/*

 * Copyright 2020-2026 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 <openssl/err.h>

#include <openssl/core_names.h>

#ifndef FIPS_MODULE

#include <openssl/x509.h>

#endif

#include "internal/param_build_set.h"

#include "crypto/dh.h"

#include "dh_local.h"

#include <crypto/asn1.h>

/*

 * The intention with the "backend" source file is to offer backend functions

 * for legacy backends (EVP_PKEY_ASN1_METHOD) and provider implementations

 * alike.

 */

static int dh_ffc_params_fromdata(DH *dh, const OSSL_PARAM params[])

{

    int ret;

    FFC_PARAMS *ffc = ossl_dh_get0_params(dh);

    ret = ossl_ffc_params_fromdata(ffc, params);

    if (ret)

        ossl_dh_cache_named_group(dh); /* This increments dh->dirty_cnt */

    return ret;

}

int ossl_dh_params_fromdata(DH *dh, const OSSL_PARAM params[])

{

    const OSSL_PARAM *param_priv_len;

    long priv_len;

    if (!dh_ffc_params_fromdata(dh, params))

        return 0;

    param_priv_len = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_DH_PRIV_LEN);

    if (param_priv_len != NULL

        && (!OSSL_PARAM_get_long(param_priv_len, &priv_len)

            || !DH_set_length(dh, priv_len)))

        return 0;

    return 1;

}

int ossl_dh_key_fromdata(DH *dh, const OSSL_PARAM params[], int include_private)

{

    const OSSL_PARAM *param_priv_key, *param_pub_key;

    BIGNUM *priv_key = NULL, *pub_key = NULL;

    if (dh == NULL)

        return 0;

    param_priv_key = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_PRIV_KEY);

    param_pub_key = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_PUB_KEY);

    if (include_private

        && param_priv_key != NULL

        && !OSSL_PARAM_get_BN(param_priv_key, &priv_key))

        goto err;

    if (param_pub_key != NULL

        && !OSSL_PARAM_get_BN(param_pub_key, &pub_key))

        goto err;

    if (!DH_set0_key(dh, pub_key, priv_key))

        goto err;

    return 1;

err:

    BN_clear_free(priv_key);

    BN_free(pub_key);

    return 0;

}

int ossl_dh_params_todata(DH *dh, OSSL_PARAM_BLD *bld, OSSL_PARAM *privlen,

    const FFC_OSSL_PARAMS *pp)

{

    const long l = DH_get_length(dh);

    if (!ossl_ffc_params_todata(ossl_dh_get0_params(dh), bld, pp))

        return 0;

    if (l > 0

        && !ossl_param_build_set_long(bld, privlen, OSSL_PKEY_PARAM_DH_PRIV_LEN, l))

        return 0;

    return 1;

}

int ossl_dh_key_todata(DH *dh, OSSL_PARAM_BLD *bld, OSSL_PARAM *pubkey,

    OSSL_PARAM *privkey, int include_private)

{

    const BIGNUM *priv = NULL, *pub = NULL;

    if (dh == NULL)

        return 0;

    DH_get0_key(dh, &pub, &priv);

    if (priv != NULL

        && include_private

        && !ossl_param_build_set_bn(bld, privkey, OSSL_PKEY_PARAM_PRIV_KEY, priv))

        return 0;

    if (pub != NULL

        && !ossl_param_build_set_bn(bld, pubkey, OSSL_PKEY_PARAM_PUB_KEY, pub))

        return 0;

    return 1;

}

int ossl_dh_is_foreign(const DH *dh)

{

#ifndef FIPS_MODULE

    if (ossl_dh_get_method(dh) != DH_OpenSSL())

        return 1;

#endif

    return 0;

}

static ossl_inline int dh_bn_dup_check(BIGNUM **out, const BIGNUM *f)

{

    if (f != NULL && (*out = BN_dup(f)) == NULL)

        return 0;

    return 1;

}

DH *ossl_dh_dup(const DH *dh, int selection)

{

    DH *dupkey = NULL;

    /* Do not try to duplicate foreign DH keys */

    if (ossl_dh_is_foreign(dh))

        return NULL;

    if ((dupkey = ossl_dh_new_ex(dh->libctx)) == NULL)

        return NULL;

    dupkey->length = DH_get_length(dh);

    if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0

        && !ossl_ffc_params_copy(&dupkey->params, &dh->params))

        goto err;

    dupkey->flags = dh->flags;

    if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0

        && ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0

            || !dh_bn_dup_check(&dupkey->pub_key, dh->pub_key)))

        goto err;

    if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0

        && ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0

            || !dh_bn_dup_check(&dupkey->priv_key, dh->priv_key)))

        goto err;

#ifndef FIPS_MODULE

    if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_DH,

            &dupkey->ex_data, &dh->ex_data))

        goto err;

#endif

    return dupkey;

err:

    DH_free(dupkey);

    return NULL;

}

#ifndef FIPS_MODULE

DH *ossl_dh_key_from_pkcs8(const PKCS8_PRIV_KEY_INFO *p8inf,

    OSSL_LIB_CTX *libctx, const char *propq)

{

    const unsigned char *p, *pm;

    int pklen, pmlen;

    int ptype;

    const void *pval;

    const ASN1_STRING *pstr;

    const X509_ALGOR *palg;

    BIGNUM *privkey_bn = NULL;

    ASN1_INTEGER *privkey = NULL;

    DH *dh = NULL;

    if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8inf))

        return 0;

    X509_ALGOR_get0(NULL, &ptype, &pval, palg);

    if (ptype != V_ASN1_SEQUENCE)

        goto decerr;

    if ((privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL)

        goto decerr;

    pstr = pval;

    pm = pstr->data;

    pmlen = pstr->length;

    switch (OBJ_obj2nid(palg->algorithm)) {

    case NID_dhKeyAgreement:

        dh = d2i_DHparams(NULL, &pm, pmlen);

        break;

    case NID_dhpublicnumber:

        dh = d2i_DHxparams(NULL, &pm, pmlen);

        break;

    default:

        goto decerr;

    }

    if (dh == NULL)

        goto decerr;

    /* We have parameters now set private key */

    if ((privkey_bn = BN_secure_new()) == NULL

        || !ASN1_INTEGER_to_BN(privkey, privkey_bn)) {

        ERR_raise(ERR_LIB_DH, DH_R_BN_ERROR);

        BN_clear_free(privkey_bn);

        goto dherr;

    }

    if (!DH_set0_key(dh, NULL, privkey_bn))

        goto dherr;

    /* Calculate public key, increments dirty_cnt */

    if (!DH_generate_key(dh))

        goto dherr;

    goto done;

decerr:

    ERR_raise(ERR_LIB_DH, DH_R_DECODE_ERROR);

dherr:

    DH_free(dh);

    dh = NULL;

done:

    ASN1_STRING_clear_free(privkey);

    return dh;

}

#endif