[linux.git] / crypto / pcbc.c

/*
 * PCBC: Propagating Cipher Block Chaining mode
 *
 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * Derived from cbc.c
 * - Copyright (c) 2006 Herbert Xu <[email protected]>
 *
 * 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/internal/skcipher.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/compiler.h>

struct crypto_pcbc_ctx {
	struct crypto_cipher *child;
};

static int crypto_pcbc_setkey(struct crypto_skcipher *parent, const u8 *key,
			      unsigned int keylen)
{
	struct crypto_pcbc_ctx *ctx = crypto_skcipher_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_skcipher_get_flags(parent) &
				       CRYPTO_TFM_REQ_MASK);
	err = crypto_cipher_setkey(child, key, keylen);
	crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &
					  CRYPTO_TFM_RES_MASK);
	return err;
}

static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,
				       struct skcipher_walk *walk,
				       struct crypto_cipher *tfm)
{
	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);
		crypto_cipher_encrypt_one(tfm, dst, iv);
		crypto_xor_cpy(iv, dst, src, bsize);

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

	return nbytes;
}

static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,
				       struct skcipher_walk *walk,
				       struct crypto_cipher *tfm)
{
	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);
		crypto_cipher_encrypt_one(tfm, src, iv);
		crypto_xor_cpy(iv, tmpbuf, src, bsize);

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

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

	return nbytes;
}

static int crypto_pcbc_encrypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_cipher *child = ctx->child;
	struct skcipher_walk walk;
	unsigned int nbytes;
	int err;

	err = skcipher_walk_virt(&walk, req, false);

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

	return err;
}

static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,
				       struct skcipher_walk *walk,
				       struct crypto_cipher *tfm)
{
	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_cipher_decrypt_one(tfm, dst, src);
		crypto_xor(dst, iv, bsize);
		crypto_xor_cpy(iv, dst, src, bsize);

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

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

	return nbytes;
}

static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,
				       struct skcipher_walk *walk,
				       struct crypto_cipher *tfm)
{
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *iv = walk->iv;
	u8 tmpbuf[bsize] __aligned(__alignof__(u32));

	do {
		memcpy(tmpbuf, src, bsize);
		crypto_cipher_decrypt_one(tfm, src, src);
		crypto_xor(src, iv, bsize);
		crypto_xor_cpy(iv, src, tmpbuf, bsize);

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

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

	return nbytes;
}

static int crypto_pcbc_decrypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_cipher *child = ctx->child;
	struct skcipher_walk walk;
	unsigned int nbytes;
	int err;

	err = skcipher_walk_virt(&walk, req, false);

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

	return err;
}

static int crypto_pcbc_init_tfm(struct crypto_skcipher *tfm)
{
	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
	struct crypto_pcbc_ctx *ctx = crypto_skcipher_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_skcipher *tfm)
{
	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);

	crypto_free_cipher(ctx->child);
}

static void crypto_pcbc_free(struct skcipher_instance *inst)
{
	crypto_drop_skcipher(skcipher_instance_ctx(inst));
	kfree(inst);
}

static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	struct skcipher_instance *inst;
	struct crypto_attr_type *algt;
	struct crypto_spawn *spawn;
	struct crypto_alg *alg;
	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) &
	    ~CRYPTO_ALG_INTERNAL)
		return -EINVAL;

	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
	if (!inst)
		return -ENOMEM;

	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER |
				      (algt->type & CRYPTO_ALG_INTERNAL),
				  CRYPTO_ALG_TYPE_MASK |
				  (algt->mask & CRYPTO_ALG_INTERNAL));
	err = PTR_ERR(alg);
	if (IS_ERR(alg))
		goto err_free_inst;

	spawn = skcipher_instance_ctx(inst);
	err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
				CRYPTO_ALG_TYPE_MASK);
	crypto_mod_put(alg);
	if (err)
		goto err_free_inst;

	err = crypto_inst_setname(skcipher_crypto_instance(inst), "pcbc", alg);
	if (err)
		goto err_drop_spawn;

	inst->alg.base.cra_flags = alg->cra_flags & CRYPTO_ALG_INTERNAL;
	inst->alg.base.cra_priority = alg->cra_priority;
	inst->alg.base.cra_blocksize = alg->cra_blocksize;
	inst->alg.base.cra_alignmask = alg->cra_alignmask;

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

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

	inst->alg.init = crypto_pcbc_init_tfm;
	inst->alg.exit = crypto_pcbc_exit_tfm;

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

	inst->free = crypto_pcbc_free;

	err = skcipher_register_instance(tmpl, inst);
	if (err)
		goto err_drop_spawn;

out:
	return err;

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

static struct crypto_template crypto_pcbc_tmpl = {
	.name = "pcbc",
	.create = crypto_pcbc_create,
	.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");
MODULE_ALIAS_CRYPTO("pcbc");
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 ([email protected])
	6	*
	7	* Derived from cbc.c
	8	* - Copyright (c) 2006 Herbert Xu <[email protected]>
	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
043a4400	17	#include <crypto/internal/skcipher.h>
91652be5 DH	18	#include <linux/err.h>
	19	#include <linux/init.h>
	20	#include <linux/kernel.h>
	21	#include <linux/module.h>
91652be5	22	#include <linux/slab.h>
d8c34b94	23	#include <linux/compiler.h>
91652be5 DH	24
	25	struct crypto_pcbc_ctx {
	26	struct crypto_cipher *child;
91652be5 DH	27	};
91652be5 DH	28
043a4400	29	static int crypto_pcbc_setkey(struct crypto_skcipher parent, const u8 key,
91652be5 DH	30	unsigned int keylen)
91652be5 DH	31	{
043a4400	32	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(parent);
91652be5 DH	33	struct crypto_cipher *child = ctx->child;
	34	int err;
	35
	36	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
043a4400 HX	37	crypto_cipher_set_flags(child, crypto_skcipher_get_flags(parent) &
043a4400 HX	38	CRYPTO_TFM_REQ_MASK);
91652be5	39	err = crypto_cipher_setkey(child, key, keylen);
043a4400 HX	40	crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &
043a4400 HX	41	CRYPTO_TFM_RES_MASK);
91652be5 DH	42	return err;
	43	}
	44
043a4400 HX	45	static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,
043a4400 HX	46	struct skcipher_walk *walk,
d0b9007a	47	struct crypto_cipher *tfm)
91652be5	48	{
91652be5 DH	49	int bsize = crypto_cipher_blocksize(tfm);
	50	unsigned int nbytes = walk->nbytes;
	51	u8 *src = walk->src.virt.addr;
	52	u8 *dst = walk->dst.virt.addr;
	53	u8 *iv = walk->iv;
	54
	55	do {
d0b9007a	56	crypto_xor(iv, src, bsize);
043a4400	57	crypto_cipher_encrypt_one(tfm, dst, iv);
45fe93df	58	crypto_xor_cpy(iv, dst, src, bsize);
91652be5 DH	59
	60	src += bsize;
	61	dst += bsize;
	62	} while ((nbytes -= bsize) >= bsize);
	63
	64	return nbytes;
	65	}
	66
043a4400 HX	67	static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,
043a4400 HX	68	struct skcipher_walk *walk,
d0b9007a	69	struct crypto_cipher *tfm)
91652be5	70	{
91652be5 DH	71	int bsize = crypto_cipher_blocksize(tfm);
	72	unsigned int nbytes = walk->nbytes;
	73	u8 *src = walk->src.virt.addr;
	74	u8 *iv = walk->iv;
	75	u8 tmpbuf[bsize];
	76
	77	do {
	78	memcpy(tmpbuf, src, bsize);
d0b9007a	79	crypto_xor(iv, src, bsize);
043a4400	80	crypto_cipher_encrypt_one(tfm, src, iv);
45fe93df	81	crypto_xor_cpy(iv, tmpbuf, src, bsize);
91652be5 DH	82
	83	src += bsize;
	84	} while ((nbytes -= bsize) >= bsize);
	85
	86	memcpy(walk->iv, iv, bsize);
	87
	88	return nbytes;
	89	}
	90
043a4400	91	static int crypto_pcbc_encrypt(struct skcipher_request *req)
91652be5	92	{
043a4400 HX	93	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
043a4400 HX	94	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
91652be5	95	struct crypto_cipher *child = ctx->child;
043a4400 HX	96	struct skcipher_walk walk;
043a4400 HX	97	unsigned int nbytes;
91652be5 DH	98	int err;
91652be5 DH	99
043a4400	100	err = skcipher_walk_virt(&walk, req, false);
91652be5 DH	101
	102	while ((nbytes = walk.nbytes)) {
	103	if (walk.src.virt.addr == walk.dst.virt.addr)
043a4400	104	nbytes = crypto_pcbc_encrypt_inplace(req, &walk,
d0b9007a	105	child);
91652be5	106	else
043a4400	107	nbytes = crypto_pcbc_encrypt_segment(req, &walk,
d0b9007a	108	child);
043a4400	109	err = skcipher_walk_done(&walk, nbytes);
91652be5 DH	110	}
	111
	112	return err;
	113	}
	114
043a4400 HX	115	static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,
043a4400 HX	116	struct skcipher_walk *walk,
d0b9007a	117	struct crypto_cipher *tfm)
91652be5	118	{
91652be5 DH	119	int bsize = crypto_cipher_blocksize(tfm);
	120	unsigned int nbytes = walk->nbytes;
	121	u8 *src = walk->src.virt.addr;
	122	u8 *dst = walk->dst.virt.addr;
	123	u8 *iv = walk->iv;
	124
	125	do {
043a4400	126	crypto_cipher_decrypt_one(tfm, dst, src);
d0b9007a	127	crypto_xor(dst, iv, bsize);
45fe93df	128	crypto_xor_cpy(iv, dst, src, bsize);
91652be5 DH	129
	130	src += bsize;
	131	dst += bsize;
	132	} while ((nbytes -= bsize) >= bsize);
	133
	134	memcpy(walk->iv, iv, bsize);
	135
	136	return nbytes;
	137	}
	138
043a4400 HX	139	static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,
043a4400 HX	140	struct skcipher_walk *walk,
d0b9007a	141	struct crypto_cipher *tfm)
91652be5	142	{
91652be5 DH	143	int bsize = crypto_cipher_blocksize(tfm);
	144	unsigned int nbytes = walk->nbytes;
	145	u8 *src = walk->src.virt.addr;
	146	u8 *iv = walk->iv;
d8c34b94	147	u8 tmpbuf[bsize] __aligned(__alignof__(u32));
91652be5 DH	148
	149	do {
	150	memcpy(tmpbuf, src, bsize);
043a4400	151	crypto_cipher_decrypt_one(tfm, src, src);
d0b9007a	152	crypto_xor(src, iv, bsize);
45fe93df	153	crypto_xor_cpy(iv, src, tmpbuf, bsize);
91652be5 DH	154
	155	src += bsize;
	156	} while ((nbytes -= bsize) >= bsize);
	157
	158	memcpy(walk->iv, iv, bsize);
	159
	160	return nbytes;
	161	}
	162
043a4400	163	static int crypto_pcbc_decrypt(struct skcipher_request *req)
91652be5	164	{
043a4400 HX	165	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
043a4400 HX	166	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
91652be5	167	struct crypto_cipher *child = ctx->child;
043a4400 HX	168	struct skcipher_walk walk;
043a4400 HX	169	unsigned int nbytes;
91652be5 DH	170	int err;
91652be5 DH	171
043a4400	172	err = skcipher_walk_virt(&walk, req, false);
91652be5 DH	173
	174	while ((nbytes = walk.nbytes)) {
	175	if (walk.src.virt.addr == walk.dst.virt.addr)
043a4400	176	nbytes = crypto_pcbc_decrypt_inplace(req, &walk,
d0b9007a	177	child);
91652be5	178	else
043a4400	179	nbytes = crypto_pcbc_decrypt_segment(req, &walk,
d0b9007a	180	child);
043a4400	181	err = skcipher_walk_done(&walk, nbytes);
91652be5 DH	182	}
	183
	184	return err;
	185	}
	186
043a4400	187	static int crypto_pcbc_init_tfm(struct crypto_skcipher *tfm)
91652be5	188	{
043a4400 HX	189	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	190	struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
	191	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
2e306ee0	192	struct crypto_cipher *cipher;
91652be5	193
2e306ee0 HX	194	cipher = crypto_spawn_cipher(spawn);
	195	if (IS_ERR(cipher))
	196	return PTR_ERR(cipher);
91652be5	197
2e306ee0	198	ctx->child = cipher;
91652be5 DH	199	return 0;
	200	}
	201
043a4400	202	static void crypto_pcbc_exit_tfm(struct crypto_skcipher *tfm)
91652be5	203	{
043a4400 HX	204	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
043a4400 HX	205
91652be5 DH	206	crypto_free_cipher(ctx->child);
	207	}
	208
043a4400 HX	209	static void crypto_pcbc_free(struct skcipher_instance *inst)
	210	{
	211	crypto_drop_skcipher(skcipher_instance_ctx(inst));
	212	kfree(inst);
	213	}
	214
	215	static int crypto_pcbc_create(struct crypto_template tmpl, struct rtattr *tb)
91652be5	216	{
043a4400 HX	217	struct skcipher_instance *inst;
	218	struct crypto_attr_type *algt;
	219	struct crypto_spawn *spawn;
91652be5	220	struct crypto_alg *alg;
ebc610e5 HX	221	int err;
ebc610e5 HX	222
043a4400 HX	223	algt = crypto_get_attr_type(tb);
	224	if (IS_ERR(algt))
	225	return PTR_ERR(algt);
	226
	227	if (((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask) &
	228	~CRYPTO_ALG_INTERNAL)
	229	return -EINVAL;
91652be5	230
043a4400 HX	231	inst = kzalloc(sizeof(inst) + sizeof(spawn), GFP_KERNEL);
	232	if (!inst)
	233	return -ENOMEM;
	234
	235	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER \|
	236	(algt->type & CRYPTO_ALG_INTERNAL),
	237	CRYPTO_ALG_TYPE_MASK \|
	238	(algt->mask & CRYPTO_ALG_INTERNAL));
	239	err = PTR_ERR(alg);
91652be5	240	if (IS_ERR(alg))
043a4400 HX	241	goto err_free_inst;
	242
	243	spawn = skcipher_instance_ctx(inst);
	244	err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
	245	CRYPTO_ALG_TYPE_MASK);
	246	crypto_mod_put(alg);
	247	if (err)
	248	goto err_free_inst;
91652be5	249
043a4400 HX	250	err = crypto_inst_setname(skcipher_crypto_instance(inst), "pcbc", alg);
	251	if (err)
	252	goto err_drop_spawn;
91652be5	253
043a4400 HX	254	inst->alg.base.cra_flags = alg->cra_flags & CRYPTO_ALG_INTERNAL;
	255	inst->alg.base.cra_priority = alg->cra_priority;
	256	inst->alg.base.cra_blocksize = alg->cra_blocksize;
	257	inst->alg.base.cra_alignmask = alg->cra_alignmask;
91652be5	258
043a4400 HX	259	inst->alg.ivsize = alg->cra_blocksize;
	260	inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize;
	261	inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize;
91652be5	262
043a4400	263	inst->alg.base.cra_ctxsize = sizeof(struct crypto_pcbc_ctx);
91652be5	264
043a4400 HX	265	inst->alg.init = crypto_pcbc_init_tfm;
043a4400 HX	266	inst->alg.exit = crypto_pcbc_exit_tfm;
91652be5	267
043a4400 HX	268	inst->alg.setkey = crypto_pcbc_setkey;
	269	inst->alg.encrypt = crypto_pcbc_encrypt;
	270	inst->alg.decrypt = crypto_pcbc_decrypt;
91652be5	271
043a4400	272	inst->free = crypto_pcbc_free;
91652be5	273
043a4400 HX	274	err = skcipher_register_instance(tmpl, inst);
	275	if (err)
	276	goto err_drop_spawn;
	277
	278	out:
	279	return err;
	280
	281	err_drop_spawn:
	282	crypto_drop_spawn(spawn);
	283	err_free_inst:
91652be5	284	kfree(inst);
043a4400	285	goto out;
91652be5 DH	286	}
	287
	288	static struct crypto_template crypto_pcbc_tmpl = {
	289	.name = "pcbc",
043a4400	290	.create = crypto_pcbc_create,
91652be5 DH	291	.module = THIS_MODULE,
	292	};
	293
	294	static int __init crypto_pcbc_module_init(void)
	295	{
	296	return crypto_register_template(&crypto_pcbc_tmpl);
	297	}
	298
	299	static void __exit crypto_pcbc_module_exit(void)
	300	{
	301	crypto_unregister_template(&crypto_pcbc_tmpl);
	302	}
	303
	304	module_init(crypto_pcbc_module_init);
	305	module_exit(crypto_pcbc_module_exit);
	306
	307	MODULE_LICENSE("GPL");
	308	MODULE_DESCRIPTION("PCBC block cipher algorithm");
4943ba16	309	MODULE_ALIAS_CRYPTO("pcbc");