/*

 * Copyright 2013-2022 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (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

 */

/*

 * DH low level APIs are deprecated for public use, but still ok for

 * internal use.

 */

#include "internal/deprecated.h"

#include "internal/e_os.h"

#include <string.h>

#include <openssl/core_names.h>

#include <openssl/dh.h>

#include <openssl/evp.h>

#include <openssl/asn1.h>

#include <openssl/kdf.h>

#include "internal/provider.h"

#include "crypto/dh.h"

/* Key derivation function from X9.63/SECG */

int ossl_dh_kdf_X9_42_asn1(unsigned char *out, size_t outlen,

                           const unsigned char *Z, size_t Zlen,

                           const char *cek_alg,

                           const unsigned char *ukm, size_t ukmlen,

                           const EVP_MD *md,

                           OSSL_LIB_CTX *libctx, const char *propq)

{

    int ret = 0;

    EVP_KDF_CTX *kctx = NULL;

    EVP_KDF *kdf = NULL;

    OSSL_PARAM params[5], *p = params;

    const char *mdname = EVP_MD_get0_name(md);

    kdf = EVP_KDF_fetch(libctx, OSSL_KDF_NAME_X942KDF_ASN1, propq);

    if (kdf == NULL)

        return 0;

    kctx = EVP_KDF_CTX_new(kdf);

    if (kctx == NULL)

        goto err;

    *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,

                                            (char *)mdname, 0);

    *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,

                                             (unsigned char *)Z, Zlen);

    if (ukm != NULL)

        *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_UKM,

                                                 (unsigned char *)ukm, ukmlen);

    *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_CEK_ALG,

                                            (char *)cek_alg, 0);

    *p = OSSL_PARAM_construct_end();

    ret = EVP_KDF_derive(kctx, out, outlen, params) > 0;

err:

    EVP_KDF_CTX_free(kctx);

    EVP_KDF_free(kdf);

    return ret;

}

#if !defined(FIPS_MODULE)

int DH_KDF_X9_42(unsigned char *out, size_t outlen,

                 const unsigned char *Z, size_t Zlen,

                 ASN1_OBJECT *key_oid,

                 const unsigned char *ukm, size_t ukmlen, const EVP_MD *md)

{

    char key_alg[OSSL_MAX_NAME_SIZE];

    const OSSL_PROVIDER *prov = EVP_MD_get0_provider(md);

    OSSL_LIB_CTX *libctx = ossl_provider_libctx(prov);

    if (OBJ_obj2txt(key_alg, sizeof(key_alg), key_oid, 0) <= 0)

        return 0;

    return ossl_dh_kdf_X9_42_asn1(out, outlen, Z, Zlen, key_alg,

                                  ukm, ukmlen, md, libctx, NULL);

}

#endif /* !defined(FIPS_MODULE) */