f95a2b1190
Add key slot access counter to be able to state if a key slot containing the description of a permanent key can be reset or reset and re-used. Signed-off-by: Ronald Cron <ronald.cron@arm.com>
213 lines
6.7 KiB
C
213 lines
6.7 KiB
C
/*
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* PSA crypto core internal interfaces
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*/
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/*
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* Copyright The Mbed TLS Contributors
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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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#ifndef PSA_CRYPTO_CORE_H
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#define PSA_CRYPTO_CORE_H
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#if !defined(MBEDTLS_CONFIG_FILE)
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#include "mbedtls/config.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#include "psa/crypto.h"
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#include "psa/crypto_se_driver.h"
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/** The data structure representing a key slot, containing key material
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* and metadata for one key.
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*/
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typedef struct
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{
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psa_core_key_attributes_t attr;
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/*
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* Number of on-going accesses, read and/or write, to the key slot by the
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* library.
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*
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* This counter is incremented by one each time a library function
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* retrieves through one of the dedicated internal API a pointer to the
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* key slot.
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*
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* This counter is decremented by one each time a library function stops
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* accessing to the key slot and states it by calling the
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* psa_decrement_key_slot_access_count() API.
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*
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* This counter is used to prevent resetting the key slot while the library
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* may access it. For example, such control is needed in the following
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* scenarios:
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* . In case of key slot starvation, all key slots contain the description
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* of a key, and the library asks for the description of a permanent
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* key not present in the key slots, the key slots currently accessed by
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* the library cannot be reclaimed to free a key slot to load the
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* permanent key.
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* . In case of a multi-threaded application where one thread asks to close
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* or purge or destroy a key while it is in used by the library through
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* another thread.
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*/
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size_t access_count;
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union
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{
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/* Dynamically allocated key data buffer.
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* Format as specified in psa_export_key(). */
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struct key_data
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{
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uint8_t *data;
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size_t bytes;
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} key;
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#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
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/* Any key type in a secure element */
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struct se
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{
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psa_key_slot_number_t slot_number;
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} se;
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#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
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} data;
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} psa_key_slot_t;
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/* A mask of key attribute flags used only internally.
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* Currently there aren't any. */
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#define PSA_KA_MASK_INTERNAL_ONLY ( \
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0 )
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/** Test whether a key slot is occupied.
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*
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* A key slot is occupied iff the key type is nonzero. This works because
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* no valid key can have 0 as its key type.
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*
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* \param[in] slot The key slot to test.
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*
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* \return 1 if the slot is occupied, 0 otherwise.
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*/
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static inline int psa_is_key_slot_occupied( const psa_key_slot_t *slot )
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{
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return( slot->attr.type != 0 );
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}
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/** Test whether a key slot is accessed.
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*
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* A key slot is accessed iff its access counter is strickly greater than
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* 0.
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*
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* \param[in] slot The key slot to test.
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*
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* \return 1 if the slot is accessed, 0 otherwise.
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*/
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static inline int psa_is_key_slot_accessed( const psa_key_slot_t *slot )
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{
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return( slot->access_count > 0 );
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}
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/** Retrieve flags from psa_key_slot_t::attr::core::flags.
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*
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* \param[in] slot The key slot to query.
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* \param mask The mask of bits to extract.
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*
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* \return The key attribute flags in the given slot,
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* bitwise-anded with \p mask.
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*/
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static inline uint16_t psa_key_slot_get_flags( const psa_key_slot_t *slot,
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uint16_t mask )
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{
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return( slot->attr.flags & mask );
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}
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/** Set flags in psa_key_slot_t::attr::core::flags.
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*
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* \param[in,out] slot The key slot to modify.
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* \param mask The mask of bits to modify.
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* \param value The new value of the selected bits.
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*/
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static inline void psa_key_slot_set_flags( psa_key_slot_t *slot,
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uint16_t mask,
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uint16_t value )
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{
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slot->attr.flags = ( ( ~mask & slot->attr.flags ) |
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( mask & value ) );
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}
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/** Turn on flags in psa_key_slot_t::attr::core::flags.
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*
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* \param[in,out] slot The key slot to modify.
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* \param mask The mask of bits to set.
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*/
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static inline void psa_key_slot_set_bits_in_flags( psa_key_slot_t *slot,
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uint16_t mask )
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{
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slot->attr.flags |= mask;
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}
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/** Turn off flags in psa_key_slot_t::attr::core::flags.
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*
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* \param[in,out] slot The key slot to modify.
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* \param mask The mask of bits to clear.
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*/
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static inline void psa_key_slot_clear_bits( psa_key_slot_t *slot,
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uint16_t mask )
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{
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slot->attr.flags &= ~mask;
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}
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/** Completely wipe a slot in memory, including its policy.
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*
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* Persistent storage is not affected.
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*
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* \param[in,out] slot The key slot to wipe.
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*
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* \retval #PSA_SUCCESS
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* Success. This includes the case of a key slot that was
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* already fully wiped.
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* \retval #PSA_ERROR_CORRUPTION_DETECTED
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*/
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psa_status_t psa_wipe_key_slot( psa_key_slot_t *slot );
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/** Copy key data (in export format) into an empty key slot.
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*
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* This function assumes that the slot does not contain
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* any key material yet. On failure, the slot content is unchanged.
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*
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* \param[in,out] slot Key slot to copy the key into.
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* \param[in] data Buffer containing the key material.
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* \param data_length Size of the key buffer.
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*
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* \retval #PSA_SUCCESS
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* The key has been copied successfully.
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* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
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* Not enough memory was available for allocation of the
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* copy buffer.
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* \retval #PSA_ERROR_ALREADY_EXISTS
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* There was other key material already present in the slot.
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*/
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psa_status_t psa_copy_key_material_into_slot( psa_key_slot_t *slot,
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const uint8_t *data,
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size_t data_length );
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/** Convert an mbed TLS error code to a PSA error code
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*
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* \note This function is provided solely for the convenience of
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* Mbed TLS and may be removed at any time without notice.
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*
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* \param ret An mbed TLS-thrown error code
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*
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* \return The corresponding PSA error code
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*/
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psa_status_t mbedtls_to_psa_error( int ret );
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#endif /* PSA_CRYPTO_CORE_H */
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