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/*
* Copyright (c) 2016, Intel Corporation
* Authors: Salvatore 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/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, ¶ms->curve_id, sizeof(params->curve_id));
ptr = ecdh_pack_data(ptr, ¶ms->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;
if (unlikely(len < secret.len))
return -EINVAL;
ptr = ecdh_unpack_data(¶ms->curve_id, ptr, sizeof(params->curve_id));
ptr = ecdh_unpack_data(¶ms->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);
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