent,
69d3150c	175	const u8 *key, unsigned int keylen)
5311f248	176	{
b2b39c2f HX	177	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(parent);
b2b39c2f HX	178	struct crypto_skcipher *child = ctx->child;
5311f248 HX	179	int err;
	180
	181	/* the nonce is stored in bytes at end of key */
	182	if (keylen < CTR_RFC3686_NONCE_SIZE)
	183	return -EINVAL;
	184
	185	memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
	186	CTR_RFC3686_NONCE_SIZE);
	187
	188	keylen -= CTR_RFC3686_NONCE_SIZE;
	189
b2b39c2f HX	190	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	191	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
	192	CRYPTO_TFM_REQ_MASK);
	193	err = crypto_skcipher_setkey(child, key, keylen);
	194	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
	195	CRYPTO_TFM_RES_MASK);
5311f248 HX	196
	197	return err;
	198	}
	199
b2b39c2f	200	static int crypto_rfc3686_crypt(struct skcipher_request *req)
5311f248	201	{
b2b39c2f HX	202	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	203	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
	204	struct crypto_skcipher *child = ctx->child;
	205	unsigned long align = crypto_skcipher_alignmask(tfm);
69d3150c	206	struct crypto_rfc3686_req_ctx *rctx =
b2b39c2f HX	207	(void )PTR_ALIGN((u8 )skcipher_request_ctx(req), align + 1);
b2b39c2f HX	208	struct skcipher_request *subreq = &rctx->subreq;
69d3150c	209	u8 *iv = rctx->iv;
5311f248 HX	210
	211	/* set up counter block */
	212	memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
b2b39c2f	213	memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->iv, CTR_RFC3686_IV_SIZE);
5311f248 HX	214
	215	/* initialize counter portion of counter block */
	216	(__be32 )(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
	217	cpu_to_be32(1);
	218
b2b39c2f HX	219	skcipher_request_set_tfm(subreq, child);
	220	skcipher_request_set_callback(subreq, req->base.flags,
	221	req->base.complete, req->base.data);
	222	skcipher_request_set_crypt(subreq, req->src, req->dst,
	223	req->cryptlen, iv);
5311f248	224
b2b39c2f	225	return crypto_skcipher_encrypt(subreq);
5311f248 HX	226	}
5311f248 HX	227
b2b39c2f	228	static int crypto_rfc3686_init_tfm(struct crypto_skcipher *tfm)
5311f248	229	{
b2b39c2f HX	230	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	231	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
	232	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
	233	struct crypto_skcipher *cipher;
69d3150c	234	unsigned long align;
b2b39c2f	235	unsigned int reqsize;
5311f248	236
60425a8b	237	cipher = crypto_spawn_skcipher(spawn);
5311f248 HX	238	if (IS_ERR(cipher))
	239	return PTR_ERR(cipher);
	240
	241	ctx->child = cipher;
	242
b2b39c2f	243	align = crypto_skcipher_alignmask(tfm);
69d3150c	244	align &= ~(crypto_tfm_ctx_alignment() - 1);
b2b39c2f HX	245	reqsize = align + sizeof(struct crypto_rfc3686_req_ctx) +
	246	crypto_skcipher_reqsize(cipher);
	247	crypto_skcipher_set_reqsize(tfm, reqsize);
69d3150c	248
5311f248 HX	249	return 0;
	250	}
	251
b2b39c2f	252	static void crypto_rfc3686_exit_tfm(struct crypto_skcipher *tfm)
5311f248	253	{
b2b39c2f HX	254	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
	255
	256	crypto_free_skcipher(ctx->child);
	257	}
5311f248	258
b2b39c2f HX	259	static void crypto_rfc3686_free(struct skcipher_instance *inst)
	260	{
	261	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
	262
	263	crypto_drop_skcipher(spawn);
	264	kfree(inst);
5311f248 HX	265	}
5311f248 HX	266
b2b39c2f HX	267	static int crypto_rfc3686_create(struct crypto_template *tmpl,
b2b39c2f HX	268	struct rtattr **tb)
5311f248	269	{
69d3150c	270	struct crypto_attr_type *algt;
b2b39c2f HX	271	struct skcipher_instance *inst;
b2b39c2f HX	272	struct skcipher_alg *alg;
69d3150c JK	273	struct crypto_skcipher_spawn *spawn;
69d3150c JK	274	const char *cipher_name;
d2c2a85c MC	275	u32 mask;
d2c2a85c MC	276
5311f248 HX	277	int err;
5311f248 HX	278
69d3150c	279	algt = crypto_get_attr_type(tb);
69d3150c	280	if (IS_ERR(algt))
b2b39c2f	281	return PTR_ERR(algt);
5311f248	282
b2b39c2f HX	283	if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
b2b39c2f HX	284	return -EINVAL;
69d3150c JK	285
69d3150c JK	286	cipher_name = crypto_attr_alg_name(tb[1]);
69d3150c	287	if (IS_ERR(cipher_name))
b2b39c2f	288	return PTR_ERR(cipher_name);
5311f248	289
69d3150c JK	290	inst = kzalloc(sizeof(inst) + sizeof(spawn), GFP_KERNEL);
69d3150c JK	291	if (!inst)
b2b39c2f	292	return -ENOMEM;
69d3150c	293
d2c2a85c MC	294	mask = crypto_requires_sync(algt->type, algt->mask) \|
	295	crypto_requires_off(algt->type, algt->mask,
	296	CRYPTO_ALG_NEED_FALLBACK);
	297
b2b39c2f	298	spawn = skcipher_instance_ctx(inst);
69d3150c	299
b2b39c2f	300	crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
d2c2a85c	301	err = crypto_grab_skcipher(spawn, cipher_name, 0, mask);
69d3150c JK	302	if (err)
	303	goto err_free_inst;
	304
b2b39c2f	305	alg = crypto_spawn_skcipher_alg(spawn);
69d3150c	306
5311f248 HX	307	/* We only support 16-byte blocks. */
5311f248 HX	308	err = -EINVAL;
b2b39c2f	309	if (crypto_skcipher_alg_ivsize(alg) != CTR_RFC3686_BLOCK_SIZE)
69d3150c	310	goto err_drop_spawn;
5311f248 HX	311
5311f248 HX	312	/* Not a stream cipher? */
b2b39c2f	313	if (alg->base.cra_blocksize != 1)
69d3150c	314	goto err_drop_spawn;
5311f248	315
69d3150c	316	err = -ENAMETOOLONG;
b2b39c2f HX	317	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
b2b39c2f HX	318	"rfc3686(%s)", alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
69d3150c	319	goto err_drop_spawn;
b2b39c2f HX	320	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
	321	"rfc3686(%s)", alg->base.cra_driver_name) >=
	322	CRYPTO_MAX_ALG_NAME)
69d3150c	323	goto err_drop_spawn;
5311f248	324
b2b39c2f HX	325	inst->alg.base.cra_priority = alg->base.cra_priority;
	326	inst->alg.base.cra_blocksize = 1;
	327	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
5311f248	328
b2b39c2f	329	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
69d3150c	330
b2b39c2f HX	331	inst->alg.ivsize = CTR_RFC3686_IV_SIZE;
	332	inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
	333	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
	334	CTR_RFC3686_NONCE_SIZE;
	335	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
	336	CTR_RFC3686_NONCE_SIZE;
5311f248	337
b2b39c2f HX	338	inst->alg.setkey = crypto_rfc3686_setkey;
	339	inst->alg.encrypt = crypto_rfc3686_crypt;
	340	inst->alg.decrypt = crypto_rfc3686_crypt;
69d3150c	341
b2b39c2f	342	inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
0a270321	343
b2b39c2f HX	344	inst->alg.init = crypto_rfc3686_init_tfm;
b2b39c2f HX	345	inst->alg.exit = crypto_rfc3686_exit_tfm;
5311f248	346
b2b39c2f	347	inst->free = crypto_rfc3686_free;
5311f248	348
b2b39c2f HX	349	err = skcipher_register_instance(tmpl, inst);
	350	if (err)
	351	goto err_drop_spawn;
	352
	353	out:
	354	return err;
5311f248	355
69d3150c JK	356	err_drop_spawn:
	357	crypto_drop_skcipher(spawn);
	358	err_free_inst:
	359	kfree(inst);
b2b39c2f	360	goto out;
5311f248 HX	361	}
5311f248 HX	362
9f8ef365 XW	363	static struct crypto_template crypto_ctr_tmpls[] = {
	364	{
	365	.name = "ctr",
	366	.create = crypto_ctr_create,
	367	.module = THIS_MODULE,
	368	}, {
	369	.name = "rfc3686",
	370	.create = crypto_rfc3686_create,
	371	.module = THIS_MODULE,
	372	},
5311f248 HX	373	};
5311f248 HX	374
23e353c8 JL	375	static int __init crypto_ctr_module_init(void)
23e353c8 JL	376	{
9f8ef365 XW	377	return crypto_register_templates(crypto_ctr_tmpls,
9f8ef365 XW	378	ARRAY_SIZE(crypto_ctr_tmpls));
23e353c8 JL	379	}
	380
	381	static void __exit crypto_ctr_module_exit(void)
	382	{
9f8ef365 XW	383	crypto_unregister_templates(crypto_ctr_tmpls,
9f8ef365 XW	384	ARRAY_SIZE(crypto_ctr_tmpls));
23e353c8 JL	385	}
	386
	387	module_init(crypto_ctr_module_init);
	388	module_exit(crypto_ctr_module_exit);
	389
	390	MODULE_LICENSE("GPL");
11f14630	391	MODULE_DESCRIPTION("CTR block cipher mode of operation");
5d26a105	392	MODULE_ALIAS_CRYPTO("rfc3686");
4943ba16	393	MODULE_ALIAS_CRYPTO("ctr");