[linux-2.6-block.git] / crypto / lrw.c

/* LRW: as defined by Cyril Guyot in
 *	http://grouper.ieee.org/groups/1619/email/pdf00017.pdf
 *
 * Copyright (c) 2006 Rik Snel <rsnel@cube.dyndns.org>
 *
 * 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.
 */
/* This implementation is checked against the test vectors in the above
 * document and by a test vector provided by Ken Buchanan at
 * http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html
 *
 * The test vectors are included in the testing module tcrypt.[ch] */

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

#define LRW_BLOCK_SIZE 16

struct priv {
	struct crypto_skcipher *child;

	/*
	 * optimizes multiplying a random (non incrementing, as at the
	 * start of a new sector) value with key2, we could also have
	 * used 4k optimization tables or no optimization at all. In the
	 * latter case we would have to store key2 here
	 */
	struct gf128mul_64k *table;

	/*
	 * stores:
	 *  key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 },
	 *  key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 }
	 *  key2*{ 0,0,...1,1,1,1,1 }, etc
	 * needed for optimized multiplication of incrementing values
	 * with key2
	 */
	be128 mulinc[128];
};

struct rctx {
	be128 t;
	struct skcipher_request subreq;
};

static inline void setbit128_bbe(void *b, int bit)
{
	__set_bit(bit ^ (0x80 -
#ifdef __BIG_ENDIAN
			 BITS_PER_LONG
#else
			 BITS_PER_BYTE
#endif
			), b);
}

static int setkey(struct crypto_skcipher *parent, const u8 *key,
		  unsigned int keylen)
{
	struct priv *ctx = crypto_skcipher_ctx(parent);
	struct crypto_skcipher *child = ctx->child;
	int err, bsize = LRW_BLOCK_SIZE;
	const u8 *tweak = key + keylen - bsize;
	be128 tmp = { 0 };
	int i;

	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 - bsize);
	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
					  CRYPTO_TFM_RES_MASK);
	if (err)
		return err;

	if (ctx->table)
		gf128mul_free_64k(ctx->table);

	/* initialize multiplication table for Key2 */
	ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
	if (!ctx->table)
		return -ENOMEM;

	/* initialize optimization table */
	for (i = 0; i < 128; i++) {
		setbit128_bbe(&tmp, i);
		ctx->mulinc[i] = tmp;
		gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
	}

	return 0;
}

/*
 * Returns the number of trailing '1' bits in the words of the counter, which is
 * represented by 4 32-bit words, arranged from least to most significant.
 * At the same time, increments the counter by one.
 *
 * For example:
 *
 * u32 counter[4] = { 0xFFFFFFFF, 0x1, 0x0, 0x0 };
 * int i = next_index(&counter);
 * // i == 33, counter == { 0x0, 0x2, 0x0, 0x0 }
 */
static int next_index(u32 *counter)
{
	int i, res = 0;

	for (i = 0; i < 4; i++) {
		if (counter[i] + 1 != 0)
			return res + ffz(counter[i]++);

		counter[i] = 0;
		res += 32;
	}

	/*
	 * If we get here, then x == 128 and we are incrementing the counter
	 * from all ones to all zeros. This means we must return index 127, i.e.
	 * the one corresponding to key2*{ 1,...,1 }.
	 */
	return 127;
}

/*
 * 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 next_index() calls again.
 */
static int xor_tweak(struct skcipher_request *req, bool second_pass)
{
	const int bs = LRW_BLOCK_SIZE;
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct priv *ctx = crypto_skcipher_ctx(tfm);
	struct rctx *rctx = skcipher_request_ctx(req);
	be128 t = rctx->t;
	struct skcipher_walk w;
	__be32 *iv;
	u32 counter[4];
	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);
	iv = (__be32 *)w.iv;

	counter[0] = be32_to_cpu(iv[3]);
	counter[1] = be32_to_cpu(iv[2]);
	counter[2] = be32_to_cpu(iv[1]);
	counter[3] = be32_to_cpu(iv[0]);

	while (w.nbytes) {
		unsigned int avail = w.nbytes;
		be128 *wsrc;
		be128 *wdst;

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

		do {
			be128_xor(wdst++, &t, wsrc++);

			/* T <- I*Key2, using the optimization
			 * discussed in the specification */
			be128_xor(&t, &t, &ctx->mulinc[next_index(counter)]);
		} while ((avail -= bs) >= bs);

		if (second_pass && w.nbytes == w.total) {
			iv[0] = cpu_to_be32(counter[3]);
			iv[1] = cpu_to_be32(counter[2]);
			iv[2] = cpu_to_be32(counter[1]);
			iv[3] = cpu_to_be32(counter[0]);
		}

		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) {
		struct rctx *rctx = skcipher_request_ctx(req);

		rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
		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);
	/* pass req->iv as IV (will be used by xor_tweak, ECB will ignore it) */
	skcipher_request_set_crypt(subreq, req->dst, req->dst,
				   req->cryptlen, req->iv);

	/* calculate first value of T */
	memcpy(&rctx->t, req->iv, sizeof(rctx->t));

	/* T <- I*Key2 */
	gf128mul_64k_bbe(&rctx->t, ctx->table);
}

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 crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
	struct priv *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_skcipher *cipher;

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

	ctx->child = cipher;

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

	return 0;
}

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

	if (ctx->table)
		gf128mul_free_64k(ctx->table);
	crypto_free_skcipher(ctx->child);
}

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 crypto_skcipher_spawn *spawn;
	struct skcipher_instance *inst;
	struct crypto_attr_type *algt;
	struct skcipher_alg *alg;
	const char *cipher_name;
	char ecb_name[CRYPTO_MAX_ALG_NAME];
	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;

	spawn = skcipher_instance_ctx(inst);

	crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
	err = crypto_grab_skcipher(spawn, cipher_name, 0,
				   crypto_requires_sync(algt->type,
							algt->mask));
	if (err == -ENOENT) {
		err = -ENAMETOOLONG;
		if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
			     cipher_name) >= CRYPTO_MAX_ALG_NAME)
			goto err_free_inst;

		err = crypto_grab_skcipher(spawn, ecb_name, 0,
					   crypto_requires_sync(algt->type,
								algt->mask));
	}

	if (err)
		goto err_free_inst;

	alg = crypto_skcipher_spawn_alg(spawn);

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

	if (crypto_skcipher_alg_ivsize(alg))
		goto err_drop_spawn;

	err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
				  &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(ecb_name, cipher_name + 4, sizeof(ecb_name));
		if (len < 2 || len >= sizeof(ecb_name))
			goto err_drop_spawn;

		if (ecb_name[len - 1] != ')')
			goto err_drop_spawn;

		ecb_name[len - 1] = 0;

		if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
			     "lrw(%s)", ecb_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 = LRW_BLOCK_SIZE;
	inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
				       (__alignof__(__be32) - 1);

	inst->alg.ivsize = LRW_BLOCK_SIZE;
	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
				LRW_BLOCK_SIZE;
	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
				LRW_BLOCK_SIZE;

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

static struct crypto_template crypto_tmpl = {
	.name = "lrw",
	.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("LRW block cipher mode");
MODULE_ALIAS_CRYPTO("lrw");
Commit	Line	Data
64470f1b RS	1	/* LRW: as defined by Cyril Guyot in
	2	* http://grouper.ieee.org/groups/1619/email/pdf00017.pdf
	3	*
	4	* Copyright (c) 2006 Rik Snel <rsnel@cube.dyndns.org>
	5	*
6c2205b8	6	* Based on ecb.c
64470f1b RS	7	* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
	8	*
	9	* This program is free software; you can redistribute it and/or modify it
	10	* under the terms of the GNU General Public License as published by the Free
	11	* Software Foundation; either version 2 of the License, or (at your option)
	12	* any later version.
	13	*/
	14	/* This implementation is checked against the test vectors in the above
	15	* document and by a test vector provided by Ken Buchanan at
	16	* http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html
	17	*
	18	* The test vectors are included in the testing module tcrypt.[ch] */
6c2205b8	19
700cb3f5 HX	20	#include <crypto/internal/skcipher.h>
700cb3f5 HX	21	#include <crypto/scatterwalk.h>
64470f1b RS	22	#include <linux/err.h>
	23	#include <linux/init.h>
	24	#include <linux/kernel.h>
	25	#include <linux/module.h>
	26	#include <linux/scatterlist.h>
	27	#include <linux/slab.h>
	28
	29	#include <crypto/b128ops.h>
	30	#include <crypto/gf128mul.h>
64470f1b	31
217afccf EB	32	#define LRW_BLOCK_SIZE 16
217afccf EB	33
171c0204	34	struct priv {
700cb3f5	35	struct crypto_skcipher *child;
217afccf EB	36
	37	/*
	38	* optimizes multiplying a random (non incrementing, as at the
	39	* start of a new sector) value with key2, we could also have
	40	* used 4k optimization tables or no optimization at all. In the
	41	* latter case we would have to store key2 here
	42	*/
	43	struct gf128mul_64k *table;
	44
	45	/*
	46	* stores:
	47	* key2{ 0,0,...0,0,0,0,1 }, key2{ 0,0,...0,0,0,1,1 },
	48	* key2{ 0,0,...0,0,1,1,1 }, key2{ 0,0,...0,1,1,1,1 }
	49	* key2*{ 0,0,...1,1,1,1,1 }, etc
	50	* needed for optimized multiplication of incrementing values
	51	* with key2
	52	*/
	53	be128 mulinc[128];
171c0204 JK	54	};
171c0204 JK	55
700cb3f5	56	struct rctx {
700cb3f5	57	be128 t;
700cb3f5 HX	58	struct skcipher_request subreq;
	59	};
	60
64470f1b RS	61	static inline void setbit128_bbe(void *b, int bit)
64470f1b RS	62	{
8eb2dfac HX	63	__set_bit(bit ^ (0x80 -
	64	#ifdef __BIG_ENDIAN
	65	BITS_PER_LONG
	66	#else
	67	BITS_PER_BYTE
	68	#endif
	69	), b);
64470f1b RS	70	}
64470f1b RS	71
217afccf EB	72	static int setkey(struct crypto_skcipher parent, const u8 key,
217afccf EB	73	unsigned int keylen)
64470f1b	74	{
217afccf EB	75	struct priv *ctx = crypto_skcipher_ctx(parent);
	76	struct crypto_skcipher *child = ctx->child;
	77	int err, bsize = LRW_BLOCK_SIZE;
	78	const u8 *tweak = key + keylen - bsize;
64470f1b	79	be128 tmp = { 0 };
171c0204	80	int i;
64470f1b	81
217afccf EB	82	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	83	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
	84	CRYPTO_TFM_REQ_MASK);
	85	err = crypto_skcipher_setkey(child, key, keylen - bsize);
	86	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
	87	CRYPTO_TFM_RES_MASK);
	88	if (err)
	89	return err;
	90
64470f1b RS	91	if (ctx->table)
	92	gf128mul_free_64k(ctx->table);
	93
	94	/* initialize multiplication table for Key2 */
171c0204	95	ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
64470f1b RS	96	if (!ctx->table)
	97	return -ENOMEM;
	98
	99	/* initialize optimization table */
	100	for (i = 0; i < 128; i++) {
	101	setbit128_bbe(&tmp, i);
	102	ctx->mulinc[i] = tmp;
	103	gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
	104	}
	105
	106	return 0;
	107	}
171c0204	108
c778f96b OM	109	/*
	110	* Returns the number of trailing '1' bits in the words of the counter, which is
	111	* represented by 4 32-bit words, arranged from least to most significant.
	112	* At the same time, increments the counter by one.
	113	*
	114	* For example:
	115	*
	116	* u32 counter[4] = { 0xFFFFFFFF, 0x1, 0x0, 0x0 };
	117	* int i = next_index(&counter);
	118	* // i == 33, counter == { 0x0, 0x2, 0x0, 0x0 }
	119	*/
	120	static int next_index(u32 *counter)
64470f1b	121	{
c778f96b	122	int i, res = 0;
64470f1b	123
c778f96b	124	for (i = 0; i < 4; i++) {
fd27b571 AB	125	if (counter[i] + 1 != 0)
	126	return res + ffz(counter[i]++);
	127
c778f96b OM	128	counter[i] = 0;
c778f96b OM	129	res += 32;
64470f1b RS	130	}
64470f1b RS	131
fbe1a850 OM	132	/*
	133	* If we get here, then x == 128 and we are incrementing the counter
	134	* from all ones to all zeros. This means we must return index 127, i.e.
	135	* the one corresponding to key2*{ 1,...,1 }.
	136	*/
	137	return 127;
64470f1b RS	138	}
64470f1b RS	139
ac3c8f36 OM	140	/*
	141	* We compute the tweak masks twice (both before and after the ECB encryption or
	142	* decryption) to avoid having to allocate a temporary buffer and/or make
	143	* mutliple calls to the 'ecb(..)' instance, which usually would be slower than
	144	* just doing the next_index() calls again.
	145	*/
	146	static int xor_tweak(struct skcipher_request *req, bool second_pass)
64470f1b	147	{
700cb3f5	148	const int bs = LRW_BLOCK_SIZE;
700cb3f5	149	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
700cb3f5	150	struct priv *ctx = crypto_skcipher_ctx(tfm);
ac3c8f36 OM	151	struct rctx *rctx = skcipher_request_ctx(req);
ac3c8f36 OM	152	be128 t = rctx->t;
700cb3f5	153	struct skcipher_walk w;
c778f96b OM	154	__be32 *iv;
c778f96b OM	155	u32 counter[4];
700cb3f5	156	int err;
64470f1b	157
ac3c8f36 OM	158	if (second_pass) {
	159	req = &rctx->subreq;
	160	/* set to our TFM to enforce correct alignment: */
	161	skcipher_request_set_tfm(req, tfm);
	162	}
64470f1b	163
ac3c8f36	164	err = skcipher_walk_virt(&w, req, false);
c778f96b OM	165	iv = (__be32 *)w.iv;
	166
	167	counter[0] = be32_to_cpu(iv[3]);
	168	counter[1] = be32_to_cpu(iv[2]);
	169	counter[2] = be32_to_cpu(iv[1]);
	170	counter[3] = be32_to_cpu(iv[0]);
64470f1b	171
700cb3f5 HX	172	while (w.nbytes) {
	173	unsigned int avail = w.nbytes;
	174	be128 *wsrc;
	175	be128 *wdst;
	176
	177	wsrc = w.src.virt.addr;
	178	wdst = w.dst.virt.addr;
64470f1b	179
64470f1b	180	do {
ac3c8f36	181	be128_xor(wdst++, &t, wsrc++);
700cb3f5	182
64470f1b RS	183	/* T <- I*Key2, using the optimization
64470f1b RS	184	* discussed in the specification */
ac3c8f36	185	be128_xor(&t, &t, &ctx->mulinc[next_index(counter)]);
700cb3f5	186	} while ((avail -= bs) >= bs);
64470f1b	187
ac3c8f36	188	if (second_pass && w.nbytes == w.total) {
c778f96b OM	189	iv[0] = cpu_to_be32(counter[3]);
	190	iv[1] = cpu_to_be32(counter[2]);
	191	iv[2] = cpu_to_be32(counter[1]);
	192	iv[3] = cpu_to_be32(counter[0]);
	193	}
	194
700cb3f5 HX	195	err = skcipher_walk_done(&w, avail);
700cb3f5 HX	196	}
64470f1b	197
700cb3f5 HX	198	return err;
	199	}
	200
ac3c8f36	201	static int xor_tweak_pre(struct skcipher_request *req)
700cb3f5	202	{
ac3c8f36	203	return xor_tweak(req, false);
700cb3f5 HX	204	}
700cb3f5 HX	205
ac3c8f36	206	static int xor_tweak_post(struct skcipher_request *req)
700cb3f5	207	{
ac3c8f36	208	return xor_tweak(req, true);
64470f1b RS	209	}
64470f1b RS	210
ac3c8f36	211	static void crypt_done(struct crypto_async_request *areq, int err)
700cb3f5 HX	212	{
700cb3f5 HX	213	struct skcipher_request *req = areq->data;
700cb3f5	214
b257b48c HX	215	if (!err) {
	216	struct rctx *rctx = skcipher_request_ctx(req);
	217
	218	rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
ac3c8f36	219	err = xor_tweak_post(req);
b257b48c	220	}
700cb3f5 HX	221
	222	skcipher_request_complete(req, err);
	223	}
	224
ac3c8f36	225	static void init_crypt(struct skcipher_request *req)
64470f1b	226	{
ac3c8f36	227	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
700cb3f5	228	struct rctx *rctx = skcipher_request_ctx(req);
ac3c8f36	229	struct skcipher_request *subreq = &rctx->subreq;
700cb3f5	230
ac3c8f36 OM	231	skcipher_request_set_tfm(subreq, ctx->child);
	232	skcipher_request_set_callback(subreq, req->base.flags, crypt_done, req);
	233	/* pass req->iv as IV (will be used by xor_tweak, ECB will ignore it) */
	234	skcipher_request_set_crypt(subreq, req->dst, req->dst,
	235	req->cryptlen, req->iv);
700cb3f5	236
ac3c8f36 OM	237	/* calculate first value of T */
ac3c8f36 OM	238	memcpy(&rctx->t, req->iv, sizeof(rctx->t));
64470f1b	239
ac3c8f36 OM	240	/* T <- IKey2 /
ac3c8f36 OM	241	gf128mul_64k_bbe(&rctx->t, ctx->table);
64470f1b RS	242	}
64470f1b RS	243
ac3c8f36	244	static int encrypt(struct skcipher_request *req)
64470f1b	245	{
ac3c8f36 OM	246	struct rctx *rctx = skcipher_request_ctx(req);
ac3c8f36 OM	247	struct skcipher_request *subreq = &rctx->subreq;
64470f1b	248
ac3c8f36 OM	249	init_crypt(req);
	250	return xor_tweak_pre(req) ?:
	251	crypto_skcipher_encrypt(subreq) ?:
	252	xor_tweak_post(req);
700cb3f5 HX	253	}
	254
	255	static int decrypt(struct skcipher_request *req)
	256	{
ac3c8f36 OM	257	struct rctx *rctx = skcipher_request_ctx(req);
	258	struct skcipher_request *subreq = &rctx->subreq;
	259
	260	init_crypt(req);
	261	return xor_tweak_pre(req) ?:
	262	crypto_skcipher_decrypt(subreq) ?:
	263	xor_tweak_post(req);
64470f1b RS	264	}
64470f1b RS	265
700cb3f5	266	static int init_tfm(struct crypto_skcipher *tfm)
64470f1b	267	{
700cb3f5 HX	268	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	269	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
	270	struct priv *ctx = crypto_skcipher_ctx(tfm);
	271	struct crypto_skcipher *cipher;
64470f1b	272
700cb3f5	273	cipher = crypto_spawn_skcipher(spawn);
2e306ee0 HX	274	if (IS_ERR(cipher))
2e306ee0 HX	275	return PTR_ERR(cipher);
64470f1b	276
2e306ee0	277	ctx->child = cipher;
700cb3f5 HX	278
	279	crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(cipher) +
	280	sizeof(struct rctx));
	281
64470f1b RS	282	return 0;
	283	}
	284
700cb3f5	285	static void exit_tfm(struct crypto_skcipher *tfm)
64470f1b	286	{
700cb3f5	287	struct priv *ctx = crypto_skcipher_ctx(tfm);
171c0204	288
217afccf EB	289	if (ctx->table)
217afccf EB	290	gf128mul_free_64k(ctx->table);
700cb3f5 HX	291	crypto_free_skcipher(ctx->child);
	292	}
	293
	294	static void free(struct skcipher_instance *inst)
	295	{
	296	crypto_drop_skcipher(skcipher_instance_ctx(inst));
	297	kfree(inst);
64470f1b RS	298	}
64470f1b RS	299
700cb3f5	300	static int create(struct crypto_template tmpl, struct rtattr *tb)
64470f1b	301	{
700cb3f5 HX	302	struct crypto_skcipher_spawn *spawn;
	303	struct skcipher_instance *inst;
	304	struct crypto_attr_type *algt;
	305	struct skcipher_alg *alg;
	306	const char *cipher_name;
	307	char ecb_name[CRYPTO_MAX_ALG_NAME];
ebc610e5 HX	308	int err;
ebc610e5 HX	309
700cb3f5 HX	310	algt = crypto_get_attr_type(tb);
	311	if (IS_ERR(algt))
	312	return PTR_ERR(algt);
	313
	314	if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
	315	return -EINVAL;
	316
	317	cipher_name = crypto_attr_alg_name(tb[1]);
	318	if (IS_ERR(cipher_name))
	319	return PTR_ERR(cipher_name);
	320
	321	inst = kzalloc(sizeof(inst) + sizeof(spawn), GFP_KERNEL);
	322	if (!inst)
	323	return -ENOMEM;
	324
	325	spawn = skcipher_instance_ctx(inst);
	326
	327	crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
	328	err = crypto_grab_skcipher(spawn, cipher_name, 0,
	329	crypto_requires_sync(algt->type,
	330	algt->mask));
	331	if (err == -ENOENT) {
	332	err = -ENAMETOOLONG;
	333	if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
	334	cipher_name) >= CRYPTO_MAX_ALG_NAME)
	335	goto err_free_inst;
	336
	337	err = crypto_grab_skcipher(spawn, ecb_name, 0,
	338	crypto_requires_sync(algt->type,
	339	algt->mask));
	340	}
	341
ebc610e5	342	if (err)
700cb3f5	343	goto err_free_inst;
64470f1b	344
700cb3f5	345	alg = crypto_skcipher_spawn_alg(spawn);
64470f1b	346
700cb3f5 HX	347	err = -EINVAL;
	348	if (alg->base.cra_blocksize != LRW_BLOCK_SIZE)
	349	goto err_drop_spawn;
64470f1b	350
700cb3f5 HX	351	if (crypto_skcipher_alg_ivsize(alg))
700cb3f5 HX	352	goto err_drop_spawn;
64470f1b	353
700cb3f5 HX	354	err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
	355	&alg->base);
	356	if (err)
	357	goto err_drop_spawn;
64470f1b	358
700cb3f5 HX	359	err = -EINVAL;
700cb3f5 HX	360	cipher_name = alg->base.cra_name;
64470f1b	361
700cb3f5 HX	362	/* Alas we screwed up the naming so we have to mangle the
	363	* cipher name.
	364	*/
	365	if (!strncmp(cipher_name, "ecb(", 4)) {
	366	unsigned len;
64470f1b	367
700cb3f5 HX	368	len = strlcpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
	369	if (len < 2 \|\| len >= sizeof(ecb_name))
	370	goto err_drop_spawn;
64470f1b	371
700cb3f5 HX	372	if (ecb_name[len - 1] != ')')
700cb3f5 HX	373	goto err_drop_spawn;
64470f1b	374
700cb3f5	375	ecb_name[len - 1] = 0;
64470f1b	376
700cb3f5	377	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
616129cc CJ	378	"lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME) {
	379	err = -ENAMETOOLONG;
	380	goto err_drop_spawn;
	381	}
d38efad2 CJ	382	} else
d38efad2 CJ	383	goto err_drop_spawn;
700cb3f5 HX	384
	385	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
	386	inst->alg.base.cra_priority = alg->base.cra_priority;
	387	inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
	388	inst->alg.base.cra_alignmask = alg->base.cra_alignmask \|
c778f96b	389	(__alignof__(__be32) - 1);
700cb3f5 HX	390
	391	inst->alg.ivsize = LRW_BLOCK_SIZE;
	392	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
	393	LRW_BLOCK_SIZE;
	394	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
	395	LRW_BLOCK_SIZE;
	396
	397	inst->alg.base.cra_ctxsize = sizeof(struct priv);
	398
	399	inst->alg.init = init_tfm;
	400	inst->alg.exit = exit_tfm;
	401
	402	inst->alg.setkey = setkey;
	403	inst->alg.encrypt = encrypt;
	404	inst->alg.decrypt = decrypt;
	405
	406	inst->free = free;
	407
	408	err = skcipher_register_instance(tmpl, inst);
	409	if (err)
	410	goto err_drop_spawn;
	411
	412	out:
	413	return err;
	414
	415	err_drop_spawn:
	416	crypto_drop_skcipher(spawn);
	417	err_free_inst:
64470f1b	418	kfree(inst);
700cb3f5	419	goto out;
64470f1b RS	420	}
	421
	422	static struct crypto_template crypto_tmpl = {
	423	.name = "lrw",
700cb3f5	424	.create = create,
64470f1b RS	425	.module = THIS_MODULE,
	426	};
	427
	428	static int __init crypto_module_init(void)
	429	{
	430	return crypto_register_template(&crypto_tmpl);
	431	}
	432
	433	static void __exit crypto_module_exit(void)
	434	{
	435	crypto_unregister_template(&crypto_tmpl);
	436	}
	437
	438	module_init(crypto_module_init);
	439	module_exit(crypto_module_exit);
	440
	441	MODULE_LICENSE("GPL");
	442	MODULE_DESCRIPTION("LRW block cipher mode");
4943ba16	443	MODULE_ALIAS_CRYPTO("lrw");