[linux.git] / crypto / ecdh_helper.c

/*
 * Copyright (c) 2016, Intel Corporation
 * Authors: Salvatore Benedetto <[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 <linux/kernel.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/string.h>
#include <crypto/ecdh.h>
#include <crypto/kpp.h>

#define ECDH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 2 * sizeof(short))

static inline u8 *ecdh_pack_data(void *dst, const void *src, size_t sz)
{
	memcpy(dst, src, sz);
	return dst + sz;
}

static inline const u8 *ecdh_unpack_data(void *dst, const void *src, size_t sz)
{
	memcpy(dst, src, sz);
	return src + sz;
}

unsigned int crypto_ecdh_key_len(const struct ecdh *params)
{
	return ECDH_KPP_SECRET_MIN_SIZE + params->key_size;
}
EXPORT_SYMBOL_GPL(crypto_ecdh_key_len);

int crypto_ecdh_encode_key(char *buf, unsigned int len,
			   const struct ecdh *params)
{
	u8 *ptr = buf;
	struct kpp_secret secret = {
		.type = CRYPTO_KPP_SECRET_TYPE_ECDH,
		.len = len
	};

	if (unlikely(!buf))
		return -EINVAL;

	if (len != crypto_ecdh_key_len(params))
		return -EINVAL;

	ptr = ecdh_pack_data(ptr, &secret, sizeof(secret));
	ptr = ecdh_pack_data(ptr, &params->curve_id, sizeof(params->curve_id));
	ptr = ecdh_pack_data(ptr, &params->key_size, sizeof(params->key_size));
	ecdh_pack_data(ptr, params->key, params->key_size);

	return 0;
}
EXPORT_SYMBOL_GPL(crypto_ecdh_encode_key);

int crypto_ecdh_decode_key(const char *buf, unsigned int len,
			   struct ecdh *params)
{
	const u8 *ptr = buf;
	struct kpp_secret secret;

	if (unlikely(!buf || len < ECDH_KPP_SECRET_MIN_SIZE))
		return -EINVAL;

	ptr = ecdh_unpack_data(&secret, ptr, sizeof(secret));
	if (secret.type != CRYPTO_KPP_SECRET_TYPE_ECDH)
		return -EINVAL;

	ptr = ecdh_unpack_data(&params->curve_id, ptr, sizeof(params->curve_id));
	ptr = ecdh_unpack_data(&params->key_size, ptr, sizeof(params->key_size));
	if (secret.len != crypto_ecdh_key_len(params))
		return -EINVAL;

	/* Don't allocate memory. Set pointer to data
	 * within the given buffer
	 */
	params->key = (void *)ptr;

	return 0;
}
EXPORT_SYMBOL_GPL(crypto_ecdh_decode_key);
Commit	Line	Data
3c4b2390 SB	1	/*
	2	* Copyright (c) 2016, Intel Corporation
	3	* Authors: Salvatore Benedetto <[email protected]>
	4	*
	5	* This program is free software; you can redistribute it and/or
c0ca1215	6	* modify it under the terms of the GNU General Public License
3c4b2390	7	* as published by the Free Software Foundation; either version
c0ca1215	8	* 2 of the License, or (at your option) any later version.
3c4b2390 SB	9	*/
	10	#include <linux/kernel.h>
	11	#include <linux/export.h>
	12	#include <linux/err.h>
	13	#include <linux/string.h>
	14	#include <crypto/ecdh.h>
	15	#include <crypto/kpp.h>
	16
	17	#define ECDH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 2 * sizeof(short))
	18
	19	static inline u8 ecdh_pack_data(void dst, const void *src, size_t sz)
	20	{
	21	memcpy(dst, src, sz);
	22	return dst + sz;
	23	}
	24
	25	static inline const u8 ecdh_unpack_data(void dst, const void *src, size_t sz)
	26	{
	27	memcpy(dst, src, sz);
	28	return src + sz;
	29	}
	30
6e97e08d	31	unsigned int crypto_ecdh_key_len(const struct ecdh *params)
3c4b2390 SB	32	{
	33	return ECDH_KPP_SECRET_MIN_SIZE + params->key_size;
	34	}
	35	EXPORT_SYMBOL_GPL(crypto_ecdh_key_len);
	36
	37	int crypto_ecdh_encode_key(char *buf, unsigned int len,
	38	const struct ecdh *params)
	39	{
	40	u8 *ptr = buf;
	41	struct kpp_secret secret = {
	42	.type = CRYPTO_KPP_SECRET_TYPE_ECDH,
	43	.len = len
	44	};
	45
	46	if (unlikely(!buf))
	47	return -EINVAL;
	48
	49	if (len != crypto_ecdh_key_len(params))
	50	return -EINVAL;
	51
	52	ptr = ecdh_pack_data(ptr, &secret, sizeof(secret));
	53	ptr = ecdh_pack_data(ptr, &params->curve_id, sizeof(params->curve_id));
	54	ptr = ecdh_pack_data(ptr, &params->key_size, sizeof(params->key_size));
	55	ecdh_pack_data(ptr, params->key, params->key_size);
	56
	57	return 0;
	58	}
	59	EXPORT_SYMBOL_GPL(crypto_ecdh_encode_key);
	60
	61	int crypto_ecdh_decode_key(const char *buf, unsigned int len,
	62	struct ecdh *params)
	63	{
	64	const u8 *ptr = buf;
	65	struct kpp_secret secret;
	66
	67	if (unlikely(!buf \|\| len < ECDH_KPP_SECRET_MIN_SIZE))
	68	return -EINVAL;
	69
	70	ptr = ecdh_unpack_data(&secret, ptr, sizeof(secret));
	71	if (secret.type != CRYPTO_KPP_SECRET_TYPE_ECDH)
	72	return -EINVAL;
	73
	74	ptr = ecdh_unpack_data(&params->curve_id, ptr, sizeof(params->curve_id));
	75	ptr = ecdh_unpack_data(&params->key_size, ptr, sizeof(params->key_size));
	76	if (secret.len != crypto_ecdh_key_len(params))
	77	return -EINVAL;
	78
	79	/* Don't allocate memory. Set pointer to data
	80	* within the given buffer
	81	*/
	82	params->key = (void *)ptr;
	83
	84	return 0;
	85	}
	86	EXPORT_SYMBOL_GPL(crypto_ecdh_decode_key);