[mirror_ubuntu-bionic-kernel.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>
#include <crypto/lrw.h>

#define LRW_BUFFER_SIZE 128u

struct priv {
	struct crypto_skcipher *child;
	struct lrw_table_ctx table;
};

struct rctx {
	be128 buf[LRW_BUFFER_SIZE / sizeof(be128)];

	be128 t;

	be128 *ext;

	struct scatterlist srcbuf[2];
	struct scatterlist dstbuf[2];
	struct scatterlist *src;
	struct scatterlist *dst;

	unsigned int left;

	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);
}

int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak)
{
	be128 tmp = { 0 };
	int i;

	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;
}
EXPORT_SYMBOL_GPL(lrw_init_table);

void lrw_free_table(struct lrw_table_ctx *ctx)
{
	if (ctx->table)
		gf128mul_free_64k(ctx->table);
}
EXPORT_SYMBOL_GPL(lrw_free_table);

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;

	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;

	return lrw_init_table(&ctx->table, tweak);
}

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

/* 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 post_crypt(struct skcipher_request *req)
{
	struct rctx *rctx = skcipher_request_ctx(req);
	be128 *buf = rctx->ext ?: rctx->buf;
	struct skcipher_request *subreq;
	const int bs = LRW_BLOCK_SIZE;
	struct skcipher_walk w;
	struct scatterlist *sg;
	unsigned offset;
	int err;

	subreq = &rctx->subreq;
	err = skcipher_walk_virt(&w, subreq, false);

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

		wdst = w.dst.virt.addr;

		do {
			be128_xor(wdst, buf++, wdst);
			wdst++;
		} while ((avail -= bs) >= bs);

		err = skcipher_walk_done(&w, avail);
	}

	rctx->left -= subreq->cryptlen;

	if (err || !rctx->left)
		goto out;

	rctx->dst = rctx->dstbuf;

	scatterwalk_done(&w.out, 0, 1);
	sg = w.out.sg;
	offset = w.out.offset;

	if (rctx->dst != sg) {
		rctx->dst[0] = *sg;
		sg_unmark_end(rctx->dst);
		scatterwalk_crypto_chain(rctx->dst, sg_next(sg), 0, 2);
	}
	rctx->dst[0].length -= offset - sg->offset;
	rctx->dst[0].offset = offset;

out:
	return err;
}

static int pre_crypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct rctx *rctx = skcipher_request_ctx(req);
	struct priv *ctx = crypto_skcipher_ctx(tfm);
	be128 *buf = rctx->ext ?: rctx->buf;
	struct skcipher_request *subreq;
	const int bs = LRW_BLOCK_SIZE;
	struct skcipher_walk w;
	struct scatterlist *sg;
	unsigned cryptlen;
	unsigned offset;
	be128 *iv;
	bool more;
	int err;

	subreq = &rctx->subreq;
	skcipher_request_set_tfm(subreq, tfm);

	cryptlen = subreq->cryptlen;
	more = rctx->left > cryptlen;
	if (!more)
		cryptlen = rctx->left;

	skcipher_request_set_crypt(subreq, rctx->src, rctx->dst,
				   cryptlen, req->iv);

	err = skcipher_walk_virt(&w, subreq, false);
	iv = w.iv;

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

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

		do {
			*buf++ = rctx->t;
			be128_xor(wdst++, &rctx->t, wsrc++);

			/* T <- I*Key2, using the optimization
			 * discussed in the specification */
			be128_xor(&rctx->t, &rctx->t,
				  &ctx->table.mulinc[get_index128(iv)]);
			inc(iv);
		} while ((avail -= bs) >= bs);

		err = skcipher_walk_done(&w, avail);
	}

	skcipher_request_set_tfm(subreq, ctx->child);
	skcipher_request_set_crypt(subreq, rctx->dst, rctx->dst,
				   cryptlen, NULL);

	if (err || !more)
		goto out;

	rctx->src = rctx->srcbuf;

	scatterwalk_done(&w.in, 0, 1);
	sg = w.in.sg;
	offset = w.in.offset;

	if (rctx->src != sg) {
		rctx->src[0] = *sg;
		sg_unmark_end(rctx->src);
		scatterwalk_crypto_chain(rctx->src, sg_next(sg), 0, 2);
	}
	rctx->src[0].length -= offset - sg->offset;
	rctx->src[0].offset = offset;

out:
	return err;
}

static int init_crypt(struct skcipher_request *req, crypto_completion_t done)
{
	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
	struct rctx *rctx = skcipher_request_ctx(req);
	struct skcipher_request *subreq;
	gfp_t gfp;

	subreq = &rctx->subreq;
	skcipher_request_set_callback(subreq, req->base.flags, done, req);

	gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
							   GFP_ATOMIC;
	rctx->ext = NULL;

	subreq->cryptlen = LRW_BUFFER_SIZE;
	if (req->cryptlen > LRW_BUFFER_SIZE) {
		unsigned int n = min(req->cryptlen, (unsigned int)PAGE_SIZE);

		rctx->ext = kmalloc(n, gfp);
		if (rctx->ext)
			subreq->cryptlen = n;
	}

	rctx->src = req->src;
	rctx->dst = req->dst;
	rctx->left = req->cryptlen;

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

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

	return 0;
}

static void exit_crypt(struct skcipher_request *req)
{
	struct rctx *rctx = skcipher_request_ctx(req);

	rctx->left = 0;

	if (rctx->ext)
		kfree(rctx->ext);
}

static int do_encrypt(struct skcipher_request *req, int err)
{
	struct rctx *rctx = skcipher_request_ctx(req);
	struct skcipher_request *subreq;

	subreq = &rctx->subreq;

	while (!err && rctx->left) {
		err = pre_crypt(req) ?:
		      crypto_skcipher_encrypt(subreq) ?:
		      post_crypt(req);

		if (err == -EINPROGRESS || err == -EBUSY)
			return err;
	}

	exit_crypt(req);
	return err;
}

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

	rctx = skcipher_request_ctx(req);

	if (err == -EINPROGRESS) {
		if (rctx->left != req->cryptlen)
			return;
		goto out;
	}

	subreq = &rctx->subreq;
	subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;

	err = do_encrypt(req, err ?: post_crypt(req));
	if (rctx->left)
		return;

out:
	skcipher_request_complete(req, err);
}

static int encrypt(struct skcipher_request *req)
{
	return do_encrypt(req, init_crypt(req, encrypt_done));
}

static int do_decrypt(struct skcipher_request *req, int err)
{
	struct rctx *rctx = skcipher_request_ctx(req);
	struct skcipher_request *subreq;

	subreq = &rctx->subreq;

	while (!err && rctx->left) {
		err = pre_crypt(req) ?:
		      crypto_skcipher_decrypt(subreq) ?:
		      post_crypt(req);

		if (err == -EINPROGRESS || err == -EBUSY)
			return err;
	}

	exit_crypt(req);
	return err;
}

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

	rctx = skcipher_request_ctx(req);

	if (err == -EINPROGRESS) {
		if (rctx->left != req->cryptlen)
			return;
		goto out;
	}

	subreq = &rctx->subreq;
	subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;

	err = do_decrypt(req, err ?: post_crypt(req));
	if (rctx->left)
		return;

out:
	skcipher_request_complete(req, err);
}

static int decrypt(struct skcipher_request *req)
{
	return do_decrypt(req, init_crypt(req, decrypt_done));
}

int lrw_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst,
	      struct scatterlist *ssrc, unsigned int nbytes,
	      struct lrw_crypt_req *req)
{
	const unsigned int bsize = LRW_BLOCK_SIZE;
	const unsigned int max_blks = req->tbuflen / bsize;
	struct lrw_table_ctx *ctx = req->table_ctx;
	struct blkcipher_walk walk;
	unsigned int nblocks;
	be128 *iv, *src, *dst, *t;
	be128 *t_buf = req->tbuf;
	int err, i;

	BUG_ON(max_blks < 1);

	blkcipher_walk_init(&walk, sdst, ssrc, nbytes);

	err = blkcipher_walk_virt(desc, &walk);
	nbytes = walk.nbytes;
	if (!nbytes)
		return err;

	nblocks = min(walk.nbytes / bsize, max_blks);
	src = (be128 *)walk.src.virt.addr;
	dst = (be128 *)walk.dst.virt.addr;

	/* calculate first value of T */
	iv = (be128 *)walk.iv;
	t_buf[0] = *iv;

	/* T <- I*Key2 */
	gf128mul_64k_bbe(&t_buf[0], ctx->table);

	i = 0;
	goto first;

	for (;;) {
		do {
			for (i = 0; i < nblocks; i++) {
				/* T <- I*Key2, using the optimization
				 * discussed in the specification */
				be128_xor(&t_buf[i], t,
						&ctx->mulinc[get_index128(iv)]);
				inc(iv);
first:
				t = &t_buf[i];

				/* PP <- T xor P */
				be128_xor(dst + i, t, src + i);
			}

			/* CC <- E(Key2,PP) */
			req->crypt_fn(req->crypt_ctx, (u8 *)dst,
				      nblocks * bsize);

			/* C <- T xor CC */
			for (i = 0; i < nblocks; i++)
				be128_xor(dst + i, dst + i, &t_buf[i]);

			src += nblocks;
			dst += nblocks;
			nbytes -= nblocks * bsize;
			nblocks = min(nbytes / bsize, max_blks);
		} while (nblocks > 0);

		err = blkcipher_walk_done(desc, &walk, nbytes);
		nbytes = walk.nbytes;
		if (!nbytes)
			break;

		nblocks = min(nbytes / bsize, max_blks);
		src = (be128 *)walk.src.virt.addr;
		dst = (be128 *)walk.dst.virt.addr;
	}

	return err;
}
EXPORT_SYMBOL_GPL(lrw_crypt);

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);

	lrw_free_table(&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__(u64) - 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>
6c2205b8	31	#include <crypto/lrw.h>
64470f1b	32
700cb3f5 HX	33	#define LRW_BUFFER_SIZE 128u
700cb3f5 HX	34
171c0204	35	struct priv {
700cb3f5	36	struct crypto_skcipher *child;
171c0204 JK	37	struct lrw_table_ctx table;
	38	};
	39
700cb3f5 HX	40	struct rctx {
	41	be128 buf[LRW_BUFFER_SIZE / sizeof(be128)];
	42
	43	be128 t;
	44
	45	be128 *ext;
	46
	47	struct scatterlist srcbuf[2];
	48	struct scatterlist dstbuf[2];
	49	struct scatterlist *src;
	50	struct scatterlist *dst;
	51
	52	unsigned int left;
	53
	54	struct skcipher_request subreq;
	55	};
	56
64470f1b RS	57	static inline void setbit128_bbe(void *b, int bit)
64470f1b RS	58	{
8eb2dfac HX	59	__set_bit(bit ^ (0x80 -
	60	#ifdef __BIG_ENDIAN
	61	BITS_PER_LONG
	62	#else
	63	BITS_PER_BYTE
	64	#endif
	65	), b);
64470f1b RS	66	}
64470f1b RS	67
6c2205b8	68	int lrw_init_table(struct lrw_table_ctx ctx, const u8 tweak)
64470f1b	69	{
64470f1b	70	be128 tmp = { 0 };
171c0204	71	int i;
64470f1b RS	72
	73	if (ctx->table)
	74	gf128mul_free_64k(ctx->table);
	75
	76	/* initialize multiplication table for Key2 */
171c0204	77	ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
64470f1b RS	78	if (!ctx->table)
	79	return -ENOMEM;
	80
	81	/* initialize optimization table */
	82	for (i = 0; i < 128; i++) {
	83	setbit128_bbe(&tmp, i);
	84	ctx->mulinc[i] = tmp;
	85	gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
	86	}
	87
	88	return 0;
	89	}
6c2205b8	90	EXPORT_SYMBOL_GPL(lrw_init_table);
64470f1b	91
6c2205b8	92	void lrw_free_table(struct lrw_table_ctx *ctx)
171c0204 JK	93	{
	94	if (ctx->table)
	95	gf128mul_free_64k(ctx->table);
	96	}
6c2205b8	97	EXPORT_SYMBOL_GPL(lrw_free_table);
171c0204	98
700cb3f5	99	static int setkey(struct crypto_skcipher parent, const u8 key,
171c0204 JK	100	unsigned int keylen)
171c0204 JK	101	{
700cb3f5 HX	102	struct priv *ctx = crypto_skcipher_ctx(parent);
700cb3f5 HX	103	struct crypto_skcipher *child = ctx->child;
171c0204 JK	104	int err, bsize = LRW_BLOCK_SIZE;
	105	const u8 *tweak = key + keylen - bsize;
	106
700cb3f5 HX	107	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	108	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
	109	CRYPTO_TFM_REQ_MASK);
	110	err = crypto_skcipher_setkey(child, key, keylen - bsize);
	111	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
	112	CRYPTO_TFM_RES_MASK);
171c0204 JK	113	if (err)
171c0204 JK	114	return err;
171c0204 JK	115
	116	return lrw_init_table(&ctx->table, tweak);
	117	}
	118
64470f1b RS	119	static inline void inc(be128 *iv)
64470f1b RS	120	{
fd4609a8 MS	121	be64_add_cpu(&iv->b, 1);
	122	if (!iv->b)
	123	be64_add_cpu(&iv->a, 1);
64470f1b RS	124	}
64470f1b RS	125
64470f1b RS	126	/* this returns the number of consequative 1 bits starting
	127	* from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */
	128	static inline int get_index128(be128 *block)
	129	{
	130	int x;
	131	__be32 p = (__be32 ) block;
	132
	133	for (p += 3, x = 0; x < 128; p--, x += 32) {
	134	u32 val = be32_to_cpup(p);
	135
	136	if (!~val)
	137	continue;
	138
	139	return x + ffz(val);
	140	}
	141
	142	return x;
	143	}
	144
700cb3f5	145	static int post_crypt(struct skcipher_request *req)
64470f1b	146	{
700cb3f5 HX	147	struct rctx *rctx = skcipher_request_ctx(req);
	148	be128 *buf = rctx->ext ?: rctx->buf;
	149	struct skcipher_request *subreq;
	150	const int bs = LRW_BLOCK_SIZE;
	151	struct skcipher_walk w;
	152	struct scatterlist *sg;
	153	unsigned offset;
64470f1b	154	int err;
700cb3f5 HX	155
	156	subreq = &rctx->subreq;
	157	err = skcipher_walk_virt(&w, subreq, false);
	158
	159	while (w.nbytes) {
	160	unsigned int avail = w.nbytes;
	161	be128 *wdst;
	162
	163	wdst = w.dst.virt.addr;
	164
	165	do {
	166	be128_xor(wdst, buf++, wdst);
	167	wdst++;
	168	} while ((avail -= bs) >= bs);
	169
	170	err = skcipher_walk_done(&w, avail);
	171	}
	172
	173	rctx->left -= subreq->cryptlen;
	174
	175	if (err \|\| !rctx->left)
	176	goto out;
	177
	178	rctx->dst = rctx->dstbuf;
	179
	180	scatterwalk_done(&w.out, 0, 1);
	181	sg = w.out.sg;
	182	offset = w.out.offset;
	183
	184	if (rctx->dst != sg) {
	185	rctx->dst[0] = *sg;
	186	sg_unmark_end(rctx->dst);
	187	scatterwalk_crypto_chain(rctx->dst, sg_next(sg), 0, 2);
	188	}
	189	rctx->dst[0].length -= offset - sg->offset;
	190	rctx->dst[0].offset = offset;
	191
	192	out:
	193	return err;
	194	}
	195
	196	static int pre_crypt(struct skcipher_request *req)
	197	{
	198	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	199	struct rctx *rctx = skcipher_request_ctx(req);
	200	struct priv *ctx = crypto_skcipher_ctx(tfm);
	201	be128 *buf = rctx->ext ?: rctx->buf;
	202	struct skcipher_request *subreq;
4660720d	203	const int bs = LRW_BLOCK_SIZE;
700cb3f5 HX	204	struct skcipher_walk w;
	205	struct scatterlist *sg;
	206	unsigned cryptlen;
	207	unsigned offset;
64470f1b	208	be128 *iv;
700cb3f5 HX	209	bool more;
700cb3f5 HX	210	int err;
64470f1b	211
700cb3f5 HX	212	subreq = &rctx->subreq;
700cb3f5 HX	213	skcipher_request_set_tfm(subreq, tfm);
64470f1b	214
700cb3f5 HX	215	cryptlen = subreq->cryptlen;
	216	more = rctx->left > cryptlen;
	217	if (!more)
	218	cryptlen = rctx->left;
64470f1b	219
700cb3f5 HX	220	skcipher_request_set_crypt(subreq, rctx->src, rctx->dst,
700cb3f5 HX	221	cryptlen, req->iv);
64470f1b	222
700cb3f5 HX	223	err = skcipher_walk_virt(&w, subreq, false);
700cb3f5 HX	224	iv = w.iv;
64470f1b	225
700cb3f5 HX	226	while (w.nbytes) {
	227	unsigned int avail = w.nbytes;
	228	be128 *wsrc;
	229	be128 *wdst;
	230
	231	wsrc = w.src.virt.addr;
	232	wdst = w.dst.virt.addr;
64470f1b	233
64470f1b	234	do {
700cb3f5 HX	235	*buf++ = rctx->t;
	236	be128_xor(wdst++, &rctx->t, wsrc++);
	237
64470f1b RS	238	/* T <- I*Key2, using the optimization
64470f1b RS	239	* discussed in the specification */
700cb3f5	240	be128_xor(&rctx->t, &rctx->t,
171c0204	241	&ctx->table.mulinc[get_index128(iv)]);
64470f1b	242	inc(iv);
700cb3f5	243	} while ((avail -= bs) >= bs);
64470f1b	244
700cb3f5 HX	245	err = skcipher_walk_done(&w, avail);
700cb3f5 HX	246	}
64470f1b	247
700cb3f5 HX	248	skcipher_request_set_tfm(subreq, ctx->child);
	249	skcipher_request_set_crypt(subreq, rctx->dst, rctx->dst,
	250	cryptlen, NULL);
64470f1b	251
700cb3f5 HX	252	if (err \|\| !more)
	253	goto out;
	254
	255	rctx->src = rctx->srcbuf;
	256
	257	scatterwalk_done(&w.in, 0, 1);
	258	sg = w.in.sg;
	259	offset = w.in.offset;
	260
	261	if (rctx->src != sg) {
	262	rctx->src[0] = *sg;
	263	sg_unmark_end(rctx->src);
	264	scatterwalk_crypto_chain(rctx->src, sg_next(sg), 0, 2);
	265	}
	266	rctx->src[0].length -= offset - sg->offset;
	267	rctx->src[0].offset = offset;
	268
	269	out:
	270	return err;
	271	}
	272
	273	static int init_crypt(struct skcipher_request *req, crypto_completion_t done)
	274	{
	275	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
	276	struct rctx *rctx = skcipher_request_ctx(req);
	277	struct skcipher_request *subreq;
	278	gfp_t gfp;
	279
	280	subreq = &rctx->subreq;
	281	skcipher_request_set_callback(subreq, req->base.flags, done, req);
	282
	283	gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
	284	GFP_ATOMIC;
	285	rctx->ext = NULL;
	286
	287	subreq->cryptlen = LRW_BUFFER_SIZE;
	288	if (req->cryptlen > LRW_BUFFER_SIZE) {
9df0eb18 EB	289	unsigned int n = min(req->cryptlen, (unsigned int)PAGE_SIZE);
	290
	291	rctx->ext = kmalloc(n, gfp);
	292	if (rctx->ext)
	293	subreq->cryptlen = n;
700cb3f5 HX	294	}
	295
	296	rctx->src = req->src;
	297	rctx->dst = req->dst;
	298	rctx->left = req->cryptlen;
	299
	300	/* calculate first value of T */
	301	memcpy(&rctx->t, req->iv, sizeof(rctx->t));
	302
	303	/* T <- IKey2 /
	304	gf128mul_64k_bbe(&rctx->t, ctx->table.table);
64470f1b	305
700cb3f5 HX	306	return 0;
	307	}
	308
	309	static void exit_crypt(struct skcipher_request *req)
	310	{
	311	struct rctx *rctx = skcipher_request_ctx(req);
	312
	313	rctx->left = 0;
	314
	315	if (rctx->ext)
	316	kfree(rctx->ext);
	317	}
	318
	319	static int do_encrypt(struct skcipher_request *req, int err)
	320	{
	321	struct rctx *rctx = skcipher_request_ctx(req);
	322	struct skcipher_request *subreq;
	323
	324	subreq = &rctx->subreq;
	325
	326	while (!err && rctx->left) {
	327	err = pre_crypt(req) ?:
	328	crypto_skcipher_encrypt(subreq) ?:
	329	post_crypt(req);
	330
4e5b0ad5	331	if (err == -EINPROGRESS \|\| err == -EBUSY)
700cb3f5	332	return err;
64470f1b RS	333	}
64470f1b RS	334
700cb3f5	335	exit_crypt(req);
64470f1b RS	336	return err;
	337	}
	338
700cb3f5 HX	339	static void encrypt_done(struct crypto_async_request *areq, int err)
	340	{
	341	struct skcipher_request *req = areq->data;
	342	struct skcipher_request *subreq;
	343	struct rctx *rctx;
	344
	345	rctx = skcipher_request_ctx(req);
4702bbee HX	346
	347	if (err == -EINPROGRESS) {
	348	if (rctx->left != req->cryptlen)
	349	return;
	350	goto out;
	351	}
	352
700cb3f5 HX	353	subreq = &rctx->subreq;
	354	subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
	355
	356	err = do_encrypt(req, err ?: post_crypt(req));
	357	if (rctx->left)
	358	return;
	359
4702bbee	360	out:
700cb3f5 HX	361	skcipher_request_complete(req, err);
	362	}
	363
	364	static int encrypt(struct skcipher_request *req)
	365	{
	366	return do_encrypt(req, init_crypt(req, encrypt_done));
	367	}
	368
	369	static int do_decrypt(struct skcipher_request *req, int err)
64470f1b	370	{
700cb3f5 HX	371	struct rctx *rctx = skcipher_request_ctx(req);
	372	struct skcipher_request *subreq;
	373
	374	subreq = &rctx->subreq;
	375
	376	while (!err && rctx->left) {
	377	err = pre_crypt(req) ?:
	378	crypto_skcipher_decrypt(subreq) ?:
	379	post_crypt(req);
	380
4e5b0ad5	381	if (err == -EINPROGRESS \|\| err == -EBUSY)
700cb3f5 HX	382	return err;
700cb3f5 HX	383	}
64470f1b	384
700cb3f5 HX	385	exit_crypt(req);
700cb3f5 HX	386	return err;
64470f1b RS	387	}
64470f1b RS	388
700cb3f5	389	static void decrypt_done(struct crypto_async_request *areq, int err)
64470f1b	390	{
700cb3f5 HX	391	struct skcipher_request *req = areq->data;
	392	struct skcipher_request *subreq;
	393	struct rctx *rctx;
	394
	395	rctx = skcipher_request_ctx(req);
4702bbee HX	396
	397	if (err == -EINPROGRESS) {
	398	if (rctx->left != req->cryptlen)
	399	return;
	400	goto out;
	401	}
	402
700cb3f5 HX	403	subreq = &rctx->subreq;
	404	subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
	405
	406	err = do_decrypt(req, err ?: post_crypt(req));
	407	if (rctx->left)
	408	return;
64470f1b	409
4702bbee	410	out:
700cb3f5 HX	411	skcipher_request_complete(req, err);
	412	}
	413
	414	static int decrypt(struct skcipher_request *req)
	415	{
	416	return do_decrypt(req, init_crypt(req, decrypt_done));
64470f1b RS	417	}
64470f1b RS	418
6c2205b8 JK	419	int lrw_crypt(struct blkcipher_desc desc, struct scatterlist sdst,
	420	struct scatterlist *ssrc, unsigned int nbytes,
	421	struct lrw_crypt_req *req)
	422	{
	423	const unsigned int bsize = LRW_BLOCK_SIZE;
	424	const unsigned int max_blks = req->tbuflen / bsize;
	425	struct lrw_table_ctx *ctx = req->table_ctx;
	426	struct blkcipher_walk walk;
	427	unsigned int nblocks;
	428	be128 iv, src, dst, t;
	429	be128 *t_buf = req->tbuf;
	430	int err, i;
	431
	432	BUG_ON(max_blks < 1);
	433
	434	blkcipher_walk_init(&walk, sdst, ssrc, nbytes);
	435
	436	err = blkcipher_walk_virt(desc, &walk);
	437	nbytes = walk.nbytes;
	438	if (!nbytes)
	439	return err;
	440
	441	nblocks = min(walk.nbytes / bsize, max_blks);
	442	src = (be128 *)walk.src.virt.addr;
	443	dst = (be128 *)walk.dst.virt.addr;
	444
	445	/* calculate first value of T */
	446	iv = (be128 *)walk.iv;
	447	t_buf[0] = *iv;
	448
	449	/* T <- IKey2 /
	450	gf128mul_64k_bbe(&t_buf[0], ctx->table);
	451
	452	i = 0;
	453	goto first;
	454
	455	for (;;) {
	456	do {
	457	for (i = 0; i < nblocks; i++) {
	458	/* T <- I*Key2, using the optimization
	459	* discussed in the specification */
	460	be128_xor(&t_buf[i], t,
	461	&ctx->mulinc[get_index128(iv)]);
	462	inc(iv);
	463	first:
	464	t = &t_buf[i];
	465
	466	/* PP <- T xor P */
	467	be128_xor(dst + i, t, src + i);
	468	}
	469
	470	/* CC <- E(Key2,PP) */
	471	req->crypt_fn(req->crypt_ctx, (u8 *)dst,
	472	nblocks * bsize);
	473
	474	/* C <- T xor CC */
	475	for (i = 0; i < nblocks; i++)
	476	be128_xor(dst + i, dst + i, &t_buf[i]);
	477
	478	src += nblocks;
	479	dst += nblocks;
	480	nbytes -= nblocks * bsize;
	481	nblocks = min(nbytes / bsize, max_blks);
	482	} while (nblocks > 0);
483
484	err = blkcipher_walk_done(desc, &walk, nbytes);
485	nbytes = walk.nbytes;
486	if (!nbytes)
487	break;
488
489	nblocks = min(nbytes / bsize, max_blks);
490	src = (be128 *)walk.src.virt.addr;
491	dst = (be128 *)walk.dst.virt.addr;
492	}
493
494	return err;
495	}
496	EXPORT_SYMBOL_GPL(lrw_crypt);
497
700cb3f5	498	static int init_tfm(struct crypto_skcipher *tfm)
64470f1b	499	{
700cb3f5 HX	500	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	501	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
	502	struct priv *ctx = crypto_skcipher_ctx(tfm);
	503	struct crypto_skcipher *cipher;
64470f1b	504
700cb3f5	505	cipher = crypto_spawn_skcipher(spawn);
2e306ee0 HX	506	if (IS_ERR(cipher))
2e306ee0 HX	507	return PTR_ERR(cipher);
64470f1b	508
2e306ee0	509	ctx->child = cipher;
700cb3f5 HX	510
	511	crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(cipher) +
	512	sizeof(struct rctx));
	513
64470f1b RS	514	return 0;
	515	}
	516
700cb3f5	517	static void exit_tfm(struct crypto_skcipher *tfm)
64470f1b	518	{
700cb3f5	519	struct priv *ctx = crypto_skcipher_ctx(tfm);
171c0204 JK	520
171c0204 JK	521	lrw_free_table(&ctx->table);
700cb3f5 HX	522	crypto_free_skcipher(ctx->child);
	523	}
	524
	525	static void free(struct skcipher_instance *inst)
	526	{
	527	crypto_drop_skcipher(skcipher_instance_ctx(inst));
	528	kfree(inst);
64470f1b RS	529	}
64470f1b RS	530
700cb3f5	531	static int create(struct crypto_template tmpl, struct rtattr *tb)
64470f1b	532	{
700cb3f5 HX	533	struct crypto_skcipher_spawn *spawn;
	534	struct skcipher_instance *inst;
	535	struct crypto_attr_type *algt;
	536	struct skcipher_alg *alg;
	537	const char *cipher_name;
	538	char ecb_name[CRYPTO_MAX_ALG_NAME];
ebc610e5 HX	539	int err;
ebc610e5 HX	540
700cb3f5 HX	541	algt = crypto_get_attr_type(tb);
	542	if (IS_ERR(algt))
	543	return PTR_ERR(algt);
	544
	545	if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
	546	return -EINVAL;
	547
	548	cipher_name = crypto_attr_alg_name(tb[1]);
	549	if (IS_ERR(cipher_name))
	550	return PTR_ERR(cipher_name);
	551
	552	inst = kzalloc(sizeof(inst) + sizeof(spawn), GFP_KERNEL);
	553	if (!inst)
	554	return -ENOMEM;
	555
	556	spawn = skcipher_instance_ctx(inst);
	557
	558	crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
	559	err = crypto_grab_skcipher(spawn, cipher_name, 0,
	560	crypto_requires_sync(algt->type,
	561	algt->mask));
	562	if (err == -ENOENT) {
	563	err = -ENAMETOOLONG;
	564	if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
	565	cipher_name) >= CRYPTO_MAX_ALG_NAME)
	566	goto err_free_inst;
	567
	568	err = crypto_grab_skcipher(spawn, ecb_name, 0,
	569	crypto_requires_sync(algt->type,
	570	algt->mask));
	571	}
	572
ebc610e5	573	if (err)
700cb3f5	574	goto err_free_inst;
64470f1b	575
700cb3f5	576	alg = crypto_skcipher_spawn_alg(spawn);
64470f1b	577
700cb3f5 HX	578	err = -EINVAL;
	579	if (alg->base.cra_blocksize != LRW_BLOCK_SIZE)
	580	goto err_drop_spawn;
64470f1b	581
700cb3f5 HX	582	if (crypto_skcipher_alg_ivsize(alg))
700cb3f5 HX	583	goto err_drop_spawn;
64470f1b	584
700cb3f5 HX	585	err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
	586	&alg->base);
	587	if (err)
	588	goto err_drop_spawn;
64470f1b	589
700cb3f5 HX	590	err = -EINVAL;
700cb3f5 HX	591	cipher_name = alg->base.cra_name;
64470f1b	592
700cb3f5 HX	593	/* Alas we screwed up the naming so we have to mangle the
	594	* cipher name.
	595	*/
	596	if (!strncmp(cipher_name, "ecb(", 4)) {
	597	unsigned len;
64470f1b	598
700cb3f5 HX	599	len = strlcpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
	600	if (len < 2 \|\| len >= sizeof(ecb_name))
	601	goto err_drop_spawn;
64470f1b	602
700cb3f5 HX	603	if (ecb_name[len - 1] != ')')
700cb3f5 HX	604	goto err_drop_spawn;
64470f1b	605
700cb3f5	606	ecb_name[len - 1] = 0;
64470f1b	607
700cb3f5	608	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
616129cc CJ	609	"lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME) {
	610	err = -ENAMETOOLONG;
	611	goto err_drop_spawn;
	612	}
d38efad2 CJ	613	} else
d38efad2 CJ	614	goto err_drop_spawn;
700cb3f5 HX	615
	616	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
	617	inst->alg.base.cra_priority = alg->base.cra_priority;
	618	inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
	619	inst->alg.base.cra_alignmask = alg->base.cra_alignmask \|
	620	(__alignof__(u64) - 1);
	621
	622	inst->alg.ivsize = LRW_BLOCK_SIZE;
	623	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
	624	LRW_BLOCK_SIZE;
	625	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
	626	LRW_BLOCK_SIZE;
	627
	628	inst->alg.base.cra_ctxsize = sizeof(struct priv);
	629
	630	inst->alg.init = init_tfm;
	631	inst->alg.exit = exit_tfm;
	632
	633	inst->alg.setkey = setkey;
	634	inst->alg.encrypt = encrypt;
	635	inst->alg.decrypt = decrypt;
	636
	637	inst->free = free;
	638
	639	err = skcipher_register_instance(tmpl, inst);
	640	if (err)
	641	goto err_drop_spawn;
	642
	643	out:
	644	return err;
	645
	646	err_drop_spawn:
	647	crypto_drop_skcipher(spawn);
	648	err_free_inst:
64470f1b	649	kfree(inst);
700cb3f5	650	goto out;
64470f1b RS	651	}
	652
	653	static struct crypto_template crypto_tmpl = {
	654	.name = "lrw",
700cb3f5	655	.create = create,
64470f1b RS	656	.module = THIS_MODULE,
	657	};
	658
	659	static int __init crypto_module_init(void)
	660	{
	661	return crypto_register_template(&crypto_tmpl);
	662	}
	663
	664	static void __exit crypto_module_exit(void)
	665	{
	666	crypto_unregister_template(&crypto_tmpl);
	667	}
	668
	669	module_init(crypto_module_init);
	670	module_exit(crypto_module_exit);
	671
	672	MODULE_LICENSE("GPL");
	673	MODULE_DESCRIPTION("LRW block cipher mode");
4943ba16	674	MODULE_ALIAS_CRYPTO("lrw");