[GitHub/LineageOS/android_kernel_motorola_exynos9610.git] / crypto / ecdh.c

/* ECDH key-agreement protocol
 *
 * Copyright (c) 2016, Intel Corporation
 * Authors: Salvator Benedetto <salvatore.benedetto@intel.com>
 *
 * 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 <linux/module.h>
#include <crypto/internal/kpp.h>
#include <crypto/kpp.h>
#include <crypto/ecdh.h>
#include <linux/scatterlist.h>
#include "ecc.h"

struct ecdh_ctx {
	unsigned int curve_id;
	unsigned int ndigits;
	u64 private_key[ECC_MAX_DIGITS];
	u64 public_key[2 * ECC_MAX_DIGITS];
	u64 shared_secret[ECC_MAX_DIGITS];
};

static inline struct ecdh_ctx *ecdh_get_ctx(struct crypto_kpp *tfm)
{
	return kpp_tfm_ctx(tfm);
}

static unsigned int ecdh_supported_curve(unsigned int curve_id)
{
	switch (curve_id) {
	case ECC_CURVE_NIST_P192: return 3;
	case ECC_CURVE_NIST_P256: return 4;
	default: return 0;
	}
}

static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
			   unsigned int len)
{
	struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
	struct ecdh params;
	unsigned int ndigits;

	if (crypto_ecdh_decode_key(buf, len, &params) < 0)
		return -EINVAL;

	ndigits = ecdh_supported_curve(params.curve_id);
	if (!ndigits)
		return -EINVAL;

	ctx->curve_id = params.curve_id;
	ctx->ndigits = ndigits;

	if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits,
			     (const u64 *)params.key, params.key_size) < 0)
		return -EINVAL;

	memcpy(ctx->private_key, params.key, params.key_size);

	return 0;
}

static int ecdh_compute_value(struct kpp_request *req)
{
	int ret = 0;
	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
	struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
	size_t copied, nbytes;
	void *buf;

	nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;

	if (req->src) {
		copied = sg_copy_to_buffer(req->src, 1, ctx->public_key,
					   2 * nbytes);
		if (copied != 2 * nbytes)
			return -EINVAL;

		ret = crypto_ecdh_shared_secret(ctx->curve_id, ctx->ndigits,
						ctx->private_key,
						ctx->public_key,
						ctx->shared_secret);

		buf = ctx->shared_secret;
	} else {
		ret = ecdh_make_pub_key(ctx->curve_id, ctx->ndigits,
					ctx->private_key, ctx->public_key);
		buf = ctx->public_key;
		/* Public part is a point thus it has both coordinates */
		nbytes *= 2;
	}

	if (ret < 0)
		return ret;

	copied = sg_copy_from_buffer(req->dst, 1, buf, nbytes);
	if (copied != nbytes)
		return -EINVAL;

	return ret;
}

static int ecdh_max_size(struct crypto_kpp *tfm)
{
	struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
	int nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;

	/* Public key is made of two coordinates */
	return 2 * nbytes;
}

static void no_exit_tfm(struct crypto_kpp *tfm)
{
	return;
}

static struct kpp_alg ecdh = {
	.set_secret = ecdh_set_secret,
	.generate_public_key = ecdh_compute_value,
	.compute_shared_secret = ecdh_compute_value,
	.max_size = ecdh_max_size,
	.exit = no_exit_tfm,
	.base = {
		.cra_name = "ecdh",
		.cra_driver_name = "ecdh-generic",
		.cra_priority = 100,
		.cra_module = THIS_MODULE,
		.cra_ctxsize = sizeof(struct ecdh_ctx),
	},
};

static int ecdh_init(void)
{
	return crypto_register_kpp(&ecdh);
}

static void ecdh_exit(void)
{
	crypto_unregister_kpp(&ecdh);
}

module_init(ecdh_init);
module_exit(ecdh_exit);
MODULE_ALIAS_CRYPTO("ecdh");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ECDH generic algorithm");
Commit	Line	Data
3c4b2390 SB	1	/* ECDH key-agreement protocol
	2	*
	3	* Copyright (c) 2016, Intel Corporation
	4	* Authors: Salvator Benedetto <salvatore.benedetto@intel.com>
	5	*
	6	* This program is free software; you can redistribute it and/or
c0ca1215	7	* modify it under the terms of the GNU General Public License
3c4b2390	8	* as published by the Free Software Foundation; either version
c0ca1215	9	* 2 of the License, or (at your option) any later version.
3c4b2390 SB	10	*/
	11
	12	#include <linux/module.h>
	13	#include <crypto/internal/kpp.h>
	14	#include <crypto/kpp.h>
	15	#include <crypto/ecdh.h>
	16	#include <linux/scatterlist.h>
	17	#include "ecc.h"
	18
	19	struct ecdh_ctx {
	20	unsigned int curve_id;
	21	unsigned int ndigits;
	22	u64 private_key[ECC_MAX_DIGITS];
	23	u64 public_key[2 * ECC_MAX_DIGITS];
	24	u64 shared_secret[ECC_MAX_DIGITS];
	25	};
	26
	27	static inline struct ecdh_ctx ecdh_get_ctx(struct crypto_kpp tfm)
	28	{
	29	return kpp_tfm_ctx(tfm);
	30	}
	31
	32	static unsigned int ecdh_supported_curve(unsigned int curve_id)
	33	{
	34	switch (curve_id) {
	35	case ECC_CURVE_NIST_P192: return 3;
	36	case ECC_CURVE_NIST_P256: return 4;
	37	default: return 0;
	38	}
	39	}
	40
5527dfb6 EB	41	static int ecdh_set_secret(struct crypto_kpp tfm, const void buf,
5527dfb6 EB	42	unsigned int len)
3c4b2390 SB	43	{
	44	struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
	45	struct ecdh params;
	46	unsigned int ndigits;
	47
	48	if (crypto_ecdh_decode_key(buf, len, &params) < 0)
	49	return -EINVAL;
	50
	51	ndigits = ecdh_supported_curve(params.curve_id);
	52	if (!ndigits)
	53	return -EINVAL;
	54
	55	ctx->curve_id = params.curve_id;
	56	ctx->ndigits = ndigits;
	57
	58	if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits,
ad269597	59	(const u64 *)params.key, params.key_size) < 0)
3c4b2390 SB	60	return -EINVAL;
	61
	62	memcpy(ctx->private_key, params.key, params.key_size);
	63
	64	return 0;
	65	}
	66
	67	static int ecdh_compute_value(struct kpp_request *req)
	68	{
	69	int ret = 0;
	70	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
	71	struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
	72	size_t copied, nbytes;
	73	void *buf;
	74
	75	nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
	76
	77	if (req->src) {
	78	copied = sg_copy_to_buffer(req->src, 1, ctx->public_key,
	79	2 * nbytes);
	80	if (copied != 2 * nbytes)
	81	return -EINVAL;
	82
8f44df15	83	ret = crypto_ecdh_shared_secret(ctx->curve_id, ctx->ndigits,
ad269597 TDA	84	ctx->private_key,
	85	ctx->public_key,
	86	ctx->shared_secret);
3c4b2390 SB	87
	88	buf = ctx->shared_secret;
	89	} else {
	90	ret = ecdh_make_pub_key(ctx->curve_id, ctx->ndigits,
ad269597	91	ctx->private_key, ctx->public_key);
3c4b2390 SB	92	buf = ctx->public_key;
	93	/* Public part is a point thus it has both coordinates */
	94	nbytes *= 2;
	95	}
	96
	97	if (ret < 0)
	98	return ret;
	99
	100	copied = sg_copy_from_buffer(req->dst, 1, buf, nbytes);
	101	if (copied != nbytes)
	102	return -EINVAL;
	103
	104	return ret;
	105	}
	106
	107	static int ecdh_max_size(struct crypto_kpp *tfm)
	108	{
	109	struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
	110	int nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
	111
	112	/* Public key is made of two coordinates */
	113	return 2 * nbytes;
	114	}
	115
	116	static void no_exit_tfm(struct crypto_kpp *tfm)
	117	{
	118	return;
	119	}
	120
	121	static struct kpp_alg ecdh = {
	122	.set_secret = ecdh_set_secret,
	123	.generate_public_key = ecdh_compute_value,
	124	.compute_shared_secret = ecdh_compute_value,
	125	.max_size = ecdh_max_size,
	126	.exit = no_exit_tfm,
	127	.base = {
	128	.cra_name = "ecdh",
	129	.cra_driver_name = "ecdh-generic",
	130	.cra_priority = 100,
	131	.cra_module = THIS_MODULE,
	132	.cra_ctxsize = sizeof(struct ecdh_ctx),
	133	},
	134	};
	135
	136	static int ecdh_init(void)
	137	{
	138	return crypto_register_kpp(&ecdh);
	139	}
	140
	141	static void ecdh_exit(void)
	142	{
	143	crypto_unregister_kpp(&ecdh);
	144	}
	145
	146	module_init(ecdh_init);
	147	module_exit(ecdh_exit);
	148	MODULE_ALIAS_CRYPTO("ecdh");
	149	MODULE_LICENSE("GPL");
	150	MODULE_DESCRIPTION("ECDH generic algorithm");