/*

 * 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

 */

#include <string.h>

#include <openssl/err.h>

#include <openssl/proverr.h>

#include "crypto/ecx.h"

#include "internal/common.h" /* for ossl_assert() */

#ifdef S390X_EC_ASM

#include "s390x_arch.h"

#endif

ECX_KEY *ossl_ecx_key_new(OSSL_LIB_CTX *libctx, ECX_KEY_TYPE type, int haspubkey,

    const char *propq)

{

    ECX_KEY *ret = OPENSSL_zalloc(sizeof(*ret));

    if (ret == NULL)

        return NULL;

    ret->libctx = libctx;

    ret->haspubkey = haspubkey;

    switch (type) {

    case ECX_KEY_TYPE_X25519:

        ret->keylen = X25519_KEYLEN;

        break;

    case ECX_KEY_TYPE_X448:

        ret->keylen = X448_KEYLEN;

        break;

    case ECX_KEY_TYPE_ED25519:

        ret->keylen = ED25519_KEYLEN;

        break;

    case ECX_KEY_TYPE_ED448:

        ret->keylen = ED448_KEYLEN;

        break;

    }

    ret->type = type;

    if (!CRYPTO_NEW_REF(&ret->references, 1))

        goto err;

    if (propq != NULL) {

        ret->propq = OPENSSL_strdup(propq);

        if (ret->propq == NULL)

            goto err;

    }

    return ret;

err:

    if (ret != NULL) {

        OPENSSL_free(ret->propq);

        CRYPTO_FREE_REF(&ret->references);

    }

    OPENSSL_free(ret);

    return NULL;

}

void ossl_ecx_key_free(ECX_KEY *key)

{

    int i;

    if (key == NULL)

        return;

    CRYPTO_DOWN_REF(&key->references, &i);

    REF_PRINT_COUNT("ECX_KEY", i, key);

    if (i > 0)

        return;

    REF_ASSERT_ISNT(i < 0);

    OPENSSL_free(key->propq);

#ifdef OPENSSL_PEDANTIC_ZEROIZATION

    OPENSSL_cleanse(&key->pubkey, sizeof(key->pubkey));

#endif

    OPENSSL_secure_clear_free(key->privkey, key->keylen);

    CRYPTO_FREE_REF(&key->references);

    OPENSSL_free(key);

}

void ossl_ecx_key_set0_libctx(ECX_KEY *key, OSSL_LIB_CTX *libctx)

{

    key->libctx = libctx;

}

int ossl_ecx_key_up_ref(ECX_KEY *key)

{

    int i;

    if (CRYPTO_UP_REF(&key->references, &i) <= 0)

        return 0;

    REF_PRINT_COUNT("ECX_KEY", i, key);

    REF_ASSERT_ISNT(i < 2);

    return ((i > 1) ? 1 : 0);

}

unsigned char *ossl_ecx_key_allocate_privkey(ECX_KEY *key)

{

    key->privkey = OPENSSL_secure_zalloc(key->keylen);

    return key->privkey;

}

int ossl_ecx_compute_key(ECX_KEY *peer, ECX_KEY *priv, size_t keylen,

    unsigned char *secret, size_t *secretlen, size_t outlen)

{

    if (priv == NULL

        || priv->privkey == NULL

        || peer == NULL) {

        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);

        return 0;

    }

    if (!ossl_assert(keylen == X25519_KEYLEN

            || keylen == X448_KEYLEN)) {

        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);

        return 0;

    }

    if (secret == NULL) {

        *secretlen = keylen;

        return 1;

    }

    if (outlen < keylen) {

        ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);

        return 0;

    }

    if (keylen == X25519_KEYLEN) {

#ifdef S390X_EC_ASM

        if (OPENSSL_s390xcap_P.pcc[1]

            & S390X_CAPBIT(S390X_SCALAR_MULTIPLY_X25519)) {

            if (s390x_x25519_mul(secret, peer->pubkey, priv->privkey) == 0) {

                ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_DURING_DERIVATION);

                return 0;

            }

        } else

#endif

            if (ossl_x25519(secret, priv->privkey, peer->pubkey) == 0) {

            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_DURING_DERIVATION);

            return 0;

        }

    } else {

#ifdef S390X_EC_ASM

        if (OPENSSL_s390xcap_P.pcc[1]

            & S390X_CAPBIT(S390X_SCALAR_MULTIPLY_X448)) {

            if (s390x_x448_mul(secret, peer->pubkey, priv->privkey) == 0) {

                ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_DURING_DERIVATION);

                return 0;

            }

        } else

#endif

            if (ossl_x448(secret, priv->privkey, peer->pubkey) == 0) {

            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_DURING_DERIVATION);

            return 0;

        }

    }

    *secretlen = keylen;

    return 1;

}