[linux.git] / crypto / xts.c

/* XTS: as defined in IEEE1619/D16
 *	http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
 *	(sector sizes which are not a multiple of 16 bytes are,
 *	however currently unsupported)
 *
 * Copyright (c) 2007 Rik Snel <[email protected]>
 *
 * Based on ecb.c
 * 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/internal/skcipher.h>
#include <crypto/scatterwalk.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>

#include <crypto/xts.h>
#include <crypto/b128ops.h>
#include <crypto/gf128mul.h>

struct priv {
	struct crypto_skcipher *child;
	struct crypto_cipher *tweak;
};

struct xts_instance_ctx {
	struct crypto_skcipher_spawn spawn;
	char name[CRYPTO_MAX_ALG_NAME];
};

struct rctx {
	le128 t;
	struct skcipher_request subreq;
};

static int setkey(struct crypto_skcipher *parent, const u8 *key,
		  unsigned int keylen)
{
	struct priv *ctx = crypto_skcipher_ctx(parent);
	struct crypto_skcipher *child;
	struct crypto_cipher *tweak;
	int err;

	err = xts_verify_key(parent, key, keylen);
	if (err)
		return err;

	keylen /= 2;

	/* we need two cipher instances: one to compute the initial 'tweak'
	 * by encrypting the IV (usually the 'plain' iv) and the other
	 * one to encrypt and decrypt the data */

	/* tweak cipher, uses Key2 i.e. the second half of *key */
	tweak = ctx->tweak;
	crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK);
	crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) &
				       CRYPTO_TFM_REQ_MASK);
	err = crypto_cipher_setkey(tweak, key + keylen, keylen);
	crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(tweak) &
					  CRYPTO_TFM_RES_MASK);
	if (err)
		return err;

	/* data cipher, uses Key1 i.e. the first half of *key */
	child = ctx->child;
	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;
}

/*
 * We compute the tweak masks twice (both before and after the ECB encryption or
 * decryption) to avoid having to allocate a temporary buffer and/or make
 * mutliple calls to the 'ecb(..)' instance, which usually would be slower than
 * just doing the gf128mul_x_ble() calls again.
 */
static int xor_tweak(struct skcipher_request *req, bool second_pass)
{
	struct rctx *rctx = skcipher_request_ctx(req);
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	const int bs = XTS_BLOCK_SIZE;
	struct skcipher_walk w;
	le128 t = rctx->t;
	int err;

	if (second_pass) {
		req = &rctx->subreq;
		/* set to our TFM to enforce correct alignment: */
		skcipher_request_set_tfm(req, tfm);
	}
	err = skcipher_walk_virt(&w, req, false);

	while (w.nbytes) {
		unsigned int avail = w.nbytes;
		le128 *wsrc;
		le128 *wdst;

		wsrc = w.src.virt.addr;
		wdst = w.dst.virt.addr;

		do {
			le128_xor(wdst++, &t, wsrc++);
			gf128mul_x_ble(&t, &t);
		} while ((avail -= bs) >= bs);

		err = skcipher_walk_done(&w, avail);
	}

	return err;
}

static int xor_tweak_pre(struct skcipher_request *req)
{
	return xor_tweak(req, false);
}

static int xor_tweak_post(struct skcipher_request *req)
{
	return xor_tweak(req, true);
}

static void crypt_done(struct crypto_async_request *areq, int err)
{
	struct skcipher_request *req = areq->data;

	if (!err)
		err = xor_tweak_post(req);

	skcipher_request_complete(req, err);
}

static void init_crypt(struct skcipher_request *req)
{
	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
	struct rctx *rctx = skcipher_request_ctx(req);
	struct skcipher_request *subreq = &rctx->subreq;

	skcipher_request_set_tfm(subreq, ctx->child);
	skcipher_request_set_callback(subreq, req->base.flags, crypt_done, req);
	skcipher_request_set_crypt(subreq, req->dst, req->dst,
				   req->cryptlen, NULL);

	/* calculate first value of T */
	crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
}

static int encrypt(struct skcipher_request *req)
{
	struct rctx *rctx = skcipher_request_ctx(req);
	struct skcipher_request *subreq = &rctx->subreq;

	init_crypt(req);
	return xor_tweak_pre(req) ?:
		crypto_skcipher_encrypt(subreq) ?:
		xor_tweak_post(req);
}

static int decrypt(struct skcipher_request *req)
{
	struct rctx *rctx = skcipher_request_ctx(req);
	struct skcipher_request *subreq = &rctx->subreq;

	init_crypt(req);
	return xor_tweak_pre(req) ?:
		crypto_skcipher_decrypt(subreq) ?:
		xor_tweak_post(req);
}

static int init_tfm(struct crypto_skcipher *tfm)
{
	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
	struct priv *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_skcipher *child;
	struct crypto_cipher *tweak;

	child = crypto_spawn_skcipher(&ictx->spawn);
	if (IS_ERR(child))
		return PTR_ERR(child);

	ctx->child = child;

	tweak = crypto_alloc_cipher(ictx->name, 0, 0);
	if (IS_ERR(tweak)) {
		crypto_free_skcipher(ctx->child);
		return PTR_ERR(tweak);
	}

	ctx->tweak = tweak;

	crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
					 sizeof(struct rctx));

	return 0;
}

static void exit_tfm(struct crypto_skcipher *tfm)
{
	struct priv *ctx = crypto_skcipher_ctx(tfm);

	crypto_free_skcipher(ctx->child);
	crypto_free_cipher(ctx->tweak);
}

static void free(struct skcipher_instance *inst)
{
	crypto_drop_skcipher(skcipher_instance_ctx(inst));
	kfree(inst);
}

static int create(struct crypto_template *tmpl, struct rtattr **tb)
{
	struct skcipher_instance *inst;
	struct crypto_attr_type *algt;
	struct xts_instance_ctx *ctx;
	struct skcipher_alg *alg;
	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(*ctx), GFP_KERNEL);
	if (!inst)
		return -ENOMEM;

	ctx = skcipher_instance_ctx(inst);

	crypto_set_skcipher_spawn(&ctx->spawn, skcipher_crypto_instance(inst));

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

	err = crypto_grab_skcipher(&ctx->spawn, cipher_name, 0, mask);
	if (err == -ENOENT) {
		err = -ENAMETOOLONG;
		if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
			     cipher_name) >= CRYPTO_MAX_ALG_NAME)
			goto err_free_inst;

		err = crypto_grab_skcipher(&ctx->spawn, ctx->name, 0, mask);
	}

	if (err)
		goto err_free_inst;

	alg = crypto_skcipher_spawn_alg(&ctx->spawn);

	err = -EINVAL;
	if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
		goto err_drop_spawn;

	if (crypto_skcipher_alg_ivsize(alg))
		goto err_drop_spawn;

	err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
				  &alg->base);
	if (err)
		goto err_drop_spawn;

	err = -EINVAL;
	cipher_name = alg->base.cra_name;

	/* Alas we screwed up the naming so we have to mangle the
	 * cipher name.
	 */
	if (!strncmp(cipher_name, "ecb(", 4)) {
		unsigned len;

		len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
		if (len < 2 || len >= sizeof(ctx->name))
			goto err_drop_spawn;

		if (ctx->name[len - 1] != ')')
			goto err_drop_spawn;

		ctx->name[len - 1] = 0;

		if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
			     "xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) {
			err = -ENAMETOOLONG;
			goto err_drop_spawn;
		}
	} else
		goto err_drop_spawn;

	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
	inst->alg.base.cra_priority = alg->base.cra_priority;
	inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
	inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
				       (__alignof__(u64) - 1);

	inst->alg.ivsize = XTS_BLOCK_SIZE;
	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;

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

	inst->alg.init = init_tfm;
	inst->alg.exit = exit_tfm;

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

	inst->free = free;

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

out:
	return err;

err_drop_spawn:
	crypto_drop_skcipher(&ctx->spawn);
err_free_inst:
	kfree(inst);
	goto out;
}

static struct crypto_template crypto_tmpl = {
	.name = "xts",
	.create = create,
	.module = THIS_MODULE,
};

static int __init crypto_module_init(void)
{
	return crypto_register_template(&crypto_tmpl);
}

static void __exit crypto_module_exit(void)
{
	crypto_unregister_template(&crypto_tmpl);
}

module_init(crypto_module_init);
module_exit(crypto_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("XTS block cipher mode");
MODULE_ALIAS_CRYPTO("xts");
Commit	Line	Data
f19f5111 RS	1	/* XTS: as defined in IEEE1619/D16
	2	* http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
	3	* (sector sizes which are not a multiple of 16 bytes are,
	4	* however currently unsupported)
	5	*
	6	* Copyright (c) 2007 Rik Snel <[email protected]>
	7	*
ddbc7361	8	* Based on ecb.c
f19f5111 RS	9	* Copyright (c) 2006 Herbert Xu <[email protected]>
	10	*
	11	* This program is free software; you can redistribute it and/or modify it
	12	* under the terms of the GNU General Public License as published by the Free
	13	* Software Foundation; either version 2 of the License, or (at your option)
	14	* any later version.
	15	*/
f1c131b4 HX	16	#include <crypto/internal/skcipher.h>
f1c131b4 HX	17	#include <crypto/scatterwalk.h>
f19f5111 RS	18	#include <linux/err.h>
	19	#include <linux/init.h>
	20	#include <linux/kernel.h>
	21	#include <linux/module.h>
	22	#include <linux/scatterlist.h>
	23	#include <linux/slab.h>
	24
ce004556	25	#include <crypto/xts.h>
f19f5111 RS	26	#include <crypto/b128ops.h>
	27	#include <crypto/gf128mul.h>
	28
	29	struct priv {
f1c131b4	30	struct crypto_skcipher *child;
f19f5111 RS	31	struct crypto_cipher *tweak;
	32	};
	33
f1c131b4 HX	34	struct xts_instance_ctx {
	35	struct crypto_skcipher_spawn spawn;
	36	char name[CRYPTO_MAX_ALG_NAME];
	37	};
	38
	39	struct rctx {
e55318c8	40	le128 t;
f1c131b4 HX	41	struct skcipher_request subreq;
	42	};
	43
	44	static int setkey(struct crypto_skcipher parent, const u8 key,
f19f5111 RS	45	unsigned int keylen)
f19f5111 RS	46	{
f1c131b4 HX	47	struct priv *ctx = crypto_skcipher_ctx(parent);
	48	struct crypto_skcipher *child;
	49	struct crypto_cipher *tweak;
f19f5111 RS	50	int err;
f19f5111 RS	51
f1c131b4	52	err = xts_verify_key(parent, key, keylen);
28856a9e SM	53	if (err)
28856a9e SM	54	return err;
f19f5111	55
f1c131b4 HX	56	keylen /= 2;
f1c131b4 HX	57
25985edc	58	/* we need two cipher instances: one to compute the initial 'tweak'
f19f5111 RS	59	* by encrypting the IV (usually the 'plain' iv) and the other
	60	* one to encrypt and decrypt the data */
	61
	62	/* tweak cipher, uses Key2 i.e. the second half of key /
f1c131b4 HX	63	tweak = ctx->tweak;
	64	crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK);
	65	crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) &
f19f5111	66	CRYPTO_TFM_REQ_MASK);
f1c131b4 HX	67	err = crypto_cipher_setkey(tweak, key + keylen, keylen);
	68	crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(tweak) &
	69	CRYPTO_TFM_RES_MASK);
f19f5111 RS	70	if (err)
	71	return err;
	72
f1c131b4	73	/* data cipher, uses Key1 i.e. the first half of key /
f19f5111	74	child = ctx->child;
f1c131b4 HX	75	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	76	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
	77	CRYPTO_TFM_REQ_MASK);
	78	err = crypto_skcipher_setkey(child, key, keylen);
	79	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
	80	CRYPTO_TFM_RES_MASK);
f19f5111	81
f1c131b4 HX	82	return err;
f1c131b4 HX	83	}
f19f5111	84
78105c7e OM	85	/*
	86	* We compute the tweak masks twice (both before and after the ECB encryption or
	87	* decryption) to avoid having to allocate a temporary buffer and/or make
	88	* mutliple calls to the 'ecb(..)' instance, which usually would be slower than
	89	* just doing the gf128mul_x_ble() calls again.
	90	*/
	91	static int xor_tweak(struct skcipher_request *req, bool second_pass)
f1c131b4 HX	92	{
f1c131b4 HX	93	struct rctx *rctx = skcipher_request_ctx(req);
78105c7e	94	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
f1c131b4 HX	95	const int bs = XTS_BLOCK_SIZE;
f1c131b4 HX	96	struct skcipher_walk w;
78105c7e	97	le128 t = rctx->t;
f1c131b4	98	int err;
f19f5111	99
78105c7e OM	100	if (second_pass) {
	101	req = &rctx->subreq;
	102	/* set to our TFM to enforce correct alignment: */
	103	skcipher_request_set_tfm(req, tfm);
f1c131b4	104	}
78105c7e	105	err = skcipher_walk_virt(&w, req, false);
f19f5111	106
f1c131b4 HX	107	while (w.nbytes) {
f1c131b4 HX	108	unsigned int avail = w.nbytes;
e55318c8 OM	109	le128 *wsrc;
e55318c8 OM	110	le128 *wdst;
f19f5111	111
f1c131b4 HX	112	wsrc = w.src.virt.addr;
f1c131b4 HX	113	wdst = w.dst.virt.addr;
f19f5111	114
f1c131b4	115	do {
78105c7e OM	116	le128_xor(wdst++, &t, wsrc++);
78105c7e OM	117	gf128mul_x_ble(&t, &t);
f19f5111 RS	118	} while ((avail -= bs) >= bs);
f19f5111 RS	119
f1c131b4 HX	120	err = skcipher_walk_done(&w, avail);
	121	}
	122
f19f5111 RS	123	return err;
	124	}
	125
78105c7e	126	static int xor_tweak_pre(struct skcipher_request *req)
f19f5111	127	{
78105c7e	128	return xor_tweak(req, false);
f1c131b4 HX	129	}
f1c131b4 HX	130
78105c7e	131	static int xor_tweak_post(struct skcipher_request *req)
f1c131b4	132	{
78105c7e	133	return xor_tweak(req, true);
f1c131b4 HX	134	}
f1c131b4 HX	135
78105c7e	136	static void crypt_done(struct crypto_async_request *areq, int err)
f1c131b4 HX	137	{
f1c131b4 HX	138	struct skcipher_request *req = areq->data;
aa4a829b	139
78105c7e OM	140	if (!err)
78105c7e OM	141	err = xor_tweak_post(req);
f1c131b4	142
f1c131b4 HX	143	skcipher_request_complete(req, err);
	144	}
	145
78105c7e	146	static void init_crypt(struct skcipher_request *req)
f1c131b4	147	{
78105c7e	148	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
f1c131b4	149	struct rctx *rctx = skcipher_request_ctx(req);
78105c7e	150	struct skcipher_request *subreq = &rctx->subreq;
f1c131b4	151
78105c7e OM	152	skcipher_request_set_tfm(subreq, ctx->child);
	153	skcipher_request_set_callback(subreq, req->base.flags, crypt_done, req);
	154	skcipher_request_set_crypt(subreq, req->dst, req->dst,
	155	req->cryptlen, NULL);
f1c131b4	156
78105c7e OM	157	/* calculate first value of T */
78105c7e OM	158	crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
f1c131b4 HX	159	}
f1c131b4 HX	160
78105c7e	161	static int encrypt(struct skcipher_request *req)
f1c131b4	162	{
78105c7e OM	163	struct rctx *rctx = skcipher_request_ctx(req);
78105c7e OM	164	struct skcipher_request *subreq = &rctx->subreq;
f1c131b4	165
78105c7e OM	166	init_crypt(req);
	167	return xor_tweak_pre(req) ?:
	168	crypto_skcipher_encrypt(subreq) ?:
	169	xor_tweak_post(req);
f1c131b4 HX	170	}
	171
	172	static int decrypt(struct skcipher_request *req)
	173	{
78105c7e OM	174	struct rctx *rctx = skcipher_request_ctx(req);
	175	struct skcipher_request *subreq = &rctx->subreq;
	176
	177	init_crypt(req);
	178	return xor_tweak_pre(req) ?:
	179	crypto_skcipher_decrypt(subreq) ?:
	180	xor_tweak_post(req);
f19f5111 RS	181	}
f19f5111 RS	182
f1c131b4	183	static int init_tfm(struct crypto_skcipher *tfm)
f19f5111	184	{
f1c131b4 HX	185	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	186	struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
	187	struct priv *ctx = crypto_skcipher_ctx(tfm);
	188	struct crypto_skcipher *child;
	189	struct crypto_cipher *tweak;
f19f5111	190
f1c131b4 HX	191	child = crypto_spawn_skcipher(&ictx->spawn);
	192	if (IS_ERR(child))
	193	return PTR_ERR(child);
f19f5111	194
f1c131b4	195	ctx->child = child;
f19f5111	196
f1c131b4 HX	197	tweak = crypto_alloc_cipher(ictx->name, 0, 0);
	198	if (IS_ERR(tweak)) {
	199	crypto_free_skcipher(ctx->child);
	200	return PTR_ERR(tweak);
f19f5111 RS	201	}
f19f5111 RS	202
f1c131b4 HX	203	ctx->tweak = tweak;
	204
	205	crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
	206	sizeof(struct rctx));
f19f5111 RS	207
	208	return 0;
	209	}
	210
f1c131b4	211	static void exit_tfm(struct crypto_skcipher *tfm)
f19f5111	212	{
f1c131b4 HX	213	struct priv *ctx = crypto_skcipher_ctx(tfm);
	214
	215	crypto_free_skcipher(ctx->child);
f19f5111 RS	216	crypto_free_cipher(ctx->tweak);
	217	}
	218
f1c131b4 HX	219	static void free(struct skcipher_instance *inst)
	220	{
	221	crypto_drop_skcipher(skcipher_instance_ctx(inst));
	222	kfree(inst);
	223	}
	224
	225	static int create(struct crypto_template tmpl, struct rtattr *tb)
f19f5111	226	{
f1c131b4 HX	227	struct skcipher_instance *inst;
	228	struct crypto_attr_type *algt;
	229	struct xts_instance_ctx *ctx;
	230	struct skcipher_alg *alg;
	231	const char *cipher_name;
89027579	232	u32 mask;
f19f5111 RS	233	int err;
f19f5111 RS	234
f1c131b4 HX	235	algt = crypto_get_attr_type(tb);
	236	if (IS_ERR(algt))
	237	return PTR_ERR(algt);
	238
	239	if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
	240	return -EINVAL;
	241
	242	cipher_name = crypto_attr_alg_name(tb[1]);
	243	if (IS_ERR(cipher_name))
	244	return PTR_ERR(cipher_name);
	245
	246	inst = kzalloc(sizeof(inst) + sizeof(ctx), GFP_KERNEL);
	247	if (!inst)
	248	return -ENOMEM;
	249
	250	ctx = skcipher_instance_ctx(inst);
	251
	252	crypto_set_skcipher_spawn(&ctx->spawn, skcipher_crypto_instance(inst));
89027579 HX	253
	254	mask = crypto_requires_off(algt->type, algt->mask,
	255	CRYPTO_ALG_NEED_FALLBACK \|
	256	CRYPTO_ALG_ASYNC);
	257
	258	err = crypto_grab_skcipher(&ctx->spawn, cipher_name, 0, mask);
f1c131b4 HX	259	if (err == -ENOENT) {
	260	err = -ENAMETOOLONG;
	261	if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
	262	cipher_name) >= CRYPTO_MAX_ALG_NAME)
	263	goto err_free_inst;
	264
89027579	265	err = crypto_grab_skcipher(&ctx->spawn, ctx->name, 0, mask);
f1c131b4 HX	266	}
f1c131b4 HX	267
f19f5111	268	if (err)
f1c131b4	269	goto err_free_inst;
f19f5111	270
f1c131b4	271	alg = crypto_skcipher_spawn_alg(&ctx->spawn);
f19f5111	272
f1c131b4 HX	273	err = -EINVAL;
	274	if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
	275	goto err_drop_spawn;
f19f5111	276
f1c131b4 HX	277	if (crypto_skcipher_alg_ivsize(alg))
f1c131b4 HX	278	goto err_drop_spawn;
f19f5111	279
f1c131b4 HX	280	err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
	281	&alg->base);
	282	if (err)
	283	goto err_drop_spawn;
f19f5111	284
f1c131b4 HX	285	err = -EINVAL;
f1c131b4 HX	286	cipher_name = alg->base.cra_name;
f19f5111	287
f1c131b4 HX	288	/* Alas we screwed up the naming so we have to mangle the
	289	* cipher name.
	290	*/
	291	if (!strncmp(cipher_name, "ecb(", 4)) {
	292	unsigned len;
f19f5111	293
f1c131b4 HX	294	len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
	295	if (len < 2 \|\| len >= sizeof(ctx->name))
	296	goto err_drop_spawn;
f19f5111	297
f1c131b4 HX	298	if (ctx->name[len - 1] != ')')
f1c131b4 HX	299	goto err_drop_spawn;
f19f5111	300
f1c131b4	301	ctx->name[len - 1] = 0;
f19f5111	302
f1c131b4	303	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
5125e4e8 CJ	304	"xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) {
	305	err = -ENAMETOOLONG;
	306	goto err_drop_spawn;
	307	}
f1c131b4 HX	308	} else
f1c131b4 HX	309	goto err_drop_spawn;
f19f5111	310
f1c131b4 HX	311	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
	312	inst->alg.base.cra_priority = alg->base.cra_priority;
	313	inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
	314	inst->alg.base.cra_alignmask = alg->base.cra_alignmask \|
	315	(__alignof__(u64) - 1);
	316
	317	inst->alg.ivsize = XTS_BLOCK_SIZE;
	318	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
	319	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;
	320
	321	inst->alg.base.cra_ctxsize = sizeof(struct priv);
	322
	323	inst->alg.init = init_tfm;
	324	inst->alg.exit = exit_tfm;
	325
	326	inst->alg.setkey = setkey;
	327	inst->alg.encrypt = encrypt;
	328	inst->alg.decrypt = decrypt;
	329
	330	inst->free = free;
	331
	332	err = skcipher_register_instance(tmpl, inst);
	333	if (err)
	334	goto err_drop_spawn;
	335
	336	out:
	337	return err;
	338
	339	err_drop_spawn:
	340	crypto_drop_skcipher(&ctx->spawn);
	341	err_free_inst:
f19f5111	342	kfree(inst);
f1c131b4	343	goto out;
f19f5111 RS	344	}
	345
	346	static struct crypto_template crypto_tmpl = {
	347	.name = "xts",
f1c131b4	348	.create = create,
f19f5111 RS	349	.module = THIS_MODULE,
	350	};
	351
	352	static int __init crypto_module_init(void)
	353	{
	354	return crypto_register_template(&crypto_tmpl);
	355	}
	356
	357	static void __exit crypto_module_exit(void)
	358	{
	359	crypto_unregister_template(&crypto_tmpl);
	360	}
	361
	362	module_init(crypto_module_init);
	363	module_exit(crypto_module_exit);
	364
	365	MODULE_LICENSE("GPL");
	366	MODULE_DESCRIPTION("XTS block cipher mode");
4943ba16	367	MODULE_ALIAS_CRYPTO("xts");