/*
 * Copyright 1995-2026 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 <stdio.h>
#include <openssl/bn.h>
#include <openssl/obj_mac.h>
#include <openssl/core_names.h>
#include "internal/cryptlib.h"
#include "internal/refcount.h"
#include "internal/common.h"
#include "crypto/evp.h"
#include "crypto/dh.h"
#include "dh_local.h"

static DH *dh_new_intern(OSSL_LIB_CTX *libctx);

#ifndef FIPS_MODULE
int DH_set_method(DH *dh, const DH_METHOD *meth)
{
    /*
     * NB: The caller is specifically setting a method, so it's not up to us
     * to deal with which ENGINE it comes from.
     */
    const DH_METHOD *mtmp;
    mtmp = dh->meth;
    if (mtmp->finish)
        mtmp->finish(dh);
    dh->meth = meth;
    if (meth->init)
        meth->init(dh);
    return 1;
}

const DH_METHOD *ossl_dh_get_method(const DH *dh)
{
    return dh->meth;
}
#ifndef OPENSSL_NO_DEPRECATED_3_0
DH *DH_new(void)
{
    return dh_new_intern(NULL);
}
#endif

DH *DH_new_method(ENGINE *engine)
{
    if (!ossl_assert(engine == NULL))
        return NULL;
    return dh_new_intern(NULL);
}
#endif /* !FIPS_MODULE */

DH *ossl_dh_new_ex(OSSL_LIB_CTX *libctx)
{
    return dh_new_intern(libctx);
}

static DH *dh_new_intern(OSSL_LIB_CTX *libctx)
{
    DH *ret = OPENSSL_zalloc(sizeof(*ret));

    if (ret == NULL)
        return NULL;

    ret->lock = CRYPTO_THREAD_lock_new();
    if (ret->lock == NULL) {
        ERR_raise(ERR_LIB_DH, ERR_R_CRYPTO_LIB);
        OPENSSL_free(ret);
        return NULL;
    }

    if (!CRYPTO_NEW_REF(&ret->references, 1)) {
        CRYPTO_THREAD_lock_free(ret->lock);
        OPENSSL_free(ret);
        return NULL;
    }

    ret->libctx = libctx;
    ret->meth = DH_get_default_method();
    ret->flags = ret->meth->flags;

#ifndef FIPS_MODULE
    if (!CRYPTO_new_ex_data(CRYPTO_EX_INDEX_DH, ret, &ret->ex_data))
        goto err;
#endif /* FIPS_MODULE */

    ossl_ffc_params_init(&ret->params);

    if ((ret->meth->init != NULL) && !ret->meth->init(ret)) {
        ERR_raise(ERR_LIB_DH, ERR_R_INIT_FAIL);
        goto err;
    }

    return ret;

err:
    DH_free(ret);
    return NULL;
}

void DH_free(DH *r)
{
    int i;

    if (r == NULL)
        return;

    CRYPTO_DOWN_REF(&r->references, &i);
    REF_PRINT_COUNT("DH", i, r);
    if (i > 0)
        return;
    REF_ASSERT_ISNT(i < 0);

    if (r->meth != NULL && r->meth->finish != NULL)
        r->meth->finish(r);
#if !defined(FIPS_MODULE)
    CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DH, r, &r->ex_data);
#endif

    CRYPTO_THREAD_lock_free(r->lock);
    CRYPTO_FREE_REF(&r->references);

    ossl_ffc_params_cleanup(&r->params);
    BN_clear_free(r->pub_key);
    BN_clear_free(r->priv_key);
    OPENSSL_free(r);
}

int DH_up_ref(DH *r)
{
    int i;

    if (CRYPTO_UP_REF(&r->references, &i) <= 0)
        return 0;

    REF_PRINT_COUNT("DH", i, r);
    REF_ASSERT_ISNT(i < 2);
    return ((i > 1) ? 1 : 0);
}

OSSL_LIB_CTX *ossl_dh_get0_libctx(const DH *dh)
{
    return dh->libctx;
}

void ossl_dh_set0_libctx(DH *d, OSSL_LIB_CTX *libctx)
{
    d->libctx = libctx;
}

#ifndef FIPS_MODULE
int DH_set_ex_data(DH *d, int idx, void *arg)
{
    return CRYPTO_set_ex_data(&d->ex_data, idx, arg);
}

void *DH_get_ex_data(const DH *d, int idx)
{
    return CRYPTO_get_ex_data(&d->ex_data, idx);
}
#endif

int DH_bits(const DH *dh)
{
    if (dh->params.p != NULL)
        return BN_num_bits(dh->params.p);
    return -1;
}

int DH_size(const DH *dh)
{
    if (dh->params.p != NULL)
        return BN_num_bytes(dh->params.p);
    return -1;
}

int DH_security_bits(const DH *dh)
{
    int N;

    if (dh->params.q != NULL)
        N = BN_num_bits(dh->params.q);
    else if (dh->length)
        N = dh->length;
    else
        N = -1;
    if (dh->params.p != NULL)
        return BN_security_bits(BN_num_bits(dh->params.p), N);
    return -1;
}

void DH_get0_pqg(const DH *dh,
    const BIGNUM **p, const BIGNUM **q, const BIGNUM **g)
{
    ossl_ffc_params_get0_pqg(&dh->params, p, q, g);
}

int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g)
{
    /*
     * If the fields p and g in dh are NULL, the corresponding input
     * parameters MUST be non-NULL.  q may remain NULL.
     */
    if ((dh->params.p == NULL && p == NULL)
        || (dh->params.g == NULL && g == NULL))
        return 0;

    ossl_ffc_params_set0_pqg(&dh->params, p, q, g);
    ossl_dh_cache_named_group(dh);
    dh->dirty_cnt++;
    return 1;
}

long DH_get_length(const DH *dh)
{
    return dh->length;
}

int DH_set_length(DH *dh, long length)
{
    dh->length = length;
    dh->dirty_cnt++;
    return 1;
}

void DH_get0_key(const DH *dh, const BIGNUM **pub_key, const BIGNUM **priv_key)
{
    if (pub_key != NULL)
        *pub_key = dh->pub_key;
    if (priv_key != NULL)
        *priv_key = dh->priv_key;
}

int DH_set0_key(DH *dh, BIGNUM *pub_key, BIGNUM *priv_key)
{
    if (pub_key != NULL) {
        BN_clear_free(dh->pub_key);
        dh->pub_key = pub_key;
    }
    if (priv_key != NULL) {
        BN_clear_free(dh->priv_key);
        dh->priv_key = priv_key;
    }

    dh->dirty_cnt++;
    return 1;
}

const BIGNUM *DH_get0_p(const DH *dh)
{
    return dh->params.p;
}

const BIGNUM *DH_get0_q(const DH *dh)
{
    return dh->params.q;
}

const BIGNUM *DH_get0_g(const DH *dh)
{
    return dh->params.g;
}

const BIGNUM *DH_get0_priv_key(const DH *dh)
{
    return dh->priv_key;
}

const BIGNUM *DH_get0_pub_key(const DH *dh)
{
    return dh->pub_key;
}

void DH_clear_flags(DH *dh, int flags)
{
    dh->flags &= ~flags;
}

int DH_test_flags(const DH *dh, int flags)
{
    return dh->flags & flags;
}

void DH_set_flags(DH *dh, int flags)
{
    dh->flags |= flags;
}

FFC_PARAMS *ossl_dh_get0_params(DH *dh)
{
    return &dh->params;
}
int ossl_dh_get0_nid(const DH *dh)
{
    return dh->params.nid;
}
