[mirror_ubuntu-artful-kernel.git] / crypto / pcbc.c

/*
 * PCBC: Propagating Cipher Block Chaining mode
 *
 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * Derived from cbc.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 <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>

struct crypto_pcbc_ctx {
	struct crypto_cipher *child;
};

static int crypto_pcbc_setkey(struct crypto_tfm *parent, const u8 *key,
			      unsigned int keylen)
{
	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(parent);
	struct crypto_cipher *child = ctx->child;
	int err;

	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);
	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
			     CRYPTO_TFM_RES_MASK);
	return err;
}

static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,
				       struct blkcipher_walk *walk,
				       struct crypto_cipher *tfm)
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		crypto_cipher_alg(tfm)->cia_encrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	u8 *iv = walk->iv;

	do {
		crypto_xor(iv, src, bsize);
		fn(crypto_cipher_tfm(tfm), dst, iv);
		memcpy(iv, dst, bsize);
		crypto_xor(iv, src, bsize);

		src += bsize;
		dst += bsize;
	} while ((nbytes -= bsize) >= bsize);

	return nbytes;
}

static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,
				       struct blkcipher_walk *walk,
				       struct crypto_cipher *tfm)
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		crypto_cipher_alg(tfm)->cia_encrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *iv = walk->iv;
	u8 tmpbuf[bsize];

	do {
		memcpy(tmpbuf, src, bsize);
		crypto_xor(iv, src, bsize);
		fn(crypto_cipher_tfm(tfm), src, iv);
		memcpy(iv, tmpbuf, bsize);
		crypto_xor(iv, src, bsize);

		src += bsize;
	} while ((nbytes -= bsize) >= bsize);

	memcpy(walk->iv, iv, bsize);

	return nbytes;
}

static int crypto_pcbc_encrypt(struct blkcipher_desc *desc,
			       struct scatterlist *dst, struct scatterlist *src,
			       unsigned int nbytes)
{
	struct blkcipher_walk walk;
	struct crypto_blkcipher *tfm = desc->tfm;
	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
	struct crypto_cipher *child = ctx->child;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
		if (walk.src.virt.addr == walk.dst.virt.addr)
			nbytes = crypto_pcbc_encrypt_inplace(desc, &walk,
							     child);
		else
			nbytes = crypto_pcbc_encrypt_segment(desc, &walk,
							     child);
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
}

static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,
				       struct blkcipher_walk *walk,
				       struct crypto_cipher *tfm)
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		crypto_cipher_alg(tfm)->cia_decrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	u8 *iv = walk->iv;

	do {
		fn(crypto_cipher_tfm(tfm), dst, src);
		crypto_xor(dst, iv, bsize);
		memcpy(iv, src, bsize);
		crypto_xor(iv, dst, bsize);

		src += bsize;
		dst += bsize;
	} while ((nbytes -= bsize) >= bsize);

	memcpy(walk->iv, iv, bsize);

	return nbytes;
}

static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,
				       struct blkcipher_walk *walk,
				       struct crypto_cipher *tfm)
{
	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
		crypto_cipher_alg(tfm)->cia_decrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *iv = walk->iv;
	u8 tmpbuf[bsize];

	do {
		memcpy(tmpbuf, src, bsize);
		fn(crypto_cipher_tfm(tfm), src, src);
		crypto_xor(src, iv, bsize);
		memcpy(iv, tmpbuf, bsize);
		crypto_xor(iv, src, bsize);

		src += bsize;
	} while ((nbytes -= bsize) >= bsize);

	memcpy(walk->iv, iv, bsize);

	return nbytes;
}

static int crypto_pcbc_decrypt(struct blkcipher_desc *desc,
			       struct scatterlist *dst, struct scatterlist *src,
			       unsigned int nbytes)
{
	struct blkcipher_walk walk;
	struct crypto_blkcipher *tfm = desc->tfm;
	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
	struct crypto_cipher *child = ctx->child;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
		if (walk.src.virt.addr == walk.dst.virt.addr)
			nbytes = crypto_pcbc_decrypt_inplace(desc, &walk,
							     child);
		else
			nbytes = crypto_pcbc_decrypt_segment(desc, &walk,
							     child);
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
}

static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm)
{
	struct crypto_instance *inst = (void *)tfm->__crt_alg;
	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);
	struct crypto_cipher *cipher;

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

	ctx->child = cipher;
	return 0;
}

static void crypto_pcbc_exit_tfm(struct crypto_tfm *tfm)
{
	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);
	crypto_free_cipher(ctx->child);
}

static struct crypto_instance *crypto_pcbc_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("pcbc", 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;
	inst->alg.cra_alignmask = alg->cra_alignmask;
	inst->alg.cra_type = &crypto_blkcipher_type;

	/* We access the data as u32s when xoring. */
	inst->alg.cra_alignmask |= __alignof__(u32) - 1;

	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;

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

	inst->alg.cra_init = crypto_pcbc_init_tfm;
	inst->alg.cra_exit = crypto_pcbc_exit_tfm;

	inst->alg.cra_blkcipher.setkey = crypto_pcbc_setkey;
	inst->alg.cra_blkcipher.encrypt = crypto_pcbc_encrypt;
	inst->alg.cra_blkcipher.decrypt = crypto_pcbc_decrypt;

out_put_alg:
	crypto_mod_put(alg);
	return inst;
}

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

static struct crypto_template crypto_pcbc_tmpl = {
	.name = "pcbc",
	.alloc = crypto_pcbc_alloc,
	.free = crypto_pcbc_free,
	.module = THIS_MODULE,
};

static int __init crypto_pcbc_module_init(void)
{
	return crypto_register_template(&crypto_pcbc_tmpl);
}

static void __exit crypto_pcbc_module_exit(void)
{
	crypto_unregister_template(&crypto_pcbc_tmpl);
}

module_init(crypto_pcbc_module_init);
module_exit(crypto_pcbc_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("PCBC block cipher algorithm");
Commit	Line	Data
91652be5 DH	1	/*
	2	* PCBC: Propagating Cipher Block Chaining mode
	3	*
	4	* Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
	6	*
	7	* Derived from cbc.c
	8	* - Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
	9	*
	10	* This program is free software; you can redistribute it and/or modify it
	11	* under the terms of the GNU General Public License as published by the Free
	12	* Software Foundation; either version 2 of the License, or (at your option)
	13	* any later version.
	14	*
	15	*/
	16
	17	#include <crypto/algapi.h>
	18	#include <linux/err.h>
	19	#include <linux/init.h>
	20	#include <linux/kernel.h>
	21	#include <linux/module.h>
	22	#include <linux/scatterlist.h>
	23	#include <linux/slab.h>
	24
	25	struct crypto_pcbc_ctx {
	26	struct crypto_cipher *child;
91652be5 DH	27	};
	28
	29	static int crypto_pcbc_setkey(struct crypto_tfm parent, const u8 key,
	30	unsigned int keylen)
	31	{
	32	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(parent);
	33	struct crypto_cipher *child = ctx->child;
	34	int err;
	35
	36	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	37	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
	38	CRYPTO_TFM_REQ_MASK);
	39	err = crypto_cipher_setkey(child, key, keylen);
	40	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
	41	CRYPTO_TFM_RES_MASK);
	42	return err;
	43	}
	44
	45	static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,
	46	struct blkcipher_walk *walk,
d0b9007a	47	struct crypto_cipher *tfm)
91652be5 DH	48	{
	49	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	50	crypto_cipher_alg(tfm)->cia_encrypt;
	51	int bsize = crypto_cipher_blocksize(tfm);
	52	unsigned int nbytes = walk->nbytes;
	53	u8 *src = walk->src.virt.addr;
	54	u8 *dst = walk->dst.virt.addr;
	55	u8 *iv = walk->iv;
	56
	57	do {
d0b9007a	58	crypto_xor(iv, src, bsize);
91652be5 DH	59	fn(crypto_cipher_tfm(tfm), dst, iv);
91652be5 DH	60	memcpy(iv, dst, bsize);
d0b9007a	61	crypto_xor(iv, src, bsize);
91652be5 DH	62
	63	src += bsize;
	64	dst += bsize;
	65	} while ((nbytes -= bsize) >= bsize);
	66
	67	return nbytes;
	68	}
	69
	70	static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,
	71	struct blkcipher_walk *walk,
d0b9007a	72	struct crypto_cipher *tfm)
91652be5 DH	73	{
	74	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	75	crypto_cipher_alg(tfm)->cia_encrypt;
	76	int bsize = crypto_cipher_blocksize(tfm);
	77	unsigned int nbytes = walk->nbytes;
	78	u8 *src = walk->src.virt.addr;
	79	u8 *iv = walk->iv;
	80	u8 tmpbuf[bsize];
	81
	82	do {
	83	memcpy(tmpbuf, src, bsize);
d0b9007a	84	crypto_xor(iv, src, bsize);
91652be5	85	fn(crypto_cipher_tfm(tfm), src, iv);
d0b9007a HX	86	memcpy(iv, tmpbuf, bsize);
d0b9007a HX	87	crypto_xor(iv, src, bsize);
91652be5 DH	88
	89	src += bsize;
	90	} while ((nbytes -= bsize) >= bsize);
	91
	92	memcpy(walk->iv, iv, bsize);
	93
	94	return nbytes;
	95	}
	96
	97	static int crypto_pcbc_encrypt(struct blkcipher_desc *desc,
	98	struct scatterlist dst, struct scatterlist src,
	99	unsigned int nbytes)
	100	{
	101	struct blkcipher_walk walk;
	102	struct crypto_blkcipher *tfm = desc->tfm;
	103	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
	104	struct crypto_cipher *child = ctx->child;
91652be5 DH	105	int err;
	106
	107	blkcipher_walk_init(&walk, dst, src, nbytes);
	108	err = blkcipher_walk_virt(desc, &walk);
	109
	110	while ((nbytes = walk.nbytes)) {
	111	if (walk.src.virt.addr == walk.dst.virt.addr)
d0b9007a HX	112	nbytes = crypto_pcbc_encrypt_inplace(desc, &walk,
d0b9007a HX	113	child);
91652be5	114	else
d0b9007a HX	115	nbytes = crypto_pcbc_encrypt_segment(desc, &walk,
d0b9007a HX	116	child);
91652be5 DH	117	err = blkcipher_walk_done(desc, &walk, nbytes);
	118	}
	119
	120	return err;
	121	}
	122
	123	static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,
	124	struct blkcipher_walk *walk,
d0b9007a	125	struct crypto_cipher *tfm)
91652be5 DH	126	{
	127	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	128	crypto_cipher_alg(tfm)->cia_decrypt;
	129	int bsize = crypto_cipher_blocksize(tfm);
	130	unsigned int nbytes = walk->nbytes;
	131	u8 *src = walk->src.virt.addr;
	132	u8 *dst = walk->dst.virt.addr;
	133	u8 *iv = walk->iv;
	134
	135	do {
	136	fn(crypto_cipher_tfm(tfm), dst, src);
d0b9007a	137	crypto_xor(dst, iv, bsize);
91652be5	138	memcpy(iv, src, bsize);
d0b9007a	139	crypto_xor(iv, dst, bsize);
91652be5 DH	140
	141	src += bsize;
	142	dst += bsize;
	143	} while ((nbytes -= bsize) >= bsize);
	144
	145	memcpy(walk->iv, iv, bsize);
	146
	147	return nbytes;
	148	}
	149
	150	static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,
	151	struct blkcipher_walk *walk,
d0b9007a	152	struct crypto_cipher *tfm)
91652be5 DH	153	{
	154	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	155	crypto_cipher_alg(tfm)->cia_decrypt;
	156	int bsize = crypto_cipher_blocksize(tfm);
	157	unsigned int nbytes = walk->nbytes;
	158	u8 *src = walk->src.virt.addr;
	159	u8 *iv = walk->iv;
	160	u8 tmpbuf[bsize];
	161
	162	do {
	163	memcpy(tmpbuf, src, bsize);
	164	fn(crypto_cipher_tfm(tfm), src, src);
d0b9007a	165	crypto_xor(src, iv, bsize);
91652be5	166	memcpy(iv, tmpbuf, bsize);
d0b9007a	167	crypto_xor(iv, src, bsize);
91652be5 DH	168
	169	src += bsize;
	170	} while ((nbytes -= bsize) >= bsize);
	171
	172	memcpy(walk->iv, iv, bsize);
	173
	174	return nbytes;
	175	}
	176
	177	static int crypto_pcbc_decrypt(struct blkcipher_desc *desc,
	178	struct scatterlist dst, struct scatterlist src,
	179	unsigned int nbytes)
	180	{
	181	struct blkcipher_walk walk;
	182	struct crypto_blkcipher *tfm = desc->tfm;
	183	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
	184	struct crypto_cipher *child = ctx->child;
91652be5 DH	185	int err;
	186
	187	blkcipher_walk_init(&walk, dst, src, nbytes);
	188	err = blkcipher_walk_virt(desc, &walk);
	189
	190	while ((nbytes = walk.nbytes)) {
	191	if (walk.src.virt.addr == walk.dst.virt.addr)
d0b9007a HX	192	nbytes = crypto_pcbc_decrypt_inplace(desc, &walk,
d0b9007a HX	193	child);
91652be5	194	else
d0b9007a HX	195	nbytes = crypto_pcbc_decrypt_segment(desc, &walk,
d0b9007a HX	196	child);
91652be5 DH	197	err = blkcipher_walk_done(desc, &walk, nbytes);
	198	}
	199
	200	return err;
	201	}
	202
91652be5 DH	203	static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm)
	204	{
	205	struct crypto_instance inst = (void )tfm->__crt_alg;
	206	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	207	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);
2e306ee0	208	struct crypto_cipher *cipher;
91652be5	209
2e306ee0 HX	210	cipher = crypto_spawn_cipher(spawn);
	211	if (IS_ERR(cipher))
	212	return PTR_ERR(cipher);
91652be5	213
2e306ee0	214	ctx->child = cipher;
91652be5 DH	215	return 0;
	216	}
	217
	218	static void crypto_pcbc_exit_tfm(struct crypto_tfm *tfm)
	219	{
	220	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);
	221	crypto_free_cipher(ctx->child);
	222	}
	223
ebc610e5	224	static struct crypto_instance crypto_pcbc_alloc(struct rtattr *tb)
91652be5 DH	225	{
	226	struct crypto_instance *inst;
	227	struct crypto_alg *alg;
ebc610e5 HX	228	int err;
	229
	230	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
	231	if (err)
	232	return ERR_PTR(err);
91652be5	233
ebc610e5 HX	234	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
ebc610e5 HX	235	CRYPTO_ALG_TYPE_MASK);
91652be5	236	if (IS_ERR(alg))
e231c2ee	237	return ERR_CAST(alg);
91652be5 DH	238
	239	inst = crypto_alloc_instance("pcbc", alg);
	240	if (IS_ERR(inst))
	241	goto out_put_alg;
	242
	243	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
	244	inst->alg.cra_priority = alg->cra_priority;
	245	inst->alg.cra_blocksize = alg->cra_blocksize;
	246	inst->alg.cra_alignmask = alg->cra_alignmask;
	247	inst->alg.cra_type = &crypto_blkcipher_type;
	248
d0b9007a HX	249	/* We access the data as u32s when xoring. */
	250	inst->alg.cra_alignmask \|= __alignof__(u32) - 1;
	251
91652be5 DH	252	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
	253	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
	254	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
	255
	256	inst->alg.cra_ctxsize = sizeof(struct crypto_pcbc_ctx);
	257
	258	inst->alg.cra_init = crypto_pcbc_init_tfm;
	259	inst->alg.cra_exit = crypto_pcbc_exit_tfm;
	260
	261	inst->alg.cra_blkcipher.setkey = crypto_pcbc_setkey;
	262	inst->alg.cra_blkcipher.encrypt = crypto_pcbc_encrypt;
	263	inst->alg.cra_blkcipher.decrypt = crypto_pcbc_decrypt;
	264
	265	out_put_alg:
	266	crypto_mod_put(alg);
	267	return inst;
	268	}
	269
	270	static void crypto_pcbc_free(struct crypto_instance *inst)
	271	{
	272	crypto_drop_spawn(crypto_instance_ctx(inst));
	273	kfree(inst);
	274	}
	275
	276	static struct crypto_template crypto_pcbc_tmpl = {
	277	.name = "pcbc",
	278	.alloc = crypto_pcbc_alloc,
	279	.free = crypto_pcbc_free,
	280	.module = THIS_MODULE,
	281	};
	282
	283	static int __init crypto_pcbc_module_init(void)
	284	{
	285	return crypto_register_template(&crypto_pcbc_tmpl);
	286	}
	287
	288	static void __exit crypto_pcbc_module_exit(void)
	289	{
	290	crypto_unregister_template(&crypto_pcbc_tmpl);
	291	}
	292
	293	module_init(crypto_pcbc_module_init);
	294	module_exit(crypto_pcbc_module_exit);
	295
	296	MODULE_LICENSE("GPL");
	297	MODULE_DESCRIPTION("PCBC block cipher algorithm");