/*

 * Copyright 2007-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stdio.h>

#include "internal/cryptlib.h"

#include <openssl/evp.h>

#include "crypto/asn1.h"

#include "crypto/evp.h"

/*

 * HMAC "ASN1" method. This is just here to indicate the maximum HMAC output

 * length and to free up an HMAC key.

 */

static int hmac_size(const EVP_PKEY *pkey)

{

    return EVP_MAX_MD_SIZE;

}

static void hmac_key_free(EVP_PKEY *pkey)

{

    ASN1_OCTET_STRING *os = EVP_PKEY_get0(pkey);

    if (os) {

        if (os->data)

            OPENSSL_cleanse(os->data, os->length);

        ASN1_OCTET_STRING_free(os);

    }

}

static int hmac_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)

{

    switch (op) {

    case ASN1_PKEY_CTRL_DEFAULT_MD_NID:

        *(int *)arg2 = NID_sha256;

        return 1;

    default:

        return -2;

    }

}

static int hmac_pkey_public_cmp(const EVP_PKEY *a, const EVP_PKEY *b)

{

    /* the ameth pub_cmp must return 1 on match, 0 on mismatch */

    return ASN1_OCTET_STRING_cmp(EVP_PKEY_get0(a), EVP_PKEY_get0(b)) == 0;

}

static int hmac_set_priv_key(EVP_PKEY *pkey, const unsigned char *priv,

                             size_t len)

{

    ASN1_OCTET_STRING *os;

    if (pkey->pkey.ptr != NULL)

        return 0;

    os = ASN1_OCTET_STRING_new();

    if (os == NULL)

        return 0;

    if (!ASN1_OCTET_STRING_set(os, priv, len)) {

        ASN1_OCTET_STRING_free(os);

        return 0;

    }

    pkey->pkey.ptr = os;

    return 1;

}

static int hmac_get_priv_key(const EVP_PKEY *pkey, unsigned char *priv,

                             size_t *len)

{

    ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;

    if (priv == NULL) {

        *len = ASN1_STRING_length(os);

        return 1;

    }

    if (os == NULL || *len < (size_t)ASN1_STRING_length(os))

        return 0;

    *len = ASN1_STRING_length(os);

    memcpy(priv, ASN1_STRING_get0_data(os), *len);

    return 1;

}

const EVP_PKEY_ASN1_METHOD hmac_asn1_meth = {

    EVP_PKEY_HMAC,

    EVP_PKEY_HMAC,

    0,

    "HMAC",

    "OpenSSL HMAC method",

    0, 0, hmac_pkey_public_cmp, 0,

    0, 0, 0,

    hmac_size,

    0, 0,

    0, 0, 0, 0, 0, 0, 0,

    hmac_key_free,

    hmac_pkey_ctrl,

    NULL,

    NULL,

    NULL,

    NULL,

    NULL,

    NULL,

    NULL,

    NULL,

    hmac_set_priv_key,

    NULL,

    hmac_get_priv_key,

    NULL,

};