/*

 * Copyright 2006-2025 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/x509.h>

#include <openssl/asn1.h>

#include <openssl/bn.h>

#include <openssl/core_names.h>

#include <openssl/param_build.h>

#include "internal/ffc.h"

#include "internal/cryptlib.h"

#include "crypto/asn1.h"

#include "crypto/dh.h"

#include "crypto/evp.h"

#include "dh_local.h"

/*

 * i2d/d2i like DH parameter functions which use the appropriate routine for

 * PKCS#3 DH or X9.42 DH.

 */

static DH *d2i_dhp(const EVP_PKEY *pkey, const unsigned char **pp,

                   long length)

{

    DH *dh = NULL;

    int is_dhx = (pkey->ameth == &ossl_dhx_asn1_meth);

    if (is_dhx)

        dh = d2i_DHxparams(NULL, pp, length);

    else

        dh = d2i_DHparams(NULL, pp, length);

    return dh;

}

static int i2d_dhp(const EVP_PKEY *pkey, const DH *a, unsigned char **pp)

{

    if (pkey->ameth == &ossl_dhx_asn1_meth)

        return i2d_DHxparams(a, pp);

    return i2d_DHparams(a, pp);

}

static void int_dh_free(EVP_PKEY *pkey)

{

    DH_free(pkey->pkey.dh);

}

static int dh_pub_decode(EVP_PKEY *pkey, const X509_PUBKEY *pubkey)

{

    const unsigned char *p, *pm;

    int pklen, pmlen;

    int ptype;

    const void *pval;

    const ASN1_STRING *pstr;

    X509_ALGOR *palg;

    ASN1_INTEGER *public_key = NULL;

    DH *dh = NULL;

    if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))

        return 0;

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

    if (ptype != V_ASN1_SEQUENCE) {

        ERR_raise(ERR_LIB_DH, DH_R_PARAMETER_ENCODING_ERROR);

        goto err;

    }

    pstr = pval;

    pm = pstr->data;

    pmlen = pstr->length;

    if ((dh = d2i_dhp(pkey, &pm, pmlen)) == NULL) {

        ERR_raise(ERR_LIB_DH, DH_R_DECODE_ERROR);

        goto err;

    }

    if ((public_key = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL) {

        ERR_raise(ERR_LIB_DH, DH_R_DECODE_ERROR);

        goto err;

    }

    /* We have parameters now set public key */

    if ((dh->pub_key = ASN1_INTEGER_to_BN(public_key, NULL)) == NULL) {

        ERR_raise(ERR_LIB_DH, DH_R_BN_DECODE_ERROR);

        goto err;

    }

    ASN1_INTEGER_free(public_key);

    EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);

    return 1;

 err:

    ASN1_INTEGER_free(public_key);

    DH_free(dh);

    return 0;

}

static int dh_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)

{

    DH *dh;

    int ptype;

    unsigned char *penc = NULL;

    int penclen;

    ASN1_STRING *str;

    ASN1_INTEGER *pub_key = NULL;

    dh = pkey->pkey.dh;

    str = ASN1_STRING_new();

    if (str == NULL) {

        ERR_raise(ERR_LIB_DH, ERR_R_ASN1_LIB);

        goto err;

    }

    str->length = i2d_dhp(pkey, dh, &str->data);

    if (str->length <= 0) {

        ERR_raise(ERR_LIB_DH, ERR_R_ASN1_LIB);

        goto err;

    }

    ptype = V_ASN1_SEQUENCE;

    pub_key = BN_to_ASN1_INTEGER(dh->pub_key, NULL);

    if (pub_key == NULL)

        goto err;

    penclen = i2d_ASN1_INTEGER(pub_key, &penc);

    ASN1_INTEGER_free(pub_key);

    if (penclen <= 0) {

        ERR_raise(ERR_LIB_DH, ERR_R_ASN1_LIB);

        goto err;

    }

    if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(pkey->ameth->pkey_id),

                               ptype, str, penc, penclen))

        return 1;

 err:

    OPENSSL_free(penc);

    ASN1_STRING_free(str);

    return 0;

}

/*

 * PKCS#8 DH is defined in PKCS#11 of all places. It is similar to DH in that

 * the AlgorithmIdentifier contains the parameters, the private key is

 * explicitly included and the pubkey must be recalculated.

 */

static int dh_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)

{

    int ret = 0;

    DH *dh = ossl_dh_key_from_pkcs8(p8, NULL, NULL);

    if (dh != NULL) {

        ret = 1;

        EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);

    }

    return ret;

}

static int dh_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)

{

    ASN1_STRING *params = NULL;

    ASN1_INTEGER *prkey = NULL;

    unsigned char *dp = NULL;

    int dplen;

    params = ASN1_STRING_new();

    if (params == NULL) {

        ERR_raise(ERR_LIB_DH, ERR_R_ASN1_LIB);

        goto err;

    }

    params->length = i2d_dhp(pkey, pkey->pkey.dh, &params->data);

    if (params->length <= 0) {

        ERR_raise(ERR_LIB_DH, ERR_R_ASN1_LIB);

        goto err;

    }

    params->type = V_ASN1_SEQUENCE;

    /* Get private key into integer */

    prkey = BN_to_ASN1_INTEGER(pkey->pkey.dh->priv_key, NULL);

    if (prkey == NULL) {

        ERR_raise(ERR_LIB_DH, DH_R_BN_ERROR);

        goto err;

    }

    dplen = i2d_ASN1_INTEGER(prkey, &dp);

    ASN1_STRING_clear_free(prkey);

    if (dplen <= 0) {

        ERR_raise(ERR_LIB_DH, DH_R_BN_ERROR);

        goto err;

    }

    if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(pkey->ameth->pkey_id), 0,

                         V_ASN1_SEQUENCE, params, dp, dplen)) {

        OPENSSL_clear_free(dp, dplen);

        goto err;

    }

    return 1;

 err:

    ASN1_STRING_free(params);

    return 0;

}

static int dh_param_decode(EVP_PKEY *pkey,

                           const unsigned char **pder, int derlen)

{

    DH *dh;

    if ((dh = d2i_dhp(pkey, pder, derlen)) == NULL)

        return 0;

    dh->dirty_cnt++;

    EVP_PKEY_assign(pkey, pkey->ameth->pkey_id, dh);

    return 1;

}

static int dh_param_encode(const EVP_PKEY *pkey, unsigned char **pder)

{

    return i2d_dhp(pkey, pkey->pkey.dh, pder);

}

static int do_dh_print(BIO *bp, const DH *x, int indent, int ptype)

{

    int reason = ERR_R_BUF_LIB;

    const char *ktype = NULL;

    BIGNUM *priv_key, *pub_key;

    if (ptype == 2)

        priv_key = x->priv_key;

    else

        priv_key = NULL;

    if (ptype > 0)

        pub_key = x->pub_key;

    else

        pub_key = NULL;

    if (x->params.p == NULL || (ptype == 2 && priv_key == NULL)

            || (ptype > 0 && pub_key == NULL)) {

        reason = ERR_R_PASSED_NULL_PARAMETER;

        goto err;

    }

    if (ptype == 2)

        ktype = "DH Private-Key";

    else if (ptype == 1)

        ktype = "DH Public-Key";

    else

        ktype = "DH Parameters";

    if (!BIO_indent(bp, indent, 128)

            || BIO_printf(bp, "%s: (%d bit)\n", ktype, DH_bits(x)) <= 0)

        goto err;

    indent += 4;

    if (!ASN1_bn_print(bp, "private-key:", priv_key, NULL, indent))

        goto err;

    if (!ASN1_bn_print(bp, "public-key:", pub_key, NULL, indent))

        goto err;

    if (!ossl_ffc_params_print(bp, &x->params, indent))

        goto err;

    if (x->length != 0) {

        if (!BIO_indent(bp, indent, 128)

                || BIO_printf(bp, "recommended-private-length: %d bits\n",

                              (int)x->length) <= 0)

            goto err;

    }

    return 1;

 err:

    ERR_raise(ERR_LIB_DH, reason);

    return 0;

}

static int int_dh_size(const EVP_PKEY *pkey)

{

    return DH_size(pkey->pkey.dh);

}

static int dh_bits(const EVP_PKEY *pkey)

{

    return DH_bits(pkey->pkey.dh);

}

static int dh_security_bits(const EVP_PKEY *pkey)

{

    return DH_security_bits(pkey->pkey.dh);

}

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

{

    return ossl_ffc_params_cmp(&a->pkey.dh->params, &b->pkey.dh->params,

                               a->ameth != &ossl_dhx_asn1_meth);

}

static int int_dh_param_copy(DH *to, const DH *from, int is_x942)

{

    if (is_x942 == -1)

        is_x942 = (from->params.q != NULL);

    if (!ossl_ffc_params_copy(&to->params, &from->params))

        return 0;

    if (!is_x942)

        to->length = from->length;

    to->dirty_cnt++;

    return 1;

}

DH *DHparams_dup(const DH *dh)

{

    DH *ret;

    ret = DH_new();

    if (ret == NULL)

        return NULL;

    if (!int_dh_param_copy(ret, dh, -1)) {

        DH_free(ret);

        return NULL;

    }

    return ret;

}

static int dh_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)

{

    if (to->pkey.dh == NULL) {

        to->pkey.dh = DH_new();

        if (to->pkey.dh == NULL)

            return 0;

    }

    return int_dh_param_copy(to->pkey.dh, from->pkey.dh,

                             from->ameth == &ossl_dhx_asn1_meth);

}

static int dh_missing_parameters(const EVP_PKEY *a)

{

    return a->pkey.dh == NULL

        || a->pkey.dh->params.p == NULL

        || a->pkey.dh->params.g == NULL;

}

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

{

    if (dh_cmp_parameters(a, b) == 0)

        return 0;

    if (BN_cmp(b->pkey.dh->pub_key, a->pkey.dh->pub_key) != 0)

        return 0;

    else

        return 1;

}

static int dh_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,

                          ASN1_PCTX *ctx)

{

    return do_dh_print(bp, pkey->pkey.dh, indent, 0);

}

static int dh_public_print(BIO *bp, const EVP_PKEY *pkey, int indent,

                           ASN1_PCTX *ctx)

{

    return do_dh_print(bp, pkey->pkey.dh, indent, 1);

}

static int dh_private_print(BIO *bp, const EVP_PKEY *pkey, int indent,

                            ASN1_PCTX *ctx)

{

    return do_dh_print(bp, pkey->pkey.dh, indent, 2);

}

int DHparams_print(BIO *bp, const DH *x)

{

    return do_dh_print(bp, x, 4, 0);

}

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

{

    DH *dh;

    switch (op) {

    case ASN1_PKEY_CTRL_SET1_TLS_ENCPT:

        /* We should only be here if we have a legacy key */

        if (!ossl_assert(evp_pkey_is_legacy(pkey)))

            return 0;

        dh = (DH *) evp_pkey_get0_DH_int(pkey);

        if (dh == NULL)

            return 0;

        return ossl_dh_buf2key(dh, arg2, arg1);

    case ASN1_PKEY_CTRL_GET1_TLS_ENCPT:

        dh = (DH *) EVP_PKEY_get0_DH(pkey);

        if (dh == NULL)

            return 0;

        return (int)ossl_dh_key2buf(dh, arg2, 0, 1);

    default:

        return -2;

    }

}

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

{

    switch (op) {

    default:

        return -2;

    }

}

static int dh_pkey_public_check(const EVP_PKEY *pkey)

{

    DH *dh = pkey->pkey.dh;

    if (dh->pub_key == NULL) {

        ERR_raise(ERR_LIB_DH, DH_R_MISSING_PUBKEY);

        return 0;

    }

    return DH_check_pub_key_ex(dh, dh->pub_key);

}

static int dh_pkey_param_check(const EVP_PKEY *pkey)

{

    DH *dh = pkey->pkey.dh;

    return DH_check_ex(dh);

}

static size_t dh_pkey_dirty_cnt(const EVP_PKEY *pkey)

{

    return pkey->pkey.dh->dirty_cnt;

}

static int dh_pkey_export_to(const EVP_PKEY *from, void *to_keydata,

                             OSSL_FUNC_keymgmt_import_fn *importer,

                             OSSL_LIB_CTX *libctx, const char *propq)

{

    DH *dh = from->pkey.dh;

    OSSL_PARAM_BLD *tmpl;

    const BIGNUM *p = DH_get0_p(dh), *g = DH_get0_g(dh), *q = DH_get0_q(dh);

    long l = DH_get_length(dh);

    const BIGNUM *pub_key = DH_get0_pub_key(dh);

    const BIGNUM *priv_key = DH_get0_priv_key(dh);

    OSSL_PARAM *params = NULL;

    int selection = 0;

    int rv = 0;

    if (p == NULL || g == NULL)

        return 0;

    tmpl = OSSL_PARAM_BLD_new();

    if (tmpl == NULL)

        return 0;

    if (!OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_P, p)

        || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_G, g))

        goto err;

    if (q != NULL) {

        if (!OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_Q, q))

            goto err;

    }

    selection |= OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS;

    if (l > 0) {

        if (!OSSL_PARAM_BLD_push_long(tmpl, OSSL_PKEY_PARAM_DH_PRIV_LEN, l))

            goto err;

        selection |= OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS;

    }

    if (pub_key != NULL) {

        if (!OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_PUB_KEY, pub_key))

            goto err;

        selection |= OSSL_KEYMGMT_SELECT_PUBLIC_KEY;

    }

    if (priv_key != NULL) {

        if (!OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_PRIV_KEY,

                                    priv_key))

            goto err;

        selection |= OSSL_KEYMGMT_SELECT_PRIVATE_KEY;

    }

    if ((params = OSSL_PARAM_BLD_to_param(tmpl)) == NULL)

        goto err;

    /* We export, the provider imports */

    rv = importer(to_keydata, selection, params);

    OSSL_PARAM_free(params);

err:

    OSSL_PARAM_BLD_free(tmpl);

    return rv;

}

static int dh_pkey_import_from_type(const OSSL_PARAM params[], void *vpctx,

                                    int type)

{

    EVP_PKEY_CTX *pctx = vpctx;

    EVP_PKEY *pkey = EVP_PKEY_CTX_get0_pkey(pctx);

    DH *dh = ossl_dh_new_ex(pctx->libctx);

    if (dh == NULL) {

        ERR_raise(ERR_LIB_DH, ERR_R_DH_LIB);

        return 0;

    }

    DH_clear_flags(dh, DH_FLAG_TYPE_MASK);

    DH_set_flags(dh, type == EVP_PKEY_DH ? DH_FLAG_TYPE_DH : DH_FLAG_TYPE_DHX);

    if (!ossl_dh_params_fromdata(dh, params)

        || !ossl_dh_key_fromdata(dh, params, 1)

        || !EVP_PKEY_assign(pkey, type, dh)) {

        DH_free(dh);

        return 0;

    }

    return 1;

}

static int dh_pkey_import_from(const OSSL_PARAM params[], void *vpctx)

{

    return dh_pkey_import_from_type(params, vpctx, EVP_PKEY_DH);

}

static int dhx_pkey_import_from(const OSSL_PARAM params[], void *vpctx)

{

    return dh_pkey_import_from_type(params, vpctx, EVP_PKEY_DHX);

}

static int dh_pkey_copy(EVP_PKEY *to, EVP_PKEY *from)

{

    DH *dh = from->pkey.dh;

    DH *dupkey = NULL;

    int ret;

    if (dh != NULL) {

        dupkey = ossl_dh_dup(dh, OSSL_KEYMGMT_SELECT_ALL);

        if (dupkey == NULL)

            return 0;

    }

    ret = EVP_PKEY_assign(to, from->type, dupkey);

    if (!ret)

        DH_free(dupkey);

    return ret;

}

const EVP_PKEY_ASN1_METHOD ossl_dh_asn1_meth = {

    EVP_PKEY_DH,

    EVP_PKEY_DH,

    0,

    "DH",

    "OpenSSL PKCS#3 DH method",

    dh_pub_decode,

    dh_pub_encode,

    dh_pub_cmp,

    dh_public_print,

    dh_priv_decode,

    dh_priv_encode,

    dh_private_print,

    int_dh_size,

    dh_bits,

    dh_security_bits,

    dh_param_decode,

    dh_param_encode,

    dh_missing_parameters,

    dh_copy_parameters,

    dh_cmp_parameters,

    dh_param_print,

    0,

    int_dh_free,

    dh_pkey_ctrl,

    0, 0, 0, 0, 0,

    0,

    dh_pkey_public_check,

    dh_pkey_param_check,

    0, 0, 0, 0,

    dh_pkey_dirty_cnt,

    dh_pkey_export_to,

    dh_pkey_import_from,

    dh_pkey_copy

};

const EVP_PKEY_ASN1_METHOD ossl_dhx_asn1_meth = {

    EVP_PKEY_DHX,

    EVP_PKEY_DHX,

    0,

    "X9.42 DH",

    "OpenSSL X9.42 DH method",

    dh_pub_decode,

    dh_pub_encode,

    dh_pub_cmp,

    dh_public_print,

    dh_priv_decode,

    dh_priv_encode,

    dh_private_print,

    int_dh_size,

    dh_bits,

    dh_security_bits,

    dh_param_decode,

    dh_param_encode,

    dh_missing_parameters,

    dh_copy_parameters,

    dh_cmp_parameters,

    dh_param_print,

    0,

    int_dh_free,

    dhx_pkey_ctrl,

    0, 0, 0, 0, 0,

    0,

    dh_pkey_public_check,

    dh_pkey_param_check,

    0, 0, 0, 0,

    dh_pkey_dirty_cnt,

    dh_pkey_export_to,

    dhx_pkey_import_from,

    dh_pkey_copy

};