[thirdparty/linux.git] / crypto / xts.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* XTS: as defined in IEEE1619/D16
 *	http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
 *
 * Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
 *
 * Based on ecb.c
 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
 */
#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 scatterlist *tail;
	struct scatterlist sg[2];
	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);
	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);
	return crypto_skcipher_setkey(child, key, keylen);
}

/*
 * 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, bool enc)
{
	struct rctx *rctx = skcipher_request_ctx(req);
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	const bool cts = (req->cryptlen % XTS_BLOCK_SIZE);
	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 {
			if (unlikely(cts) &&
			    w.total - w.nbytes + avail < 2 * XTS_BLOCK_SIZE) {
				if (!enc) {
					if (second_pass)
						rctx->t = t;
					gf128mul_x_ble(&t, &t);
				}
				le128_xor(wdst, &t, wsrc);
				if (enc && second_pass)
					gf128mul_x_ble(&rctx->t, &t);
				skcipher_walk_done(&w, avail - bs);
				return 0;
			}

			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, bool enc)
{
	return xor_tweak(req, false, enc);
}

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

static void cts_done(struct crypto_async_request *areq, int err)
{
	struct skcipher_request *req = areq->data;
	le128 b;

	if (!err) {
		struct rctx *rctx = skcipher_request_ctx(req);

		scatterwalk_map_and_copy(&b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
		le128_xor(&b, &rctx->t, &b);
		scatterwalk_map_and_copy(&b, rctx->tail, 0, XTS_BLOCK_SIZE, 1);
	}

	skcipher_request_complete(req, err);
}

static int cts_final(struct skcipher_request *req,
		     int (*crypt)(struct skcipher_request *req))
{
	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
	int offset = req->cryptlen & ~(XTS_BLOCK_SIZE - 1);
	struct rctx *rctx = skcipher_request_ctx(req);
	struct skcipher_request *subreq = &rctx->subreq;
	int tail = req->cryptlen % XTS_BLOCK_SIZE;
	le128 b[2];
	int err;

	rctx->tail = scatterwalk_ffwd(rctx->sg, req->dst,
				      offset - XTS_BLOCK_SIZE);

	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
	memcpy(b + 1, b, tail);
	scatterwalk_map_and_copy(b, req->src, offset, tail, 0);

	le128_xor(b, &rctx->t, b);

	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE + tail, 1);

	skcipher_request_set_tfm(subreq, ctx->child);
	skcipher_request_set_callback(subreq, req->base.flags, cts_done, req);
	skcipher_request_set_crypt(subreq, rctx->tail, rctx->tail,
				   XTS_BLOCK_SIZE, NULL);

	err = crypt(subreq);
	if (err)
		return err;

	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
	le128_xor(b, &rctx->t, b);
	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 1);

	return 0;
}

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

	if (!err) {
		struct rctx *rctx = skcipher_request_ctx(req);

		rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
		err = xor_tweak_post(req, true);

		if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
			err = cts_final(req, crypto_skcipher_encrypt);
			if (err == -EINPROGRESS)
				return;
		}
	}

	skcipher_request_complete(req, err);
}

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

	if (!err) {
		struct rctx *rctx = skcipher_request_ctx(req);

		rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
		err = xor_tweak_post(req, false);

		if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
			err = cts_final(req, crypto_skcipher_decrypt);
			if (err == -EINPROGRESS)
				return;
		}
	}

	skcipher_request_complete(req, err);
}

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

	if (req->cryptlen < XTS_BLOCK_SIZE)
		return -EINVAL;

	skcipher_request_set_tfm(subreq, ctx->child);
	skcipher_request_set_callback(subreq, req->base.flags, compl, req);
	skcipher_request_set_crypt(subreq, req->dst, req->dst,
				   req->cryptlen & ~(XTS_BLOCK_SIZE - 1), NULL);

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

	return 0;
}

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

	err = init_crypt(req, encrypt_done) ?:
	      xor_tweak_pre(req, true) ?:
	      crypto_skcipher_encrypt(subreq) ?:
	      xor_tweak_post(req, true);

	if (err || likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
		return err;

	return cts_final(req, crypto_skcipher_encrypt);
}

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

	err = init_crypt(req, decrypt_done) ?:
	      xor_tweak_pre(req, false) ?:
	      crypto_skcipher_decrypt(subreq) ?:
	      xor_tweak_post(req, false);

	if (err || likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
		return err;

	return cts_final(req, crypto_skcipher_decrypt);
}

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_inst(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);

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

	err = crypto_grab_skcipher(&ctx->spawn, skcipher_crypto_instance(inst),
				   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,
					   skcipher_crypto_instance(inst),
					   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_free_inst;

	if (crypto_skcipher_alg_ivsize(alg))
		goto err_free_inst;

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

	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_free_inst;

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

		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_free_inst;
		}
	} else
		goto err_free_inst;

	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_inst;

	err = skcipher_register_instance(tmpl, inst);
	if (err) {
err_free_inst:
		free_inst(inst);
	}
	return err;
}

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);
}

subsys_initcall(crypto_module_init);
module_exit(crypto_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("XTS block cipher mode");
MODULE_ALIAS_CRYPTO("xts");
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
f19f5111 RS	2	/* XTS: as defined in IEEE1619/D16
f19f5111 RS	3	* http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
f19f5111 RS	4	*
	5	* Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
	6	*
ddbc7361	7	* Based on ecb.c
f19f5111	8	* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
f19f5111	9	*/
f1c131b4 HX	10	#include <crypto/internal/skcipher.h>
f1c131b4 HX	11	#include <crypto/scatterwalk.h>
f19f5111 RS	12	#include <linux/err.h>
	13	#include <linux/init.h>
	14	#include <linux/kernel.h>
	15	#include <linux/module.h>
	16	#include <linux/scatterlist.h>
	17	#include <linux/slab.h>
	18
ce004556	19	#include <crypto/xts.h>
f19f5111 RS	20	#include <crypto/b128ops.h>
	21	#include <crypto/gf128mul.h>
	22
	23	struct priv {
f1c131b4	24	struct crypto_skcipher *child;
f19f5111 RS	25	struct crypto_cipher *tweak;
	26	};
	27
f1c131b4 HX	28	struct xts_instance_ctx {
	29	struct crypto_skcipher_spawn spawn;
	30	char name[CRYPTO_MAX_ALG_NAME];
	31	};
	32
	33	struct rctx {
e55318c8	34	le128 t;
8083b1bf AB	35	struct scatterlist *tail;
8083b1bf AB	36	struct scatterlist sg[2];
f1c131b4 HX	37	struct skcipher_request subreq;
	38	};
	39
	40	static int setkey(struct crypto_skcipher parent, const u8 key,
f19f5111 RS	41	unsigned int keylen)
f19f5111 RS	42	{
f1c131b4 HX	43	struct priv *ctx = crypto_skcipher_ctx(parent);
	44	struct crypto_skcipher *child;
	45	struct crypto_cipher *tweak;
f19f5111 RS	46	int err;
f19f5111 RS	47
f1c131b4	48	err = xts_verify_key(parent, key, keylen);
28856a9e SM	49	if (err)
28856a9e SM	50	return err;
f19f5111	51
f1c131b4 HX	52	keylen /= 2;
f1c131b4 HX	53
25985edc	54	/* we need two cipher instances: one to compute the initial 'tweak'
f19f5111 RS	55	* by encrypting the IV (usually the 'plain' iv) and the other
	56	* one to encrypt and decrypt the data */
	57
	58	/* tweak cipher, uses Key2 i.e. the second half of key /
f1c131b4 HX	59	tweak = ctx->tweak;
	60	crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK);
	61	crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) &
f19f5111	62	CRYPTO_TFM_REQ_MASK);
f1c131b4	63	err = crypto_cipher_setkey(tweak, key + keylen, keylen);
f19f5111 RS	64	if (err)
	65	return err;
	66
f1c131b4	67	/* data cipher, uses Key1 i.e. the first half of key /
f19f5111	68	child = ctx->child;
f1c131b4 HX	69	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	70	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
	71	CRYPTO_TFM_REQ_MASK);
af5034e8	72	return crypto_skcipher_setkey(child, key, keylen);
f1c131b4	73	}
f19f5111	74
78105c7e OM	75	/*
	76	* We compute the tweak masks twice (both before and after the ECB encryption or
	77	* decryption) to avoid having to allocate a temporary buffer and/or make
	78	* mutliple calls to the 'ecb(..)' instance, which usually would be slower than
	79	* just doing the gf128mul_x_ble() calls again.
	80	*/
8083b1bf	81	static int xor_tweak(struct skcipher_request *req, bool second_pass, bool enc)
f1c131b4 HX	82	{
f1c131b4 HX	83	struct rctx *rctx = skcipher_request_ctx(req);
78105c7e	84	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
8083b1bf	85	const bool cts = (req->cryptlen % XTS_BLOCK_SIZE);
f1c131b4 HX	86	const int bs = XTS_BLOCK_SIZE;
f1c131b4 HX	87	struct skcipher_walk w;
78105c7e	88	le128 t = rctx->t;
f1c131b4	89	int err;
f19f5111	90
78105c7e OM	91	if (second_pass) {
	92	req = &rctx->subreq;
	93	/* set to our TFM to enforce correct alignment: */
	94	skcipher_request_set_tfm(req, tfm);
f1c131b4	95	}
78105c7e	96	err = skcipher_walk_virt(&w, req, false);
f19f5111	97
f1c131b4 HX	98	while (w.nbytes) {
f1c131b4 HX	99	unsigned int avail = w.nbytes;
e55318c8 OM	100	le128 *wsrc;
e55318c8 OM	101	le128 *wdst;
f19f5111	102
f1c131b4 HX	103	wsrc = w.src.virt.addr;
f1c131b4 HX	104	wdst = w.dst.virt.addr;
f19f5111	105
f1c131b4	106	do {
8083b1bf AB	107	if (unlikely(cts) &&
	108	w.total - w.nbytes + avail < 2 * XTS_BLOCK_SIZE) {
	109	if (!enc) {
	110	if (second_pass)
	111	rctx->t = t;
	112	gf128mul_x_ble(&t, &t);
	113	}
	114	le128_xor(wdst, &t, wsrc);
	115	if (enc && second_pass)
	116	gf128mul_x_ble(&rctx->t, &t);
	117	skcipher_walk_done(&w, avail - bs);
	118	return 0;
	119	}
	120
78105c7e OM	121	le128_xor(wdst++, &t, wsrc++);
78105c7e OM	122	gf128mul_x_ble(&t, &t);
f19f5111 RS	123	} while ((avail -= bs) >= bs);
f19f5111 RS	124
f1c131b4 HX	125	err = skcipher_walk_done(&w, avail);
	126	}
	127
f19f5111 RS	128	return err;
	129	}
	130
8083b1bf AB	131	static int xor_tweak_pre(struct skcipher_request *req, bool enc)
	132	{
	133	return xor_tweak(req, false, enc);
	134	}
	135
	136	static int xor_tweak_post(struct skcipher_request *req, bool enc)
	137	{
	138	return xor_tweak(req, true, enc);
	139	}
	140
	141	static void cts_done(struct crypto_async_request *areq, int err)
f19f5111	142	{
8083b1bf AB	143	struct skcipher_request *req = areq->data;
	144	le128 b;
	145
	146	if (!err) {
	147	struct rctx *rctx = skcipher_request_ctx(req);
	148
	149	scatterwalk_map_and_copy(&b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
	150	le128_xor(&b, &rctx->t, &b);
	151	scatterwalk_map_and_copy(&b, rctx->tail, 0, XTS_BLOCK_SIZE, 1);
	152	}
	153
	154	skcipher_request_complete(req, err);
	155	}
	156
	157	static int cts_final(struct skcipher_request *req,
	158	int (crypt)(struct skcipher_request req))
	159	{
	160	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
	161	int offset = req->cryptlen & ~(XTS_BLOCK_SIZE - 1);
	162	struct rctx *rctx = skcipher_request_ctx(req);
	163	struct skcipher_request *subreq = &rctx->subreq;
	164	int tail = req->cryptlen % XTS_BLOCK_SIZE;
	165	le128 b[2];
	166	int err;
	167
	168	rctx->tail = scatterwalk_ffwd(rctx->sg, req->dst,
	169	offset - XTS_BLOCK_SIZE);
	170
	171	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
	172	memcpy(b + 1, b, tail);
	173	scatterwalk_map_and_copy(b, req->src, offset, tail, 0);
	174
	175	le128_xor(b, &rctx->t, b);
	176
	177	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE + tail, 1);
	178
	179	skcipher_request_set_tfm(subreq, ctx->child);
	180	skcipher_request_set_callback(subreq, req->base.flags, cts_done, req);
	181	skcipher_request_set_crypt(subreq, rctx->tail, rctx->tail,
	182	XTS_BLOCK_SIZE, NULL);
	183
	184	err = crypt(subreq);
	185	if (err)
	186	return err;
	187
	188	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
	189	le128_xor(b, &rctx->t, b);
	190	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 1);
	191
	192	return 0;
f1c131b4 HX	193	}
f1c131b4 HX	194
8083b1bf	195	static void encrypt_done(struct crypto_async_request *areq, int err)
f1c131b4	196	{
8083b1bf AB	197	struct skcipher_request *req = areq->data;
	198
	199	if (!err) {
	200	struct rctx *rctx = skcipher_request_ctx(req);
	201
	202	rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
	203	err = xor_tweak_post(req, true);
	204
	205	if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
	206	err = cts_final(req, crypto_skcipher_encrypt);
	207	if (err == -EINPROGRESS)
	208	return;
	209	}
	210	}
	211
	212	skcipher_request_complete(req, err);
f1c131b4 HX	213	}
f1c131b4 HX	214
8083b1bf	215	static void decrypt_done(struct crypto_async_request *areq, int err)
f1c131b4 HX	216	{
f1c131b4 HX	217	struct skcipher_request *req = areq->data;
aa4a829b	218
44427c0f HX	219	if (!err) {
	220	struct rctx *rctx = skcipher_request_ctx(req);
	221
	222	rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
8083b1bf AB	223	err = xor_tweak_post(req, false);
	224
	225	if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
	226	err = cts_final(req, crypto_skcipher_decrypt);
	227	if (err == -EINPROGRESS)
	228	return;
	229	}
44427c0f	230	}
f1c131b4	231
f1c131b4 HX	232	skcipher_request_complete(req, err);
	233	}
	234
8083b1bf	235	static int init_crypt(struct skcipher_request *req, crypto_completion_t compl)
f1c131b4	236	{
78105c7e	237	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
f1c131b4	238	struct rctx *rctx = skcipher_request_ctx(req);
78105c7e	239	struct skcipher_request *subreq = &rctx->subreq;
f1c131b4	240
8083b1bf AB	241	if (req->cryptlen < XTS_BLOCK_SIZE)
	242	return -EINVAL;
	243
78105c7e	244	skcipher_request_set_tfm(subreq, ctx->child);
8083b1bf	245	skcipher_request_set_callback(subreq, req->base.flags, compl, req);
78105c7e	246	skcipher_request_set_crypt(subreq, req->dst, req->dst,
8083b1bf	247	req->cryptlen & ~(XTS_BLOCK_SIZE - 1), NULL);
f1c131b4	248
78105c7e OM	249	/* calculate first value of T */
78105c7e OM	250	crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
8083b1bf AB	251
8083b1bf AB	252	return 0;
f1c131b4 HX	253	}
f1c131b4 HX	254
78105c7e	255	static int encrypt(struct skcipher_request *req)
f1c131b4	256	{
78105c7e OM	257	struct rctx *rctx = skcipher_request_ctx(req);
78105c7e OM	258	struct skcipher_request *subreq = &rctx->subreq;
8083b1bf AB	259	int err;
	260
	261	err = init_crypt(req, encrypt_done) ?:
	262	xor_tweak_pre(req, true) ?:
	263	crypto_skcipher_encrypt(subreq) ?:
	264	xor_tweak_post(req, true);
f1c131b4	265
8083b1bf AB	266	if (err \|\| likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
	267	return err;
	268
	269	return cts_final(req, crypto_skcipher_encrypt);
f1c131b4 HX	270	}
	271
	272	static int decrypt(struct skcipher_request *req)
	273	{
78105c7e OM	274	struct rctx *rctx = skcipher_request_ctx(req);
78105c7e OM	275	struct skcipher_request *subreq = &rctx->subreq;
8083b1bf AB	276	int err;
	277
	278	err = init_crypt(req, decrypt_done) ?:
	279	xor_tweak_pre(req, false) ?:
	280	crypto_skcipher_decrypt(subreq) ?:
	281	xor_tweak_post(req, false);
	282
	283	if (err \|\| likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
	284	return err;
78105c7e	285
8083b1bf	286	return cts_final(req, crypto_skcipher_decrypt);
f19f5111 RS	287	}
f19f5111 RS	288
f1c131b4	289	static int init_tfm(struct crypto_skcipher *tfm)
f19f5111	290	{
f1c131b4 HX	291	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	292	struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
	293	struct priv *ctx = crypto_skcipher_ctx(tfm);
	294	struct crypto_skcipher *child;
	295	struct crypto_cipher *tweak;
f19f5111	296
f1c131b4 HX	297	child = crypto_spawn_skcipher(&ictx->spawn);
	298	if (IS_ERR(child))
	299	return PTR_ERR(child);
f19f5111	300
f1c131b4	301	ctx->child = child;
f19f5111	302
f1c131b4 HX	303	tweak = crypto_alloc_cipher(ictx->name, 0, 0);
	304	if (IS_ERR(tweak)) {
	305	crypto_free_skcipher(ctx->child);
	306	return PTR_ERR(tweak);
f19f5111 RS	307	}
f19f5111 RS	308
f1c131b4 HX	309	ctx->tweak = tweak;
	310
	311	crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
	312	sizeof(struct rctx));
f19f5111 RS	313
	314	return 0;
	315	}
	316
f1c131b4	317	static void exit_tfm(struct crypto_skcipher *tfm)
f19f5111	318	{
f1c131b4 HX	319	struct priv *ctx = crypto_skcipher_ctx(tfm);
	320
	321	crypto_free_skcipher(ctx->child);
f19f5111 RS	322	crypto_free_cipher(ctx->tweak);
	323	}
	324
1a263ae6	325	static void free_inst(struct skcipher_instance *inst)
f1c131b4 HX	326	{
	327	crypto_drop_skcipher(skcipher_instance_ctx(inst));
	328	kfree(inst);
	329	}
	330
	331	static int create(struct crypto_template tmpl, struct rtattr *tb)
f19f5111	332	{
f1c131b4 HX	333	struct skcipher_instance *inst;
	334	struct crypto_attr_type *algt;
	335	struct xts_instance_ctx *ctx;
	336	struct skcipher_alg *alg;
	337	const char *cipher_name;
89027579	338	u32 mask;
f19f5111 RS	339	int err;
f19f5111 RS	340
f1c131b4 HX	341	algt = crypto_get_attr_type(tb);
	342	if (IS_ERR(algt))
	343	return PTR_ERR(algt);
	344
	345	if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
	346	return -EINVAL;
	347
	348	cipher_name = crypto_attr_alg_name(tb[1]);
	349	if (IS_ERR(cipher_name))
	350	return PTR_ERR(cipher_name);
	351
	352	inst = kzalloc(sizeof(inst) + sizeof(ctx), GFP_KERNEL);
	353	if (!inst)
	354	return -ENOMEM;
	355
	356	ctx = skcipher_instance_ctx(inst);
	357
89027579 HX	358	mask = crypto_requires_off(algt->type, algt->mask,
	359	CRYPTO_ALG_NEED_FALLBACK \|
	360	CRYPTO_ALG_ASYNC);
	361
b9f76ddd EB	362	err = crypto_grab_skcipher(&ctx->spawn, skcipher_crypto_instance(inst),
b9f76ddd EB	363	cipher_name, 0, mask);
f1c131b4 HX	364	if (err == -ENOENT) {
	365	err = -ENAMETOOLONG;
	366	if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
	367	cipher_name) >= CRYPTO_MAX_ALG_NAME)
	368	goto err_free_inst;
	369
b9f76ddd EB	370	err = crypto_grab_skcipher(&ctx->spawn,
	371	skcipher_crypto_instance(inst),
	372	ctx->name, 0, mask);
f1c131b4 HX	373	}
f1c131b4 HX	374
f19f5111	375	if (err)
f1c131b4	376	goto err_free_inst;
f19f5111	377
f1c131b4	378	alg = crypto_skcipher_spawn_alg(&ctx->spawn);
f19f5111	379
f1c131b4 HX	380	err = -EINVAL;
f1c131b4 HX	381	if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
732e5409	382	goto err_free_inst;
f19f5111	383
f1c131b4	384	if (crypto_skcipher_alg_ivsize(alg))
732e5409	385	goto err_free_inst;
f19f5111	386
f1c131b4 HX	387	err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
	388	&alg->base);
	389	if (err)
732e5409	390	goto err_free_inst;
f19f5111	391
f1c131b4 HX	392	err = -EINVAL;
f1c131b4 HX	393	cipher_name = alg->base.cra_name;
f19f5111	394
f1c131b4 HX	395	/* Alas we screwed up the naming so we have to mangle the
	396	* cipher name.
	397	*/
	398	if (!strncmp(cipher_name, "ecb(", 4)) {
	399	unsigned len;
f19f5111	400
f1c131b4 HX	401	len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
f1c131b4 HX	402	if (len < 2 \|\| len >= sizeof(ctx->name))
732e5409	403	goto err_free_inst;
f19f5111	404
f1c131b4	405	if (ctx->name[len - 1] != ')')
732e5409	406	goto err_free_inst;
f19f5111	407
f1c131b4	408	ctx->name[len - 1] = 0;
f19f5111	409
f1c131b4	410	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
5125e4e8 CJ	411	"xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) {
5125e4e8 CJ	412	err = -ENAMETOOLONG;
732e5409	413	goto err_free_inst;
5125e4e8	414	}
f1c131b4	415	} else
732e5409	416	goto err_free_inst;
f19f5111	417
f1c131b4 HX	418	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
	419	inst->alg.base.cra_priority = alg->base.cra_priority;
	420	inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
	421	inst->alg.base.cra_alignmask = alg->base.cra_alignmask \|
	422	(__alignof__(u64) - 1);
	423
	424	inst->alg.ivsize = XTS_BLOCK_SIZE;
	425	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
	426	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;
	427
	428	inst->alg.base.cra_ctxsize = sizeof(struct priv);
	429
	430	inst->alg.init = init_tfm;
	431	inst->alg.exit = exit_tfm;
	432
	433	inst->alg.setkey = setkey;
	434	inst->alg.encrypt = encrypt;
	435	inst->alg.decrypt = decrypt;
	436
1a263ae6	437	inst->free = free_inst;
f1c131b4 HX	438
f1c131b4 HX	439	err = skcipher_register_instance(tmpl, inst);
732e5409	440	if (err) {
f1c131b4	441	err_free_inst:
1a263ae6	442	free_inst(inst);
732e5409 EB	443	}
732e5409 EB	444	return err;
f19f5111 RS	445	}
	446
	447	static struct crypto_template crypto_tmpl = {
	448	.name = "xts",
f1c131b4	449	.create = create,
f19f5111 RS	450	.module = THIS_MODULE,
	451	};
	452
	453	static int __init crypto_module_init(void)
	454	{
	455	return crypto_register_template(&crypto_tmpl);
	456	}
	457
	458	static void __exit crypto_module_exit(void)
	459	{
	460	crypto_unregister_template(&crypto_tmpl);
	461	}
	462
c4741b23	463	subsys_initcall(crypto_module_init);
f19f5111 RS	464	module_exit(crypto_module_exit);
	465
	466	MODULE_LICENSE("GPL");
	467	MODULE_DESCRIPTION("XTS block cipher mode");
4943ba16	468	MODULE_ALIAS_CRYPTO("xts");