1 files changed, 350 insertions, 238 deletions

diff --git a/crypto/xts.c b/crypto/xts.c
index ca1608f44cb5..3da8f5e053d6 100644
--- a/crypto/xts.c
+++ b/crypto/xts.c
@@ -1,19 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* 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 <rsnel@cube.dyndns.org>
  *
- * Based om ecb.c
+ * Based on ecb.c
  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
- *
- * 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/internal/cipher.h>
+#include <crypto/internal/skcipher.h>
+#include <crypto/scatterwalk.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -25,340 +21,456 @@
 #include <crypto/b128ops.h>
 #include <crypto/gf128mul.h>
 
-struct priv {
-	struct crypto_cipher *child;
+struct xts_tfm_ctx {
+	struct crypto_skcipher *child;
 	struct crypto_cipher *tweak;
 };
 
-static int setkey(struct crypto_tfm *parent, const u8 *key,
-		  unsigned int keylen)
+struct xts_instance_ctx {
+	struct crypto_skcipher_spawn spawn;
+	struct crypto_cipher_spawn tweak_spawn;
+};
+
+struct xts_request_ctx {
+	le128 t;
+	struct scatterlist *tail;
+	struct scatterlist sg[2];
+	struct skcipher_request subreq;
+};
+
+static int xts_setkey(struct crypto_skcipher *parent, const u8 *key,
+		      unsigned int keylen)
 {
-	struct priv *ctx = crypto_tfm_ctx(parent);
-	struct crypto_cipher *child = ctx->tweak;
-	u32 *flags = &parent->crt_flags;
+	struct xts_tfm_ctx *ctx = crypto_skcipher_ctx(parent);
+	struct crypto_skcipher *child;
+	struct crypto_cipher *tweak;
 	int err;
 
-	/* key consists of keys of equal size concatenated, therefore
-	 * the length must be even */
-	if (keylen % 2) {
-		/* tell the user why there was an error */
-		*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
-		return -EINVAL;
-	}
+	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 */
-	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
-	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
+	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(child, key + keylen/2, keylen/2);
+	err = crypto_cipher_setkey(tweak, key + keylen, keylen);
 	if (err)
 		return err;
 
-	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
-				     CRYPTO_TFM_RES_MASK);
-
+	/* 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);
+}
 
-	/* data cipher, uses Key1 i.e. the first half of *key */
-	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
-	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
-				       CRYPTO_TFM_REQ_MASK);
-	err = crypto_cipher_setkey(child, key, keylen/2);
-	if (err)
-		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 xts_xor_tweak(struct skcipher_request *req, bool second_pass,
+			 bool enc)
+{
+	struct xts_request_ctx *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;
 
-	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
-				     CRYPTO_TFM_RES_MASK);
+	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);
 
-	return 0;
+	while (w.nbytes) {
+		unsigned int avail = w.nbytes;
+		const 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;
 }
 
-struct sinfo {
-	be128 *t;
-	struct crypto_tfm *tfm;
-	void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
-};
+static int xts_xor_tweak_pre(struct skcipher_request *req, bool enc)
+{
+	return xts_xor_tweak(req, false, enc);
+}
 
-static inline void xts_round(struct sinfo *s, void *dst, const void *src)
+static int xts_xor_tweak_post(struct skcipher_request *req, bool enc)
 {
-	be128_xor(dst, s->t, src);		/* PP <- T xor P */
-	s->fn(s->tfm, dst, dst);		/* CC <- E(Key1,PP) */
-	be128_xor(dst, dst, s->t);		/* C <- T xor CC */
+	return xts_xor_tweak(req, true, enc);
 }
 
-static int crypt(struct blkcipher_desc *d,
-		 struct blkcipher_walk *w, struct priv *ctx,
-		 void (*tw)(struct crypto_tfm *, u8 *, const u8 *),
-		 void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
+static void xts_cts_done(void *data, int err)
 {
-	int err;
-	unsigned int avail;
-	const int bs = XTS_BLOCK_SIZE;
-	struct sinfo s = {
-		.tfm = crypto_cipher_tfm(ctx->child),
-		.fn = fn
-	};
-	u8 *wsrc;
-	u8 *wdst;
-
-	err = blkcipher_walk_virt(d, w);
-	if (!w->nbytes)
-		return err;
+	struct skcipher_request *req = data;
+	le128 b;
 
-	s.t = (be128 *)w->iv;
-	avail = w->nbytes;
+	if (!err) {
+		struct xts_request_ctx *rctx = skcipher_request_ctx(req);
 
-	wsrc = w->src.virt.addr;
-	wdst = w->dst.virt.addr;
+		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);
+	}
 
-	/* calculate first value of T */
-	tw(crypto_cipher_tfm(ctx->tweak), w->iv, w->iv);
+	skcipher_request_complete(req, err);
+}
 
-	goto first;
+static int xts_cts_final(struct skcipher_request *req,
+			 int (*crypt)(struct skcipher_request *req))
+{
+	const struct xts_tfm_ctx *ctx =
+		crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
+	int offset = req->cryptlen & ~(XTS_BLOCK_SIZE - 1);
+	struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->subreq;
+	int tail = req->cryptlen % XTS_BLOCK_SIZE;
+	le128 b[2];
+	int err;
 
-	for (;;) {
-		do {
-			gf128mul_x_ble(s.t, s.t);
+	rctx->tail = scatterwalk_ffwd(rctx->sg, req->dst,
+				      offset - XTS_BLOCK_SIZE);
 
-first:
-			xts_round(&s, wdst, wsrc);
+	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
+	b[1] = b[0];
+	scatterwalk_map_and_copy(b, req->src, offset, tail, 0);
 
-			wsrc += bs;
-			wdst += bs;
-		} while ((avail -= bs) >= bs);
+	le128_xor(b, &rctx->t, b);
 
-		err = blkcipher_walk_done(d, w, avail);
-		if (!w->nbytes)
-			break;
+	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE + tail, 1);
 
-		avail = w->nbytes;
+	skcipher_request_set_tfm(subreq, ctx->child);
+	skcipher_request_set_callback(subreq, req->base.flags, xts_cts_done,
+				      req);
+	skcipher_request_set_crypt(subreq, rctx->tail, rctx->tail,
+				   XTS_BLOCK_SIZE, NULL);
 
-		wsrc = w->src.virt.addr;
-		wdst = w->dst.virt.addr;
-	}
+	err = crypt(subreq);
+	if (err)
+		return 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 int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
-		   struct scatterlist *src, unsigned int nbytes)
+static void xts_encrypt_done(void *data, int err)
 {
-	struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
-	struct blkcipher_walk w;
+	struct skcipher_request *req = data;
 
-	blkcipher_walk_init(&w, dst, src, nbytes);
-	return crypt(desc, &w, ctx, crypto_cipher_alg(ctx->tweak)->cia_encrypt,
-		     crypto_cipher_alg(ctx->child)->cia_encrypt);
-}
+	if (!err) {
+		struct xts_request_ctx *rctx = skcipher_request_ctx(req);
 
-static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
-		   struct scatterlist *src, unsigned int nbytes)
-{
-	struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
-	struct blkcipher_walk w;
+		rctx->subreq.base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
+		err = xts_xor_tweak_post(req, true);
+
+		if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
+			err = xts_cts_final(req, crypto_skcipher_encrypt);
+			if (err == -EINPROGRESS || err == -EBUSY)
+				return;
+		}
+	}
 
-	blkcipher_walk_init(&w, dst, src, nbytes);
-	return crypt(desc, &w, ctx, crypto_cipher_alg(ctx->tweak)->cia_encrypt,
-		     crypto_cipher_alg(ctx->child)->cia_decrypt);
+	skcipher_request_complete(req, err);
 }
 
-int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst,
-	      struct scatterlist *ssrc, unsigned int nbytes,
-	      struct xts_crypt_req *req)
+static void xts_decrypt_done(void *data, int err)
 {
-	const unsigned int bsize = XTS_BLOCK_SIZE;
-	const unsigned int max_blks = req->tbuflen / bsize;
-	struct blkcipher_walk walk;
-	unsigned int nblocks;
-	be128 *src, *dst, *t;
-	be128 *t_buf = req->tbuf;
-	int err, i;
+	struct skcipher_request *req = data;
 
-	BUG_ON(max_blks < 1);
+	if (!err) {
+		struct xts_request_ctx *rctx = skcipher_request_ctx(req);
 
-	blkcipher_walk_init(&walk, sdst, ssrc, nbytes);
+		rctx->subreq.base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
+		err = xts_xor_tweak_post(req, false);
 
-	err = blkcipher_walk_virt(desc, &walk);
-	nbytes = walk.nbytes;
-	if (!nbytes)
-		return err;
+		if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
+			err = xts_cts_final(req, crypto_skcipher_decrypt);
+			if (err == -EINPROGRESS || err == -EBUSY)
+				return;
+		}
+	}
 
-	nblocks = min(nbytes / bsize, max_blks);
-	src = (be128 *)walk.src.virt.addr;
-	dst = (be128 *)walk.dst.virt.addr;
+	skcipher_request_complete(req, err);
+}
 
-	/* calculate first value of T */
-	req->tweak_fn(req->tweak_ctx, (u8 *)&t_buf[0], walk.iv);
+static int xts_init_crypt(struct skcipher_request *req,
+			  crypto_completion_t compl)
+{
+	const struct xts_tfm_ctx *ctx =
+		crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
+	struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->subreq;
 
-	i = 0;
-	goto first;
+	if (req->cryptlen < XTS_BLOCK_SIZE)
+		return -EINVAL;
 
-	for (;;) {
-		do {
-			for (i = 0; i < nblocks; i++) {
-				gf128mul_x_ble(&t_buf[i], t);
-first:
-				t = &t_buf[i];
+	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);
 
-				/* PP <- T xor P */
-				be128_xor(dst + i, t, src + i);
-			}
+	/* calculate first value of T */
+	crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
 
-			/* CC <- E(Key2,PP) */
-			req->crypt_fn(req->crypt_ctx, (u8 *)dst,
-				      nblocks * bsize);
+	return 0;
+}
 
-			/* C <- T xor CC */
-			for (i = 0; i < nblocks; i++)
-				be128_xor(dst + i, dst + i, &t_buf[i]);
+static int xts_encrypt(struct skcipher_request *req)
+{
+	struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->subreq;
+	int err;
 
-			src += nblocks;
-			dst += nblocks;
-			nbytes -= nblocks * bsize;
-			nblocks = min(nbytes / bsize, max_blks);
-		} while (nblocks > 0);
+	err = xts_init_crypt(req, xts_encrypt_done) ?:
+	      xts_xor_tweak_pre(req, true) ?:
+	      crypto_skcipher_encrypt(subreq) ?:
+	      xts_xor_tweak_post(req, true);
 
-		*(be128 *)walk.iv = *t;
+	if (err || likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
+		return err;
 
-		err = blkcipher_walk_done(desc, &walk, nbytes);
-		nbytes = walk.nbytes;
-		if (!nbytes)
-			break;
+	return xts_cts_final(req, crypto_skcipher_encrypt);
+}
 
-		nblocks = min(nbytes / bsize, max_blks);
-		src = (be128 *)walk.src.virt.addr;
-		dst = (be128 *)walk.dst.virt.addr;
-	}
+static int xts_decrypt(struct skcipher_request *req)
+{
+	struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->subreq;
+	int err;
 
-	return err;
+	err = xts_init_crypt(req, xts_decrypt_done) ?:
+	      xts_xor_tweak_pre(req, false) ?:
+	      crypto_skcipher_decrypt(subreq) ?:
+	      xts_xor_tweak_post(req, false);
+
+	if (err || likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
+		return err;
+
+	return xts_cts_final(req, crypto_skcipher_decrypt);
 }
-EXPORT_SYMBOL_GPL(xts_crypt);
 
-static int init_tfm(struct crypto_tfm *tfm)
+static int xts_init_tfm(struct crypto_skcipher *tfm)
 {
-	struct crypto_cipher *cipher;
-	struct crypto_instance *inst = (void *)tfm->__crt_alg;
-	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
-	struct priv *ctx = crypto_tfm_ctx(tfm);
-	u32 *flags = &tfm->crt_flags;
-
-	cipher = crypto_spawn_cipher(spawn);
-	if (IS_ERR(cipher))
-		return PTR_ERR(cipher);
-
-	if (crypto_cipher_blocksize(cipher) != XTS_BLOCK_SIZE) {
-		*flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
-		crypto_free_cipher(cipher);
-		return -EINVAL;
-	}
+	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
+	struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
+	struct xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_skcipher *child;
+	struct crypto_cipher *tweak;
 
-	ctx->child = cipher;
+	child = crypto_spawn_skcipher(&ictx->spawn);
+	if (IS_ERR(child))
+		return PTR_ERR(child);
 
-	cipher = crypto_spawn_cipher(spawn);
-	if (IS_ERR(cipher)) {
-		crypto_free_cipher(ctx->child);
-		return PTR_ERR(cipher);
-	}
+	ctx->child = child;
 
-	/* this check isn't really needed, leave it here just in case */
-	if (crypto_cipher_blocksize(cipher) != XTS_BLOCK_SIZE) {
-		crypto_free_cipher(cipher);
-		crypto_free_cipher(ctx->child);
-		*flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
-		return -EINVAL;
+	tweak = crypto_spawn_cipher(&ictx->tweak_spawn);
+	if (IS_ERR(tweak)) {
+		crypto_free_skcipher(ctx->child);
+		return PTR_ERR(tweak);
 	}
 
-	ctx->tweak = cipher;
+	ctx->tweak = tweak;
+
+	crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
+					 sizeof(struct xts_request_ctx));
 
 	return 0;
 }
 
-static void exit_tfm(struct crypto_tfm *tfm)
+static void xts_exit_tfm(struct crypto_skcipher *tfm)
 {
-	struct priv *ctx = crypto_tfm_ctx(tfm);
-	crypto_free_cipher(ctx->child);
+	struct xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+	crypto_free_skcipher(ctx->child);
 	crypto_free_cipher(ctx->tweak);
 }
 
-static struct crypto_instance *alloc(struct rtattr **tb)
+static void xts_free_instance(struct skcipher_instance *inst)
 {
-	struct crypto_instance *inst;
-	struct crypto_alg *alg;
+	struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
+
+	crypto_drop_skcipher(&ictx->spawn);
+	crypto_drop_cipher(&ictx->tweak_spawn);
+	kfree(inst);
+}
+
+static int xts_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+	struct skcipher_alg_common *alg;
+	char name[CRYPTO_MAX_ALG_NAME];
+	struct skcipher_instance *inst;
+	struct xts_instance_ctx *ctx;
+	const char *cipher_name;
+	u32 mask;
 	int err;
 
-	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
+	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);
 	if (err)
-		return ERR_PTR(err);
+		return err;
+
+	cipher_name = crypto_attr_alg_name(tb[1]);
+	if (IS_ERR(cipher_name))
+		return PTR_ERR(cipher_name);
 
-	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
-				  CRYPTO_ALG_TYPE_MASK);
-	if (IS_ERR(alg))
-		return ERR_CAST(alg);
+	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
+	if (!inst)
+		return -ENOMEM;
 
-	inst = crypto_alloc_instance("xts", alg);
-	if (IS_ERR(inst))
-		goto out_put_alg;
+	ctx = skcipher_instance_ctx(inst);
 
-	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
-	inst->alg.cra_priority = alg->cra_priority;
-	inst->alg.cra_blocksize = alg->cra_blocksize;
+	err = crypto_grab_skcipher(&ctx->spawn, skcipher_crypto_instance(inst),
+				   cipher_name, 0, mask);
+	if (err == -ENOENT && memcmp(cipher_name, "ecb(", 4)) {
+		err = -ENAMETOOLONG;
+		if (snprintf(name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
+			     cipher_name) >= CRYPTO_MAX_ALG_NAME)
+			goto err_free_inst;
 
-	if (alg->cra_alignmask < 7)
-		inst->alg.cra_alignmask = 7;
-	else
-		inst->alg.cra_alignmask = alg->cra_alignmask;
+		err = crypto_grab_skcipher(&ctx->spawn,
+					   skcipher_crypto_instance(inst),
+					   name, 0, mask);
+	}
 
-	inst->alg.cra_type = &crypto_blkcipher_type;
+	if (err)
+		goto err_free_inst;
 
-	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
-	inst->alg.cra_blkcipher.min_keysize =
-		2 * alg->cra_cipher.cia_min_keysize;
-	inst->alg.cra_blkcipher.max_keysize =
-		2 * alg->cra_cipher.cia_max_keysize;
+	alg = crypto_spawn_skcipher_alg_common(&ctx->spawn);
 
-	inst->alg.cra_ctxsize = sizeof(struct priv);
+	err = -EINVAL;
+	if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
+		goto err_free_inst;
 
-	inst->alg.cra_init = init_tfm;
-	inst->alg.cra_exit = exit_tfm;
+	if (alg->ivsize)
+		goto err_free_inst;
 
-	inst->alg.cra_blkcipher.setkey = setkey;
-	inst->alg.cra_blkcipher.encrypt = encrypt;
-	inst->alg.cra_blkcipher.decrypt = decrypt;
+	err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
+				  &alg->base);
+	if (err)
+		goto err_free_inst;
 
-out_put_alg:
-	crypto_mod_put(alg);
-	return inst;
-}
+	err = -EINVAL;
+	cipher_name = alg->base.cra_name;
 
-static void free(struct crypto_instance *inst)
-{
-	crypto_drop_spawn(crypto_instance_ctx(inst));
-	kfree(inst);
+	/* Alas we screwed up the naming so we have to mangle the
+	 * cipher name.
+	 */
+	if (!memcmp(cipher_name, "ecb(", 4)) {
+		int len;
+
+		len = strscpy(name, cipher_name + 4, sizeof(name));
+		if (len < 2)
+			goto err_free_inst;
+
+		if (name[len - 1] != ')')
+			goto err_free_inst;
+
+		name[len - 1] = 0;
+
+		if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
+			     "xts(%s)", name) >= CRYPTO_MAX_ALG_NAME) {
+			err = -ENAMETOOLONG;
+			goto err_free_inst;
+		}
+	} else
+		goto err_free_inst;
+
+	err = crypto_grab_cipher(&ctx->tweak_spawn,
+				 skcipher_crypto_instance(inst), name, 0, mask);
+	if (err)
+		goto err_free_inst;
+
+	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 = alg->min_keysize * 2;
+	inst->alg.max_keysize = alg->max_keysize * 2;
+
+	inst->alg.base.cra_ctxsize = sizeof(struct xts_tfm_ctx);
+
+	inst->alg.init = xts_init_tfm;
+	inst->alg.exit = xts_exit_tfm;
+
+	inst->alg.setkey = xts_setkey;
+	inst->alg.encrypt = xts_encrypt;
+	inst->alg.decrypt = xts_decrypt;
+
+	inst->free = xts_free_instance;
+
+	err = skcipher_register_instance(tmpl, inst);
+	if (err) {
+err_free_inst:
+		xts_free_instance(inst);
+	}
+	return err;
 }
 
-static struct crypto_template crypto_tmpl = {
+static struct crypto_template xts_tmpl = {
 	.name = "xts",
-	.alloc = alloc,
-	.free = free,
+	.create = xts_create,
 	.module = THIS_MODULE,
 };
 
-static int __init crypto_module_init(void)
+static int __init xts_module_init(void)
 {
-	return crypto_register_template(&crypto_tmpl);
+	return crypto_register_template(&xts_tmpl);
 }
 
-static void __exit crypto_module_exit(void)
+static void __exit xts_module_exit(void)
 {
-	crypto_unregister_template(&crypto_tmpl);
+	crypto_unregister_template(&xts_tmpl);
 }
 
-module_init(crypto_module_init);
-module_exit(crypto_module_exit);
+module_init(xts_module_init);
+module_exit(xts_module_exit);
 
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("XTS block cipher mode");
+MODULE_ALIAS_CRYPTO("xts");
+MODULE_IMPORT_NS("CRYPTO_INTERNAL");
+MODULE_SOFTDEP("pre: ecb");