db2b8db715
Add new functions, psa_load_persistent_key(), psa_free_persistent_key_data(), and psa_save_persistent_key(), for managing persistent keys. These functions load to or save from our internal representation of key slots. Serialization is a concern of the storage backend implementation and doesn't abstraction-leak into the lifetime management code. An initial implementation for files is provided. Additional storage backends can implement this interface for other storage types.
177 lines
6.9 KiB
C
177 lines
6.9 KiB
C
/**
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* \file psa_crypto_storage.h
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*
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* \brief PSA cryptography module: Mbed TLS key storage
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*/
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/*
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* Copyright (C) 2018, ARM Limited, All Rights Reserved
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of mbed TLS (https://tls.mbed.org)
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*/
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#ifndef PSA_CRYPTO_STORAGE_H
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#define PSA_CRYPTO_STORAGE_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Include the Mbed TLS configuration file, the way Mbed TLS does it
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* in each of its header files. */
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#if defined(MBEDTLS_CONFIG_FILE)
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#include MBEDTLS_CONFIG_FILE
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#else
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#include "mbedtls/config.h"
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#endif
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#include "psa/crypto.h"
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#include <stdint.h>
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/* Limit the maximum key size to 30kB (just in case someone tries to
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* inadvertently store an obscene amount of data) */
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#define PSA_CRYPTO_MAX_STORAGE_SIZE ( 30 * 1024 )
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/**
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* \brief Format key data and metadata and save to a location for given key
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* slot.
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*
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* This function formats the key data and metadata and saves it to a
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* persistent storage backend. The storage location corresponding to the
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* key slot must be empty, otherwise this function will fail. This function
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* should be called after psa_import_key_into_slot() to ensure the
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* persistent key is not saved into a storage location corresponding to an
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* already occupied non-persistent key, as well as validating the key data.
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*
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*
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* \param key Slot number of the key to be stored. This must be a
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* valid slot for a key of the chosen type. This should be
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* an occupied key slot with an unoccupied corresponding
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* storage location.
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* \param type Key type (a \c PSA_KEY_TYPE_XXX value).
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* \param[in] policy The key policy to save.
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* \param[in] data Buffer containing the key data.
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* \param data_length The number of bytes that make up the key data.
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*
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* \retval PSA_SUCCESS
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* \retval PSA_ERROR_INSUFFICIENT_STORAGE
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* \retval PSA_ERROR_STORAGE_FAILURE
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*/
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psa_status_t psa_save_persistent_key( const psa_key_slot_t key,
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const psa_key_type_t type,
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const psa_key_policy_t *policy,
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const uint8_t *data,
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const size_t data_length );
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/**
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* \brief Parses key data and metadata and load persistent key for given
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* key slot number.
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*
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* This function reads from a storage backend, parses the key data and
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* metadata and writes them to the appropriate output parameters.
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*
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* Note: This function allocates a buffer and returns a pointer to it through
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* the data parameter. psa_free_persistent_key_data() must be called after
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* this function to zeroize and free this buffer, regardless of whether this
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* function succeeds or fails.
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*
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* \param key Slot number whose content is to be loaded. This
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* must be an unoccupied key slot with an occupied
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* corresponding storage location. The key slot
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* lifetime must be set to persistent.
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* \param[out] type On success, the key type (a \c PSA_KEY_TYPE_XXX
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* value).
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* \param[out] policy On success, the key's policy.
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* \param[out] data Pointer to an allocated key data buffer on return.
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* \param[out] data_length The number of bytes that make up the key data.
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*
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* \retval PSA_SUCCESS
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* \retval PSA_ERROR_INSUFFICIENT_MEMORY
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* \retval PSA_ERROR_STORAGE_FAILURE
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*/
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psa_status_t psa_load_persistent_key( psa_key_slot_t key,
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psa_key_type_t *type,
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psa_key_policy_t *policy,
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uint8_t **data,
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size_t *data_length );
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/**
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* \brief Remove persistent data for the given key slot number.
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*
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* \param key Slot number whose content is to be removed
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* from persistent storage.
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*
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* \retval PSA_SUCCESS
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* \retval PSA_ERROR_STORAGE_FAILURE
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*/
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psa_status_t psa_destroy_persistent_key( const psa_key_slot_t key );
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/**
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* \brief Zeroizes and frees the given buffer.
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*
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* This function must be called at some point after psa_load_persistent_key()
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* to zeroize and free the memory allocated to the buffer in that function.
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*
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* \param key_data Buffer for the key data.
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* \param key_data_length Size of the key data buffer.
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*
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*/
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void psa_free_persistent_key_data( uint8_t *key_data, size_t key_data_length );
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/**
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* \brief Formats key data and metadata for persistent storage
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*
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* \param[in] data Buffer for the key data.
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* \param data_length Length of the key data buffer.
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* \param type Key type (a \c PSA_KEY_TYPE_XXX value).
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* \param policy The key policy.
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* \param[out] storage_data Output buffer for the formatted data.
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*
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*/
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void psa_format_key_data_for_storage( const uint8_t *data,
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const size_t data_length,
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const psa_key_type_t type,
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const psa_key_policy_t *policy,
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uint8_t *storage_data );
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/**
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* \brief Parses persistent storage data into key data and metadata
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*
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* \param[in] storage_data Buffer for the storage data.
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* \param storage_data_length Length of the storage data buffer
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* \param[out] key_data On output, pointer to a newly allocated buffer
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* containing the key data. This must be freed
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* using psa_free_persistent_key_data()
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* \param[out] key_data_length Length of the key data buffer
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* \param[out] type Key type (a \c PSA_KEY_TYPE_XXX value).
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* \param[out] policy The key policy.
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*
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* \retval PSA_SUCCESS
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* \retval PSA_ERROR_INSUFFICIENT_STORAGE
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* \retval PSA_ERROR_INSUFFICIENT_MEMORY
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* \retval PSA_ERROR_STORAGE_FAILURE
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*/
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psa_status_t psa_parse_key_data_from_storage( const uint8_t *storage_data,
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size_t storage_data_length,
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uint8_t **key_data,
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size_t *key_data_length,
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psa_key_type_t *type,
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psa_key_policy_t *policy );
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#ifdef __cplusplus
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}
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#endif
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#endif /* PSA_CRYPTO_STORAGE_H */
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