[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 om 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/algapi.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>

struct priv {
	struct crypto_cipher *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];
};

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_tfm *parent, const u8 *key,
		  unsigned int keylen)
{
	struct priv *ctx = crypto_tfm_ctx(parent);
	struct crypto_cipher *child = ctx->child;
	int err, i;
	be128 tmp = { 0 };
	int bsize = crypto_cipher_blocksize(child);

	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
				       CRYPTO_TFM_REQ_MASK);
	if ((err = crypto_cipher_setkey(child, key, keylen - bsize)))
		return err;
	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
				     CRYPTO_TFM_RES_MASK);

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

	/* initialize multiplication table for Key2 */
	ctx->table = gf128mul_init_64k_bbe((be128 *)(key + keylen - bsize));
	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;
}

struct sinfo {
	be128 t;
	struct crypto_tfm *tfm;
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
};

static inline void inc(be128 *iv)
{
	be64_add_cpu(&iv->b, 1);
	if (!iv->b)
		be64_add_cpu(&iv->a, 1);
}

static inline void lrw_round(struct sinfo *s, void *dst, const void *src)
{
	be128_xor(dst, &s->t, src);		/* PP <- T xor P */
	s->fn(s->tfm, dst, dst);		/* CC <- E(Key2,PP) */
	be128_xor(dst, dst, &s->t);		/* C <- T xor CC */
}

/* this returns the number of consequative 1 bits starting
 * from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */
static inline int get_index128(be128 *block)
{
	int x;
	__be32 *p = (__be32 *) block;

	for (p += 3, x = 0; x < 128; p--, x += 32) {
		u32 val = be32_to_cpup(p);

		if (!~val)
			continue;

		return x + ffz(val);
	}

	return x;
}

static int crypt(struct blkcipher_desc *d,
		 struct blkcipher_walk *w, struct priv *ctx,
		 void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
{
	int err;
	unsigned int avail;
	const int bs = crypto_cipher_blocksize(ctx->child);
	struct sinfo s = {
		.tfm = crypto_cipher_tfm(ctx->child),
		.fn = fn
	};
	be128 *iv;
	u8 *wsrc;
	u8 *wdst;

	err = blkcipher_walk_virt(d, w);
	if (!(avail = w->nbytes))
		return err;

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

	/* calculate first value of T */
	iv = (be128 *)w->iv;
	s.t = *iv;

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

	goto first;

	for (;;) {
		do {
			/* T <- I*Key2, using the optimization
			 * discussed in the specification */
			be128_xor(&s.t, &s.t, &ctx->mulinc[get_index128(iv)]);
			inc(iv);

first:
			lrw_round(&s, wdst, wsrc);

			wsrc += bs;
			wdst += bs;
		} while ((avail -= bs) >= bs);

		err = blkcipher_walk_done(d, w, avail);
		if (!(avail = w->nbytes))
			break;

		wsrc = w->src.virt.addr;
		wdst = w->dst.virt.addr;
	}

	return err;
}

static int encrypt(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;

	blkcipher_walk_init(&w, dst, src, nbytes);
	return crypt(desc, &w, ctx,
		     crypto_cipher_alg(ctx->child)->cia_encrypt);
}

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;

	blkcipher_walk_init(&w, dst, src, nbytes);
	return crypt(desc, &w, ctx,
		     crypto_cipher_alg(ctx->child)->cia_decrypt);
}

static int init_tfm(struct crypto_tfm *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) != 16) {
		*flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
		return -EINVAL;
	}

	ctx->child = cipher;
	return 0;
}

static void exit_tfm(struct crypto_tfm *tfm)
{
	struct priv *ctx = crypto_tfm_ctx(tfm);
	if (ctx->table)
		gf128mul_free_64k(ctx->table);
	crypto_free_cipher(ctx->child);
}

static struct crypto_instance *alloc(struct rtattr **tb)
{
	struct crypto_instance *inst;
	struct crypto_alg *alg;
	int err;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
	if (err)
		return ERR_PTR(err);

	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
				  CRYPTO_ALG_TYPE_MASK);
	if (IS_ERR(alg))
		return ERR_CAST(alg);

	inst = crypto_alloc_instance("lrw", alg);
	if (IS_ERR(inst))
		goto out_put_alg;

	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
	inst->alg.cra_priority = alg->cra_priority;
	inst->alg.cra_blocksize = alg->cra_blocksize;

	if (alg->cra_alignmask < 7) inst->alg.cra_alignmask = 7;
	else inst->alg.cra_alignmask = alg->cra_alignmask;
	inst->alg.cra_type = &crypto_blkcipher_type;

	if (!(alg->cra_blocksize % 4))
		inst->alg.cra_alignmask |= 3;
	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
	inst->alg.cra_blkcipher.min_keysize =
		alg->cra_cipher.cia_min_keysize + alg->cra_blocksize;
	inst->alg.cra_blkcipher.max_keysize =
		alg->cra_cipher.cia_max_keysize + alg->cra_blocksize;

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

	inst->alg.cra_init = init_tfm;
	inst->alg.cra_exit = exit_tfm;

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

out_put_alg:
	crypto_mod_put(alg);
	return inst;
}

static void free(struct crypto_instance *inst)
{
	crypto_drop_spawn(crypto_instance_ctx(inst));
	kfree(inst);
}

static struct crypto_template crypto_tmpl = {
	.name = "lrw",
	.alloc = alloc,
	.free = free,
	.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");
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	*
	6	* Based om ecb.c
	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] */
	19	#include <crypto/algapi.h>
	20	#include <linux/err.h>
	21	#include <linux/init.h>
	22	#include <linux/kernel.h>
	23	#include <linux/module.h>
	24	#include <linux/scatterlist.h>
	25	#include <linux/slab.h>
	26
	27	#include <crypto/b128ops.h>
	28	#include <crypto/gf128mul.h>
	29
	30	struct priv {
	31	struct crypto_cipher *child;
	32	/* optimizes multiplying a random (non incrementing, as at the
	33	* start of a new sector) value with key2, we could also have
	34	* used 4k optimization tables or no optimization at all. In the
	35	* latter case we would have to store key2 here */
	36	struct gf128mul_64k *table;
	37	/* stores:
	38	* key2{ 0,0,...0,0,0,0,1 }, key2{ 0,0,...0,0,0,1,1 },
	39	* key2{ 0,0,...0,0,1,1,1 }, key2{ 0,0,...0,1,1,1,1 }
	40	* key2*{ 0,0,...1,1,1,1,1 }, etc
	41	* needed for optimized multiplication of incrementing values
	42	* with key2 */
	43	be128 mulinc[128];
	44	};
	45
	46	static inline void setbit128_bbe(void *b, int bit)
	47	{
8eb2dfac HX	48	__set_bit(bit ^ (0x80 -
	49	#ifdef __BIG_ENDIAN
	50	BITS_PER_LONG
	51	#else
	52	BITS_PER_BYTE
	53	#endif
	54	), b);
64470f1b RS	55	}
	56
	57	static int setkey(struct crypto_tfm parent, const u8 key,
	58	unsigned int keylen)
	59	{
	60	struct priv *ctx = crypto_tfm_ctx(parent);
	61	struct crypto_cipher *child = ctx->child;
	62	int err, i;
	63	be128 tmp = { 0 };
	64	int bsize = crypto_cipher_blocksize(child);
	65
	66	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	67	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
	68	CRYPTO_TFM_REQ_MASK);
	69	if ((err = crypto_cipher_setkey(child, key, keylen - bsize)))
	70	return err;
	71	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
	72	CRYPTO_TFM_RES_MASK);
	73
	74	if (ctx->table)
	75	gf128mul_free_64k(ctx->table);
	76
	77	/* initialize multiplication table for Key2 */
	78	ctx->table = gf128mul_init_64k_bbe((be128 *)(key + keylen - bsize));
	79	if (!ctx->table)
	80	return -ENOMEM;
	81
	82	/* initialize optimization table */
	83	for (i = 0; i < 128; i++) {
	84	setbit128_bbe(&tmp, i);
	85	ctx->mulinc[i] = tmp;
	86	gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
	87	}
	88
	89	return 0;
	90	}
	91
	92	struct sinfo {
	93	be128 t;
	94	struct crypto_tfm *tfm;
	95	void (fn)(struct crypto_tfm , u8 , const u8 );
	96	};
	97
	98	static inline void inc(be128 *iv)
	99	{
fd4609a8 MS	100	be64_add_cpu(&iv->b, 1);
	101	if (!iv->b)
	102	be64_add_cpu(&iv->a, 1);
64470f1b RS	103	}
64470f1b RS	104
9ebed9d1	105	static inline void lrw_round(struct sinfo s, void dst, const void *src)
64470f1b RS	106	{
	107	be128_xor(dst, &s->t, src); /* PP <- T xor P */
	108	s->fn(s->tfm, dst, dst); /* CC <- E(Key2,PP) */
	109	be128_xor(dst, dst, &s->t); /* C <- T xor CC */
	110	}
	111
	112	/* this returns the number of consequative 1 bits starting
	113	* from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */
	114	static inline int get_index128(be128 *block)
	115	{
	116	int x;
	117	__be32 p = (__be32 ) block;
	118
	119	for (p += 3, x = 0; x < 128; p--, x += 32) {
	120	u32 val = be32_to_cpup(p);
	121
	122	if (!~val)
	123	continue;
	124
	125	return x + ffz(val);
	126	}
	127
	128	return x;
	129	}
	130
	131	static int crypt(struct blkcipher_desc *d,
	132	struct blkcipher_walk w, struct priv ctx,
	133	void (fn)(struct crypto_tfm , u8 , const u8 ))
	134	{
	135	int err;
	136	unsigned int avail;
	137	const int bs = crypto_cipher_blocksize(ctx->child);
	138	struct sinfo s = {
	139	.tfm = crypto_cipher_tfm(ctx->child),
	140	.fn = fn
	141	};
	142	be128 *iv;
	143	u8 *wsrc;
	144	u8 *wdst;
	145
	146	err = blkcipher_walk_virt(d, w);
	147	if (!(avail = w->nbytes))
	148	return err;
	149
	150	wsrc = w->src.virt.addr;
	151	wdst = w->dst.virt.addr;
	152
	153	/* calculate first value of T */
	154	iv = (be128 *)w->iv;
	155	s.t = *iv;
	156
	157	/* T <- IKey2 /
	158	gf128mul_64k_bbe(&s.t, ctx->table);
	159
	160	goto first;
	161
	162	for (;;) {
	163	do {
	164	/* T <- I*Key2, using the optimization
	165	* discussed in the specification */
	166	be128_xor(&s.t, &s.t, &ctx->mulinc[get_index128(iv)]);
	167	inc(iv);
	168
	169	first:
9ebed9d1	170	lrw_round(&s, wdst, wsrc);
64470f1b RS	171
	172	wsrc += bs;
	173	wdst += bs;
	174	} while ((avail -= bs) >= bs);
	175
	176	err = blkcipher_walk_done(d, w, avail);
	177	if (!(avail = w->nbytes))
	178	break;
	179
	180	wsrc = w->src.virt.addr;
	181	wdst = w->dst.virt.addr;
	182	}
	183
	184	return err;
	185	}
	186
	187	static int encrypt(struct blkcipher_desc desc, struct scatterlist dst,
	188	struct scatterlist *src, unsigned int nbytes)
	189	{
	190	struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
	191	struct blkcipher_walk w;
	192
	193	blkcipher_walk_init(&w, dst, src, nbytes);
	194	return crypt(desc, &w, ctx,
	195	crypto_cipher_alg(ctx->child)->cia_encrypt);
	196	}
	197
	198	static int decrypt(struct blkcipher_desc desc, struct scatterlist dst,
	199	struct scatterlist *src, unsigned int nbytes)
	200	{
	201	struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
	202	struct blkcipher_walk w;
	203
	204	blkcipher_walk_init(&w, dst, src, nbytes);
	205	return crypt(desc, &w, ctx,
	206	crypto_cipher_alg(ctx->child)->cia_decrypt);
	207	}
	208
	209	static int init_tfm(struct crypto_tfm *tfm)
	210	{
2e306ee0	211	struct crypto_cipher *cipher;
64470f1b RS	212	struct crypto_instance inst = (void )tfm->__crt_alg;
	213	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	214	struct priv *ctx = crypto_tfm_ctx(tfm);
	215	u32 *flags = &tfm->crt_flags;
	216
2e306ee0 HX	217	cipher = crypto_spawn_cipher(spawn);
	218	if (IS_ERR(cipher))
	219	return PTR_ERR(cipher);
64470f1b	220
2e306ee0	221	if (crypto_cipher_blocksize(cipher) != 16) {
64470f1b RS	222	*flags \|= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
	223	return -EINVAL;
	224	}
	225
2e306ee0	226	ctx->child = cipher;
64470f1b RS	227	return 0;
	228	}
	229
	230	static void exit_tfm(struct crypto_tfm *tfm)
	231	{
	232	struct priv *ctx = crypto_tfm_ctx(tfm);
	233	if (ctx->table)
	234	gf128mul_free_64k(ctx->table);
	235	crypto_free_cipher(ctx->child);
	236	}
	237
ebc610e5	238	static struct crypto_instance alloc(struct rtattr *tb)
64470f1b RS	239	{
	240	struct crypto_instance *inst;
	241	struct crypto_alg *alg;
ebc610e5 HX	242	int err;
	243
	244	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
	245	if (err)
	246	return ERR_PTR(err);
64470f1b	247
ebc610e5 HX	248	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
ebc610e5 HX	249	CRYPTO_ALG_TYPE_MASK);
64470f1b	250	if (IS_ERR(alg))
e231c2ee	251	return ERR_CAST(alg);
64470f1b RS	252
	253	inst = crypto_alloc_instance("lrw", alg);
	254	if (IS_ERR(inst))
	255	goto out_put_alg;
	256
	257	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
	258	inst->alg.cra_priority = alg->cra_priority;
	259	inst->alg.cra_blocksize = alg->cra_blocksize;
	260
	261	if (alg->cra_alignmask < 7) inst->alg.cra_alignmask = 7;
	262	else inst->alg.cra_alignmask = alg->cra_alignmask;
	263	inst->alg.cra_type = &crypto_blkcipher_type;
	264
	265	if (!(alg->cra_blocksize % 4))
	266	inst->alg.cra_alignmask \|= 3;
	267	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
	268	inst->alg.cra_blkcipher.min_keysize =
	269	alg->cra_cipher.cia_min_keysize + alg->cra_blocksize;
	270	inst->alg.cra_blkcipher.max_keysize =
	271	alg->cra_cipher.cia_max_keysize + alg->cra_blocksize;
	272
	273	inst->alg.cra_ctxsize = sizeof(struct priv);
	274
	275	inst->alg.cra_init = init_tfm;
	276	inst->alg.cra_exit = exit_tfm;
	277
	278	inst->alg.cra_blkcipher.setkey = setkey;
	279	inst->alg.cra_blkcipher.encrypt = encrypt;
	280	inst->alg.cra_blkcipher.decrypt = decrypt;
	281
	282	out_put_alg:
	283	crypto_mod_put(alg);
	284	return inst;
	285	}
	286
	287	static void free(struct crypto_instance *inst)
	288	{
	289	crypto_drop_spawn(crypto_instance_ctx(inst));
	290	kfree(inst);
	291	}
	292
	293	static struct crypto_template crypto_tmpl = {
	294	.name = "lrw",
	295	.alloc = alloc,
	296	.free = free,
	297	.module = THIS_MODULE,
	298	};
	299
	300	static int __init crypto_module_init(void)
	301	{
	302	return crypto_register_template(&crypto_tmpl);
	303	}
	304
	305	static void __exit crypto_module_exit(void)
	306	{
	307	crypto_unregister_template(&crypto_tmpl);
	308	}
	309
	310	module_init(crypto_module_init);
	311	module_exit(crypto_module_exit);
	312
	313	MODULE_LICENSE("GPL");
	314	MODULE_DESCRIPTION("LRW block cipher mode");