[linux-block.git] / crypto / ctr.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * CTR: Counter mode
 *
 * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
 */

#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);
	if (IS_ERR(inst))
		return PTR_ERR(inst);

	alg = skcipher_ialg_simple(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) {
out_free_inst:
		inst->free(inst);
	}

	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));
}

subsys_initcall(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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
23e353c8 JL	2	/*
	3	* CTR: Counter mode
	4	*
	5	* (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
23e353c8 JL	6	*/
	7
	8	#include <crypto/algapi.h>
5311f248	9	#include <crypto/ctr.h>
69d3150c	10	#include <crypto/internal/skcipher.h>
23e353c8 JL	11	#include <linux/err.h>
	12	#include <linux/init.h>
	13	#include <linux/kernel.h>
	14	#include <linux/module.h>
23e353c8 JL	15	#include <linux/slab.h>
23e353c8 JL	16
5311f248	17	struct crypto_rfc3686_ctx {
b2b39c2f	18	struct crypto_skcipher *child;
5311f248	19	u8 nonce[CTR_RFC3686_NONCE_SIZE];
23e353c8 JL	20	};
23e353c8 JL	21
69d3150c JK	22	struct crypto_rfc3686_req_ctx {
69d3150c JK	23	u8 iv[CTR_RFC3686_BLOCK_SIZE];
b2b39c2f	24	struct skcipher_request subreq CRYPTO_MINALIGN_ATTR;
69d3150c JK	25	};
69d3150c JK	26
11f14630	27	static void crypto_ctr_crypt_final(struct skcipher_walk *walk,
5311f248	28	struct crypto_cipher *tfm)
0971eb0d HX	29	{
0971eb0d HX	30	unsigned int bsize = crypto_cipher_blocksize(tfm);
5311f248 HX	31	unsigned long alignmask = crypto_cipher_alignmask(tfm);
5311f248 HX	32	u8 *ctrblk = walk->iv;
6650c4de	33	u8 tmp[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
5311f248	34	u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
0971eb0d HX	35	u8 *src = walk->src.virt.addr;
	36	u8 *dst = walk->dst.virt.addr;
	37	unsigned int nbytes = walk->nbytes;
	38
	39	crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
45fe93df	40	crypto_xor_cpy(dst, keystream, src, nbytes);
5311f248 HX	41
5311f248 HX	42	crypto_inc(ctrblk, bsize);
0971eb0d HX	43	}
0971eb0d HX	44
11f14630	45	static int crypto_ctr_crypt_segment(struct skcipher_walk *walk,
5311f248	46	struct crypto_cipher *tfm)
23e353c8 JL	47	{
	48	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	49	crypto_cipher_alg(tfm)->cia_encrypt;
	50	unsigned int bsize = crypto_cipher_blocksize(tfm);
5311f248	51	u8 *ctrblk = walk->iv;
23e353c8 JL	52	u8 *src = walk->src.virt.addr;
	53	u8 *dst = walk->dst.virt.addr;
	54	unsigned int nbytes = walk->nbytes;
	55
	56	do {
	57	/* create keystream */
0971eb0d HX	58	fn(crypto_cipher_tfm(tfm), dst, ctrblk);
0971eb0d HX	59	crypto_xor(dst, src, bsize);
23e353c8 JL	60
23e353c8 JL	61	/* increment counter in counterblock */
5311f248	62	crypto_inc(ctrblk, bsize);
23e353c8	63
23e353c8 JL	64	src += bsize;
23e353c8 JL	65	dst += bsize;
0971eb0d	66	} while ((nbytes -= bsize) >= bsize);
23e353c8	67
0971eb0d	68	return nbytes;
23e353c8 JL	69	}
23e353c8 JL	70
11f14630	71	static int crypto_ctr_crypt_inplace(struct skcipher_walk *walk,
5311f248	72	struct crypto_cipher *tfm)
23e353c8 JL	73	{
	74	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	75	crypto_cipher_alg(tfm)->cia_encrypt;
	76	unsigned int bsize = crypto_cipher_blocksize(tfm);
5311f248	77	unsigned long alignmask = crypto_cipher_alignmask(tfm);
23e353c8	78	unsigned int nbytes = walk->nbytes;
5311f248	79	u8 *ctrblk = walk->iv;
23e353c8	80	u8 *src = walk->src.virt.addr;
6650c4de	81	u8 tmp[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
5311f248	82	u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
23e353c8 JL	83
	84	do {
	85	/* create keystream */
	86	fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
0971eb0d	87	crypto_xor(src, keystream, bsize);
23e353c8 JL	88
23e353c8 JL	89	/* increment counter in counterblock */
5311f248	90	crypto_inc(ctrblk, bsize);
23e353c8	91
23e353c8	92	src += bsize;
0971eb0d	93	} while ((nbytes -= bsize) >= bsize);
23e353c8	94
0971eb0d	95	return nbytes;
23e353c8 JL	96	}
23e353c8 JL	97
11f14630	98	static int crypto_ctr_crypt(struct skcipher_request *req)
23e353c8	99	{
11f14630 EB	100	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	101	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
	102	const unsigned int bsize = crypto_cipher_blocksize(cipher);
	103	struct skcipher_walk walk;
	104	unsigned int nbytes;
23e353c8 JL	105	int err;
23e353c8 JL	106
11f14630	107	err = skcipher_walk_virt(&walk, req, false);
23e353c8	108
0971eb0d	109	while (walk.nbytes >= bsize) {
23e353c8	110	if (walk.src.virt.addr == walk.dst.virt.addr)
11f14630	111	nbytes = crypto_ctr_crypt_inplace(&walk, cipher);
23e353c8	112	else
11f14630	113	nbytes = crypto_ctr_crypt_segment(&walk, cipher);
23e353c8	114
11f14630	115	err = skcipher_walk_done(&walk, nbytes);
23e353c8	116	}
0971eb0d HX	117
0971eb0d HX	118	if (walk.nbytes) {
11f14630 EB	119	crypto_ctr_crypt_final(&walk, cipher);
11f14630 EB	120	err = skcipher_walk_done(&walk, 0);
0971eb0d HX	121	}
0971eb0d HX	122
23e353c8 JL	123	return err;
	124	}
	125
11f14630	126	static int crypto_ctr_create(struct crypto_template tmpl, struct rtattr *tb)
23e353c8	127	{
11f14630	128	struct skcipher_instance *inst;
23e353c8	129	struct crypto_alg *alg;
23e353c8 JL	130	int err;
23e353c8 JL	131
b3c16bfc	132	inst = skcipher_alloc_instance_simple(tmpl, tb);
11f14630 EB	133	if (IS_ERR(inst))
11f14630 EB	134	return PTR_ERR(inst);
23e353c8	135
b3c16bfc HX	136	alg = skcipher_ialg_simple(inst);
b3c16bfc HX	137
5311f248	138	/* Block size must be >= 4 bytes. */
23e353c8	139	err = -EINVAL;
5311f248	140	if (alg->cra_blocksize < 4)
11f14630	141	goto out_free_inst;
23e353c8	142
3f8214ea	143	/* If this is false we'd fail the alignment of crypto_inc. */
5311f248	144	if (alg->cra_blocksize % 4)
11f14630	145	goto out_free_inst;
23e353c8	146
11f14630 EB	147	/* CTR mode is a stream cipher. */
11f14630 EB	148	inst->alg.base.cra_blocksize = 1;
23e353c8	149
11f14630 EB	150	/*
	151	* To simplify the implementation, configure the skcipher walk to only
	152	* give a partial block at the very end, never earlier.
	153	*/
	154	inst->alg.chunksize = alg->cra_blocksize;
23e353c8	155
11f14630 EB	156	inst->alg.encrypt = crypto_ctr_crypt;
11f14630 EB	157	inst->alg.decrypt = crypto_ctr_crypt;
23e353c8	158
11f14630	159	err = skcipher_register_instance(tmpl, inst);
b3c16bfc	160	if (err) {
11f14630	161	out_free_inst:
b3c16bfc HX	162	inst->free(inst);
	163	}
	164
11f14630	165	return err;
23e353c8 JL	166	}
23e353c8 JL	167
b2b39c2f	168	static int crypto_rfc3686_setkey(struct crypto_skcipher *parent,
69d3150c	169	const u8 *key, unsigned int keylen)
5311f248	170	{
b2b39c2f HX	171	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(parent);
b2b39c2f HX	172	struct crypto_skcipher *child = ctx->child;
5311f248 HX	173	int err;
	174
	175	/* the nonce is stored in bytes at end of key */
	176	if (keylen < CTR_RFC3686_NONCE_SIZE)
	177	return -EINVAL;
	178
	179	memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
	180	CTR_RFC3686_NONCE_SIZE);
	181
	182	keylen -= CTR_RFC3686_NONCE_SIZE;
	183
b2b39c2f HX	184	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	185	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
	186	CRYPTO_TFM_REQ_MASK);
	187	err = crypto_skcipher_setkey(child, key, keylen);
	188	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
	189	CRYPTO_TFM_RES_MASK);
5311f248 HX	190
	191	return err;
	192	}
	193
b2b39c2f	194	static int crypto_rfc3686_crypt(struct skcipher_request *req)
5311f248	195	{
b2b39c2f HX	196	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	197	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
	198	struct crypto_skcipher *child = ctx->child;
	199	unsigned long align = crypto_skcipher_alignmask(tfm);
69d3150c	200	struct crypto_rfc3686_req_ctx *rctx =
b2b39c2f HX	201	(void )PTR_ALIGN((u8 )skcipher_request_ctx(req), align + 1);
b2b39c2f HX	202	struct skcipher_request *subreq = &rctx->subreq;
69d3150c	203	u8 *iv = rctx->iv;
5311f248 HX	204
	205	/* set up counter block */
	206	memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
b2b39c2f	207	memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->iv, CTR_RFC3686_IV_SIZE);
5311f248 HX	208
	209	/* initialize counter portion of counter block */
	210	(__be32 )(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
	211	cpu_to_be32(1);
	212
b2b39c2f HX	213	skcipher_request_set_tfm(subreq, child);
	214	skcipher_request_set_callback(subreq, req->base.flags,
	215	req->base.complete, req->base.data);
	216	skcipher_request_set_crypt(subreq, req->src, req->dst,
	217	req->cryptlen, iv);
5311f248	218
b2b39c2f	219	return crypto_skcipher_encrypt(subreq);
5311f248 HX	220	}
5311f248 HX	221
b2b39c2f	222	static int crypto_rfc3686_init_tfm(struct crypto_skcipher *tfm)
5311f248	223	{
b2b39c2f HX	224	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	225	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
	226	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
	227	struct crypto_skcipher *cipher;
69d3150c	228	unsigned long align;
b2b39c2f	229	unsigned int reqsize;
5311f248	230
60425a8b	231	cipher = crypto_spawn_skcipher(spawn);
5311f248 HX	232	if (IS_ERR(cipher))
	233	return PTR_ERR(cipher);
	234
	235	ctx->child = cipher;
	236
b2b39c2f	237	align = crypto_skcipher_alignmask(tfm);
69d3150c	238	align &= ~(crypto_tfm_ctx_alignment() - 1);
b2b39c2f HX	239	reqsize = align + sizeof(struct crypto_rfc3686_req_ctx) +
	240	crypto_skcipher_reqsize(cipher);
	241	crypto_skcipher_set_reqsize(tfm, reqsize);
69d3150c	242
5311f248 HX	243	return 0;
	244	}
	245
b2b39c2f	246	static void crypto_rfc3686_exit_tfm(struct crypto_skcipher *tfm)
5311f248	247	{
b2b39c2f HX	248	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
	249
	250	crypto_free_skcipher(ctx->child);
	251	}
5311f248	252
b2b39c2f HX	253	static void crypto_rfc3686_free(struct skcipher_instance *inst)
	254	{
	255	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
	256
	257	crypto_drop_skcipher(spawn);
	258	kfree(inst);
5311f248 HX	259	}
5311f248 HX	260
b2b39c2f HX	261	static int crypto_rfc3686_create(struct crypto_template *tmpl,
b2b39c2f HX	262	struct rtattr **tb)
5311f248	263	{
69d3150c	264	struct crypto_attr_type *algt;
b2b39c2f HX	265	struct skcipher_instance *inst;
b2b39c2f HX	266	struct skcipher_alg *alg;
69d3150c JK	267	struct crypto_skcipher_spawn *spawn;
69d3150c JK	268	const char *cipher_name;
d2c2a85c MC	269	u32 mask;
d2c2a85c MC	270
5311f248 HX	271	int err;
5311f248 HX	272
69d3150c	273	algt = crypto_get_attr_type(tb);
69d3150c	274	if (IS_ERR(algt))
b2b39c2f	275	return PTR_ERR(algt);
5311f248	276
b2b39c2f HX	277	if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
b2b39c2f HX	278	return -EINVAL;
69d3150c JK	279
69d3150c JK	280	cipher_name = crypto_attr_alg_name(tb[1]);
69d3150c	281	if (IS_ERR(cipher_name))
b2b39c2f	282	return PTR_ERR(cipher_name);
5311f248	283
69d3150c JK	284	inst = kzalloc(sizeof(inst) + sizeof(spawn), GFP_KERNEL);
69d3150c JK	285	if (!inst)
b2b39c2f	286	return -ENOMEM;
69d3150c	287
d2c2a85c MC	288	mask = crypto_requires_sync(algt->type, algt->mask) \|
	289	crypto_requires_off(algt->type, algt->mask,
	290	CRYPTO_ALG_NEED_FALLBACK);
	291
b2b39c2f	292	spawn = skcipher_instance_ctx(inst);
69d3150c	293
b2b39c2f	294	crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
d2c2a85c	295	err = crypto_grab_skcipher(spawn, cipher_name, 0, mask);
69d3150c JK	296	if (err)
	297	goto err_free_inst;
	298
b2b39c2f	299	alg = crypto_spawn_skcipher_alg(spawn);
69d3150c	300
5311f248 HX	301	/* We only support 16-byte blocks. */
5311f248 HX	302	err = -EINVAL;
b2b39c2f	303	if (crypto_skcipher_alg_ivsize(alg) != CTR_RFC3686_BLOCK_SIZE)
69d3150c	304	goto err_drop_spawn;
5311f248 HX	305
5311f248 HX	306	/* Not a stream cipher? */
b2b39c2f	307	if (alg->base.cra_blocksize != 1)
69d3150c	308	goto err_drop_spawn;
5311f248	309
69d3150c	310	err = -ENAMETOOLONG;
b2b39c2f HX	311	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
b2b39c2f HX	312	"rfc3686(%s)", alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
69d3150c	313	goto err_drop_spawn;
b2b39c2f HX	314	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
	315	"rfc3686(%s)", alg->base.cra_driver_name) >=
	316	CRYPTO_MAX_ALG_NAME)
69d3150c	317	goto err_drop_spawn;
5311f248	318
b2b39c2f HX	319	inst->alg.base.cra_priority = alg->base.cra_priority;
	320	inst->alg.base.cra_blocksize = 1;
	321	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
5311f248	322
b2b39c2f	323	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
69d3150c	324
b2b39c2f HX	325	inst->alg.ivsize = CTR_RFC3686_IV_SIZE;
	326	inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
	327	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
	328	CTR_RFC3686_NONCE_SIZE;
	329	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
	330	CTR_RFC3686_NONCE_SIZE;
5311f248	331
b2b39c2f HX	332	inst->alg.setkey = crypto_rfc3686_setkey;
	333	inst->alg.encrypt = crypto_rfc3686_crypt;
	334	inst->alg.decrypt = crypto_rfc3686_crypt;
69d3150c	335
b2b39c2f	336	inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
0a270321	337
b2b39c2f HX	338	inst->alg.init = crypto_rfc3686_init_tfm;
b2b39c2f HX	339	inst->alg.exit = crypto_rfc3686_exit_tfm;
5311f248	340
b2b39c2f	341	inst->free = crypto_rfc3686_free;
5311f248	342
b2b39c2f HX	343	err = skcipher_register_instance(tmpl, inst);
	344	if (err)
	345	goto err_drop_spawn;
	346
	347	out:
	348	return err;
5311f248	349
69d3150c JK	350	err_drop_spawn:
	351	crypto_drop_skcipher(spawn);
	352	err_free_inst:
	353	kfree(inst);
b2b39c2f	354	goto out;
5311f248 HX	355	}
5311f248 HX	356
9f8ef365 XW	357	static struct crypto_template crypto_ctr_tmpls[] = {
	358	{
	359	.name = "ctr",
	360	.create = crypto_ctr_create,
	361	.module = THIS_MODULE,
	362	}, {
	363	.name = "rfc3686",
	364	.create = crypto_rfc3686_create,
	365	.module = THIS_MODULE,
	366	},
5311f248 HX	367	};
5311f248 HX	368
23e353c8 JL	369	static int __init crypto_ctr_module_init(void)
23e353c8 JL	370	{
9f8ef365 XW	371	return crypto_register_templates(crypto_ctr_tmpls,
9f8ef365 XW	372	ARRAY_SIZE(crypto_ctr_tmpls));
23e353c8 JL	373	}
	374
	375	static void __exit crypto_ctr_module_exit(void)
	376	{
9f8ef365 XW	377	crypto_unregister_templates(crypto_ctr_tmpls,
9f8ef365 XW	378	ARRAY_SIZE(crypto_ctr_tmpls));
23e353c8 JL	379	}
23e353c8 JL	380
c4741b23	381	subsys_initcall(crypto_ctr_module_init);
23e353c8 JL	382	module_exit(crypto_ctr_module_exit);
	383
	384	MODULE_LICENSE("GPL");
11f14630	385	MODULE_DESCRIPTION("CTR block cipher mode of operation");
5d26a105	386	MODULE_ALIAS_CRYPTO("rfc3686");
4943ba16	387	MODULE_ALIAS_CRYPTO("ctr");