secure_fw/partitions/crypto/crypto_key.c

/*
 * Copyright (c) 2018-2021, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 *
 */

#include <stddef.h>
#include <stdint.h>

#include "tfm_mbedcrypto_include.h"

#include "tfm_crypto_api.h"
#include "tfm_crypto_defs.h"
#include "tfm_crypto_private.h"

#ifndef MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER
#error "MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER must be selected in Mbed TLS config file"
#endif

/*!
 * \defgroup public Public functions
 *
 */
/*!@{*/
psa_status_t tfm_crypto_key_attributes_from_client(
                    const struct psa_client_key_attributes_s *client_key_attr,
                    int32_t client_id,
                    psa_key_attributes_t *key_attributes)
{
    psa_core_key_attributes_t *core;

    if (client_key_attr == NULL || key_attributes == NULL) {
        return PSA_ERROR_PROGRAMMER_ERROR;
    }

    *key_attributes = psa_key_attributes_init();
    core = &(key_attributes->MBEDTLS_PRIVATE(core));

    /* Copy core key attributes from the client core key attributes */
    core->MBEDTLS_PRIVATE(type) = client_key_attr->type;
    core->MBEDTLS_PRIVATE(lifetime) = client_key_attr->lifetime;
    core->MBEDTLS_PRIVATE(policy).MBEDTLS_PRIVATE(usage) =
                                                     client_key_attr->usage;
    core->MBEDTLS_PRIVATE(policy).MBEDTLS_PRIVATE(alg) =
                                                     client_key_attr->alg;
    core->MBEDTLS_PRIVATE(bits) = client_key_attr->bits;

    /* Use the client key id as the key_id and its partition id as the owner */
    core->MBEDTLS_PRIVATE(id).MBEDTLS_PRIVATE(key_id) = client_key_attr->id;
    core->MBEDTLS_PRIVATE(id).MBEDTLS_PRIVATE(owner) = client_id;

    return PSA_SUCCESS;
}

psa_status_t tfm_crypto_key_attributes_to_client(
                        const psa_key_attributes_t *key_attributes,
                        struct psa_client_key_attributes_s *client_key_attr)
{
    if (client_key_attr == NULL || key_attributes == NULL) {
        return PSA_ERROR_PROGRAMMER_ERROR;
    }

    struct psa_client_key_attributes_s v = PSA_CLIENT_KEY_ATTRIBUTES_INIT;
    *client_key_attr = v;
    psa_core_key_attributes_t core = key_attributes->MBEDTLS_PRIVATE(core);

    /* Copy core key attributes from the client core key attributes */
    client_key_attr->type = core.MBEDTLS_PRIVATE(type);
    client_key_attr->lifetime = core.MBEDTLS_PRIVATE(lifetime);
    client_key_attr->usage = core.MBEDTLS_PRIVATE(policy).MBEDTLS_PRIVATE(usage);
    client_key_attr->alg = core.MBEDTLS_PRIVATE(policy).MBEDTLS_PRIVATE(alg);
    client_key_attr->bits = core.MBEDTLS_PRIVATE(bits);

    /* Return the key_id as the client key id, do not return the owner */
    client_key_attr->id = core.MBEDTLS_PRIVATE(id).MBEDTLS_PRIVATE(key_id);

    return PSA_SUCCESS;
}

psa_status_t tfm_crypto_encode_id_and_owner(psa_key_id_t key_id,
                                            mbedtls_svc_key_id_t *enc_key_ptr)
{
    int32_t partition_id = 0;
    psa_status_t status = tfm_crypto_get_caller_id(&partition_id);

    if (status != PSA_SUCCESS) {
        return status;
    }

    /* If Null Pointer, return PSA_ERROR_PROGRAMMER_ERROR */
    if (enc_key_ptr == NULL) {
        return PSA_ERROR_PROGRAMMER_ERROR;
    }

    /* Use the client key id as the key_id and its partition id as the owner */
    *enc_key_ptr = mbedtls_svc_key_id_make(partition_id, key_id);

    return PSA_SUCCESS;
}
/*!@}*/