/*

 * Copyright 2020-2023 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

 */

/*

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

 * internal use.

 */

#include "internal/deprecated.h"

#include <openssl/core_names.h>

#include <openssl/err.h>

#ifndef FIPS_MODULE

#include <openssl/x509.h>

#endif

#include "crypto/dsa.h"

#include "dsa_local.h"

/*

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

 * for legacy backends (EVP_PKEY_ASN1_METHOD and EVP_PKEY_METHOD) and provider

 * implementations alike.

 */

int ossl_dsa_key_fromdata(DSA *dsa, const OSSL_PARAM params[],

    int include_private)

{

    const OSSL_PARAM *param_priv_key = NULL, *param_pub_key;

    BIGNUM *priv_key = NULL, *pub_key = NULL;

    if (dsa == NULL)

        return 0;

    if (include_private) {

        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);

    /* It's ok if neither half is present */

    if (param_priv_key == NULL && param_pub_key == NULL)

        return 1;

    if (param_pub_key != NULL && !OSSL_PARAM_get_BN(param_pub_key, &pub_key))

        goto err;

    if (param_priv_key != NULL && !OSSL_PARAM_get_BN(param_priv_key, &priv_key))

        goto err;

    if (!DSA_set0_key(dsa, pub_key, priv_key))

        goto err;

    return 1;

err:

    BN_clear_free(priv_key);

    BN_free(pub_key);

    return 0;

}

int ossl_dsa_is_foreign(const DSA *dsa)

{

#ifndef FIPS_MODULE

    if (DSA_get_method((DSA *)dsa) != DSA_OpenSSL())

        return 1;

#endif

    return 0;

}

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

{

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

        return 0;

    return 1;

}

DSA *ossl_dsa_dup(const DSA *dsa, int selection)

{

    DSA *dupkey = NULL;

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

    if (ossl_dsa_is_foreign(dsa))

        return NULL;

    if ((dupkey = ossl_dsa_new(dsa->libctx)) == NULL)

        return NULL;

    if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0

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

        goto err;

    dupkey->flags = dsa->flags;

    if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0

        && ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0

            || !dsa_bn_dup_check(&dupkey->pub_key, dsa->pub_key)))

        goto err;

    if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0

        && ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0

            || !dsa_bn_dup_check(&dupkey->priv_key, dsa->priv_key)))

        goto err;

#ifndef FIPS_MODULE

    if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_DSA,

            &dupkey->ex_data, &dsa->ex_data))

        goto err;

#endif

    return dupkey;

err:

    DSA_free(dupkey);

    return NULL;

}

#ifndef FIPS_MODULE

DSA *ossl_dsa_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;

    ASN1_INTEGER *privkey = NULL;

    const BIGNUM *dsa_p, *dsa_g;

    BIGNUM *dsa_pubkey = NULL, *dsa_privkey = NULL;

    BN_CTX *ctx = NULL;

    DSA *dsa = NULL;

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

        return 0;

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

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

        goto decerr;

    if (privkey->type == V_ASN1_NEG_INTEGER || ptype != V_ASN1_SEQUENCE)

        goto decerr;

    pstr = pval;

    pm = pstr->data;

    pmlen = pstr->length;

    if ((dsa = d2i_DSAparams(NULL, &pm, pmlen)) == NULL)

        goto decerr;

    /* We have parameters now set private key */

    if ((dsa_privkey = BN_secure_new()) == NULL

        || !ASN1_INTEGER_to_BN(privkey, dsa_privkey)) {

        ERR_raise(ERR_LIB_DSA, DSA_R_BN_ERROR);

        goto dsaerr;

    }

    /* Calculate public key */

    if ((dsa_pubkey = BN_new()) == NULL) {

        ERR_raise(ERR_LIB_DSA, ERR_R_BN_LIB);

        goto dsaerr;

    }

    if ((ctx = BN_CTX_new()) == NULL) {

        ERR_raise(ERR_LIB_DSA, ERR_R_BN_LIB);

        goto dsaerr;

    }

    dsa_p = DSA_get0_p(dsa);

    dsa_g = DSA_get0_g(dsa);

    BN_set_flags(dsa_privkey, BN_FLG_CONSTTIME);

    if (!BN_mod_exp(dsa_pubkey, dsa_g, dsa_privkey, dsa_p, ctx)) {

        ERR_raise(ERR_LIB_DSA, DSA_R_BN_ERROR);

        goto dsaerr;

    }

    if (!DSA_set0_key(dsa, dsa_pubkey, dsa_privkey)) {

        ERR_raise(ERR_LIB_DSA, ERR_R_INTERNAL_ERROR);

        goto dsaerr;

    }

    goto done;

decerr:

    ERR_raise(ERR_LIB_DSA, DSA_R_DECODE_ERROR);

dsaerr:

    BN_free(dsa_privkey);

    BN_free(dsa_pubkey);

    DSA_free(dsa);

    dsa = NULL;

done:

    BN_CTX_free(ctx);

    ASN1_STRING_clear_free(privkey);

    return dsa;

}

#endif