linux-imx

// SPDX-License-Identifier: GPL-2.0-or-later

/* ECDH key-agreement protocol

 *

 * Copyright (c) 2016, Intel Corporation

 * Authors: Salvator Benedetto <salvatore.benedetto@intel.com>

 */

​

#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];

};

​

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 ECC_CURVE_NIST_P192_DIGITS;

    case ECC_CURVE_NIST_P256: return ECC_CURVE_NIST_P256_DIGITS;

    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 (!params.key || !params.key_size)

        return ecc_gen_privkey(ctx->curve_id, ctx->ndigits,

                       ctx->private_key);

​

    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;

}