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

struct echainiv_ctx {
	/* aead_geniv_ctx must be first the element */
	struct aead_geniv_ctx geniv;
	struct crypto_blkcipher *null;
	u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
};

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 echainiv_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->geniv.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 - ivsize, info);
	aead_request_set_ad(subreq, req->assoclen + ivsize);

	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 echainiv_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 + crypto_aead_authsize(geniv))
		return -EINVAL;

	aead_request_set_tfm(subreq, ctx->geniv.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);
	if (req->src != req->dst)
		scatterwalk_map_and_copy(req->iv, req->dst,
					 req->assoclen, ivsize, 1);

	return crypto_aead_decrypt(subreq);
}

static int echainiv_encrypt_first(struct aead_request *req)
{
	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	int err = 0;

	spin_lock_bh(&ctx->geniv.lock);
	if (geniv->encrypt != echainiv_encrypt_first)
		goto unlock;

	geniv->encrypt = echainiv_encrypt;
	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
				   crypto_aead_ivsize(geniv));

unlock:
	spin_unlock_bh(&ctx->geniv.lock);

	if (err)
		return err;

	return echainiv_encrypt(req);
}

static int echainiv_init(struct crypto_tfm *tfm)
{
	struct crypto_aead *geniv = __crypto_aead_cast(tfm);
	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	int err;

	spin_lock_init(&ctx->geniv.lock);

	crypto_aead_set_reqsize(geniv, sizeof(struct aead_request));

	ctx->null = crypto_get_default_null_skcipher();
	err = PTR_ERR(ctx->null);
	if (IS_ERR(ctx->null))
		goto out;

	err = aead_geniv_init(tfm);
	if (err)
		goto drop_null;

	ctx->geniv.child = geniv->child;
	geniv->child = geniv;

out:
	return err;

drop_null:
	crypto_put_default_null_skcipher();
	goto out;
}

static void echainiv_exit(struct crypto_tfm *tfm)
{
	struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm);

	crypto_free_aead(ctx->geniv.child);
	crypto_put_default_null_skcipher();
}

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);

	if (alg->base.cra_aead.encrypt)
		goto done;

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

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

	inst->alg.base.cra_init = echainiv_init;
	inst->alg.base.cra_exit = echainiv_exit;

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

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

out:
	return err;

free_inst:
	aead_geniv_free(inst);
	goto out;
}

static int echainiv_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	int err;

	err = crypto_get_default_rng();
	if (err)
		goto out;

	err = echainiv_aead_create(tmpl, tb);
	if (err)
		goto put_rng;

out:
	return err;

put_rng:
	crypto_put_default_rng();
	goto out;
}

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

static struct crypto_template echainiv_tmpl = {
	.name = "echainiv",
	.create = echainiv_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/null.h>
	23	#include <crypto/rng.h>
	24	#include <crypto/scatterwalk.h>
	25	#include <linux/err.h>
	26	#include <linux/init.h>
	27	#include <linux/kernel.h>
	28	#include <linux/mm.h>
	29	#include <linux/module.h>
	30	#include <linux/percpu.h>
	31	#include <linux/spinlock.h>
	32	#include <linux/string.h>
	33
	34	#define MAX_IV_SIZE 16
	35
a10f554f	36	struct echainiv_ctx {
d97de47c HX	37	/* aead_geniv_ctx must be first the element */
d97de47c HX	38	struct aead_geniv_ctx geniv;
a10f554f HX	39	struct crypto_blkcipher *null;
	40	u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
	41	};
	42
	43	static DEFINE_PER_CPU(u32 [MAX_IV_SIZE / sizeof(u32)], echainiv_iv);
	44
a10f554f	45	/* We don't care if we get preempted and read/write IVs from the next CPU. */
622ff875	46	static void echainiv_read_iv(u8 *dst, unsigned size)
a10f554f HX	47	{
	48	u32 a = (u32 )dst;
	49	u32 __percpu *b = echainiv_iv;
	50
	51	for (; size >= 4; size -= 4) {
	52	a++ = this_cpu_read(b);
	53	b++;
	54	}
	55	}
	56
622ff875	57	static void echainiv_write_iv(const u8 *src, unsigned size)
a10f554f HX	58	{
	59	const u32 a = (const u32 )src;
	60	u32 __percpu *b = echainiv_iv;
	61
	62	for (; size >= 4; size -= 4) {
	63	this_cpu_write(b, a);
	64	a++;
	65	b++;
	66	}
	67	}
	68
a10f554f HX	69	static void echainiv_encrypt_complete2(struct aead_request *req, int err)
	70	{
	71	struct aead_request *subreq = aead_request_ctx(req);
	72	struct crypto_aead *geniv;
	73	unsigned int ivsize;
	74
	75	if (err == -EINPROGRESS)
	76	return;
	77
	78	if (err)
	79	goto out;
	80
	81	geniv = crypto_aead_reqtfm(req);
	82	ivsize = crypto_aead_ivsize(geniv);
	83
	84	echainiv_write_iv(subreq->iv, ivsize);
	85
	86	if (req->iv != subreq->iv)
	87	memcpy(req->iv, subreq->iv, ivsize);
	88
	89	out:
	90	if (req->iv != subreq->iv)
	91	kzfree(subreq->iv);
	92	}
	93
	94	static void echainiv_encrypt_complete(struct crypto_async_request *base,
	95	int err)
	96	{
	97	struct aead_request *req = base->data;
	98
	99	echainiv_encrypt_complete2(req, err);
	100	aead_request_complete(req, err);
	101	}
	102
a10f554f HX	103	static int echainiv_encrypt(struct aead_request *req)
	104	{
	105	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	106	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	107	struct aead_request *subreq = aead_request_ctx(req);
	108	crypto_completion_t compl;
	109	void *data;
	110	u8 *info;
823655c9	111	unsigned int ivsize = crypto_aead_ivsize(geniv);
a10f554f HX	112	int err;
a10f554f HX	113
823655c9 HX	114	if (req->cryptlen < ivsize)
	115	return -EINVAL;
	116
d97de47c	117	aead_request_set_tfm(subreq, ctx->geniv.child);
a10f554f HX	118
	119	compl = echainiv_encrypt_complete;
	120	data = req;
	121	info = req->iv;
	122
a10f554f	123	if (req->src != req->dst) {
a10f554f HX	124	struct blkcipher_desc desc = {
	125	.tfm = ctx->null,
	126	};
	127
	128	err = crypto_blkcipher_encrypt(
838c9d56 HX	129	&desc, req->dst, req->src,
838c9d56 HX	130	req->assoclen + req->cryptlen);
a10f554f HX	131	if (err)
	132	return err;
	133	}
	134
	135	if (unlikely(!IS_ALIGNED((unsigned long)info,
	136	crypto_aead_alignmask(geniv) + 1))) {
	137	info = kmalloc(ivsize, req->base.flags &
	138	CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
	139	GFP_ATOMIC);
	140	if (!info)
	141	return -ENOMEM;
	142
	143	memcpy(info, req->iv, ivsize);
	144	}
	145
	146	aead_request_set_callback(subreq, req->base.flags, compl, data);
	147	aead_request_set_crypt(subreq, req->dst, req->dst,
	148	req->cryptlen - ivsize, info);
374d4ad1	149	aead_request_set_ad(subreq, req->assoclen + ivsize);
a10f554f HX	150
	151	crypto_xor(info, ctx->salt, ivsize);
	152	scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
	153	echainiv_read_iv(info, ivsize);
	154
	155	err = crypto_aead_encrypt(subreq);
	156	echainiv_encrypt_complete2(req, err);
	157	return err;
	158	}
	159
a10f554f HX	160	static int echainiv_decrypt(struct aead_request *req)
	161	{
	162	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	163	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	164	struct aead_request *subreq = aead_request_ctx(req);
	165	crypto_completion_t compl;
	166	void *data;
823655c9 HX	167	unsigned int ivsize = crypto_aead_ivsize(geniv);
	168
	169	if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
	170	return -EINVAL;
a10f554f	171
d97de47c	172	aead_request_set_tfm(subreq, ctx->geniv.child);
a10f554f HX	173
	174	compl = req->base.complete;
	175	data = req->base.data;
	176
a10f554f HX	177	aead_request_set_callback(subreq, req->base.flags, compl, data);
	178	aead_request_set_crypt(subreq, req->src, req->dst,
	179	req->cryptlen - ivsize, req->iv);
374d4ad1	180	aead_request_set_ad(subreq, req->assoclen + ivsize);
a10f554f HX	181
	182	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
	183	if (req->src != req->dst)
	184	scatterwalk_map_and_copy(req->iv, req->dst,
	185	req->assoclen, ivsize, 1);
	186
	187	return crypto_aead_decrypt(subreq);
	188	}
	189
a10f554f HX	190	static int echainiv_encrypt_first(struct aead_request *req)
	191	{
	192	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
	193	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	194	int err = 0;
	195
d97de47c	196	spin_lock_bh(&ctx->geniv.lock);
a10f554f HX	197	if (geniv->encrypt != echainiv_encrypt_first)
	198	goto unlock;
	199
	200	geniv->encrypt = echainiv_encrypt;
	201	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
	202	crypto_aead_ivsize(geniv));
	203
	204	unlock:
d97de47c	205	spin_unlock_bh(&ctx->geniv.lock);
a10f554f HX	206
	207	if (err)
	208	return err;
	209
	210	return echainiv_encrypt(req);
	211	}
	212
a10f554f HX	213	static int echainiv_init(struct crypto_tfm *tfm)
	214	{
	215	struct crypto_aead *geniv = __crypto_aead_cast(tfm);
	216	struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
	217	int err;
	218
d97de47c	219	spin_lock_init(&ctx->geniv.lock);
a10f554f HX	220
	221	crypto_aead_set_reqsize(geniv, sizeof(struct aead_request));
	222
	223	ctx->null = crypto_get_default_null_skcipher();
	224	err = PTR_ERR(ctx->null);
	225	if (IS_ERR(ctx->null))
	226	goto out;
	227
	228	err = aead_geniv_init(tfm);
	229	if (err)
	230	goto drop_null;
	231
d97de47c	232	ctx->geniv.child = geniv->child;
a10f554f HX	233	geniv->child = geniv;
	234
	235	out:
	236	return err;
	237
	238	drop_null:
	239	crypto_put_default_null_skcipher();
	240	goto out;
	241	}
	242
a10f554f HX	243	static void echainiv_exit(struct crypto_tfm *tfm)
	244	{
	245	struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm);
	246
d97de47c	247	crypto_free_aead(ctx->geniv.child);
a10f554f HX	248	crypto_put_default_null_skcipher();
	249	}
	250
1e419c79 HX	251	static int echainiv_aead_create(struct crypto_template *tmpl,
1e419c79 HX	252	struct rtattr **tb)
a10f554f HX	253	{
	254	struct aead_instance *inst;
	255	struct crypto_aead_spawn *spawn;
	256	struct aead_alg *alg;
1e419c79	257	int err;
a10f554f	258
1e419c79	259	inst = aead_geniv_alloc(tmpl, tb, 0, 0);
a10f554f HX	260
a10f554f HX	261	if (IS_ERR(inst))
1e419c79	262	return PTR_ERR(inst);
a10f554f	263
d97de47c HX	264	spawn = aead_instance_ctx(inst);
	265	alg = crypto_spawn_aead_alg(spawn);
	266
	267	if (alg->base.cra_aead.encrypt)
	268	goto done;
	269
1e419c79	270	err = -EINVAL;
d97de47c	271	if (inst->alg.ivsize & (sizeof(u32) - 1) \|\|
1e419c79 HX	272	inst->alg.ivsize > MAX_IV_SIZE)
1e419c79 HX	273	goto free_inst;
a10f554f	274
a10f554f HX	275	inst->alg.encrypt = echainiv_encrypt_first;
	276	inst->alg.decrypt = echainiv_decrypt;
	277
	278	inst->alg.base.cra_init = echainiv_init;
	279	inst->alg.base.cra_exit = echainiv_exit;
	280
	281	inst->alg.base.cra_alignmask \|= __alignof__(u32) - 1;
	282	inst->alg.base.cra_ctxsize = sizeof(struct echainiv_ctx);
9d03aee1	283	inst->alg.base.cra_ctxsize += inst->alg.ivsize;
a10f554f	284
d97de47c	285	done:
1e419c79 HX	286	err = aead_register_instance(tmpl, inst);
	287	if (err)
	288	goto free_inst;
	289
a10f554f	290	out:
1e419c79 HX	291	return err;
	292
	293	free_inst:
	294	aead_geniv_free(inst);
	295	goto out;
a10f554f HX	296	}
a10f554f HX	297
1e419c79	298	static int echainiv_create(struct crypto_template tmpl, struct rtattr *tb)
a10f554f	299	{
a10f554f HX	300	int err;
	301
	302	err = crypto_get_default_rng();
	303	if (err)
1e419c79	304	goto out;
a10f554f	305
1e419c79 HX	306	err = echainiv_aead_create(tmpl, tb);
1e419c79 HX	307	if (err)
a10f554f HX	308	goto put_rng;
	309
	310	out:
1e419c79	311	return err;
a10f554f HX	312
	313	put_rng:
	314	crypto_put_default_rng();
	315	goto out;
	316	}
	317
	318	static void echainiv_free(struct crypto_instance *inst)
	319	{
	320	aead_geniv_free(aead_instance(inst));
	321	crypto_put_default_rng();
	322	}
	323
	324	static struct crypto_template echainiv_tmpl = {
	325	.name = "echainiv",
1e419c79	326	.create = echainiv_create,
a10f554f HX	327	.free = echainiv_free,
	328	.module = THIS_MODULE,
	329	};
	330
	331	static int __init echainiv_module_init(void)
	332	{
	333	return crypto_register_template(&echainiv_tmpl);
	334	}
	335
	336	static void __exit echainiv_module_exit(void)
	337	{
	338	crypto_unregister_template(&echainiv_tmpl);
	339	}
	340
	341	module_init(echainiv_module_init);
	342	module_exit(echainiv_module_exit);
	343
	344	MODULE_LICENSE("GPL");
	345	MODULE_DESCRIPTION("Encrypted Chain IV Generator");
	346	MODULE_ALIAS_CRYPTO("echainiv");