[deliverable/linux.git] / crypto / echainiv.c

/*
 * echainiv: Encrypted Chain IV Generator
 *
 * This generator generates an IV based on a sequence number by xoring it
 * with a salt and then encrypting it with the same key as used to encrypt
 * the plain text.  This algorithm requires that the block size be equal
 * to the IV size.  It is mainly useful for CBC.
 *
 * This generator can only be used by algorithms where authentication
 * is performed after encryption (i.e., authenc).
 *
 * Copyright (c) 2015 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/internal/geniv.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/spinlock.h>
#include <linux/string.h>

#define MAX_IV_SIZE 16

static DEFINE_PER_CPU(u32 [MAX_IV_SIZE / sizeof(u32)], echainiv_iv);

/* We don't care if we get preempted and read/write IVs from the next CPU. */
static void echainiv_read_iv(u8 *dst, unsigned size)
{
	u32 *a = (u32 *)dst;
	u32 __percpu *b = echainiv_iv;

	for (; size >= 4; size -= 4) {
		*a++ = this_cpu_read(*b);
		b++;
	}
}

static void echainiv_write_iv(const u8 *src, unsigned size)
{
	const u32 *a = (const u32 *)src;
	u32 __percpu *b = echainiv_iv;

	for (; size >= 4; size -= 4) {
		this_cpu_write(*b, *a);
		a++;
		b++;
	}
}

static void echainiv_encrypt_complete2(struct aead_request *req, int err)
{
	struct aead_request *subreq = aead_request_ctx(req);
	struct crypto_aead *geniv;
	unsigned int ivsize;

	if (err == -EINPROGRESS)
		return;

	if (err)
		goto out;

	geniv = crypto_aead_reqtfm(req);
	ivsize = crypto_aead_ivsize(geniv);

	echainiv_write_iv(subreq->iv, ivsize);

	if (req->iv != subreq->iv)
		memcpy(req->iv, subreq->iv, ivsize);

out:
	if (req->iv != subreq->iv)
		kzfree(subreq->iv);
}

static void echainiv_encrypt_complete(struct crypto_async_request *base,
					 int err)
{
	struct aead_request *req = base->data;

	echainiv_encrypt_complete2(req, err);
	aead_request_complete(req, err);
}

static int echainiv_encrypt(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
	struct aead_request *subreq = aead_request_ctx(req);
	crypto_completion_t compl;
	void *data;
	u8 *info;
	unsigned int ivsize = crypto_aead_ivsize(geniv);
	int err;

	if (req->cryptlen < ivsize)
		return -EINVAL;

	aead_request_set_tfm(subreq, ctx->child);

	compl = echainiv_encrypt_complete;
	data = req;
	info = req->iv;

	if (req->src != req->dst) {
		struct blkcipher_desc desc = {
			.tfm = ctx->null,
		};

		err = crypto_blkcipher_encrypt(
			&desc, req->dst, req->src,
			req->assoclen + req->cryptlen);
		if (err)
			return err;
	}

	if (unlikely(!IS_ALIGNED((unsigned long)info,
				 crypto_aead_alignmask(geniv) + 1))) {
		info = kmalloc(ivsize, req->base.flags &
				       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
								  GFP_ATOMIC);
		if (!info)
			return -ENOMEM;

		memcpy(info, req->iv, ivsize);
	}

	aead_request_set_callback(subreq, req->base.flags, compl, data);
	aead_request_set_crypt(subreq, req->dst, req->dst,
			       req->cryptlen, info);
	aead_request_set_ad(subreq, req->assoclen);

	crypto_xor(info, ctx->salt, ivsize);
	scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
	echainiv_read_iv(info, ivsize);

	err = crypto_aead_encrypt(subreq);
	echainiv_encrypt_complete2(req, err);
	return err;
}

static int echainiv_decrypt(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
	struct aead_request *subreq = aead_request_ctx(req);
	crypto_completion_t compl;
	void *data;
	unsigned int ivsize = crypto_aead_ivsize(geniv);

	if (req->cryptlen < ivsize)
		return -EINVAL;

	aead_request_set_tfm(subreq, ctx->child);

	compl = req->base.complete;
	data = req->base.data;

	aead_request_set_callback(subreq, req->base.flags, compl, data);
	aead_request_set_crypt(subreq, req->src, req->dst,
			       req->cryptlen - ivsize, req->iv);
	aead_request_set_ad(subreq, req->assoclen + ivsize);

	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);

	return crypto_aead_decrypt(subreq);
}

static int echainiv_aead_create(struct crypto_template *tmpl,
				struct rtattr **tb)
{
	struct aead_instance *inst;
	struct crypto_aead_spawn *spawn;
	struct aead_alg *alg;
	int err;

	inst = aead_geniv_alloc(tmpl, tb, 0, 0);

	if (IS_ERR(inst))
		return PTR_ERR(inst);

	spawn = aead_instance_ctx(inst);
	alg = crypto_spawn_aead_alg(spawn);

	err = -EINVAL;
	if (inst->alg.ivsize & (sizeof(u32) - 1) ||
	    inst->alg.ivsize > MAX_IV_SIZE)
		goto free_inst;

	inst->alg.encrypt = echainiv_encrypt;
	inst->alg.decrypt = echainiv_decrypt;

	inst->alg.init = aead_init_geniv;
	inst->alg.exit = aead_exit_geniv;

	inst->alg.base.cra_alignmask |= __alignof__(u32) - 1;
	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
	inst->alg.base.cra_ctxsize += inst->alg.ivsize;

	inst->free = aead_geniv_free;

	err = aead_register_instance(tmpl, inst);
	if (err)
		goto free_inst;

out:
	return err;

free_inst:
	aead_geniv_free(inst);
	goto out;
}

static void echainiv_free(struct crypto_instance *inst)
{
	aead_geniv_free(aead_instance(inst));
}

static struct crypto_template echainiv_tmpl = {
	.name = "echainiv",
	.create = echainiv_aead_create,
	.free = echainiv_free,
	.module = THIS_MODULE,
};

static int __init echainiv_module_init(void)
{
	return crypto_register_template(&echainiv_tmpl);
}

static void __exit echainiv_module_exit(void)
{
	crypto_unregister_template(&echainiv_tmpl);
}

module_init(echainiv_module_init);
module_exit(echainiv_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Encrypted Chain IV Generator");
MODULE_ALIAS_CRYPTO("echainiv");
Commit	Line	Data
a10f554f HX	1	/*
	2	* echainiv: Encrypted Chain IV Generator
	3	*
	4	* This generator generates an IV based on a sequence number by xoring it
	5	* with a salt and then encrypting it with the same key as used to encrypt
	6	* the plain text. This algorithm requires that the block size be equal
	7	* to the IV size. It is mainly useful for CBC.
	8	*
	9	* This generator can only be used by algorithms where authentication
	10	* is performed after encryption (i.e., authenc).
	11	*
	12	* Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
	13	*
	14	* This program is free software; you can redistribute it and/or modify it
	15	* under the terms of the GNU General Public License as published by the Free
	16	* Software Foundation; either version 2 of the License, or (at your option)
	17	* any later version.
	18	*
	19	*/
	20
d97de47c	21	#include <crypto/internal/geniv.h>
a10f554f HX	22	#include <crypto/scatterwalk.h>
	23	#include <linux/err.h>
	24	#include <linux/init.h>
	25	#include <linux/kernel.h>
	26	#include <linux/mm.h>
	27	#include <linux/module.h>
	28	#include <linux/percpu.h>
	29	#include <linux/spinlock.h>
	30	#include <linux/string.h>
	31
	32	#define MAX_IV_SIZE 16
	33
a10f554f HX	34	static DEFINE_PER_CPU(u32 [MAX_IV_SIZE / sizeof(u32)], echainiv_iv);
a10f554f HX	35
a10f554f	36	/* We don't care if we get preempted and read/write IVs from the next CPU. */
622ff875	37	static void echainiv_read_iv(u8 *dst, unsigned size)
a10f554f HX	38	{
	39	u32 a = (u32 )dst;
	40	u32 __percpu *b = echainiv_iv;
	41
	42	for (; size >= 4; size -= 4) {
	43	a++ = this_cpu_read(b);
	44	b++;
	45	}
	46	}
	47
622ff875	48	static void echainiv_write_iv(const u8 *src, unsigned size)
a10f554f HX	49	{
	50	const u32 a = (const u32 )src;
	51	u32 __percpu *b = echainiv_iv;
	52
	53	for (; size >= 4; size -= 4) {
	54	this_cpu_write(b, a);
	55	a++;
	56	b++;
	57	}
	58	}
	59
a10f554f HX	60	static void echainiv_encrypt_complete2(struct aead_request *req, int err)
	61	{
	62	struct aead_request *subreq = aead_request_ctx(req);
	63	struct crypto_aead *geniv;
	64	unsigned int ivsize;
	65
	66	if (err == -EINPROGRESS)
	67	return;
	68
	69	if (err)
	70	goto out;
	71
	72	geniv = crypto_aead_reqtfm(req);
	73	ivsize = crypto_aead_ivsize(geniv);
	74
	75	echainiv_write_iv(subreq->iv, ivsize);
	76
	77	if (req->iv != subreq->iv)
	78	memcpy(req->iv, subreq->iv, ivsize);
	79
	80	out:
	81	if (req->iv != subreq->iv)
	82	kzfree(subreq->iv);
	83	}
	84
	85	static void echainiv_encrypt_complete(struct crypto_async_request *base,
	86	int err)
	87	{
	88	struct aead_request *req = base->data;
	89
	90	echainiv_encrypt_complete2(req, err);
	91	aead_request_complete(req, err);
	92	}
	93
a10f554f HX	94	static int echainiv_encrypt(struct aead_request *req)
	95	{
	96	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
376e0d69	97	struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
a10f554f HX	98	struct aead_request *subreq = aead_request_ctx(req);
	99	crypto_completion_t compl;
	100	void *data;
	101	u8 *info;
823655c9	102	unsigned int ivsize = crypto_aead_ivsize(geniv);
a10f554f HX	103	int err;
a10f554f HX	104
823655c9 HX	105	if (req->cryptlen < ivsize)
	106	return -EINVAL;
	107
376e0d69	108	aead_request_set_tfm(subreq, ctx->child);
a10f554f HX	109
	110	compl = echainiv_encrypt_complete;
	111	data = req;
	112	info = req->iv;
	113
a10f554f	114	if (req->src != req->dst) {
a10f554f HX	115	struct blkcipher_desc desc = {
	116	.tfm = ctx->null,
	117	};
	118
	119	err = crypto_blkcipher_encrypt(
838c9d56 HX	120	&desc, req->dst, req->src,
838c9d56 HX	121	req->assoclen + req->cryptlen);
a10f554f HX	122	if (err)
	123	return err;
	124	}
	125
	126	if (unlikely(!IS_ALIGNED((unsigned long)info,
	127	crypto_aead_alignmask(geniv) + 1))) {
	128	info = kmalloc(ivsize, req->base.flags &
	129	CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
	130	GFP_ATOMIC);
	131	if (!info)
	132	return -ENOMEM;
	133
	134	memcpy(info, req->iv, ivsize);
	135	}
	136
	137	aead_request_set_callback(subreq, req->base.flags, compl, data);
	138	aead_request_set_crypt(subreq, req->dst, req->dst,
5499b1a7 HX	139	req->cryptlen, info);
5499b1a7 HX	140	aead_request_set_ad(subreq, req->assoclen);
a10f554f HX	141
	142	crypto_xor(info, ctx->salt, ivsize);
	143	scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
	144	echainiv_read_iv(info, ivsize);
	145
	146	err = crypto_aead_encrypt(subreq);
	147	echainiv_encrypt_complete2(req, err);
	148	return err;
	149	}
	150
a10f554f HX	151	static int echainiv_decrypt(struct aead_request *req)
	152	{
	153	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
376e0d69	154	struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
a10f554f HX	155	struct aead_request *subreq = aead_request_ctx(req);
	156	crypto_completion_t compl;
	157	void *data;
823655c9 HX	158	unsigned int ivsize = crypto_aead_ivsize(geniv);
823655c9 HX	159
5499b1a7	160	if (req->cryptlen < ivsize)
823655c9	161	return -EINVAL;
a10f554f	162
376e0d69	163	aead_request_set_tfm(subreq, ctx->child);
a10f554f HX	164
	165	compl = req->base.complete;
	166	data = req->base.data;
	167
a10f554f HX	168	aead_request_set_callback(subreq, req->base.flags, compl, data);
	169	aead_request_set_crypt(subreq, req->src, req->dst,
	170	req->cryptlen - ivsize, req->iv);
374d4ad1	171	aead_request_set_ad(subreq, req->assoclen + ivsize);
a10f554f HX	172
a10f554f HX	173	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
a10f554f HX	174
	175	return crypto_aead_decrypt(subreq);
	176	}
	177
1e419c79 HX	178	static int echainiv_aead_create(struct crypto_template *tmpl,
1e419c79 HX	179	struct rtattr **tb)
a10f554f HX	180	{
	181	struct aead_instance *inst;
	182	struct crypto_aead_spawn *spawn;
	183	struct aead_alg *alg;
1e419c79	184	int err;
a10f554f	185
1e419c79	186	inst = aead_geniv_alloc(tmpl, tb, 0, 0);
a10f554f HX	187
a10f554f HX	188	if (IS_ERR(inst))
1e419c79	189	return PTR_ERR(inst);
a10f554f	190
d97de47c HX	191	spawn = aead_instance_ctx(inst);
	192	alg = crypto_spawn_aead_alg(spawn);
	193
1e419c79	194	err = -EINVAL;
d97de47c	195	if (inst->alg.ivsize & (sizeof(u32) - 1) \|\|
1e419c79 HX	196	inst->alg.ivsize > MAX_IV_SIZE)
1e419c79 HX	197	goto free_inst;
a10f554f	198
f261c5fb	199	inst->alg.encrypt = echainiv_encrypt;
a10f554f HX	200	inst->alg.decrypt = echainiv_decrypt;
a10f554f HX	201
376e0d69 HX	202	inst->alg.init = aead_init_geniv;
376e0d69 HX	203	inst->alg.exit = aead_exit_geniv;
a10f554f HX	204
a10f554f HX	205	inst->alg.base.cra_alignmask \|= __alignof__(u32) - 1;
376e0d69	206	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
9d03aee1	207	inst->alg.base.cra_ctxsize += inst->alg.ivsize;
a10f554f	208
5499b1a7 HX	209	inst->free = aead_geniv_free;
5499b1a7 HX	210
1e419c79 HX	211	err = aead_register_instance(tmpl, inst);
	212	if (err)
	213	goto free_inst;
	214
a10f554f	215	out:
1e419c79 HX	216	return err;
	217
	218	free_inst:
	219	aead_geniv_free(inst);
	220	goto out;
a10f554f HX	221	}
a10f554f HX	222
a10f554f HX	223	static void echainiv_free(struct crypto_instance *inst)
	224	{
	225	aead_geniv_free(aead_instance(inst));
a10f554f HX	226	}
	227
	228	static struct crypto_template echainiv_tmpl = {
	229	.name = "echainiv",
9fcc704d	230	.create = echainiv_aead_create,
a10f554f HX	231	.free = echainiv_free,
	232	.module = THIS_MODULE,
	233	};
	234
	235	static int __init echainiv_module_init(void)
	236	{
	237	return crypto_register_template(&echainiv_tmpl);
	238	}
	239
	240	static void __exit echainiv_module_exit(void)
	241	{
	242	crypto_unregister_template(&echainiv_tmpl);
	243	}
	244
	245	module_init(echainiv_module_init);
	246	module_exit(echainiv_module_exit);
	247
	248	MODULE_LICENSE("GPL");
	249	MODULE_DESCRIPTION("Encrypted Chain IV Generator");
	250	MODULE_ALIAS_CRYPTO("echainiv");