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psa: Rename functions to get a key slot

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Rename functions to get a key slot:
. to make their naming more consistent
. to emphasize that those functions set a lock on the
  key slot they return to protect it from being wiped
  out and re-used while some part of the library
  is accessing it.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
This commit is contained in:
Ronald Cron 2020-11-14 16:35:34 +01:00
parent ab79bd27b6
commit 5c522920ba
6 changed files with 196 additions and 194 deletions
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4
include/psa/crypto_extra.h
View file

@ -231,8 +231,8 @@ typedef struct mbedtls_psa_stats_s
size_t cache_slots; size_t cache_slots;
/** Number of slots that are not used for anything. */ /** Number of slots that are not used for anything. */
size_t empty_slots; size_t empty_slots;
/** Number of slots that are not accessed. */ /** Number of slots that are not locked. */
size_t unaccessed_slots; size_t unlocked_slots;
/** Largest key id value among open keys in internal persistent storage. */ /** Largest key id value among open keys in internal persistent storage. */
psa_key_id_t max_open_internal_key_id; psa_key_id_t max_open_internal_key_id;
/** Largest key id value among open keys in secure elements. */ /** Largest key id value among open keys in secure elements. */

219
library/psa_crypto.c
View file

@ -1187,27 +1187,28 @@ static psa_status_t psa_restrict_key_policy(
return( PSA_SUCCESS ); return( PSA_SUCCESS );
} }
/** Retrieve a slot which must contain a key. The key must have allow all the /** Get the description of a key given its identifier and policy constraints
* usage flags set in \p usage. If \p alg is nonzero, the key must allow * and lock it.
* operations with this algorithm.
* *
* In case of a persistent key, the function loads the description of the key * The key must have allow all the usage flags set in \p usage. If \p alg is
* into a key slot if not already done. * nonzero, the key must allow operations with this algorithm.
* *
* On success, the access counter of the returned key slot is incremented by * In case of a persistent key, the function loads the description of the key
* one. It is the responsibility of the caller to call * into a key slot if not already done.
* psa_decrement_key_slot_access_count() when it does not access the key slot *
* anymore. * On success, the returned key slot is locked. It is the responsibility of
* the caller to unlock the key slot when it does not access it anymore.
*/ */
static psa_status_t psa_get_key_from_slot( mbedtls_svc_key_id_t key, static psa_status_t psa_get_and_lock_key_slot_with_policy(
psa_key_slot_t **p_slot, mbedtls_svc_key_id_t key,
psa_key_usage_t usage, psa_key_slot_t **p_slot,
psa_algorithm_t alg ) psa_key_usage_t usage,
psa_algorithm_t alg )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
status = psa_get_key_slot( key, p_slot ); status = psa_get_and_lock_key_slot( key, p_slot );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
slot = *p_slot; slot = *p_slot;
@ -1231,37 +1232,38 @@ static psa_status_t psa_get_key_from_slot( mbedtls_svc_key_id_t key,
error: error:
*p_slot = NULL; *p_slot = NULL;
psa_decrement_key_slot_access_count( slot ); psa_unlock_key_slot( slot );
return( status ); return( status );
} }
/** Retrieve a slot which must contain a transparent key. /** Get a key slot containing a transparent key and lock it.
* *
* A transparent key is a key for which the key material is directly * A transparent key is a key for which the key material is directly
* available, as opposed to a key in a secure element. * available, as opposed to a key in a secure element.
* *
* This is a temporary function to use instead of psa_get_key_from_slot() * This is a temporary function to use instead of
* until secure element support is fully implemented. * psa_get_and_lock_key_slot_with_policy() until secure element support is
* fully implemented.
* *
* On success, the access counter of the returned key slot is incremented by * On success, the returned key slot is locked. It is the responsibility of the
* one. It is the responsibility of the caller to call * caller to unlock the key slot when it does not access it anymore.
* psa_decrement_key_slot_access_count() when it does not access the key slot
* anymore.
*/ */
#if defined(MBEDTLS_PSA_CRYPTO_SE_C) #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
static psa_status_t psa_get_transparent_key( mbedtls_svc_key_id_t key, static psa_status_t psa_get_and_lock_transparent_key_slot_with_policy(
psa_key_slot_t **p_slot, mbedtls_svc_key_id_t key,
psa_key_usage_t usage, psa_key_slot_t **p_slot,
psa_algorithm_t alg ) psa_key_usage_t usage,
psa_algorithm_t alg )
{ {
psa_status_t status = psa_get_key_from_slot( key, p_slot, usage, alg ); psa_status_t status = psa_get_and_lock_key_slot_with_policy( key, p_slot,
usage, alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
if( psa_key_slot_is_external( *p_slot ) ) if( psa_key_slot_is_external( *p_slot ) )
{ {
psa_decrement_key_slot_access_count( *p_slot ); psa_unlock_key_slot( *p_slot );
*p_slot = NULL; *p_slot = NULL;
return( PSA_ERROR_NOT_SUPPORTED ); return( PSA_ERROR_NOT_SUPPORTED );
} }
@ -1270,8 +1272,8 @@ static psa_status_t psa_get_transparent_key( mbedtls_svc_key_id_t key,
} }
#else /* MBEDTLS_PSA_CRYPTO_SE_C */ #else /* MBEDTLS_PSA_CRYPTO_SE_C */
/* With no secure element support, all keys are transparent. */ /* With no secure element support, all keys are transparent. */
#define psa_get_transparent_key( key, p_slot, usage, alg ) \ #define psa_get_and_lock_transparent_key_slot_with_policy( key, p_slot, usage, alg ) \
psa_get_key_from_slot( key, p_slot, usage, alg ) psa_get_and_lock_key_slot_with_policy( key, p_slot, usage, alg )
#endif /* MBEDTLS_PSA_CRYPTO_SE_C */ #endif /* MBEDTLS_PSA_CRYPTO_SE_C */
/** Wipe key data from a slot. Preserve metadata such as the policy. */ /** Wipe key data from a slot. Preserve metadata such as the policy. */
@ -1305,15 +1307,15 @@ psa_status_t psa_wipe_key_slot( psa_key_slot_t *slot )
/* /*
* As the return error code may not be handled in case of multiple errors, * As the return error code may not be handled in case of multiple errors,
* do our best to report an unexpected access counter: if available * do our best to report an unexpected lock counter: if available
* call MBEDTLS_PARAM_FAILED that may terminate execution (if called as * call MBEDTLS_PARAM_FAILED that may terminate execution (if called as
* part of the execution of a test suite this will stop the test suite * part of the execution of a test suite this will stop the test suite
* execution). * execution).
*/ */
if( slot->access_count != 1 ) if( slot->lock_count != 1 )
{ {
#ifdef MBEDTLS_CHECK_PARAMS #ifdef MBEDTLS_CHECK_PARAMS
MBEDTLS_PARAM_FAILED( slot->access_count == 1 ); MBEDTLS_PARAM_FAILED( slot->lock_count == 1 );
#endif #endif
status = PSA_ERROR_CORRUPTION_DETECTED; status = PSA_ERROR_CORRUPTION_DETECTED;
} }
@ -1349,7 +1351,7 @@ psa_status_t psa_destroy_key( mbedtls_svc_key_id_t key )
* the key is operated by an SE or not and this information is needed by * the key is operated by an SE or not and this information is needed by
* the current implementation. * the current implementation.
*/ */
status = psa_get_key_slot( key, &slot ); status = psa_get_and_lock_key_slot( key, &slot );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
@ -1360,9 +1362,9 @@ psa_status_t psa_destroy_key( mbedtls_svc_key_id_t key )
* implemented), the key should be destroyed when all accesses have * implemented), the key should be destroyed when all accesses have
* stopped. * stopped.
*/ */
if( slot->access_count > 1 ) if( slot->lock_count > 1 )
{ {
psa_decrement_key_slot_access_count( slot ); psa_unlock_key_slot( slot );
return( PSA_ERROR_GENERIC_ERROR ); return( PSA_ERROR_GENERIC_ERROR );
} }
@ -1533,12 +1535,12 @@ psa_status_t psa_get_key_attributes( mbedtls_svc_key_id_t key,
psa_key_attributes_t *attributes ) psa_key_attributes_t *attributes )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
psa_reset_key_attributes( attributes ); psa_reset_key_attributes( attributes );
status = psa_get_key_from_slot( key, &slot, 0, 0 ); status = psa_get_and_lock_key_slot_with_policy( key, &slot, 0, 0 );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
@ -1589,9 +1591,9 @@ psa_status_t psa_get_key_attributes( mbedtls_svc_key_id_t key,
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
psa_reset_key_attributes( attributes ); psa_reset_key_attributes( attributes );
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
#if defined(MBEDTLS_PSA_CRYPTO_SE_C) #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
@ -1752,7 +1754,7 @@ psa_status_t psa_export_key( mbedtls_svc_key_id_t key,
size_t *data_length ) size_t *data_length )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
/* Set the key to empty now, so that even when there are errors, we always /* Set the key to empty now, so that even when there are errors, we always
@ -1762,16 +1764,18 @@ psa_status_t psa_export_key( mbedtls_svc_key_id_t key,
*data_length = 0; *data_length = 0;
/* Export requires the EXPORT flag. There is an exception for public keys, /* Export requires the EXPORT flag. There is an exception for public keys,
* which don't require any flag, but psa_get_key_from_slot takes * which don't require any flag, but
* care of this. */ * psa_get_and_lock_key_slot_with_policy() takes care of this.
status = psa_get_key_from_slot( key, &slot, PSA_KEY_USAGE_EXPORT, 0 ); */
status = psa_get_and_lock_key_slot_with_policy( key, &slot,
PSA_KEY_USAGE_EXPORT, 0 );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
status = psa_internal_export_key( slot, data, data_size, data_length, 0 ); status = psa_internal_export_key( slot, data, data_size, data_length, 0 );
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
psa_status_t psa_export_public_key( mbedtls_svc_key_id_t key, psa_status_t psa_export_public_key( mbedtls_svc_key_id_t key,
@ -1780,7 +1784,7 @@ psa_status_t psa_export_public_key( mbedtls_svc_key_id_t key,
size_t *data_length ) size_t *data_length )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
/* Set the key to empty now, so that even when there are errors, we always /* Set the key to empty now, so that even when there are errors, we always
@ -1790,14 +1794,14 @@ psa_status_t psa_export_public_key( mbedtls_svc_key_id_t key,
*data_length = 0; *data_length = 0;
/* Exporting a public key doesn't require a usage flag. */ /* Exporting a public key doesn't require a usage flag. */
status = psa_get_key_from_slot( key, &slot, 0, 0 ); status = psa_get_and_lock_key_slot_with_policy( key, &slot, 0, 0 );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
status = psa_internal_export_key( slot, data, data_size, data_length, 1 ); status = psa_internal_export_key( slot, data, data_size, data_length, 1 );
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
#if defined(static_assert) #if defined(static_assert)
@ -1904,10 +1908,8 @@ static psa_status_t psa_validate_key_attributes(
* In case of failure at any step, stop the sequence and call * In case of failure at any step, stop the sequence and call
* psa_fail_key_creation(). * psa_fail_key_creation().
* *
* On success, the access counter of the returned key slot is incremented by * On success, the key slot is locked. It is the responsibility of the caller
* one. It is the responsibility of the caller to call * to unlock the key slot when it does not access it anymore.
* psa_decrement_key_slot_access_count() when it does not access the key slot
* anymore.
* *
* \param method An identification of the calling function. * \param method An identification of the calling function.
* \param[in] attributes Key attributes for the new key. * \param[in] attributes Key attributes for the new key.
@ -2025,9 +2027,9 @@ static psa_status_t psa_start_key_creation(
* See the documentation of psa_start_key_creation() for the intended use * See the documentation of psa_start_key_creation() for the intended use
* of this function. * of this function.
* *
* If the finalization succeeds, the function decreases the slot access * If the finalization succeeds, the function unlocks the key slot (it was
* counter (that was incremented as part of psa_start_key_creation()) and the * locked by psa_start_key_creation()) and the key slot cannot be accessed
* slot cannot be accessed anymore as part of the key creation process. * anymore as part of the key creation process.
* *
* \param[in,out] slot Pointer to the slot with key material. * \param[in,out] slot Pointer to the slot with key material.
* \param[in] driver The secure element driver for the key, * \param[in] driver The secure element driver for the key,
@ -2101,7 +2103,7 @@ static psa_status_t psa_finish_key_creation(
if( status == PSA_SUCCESS ) if( status == PSA_SUCCESS )
{ {
*key = slot->attr.id; *key = slot->attr.id;
status = psa_decrement_key_slot_access_count( slot ); status = psa_unlock_key_slot( slot );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
*key = MBEDTLS_SVC_KEY_ID_INIT; *key = MBEDTLS_SVC_KEY_ID_INIT;
} }
@ -2344,7 +2346,7 @@ psa_status_t psa_copy_key( mbedtls_svc_key_id_t source_key,
mbedtls_svc_key_id_t *target_key ) mbedtls_svc_key_id_t *target_key )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *source_slot = NULL; psa_key_slot_t *source_slot = NULL;
psa_key_slot_t *target_slot = NULL; psa_key_slot_t *target_slot = NULL;
psa_key_attributes_t actual_attributes = *specified_attributes; psa_key_attributes_t actual_attributes = *specified_attributes;
@ -2352,8 +2354,8 @@ psa_status_t psa_copy_key( mbedtls_svc_key_id_t source_key,
*target_key = MBEDTLS_SVC_KEY_ID_INIT; *target_key = MBEDTLS_SVC_KEY_ID_INIT;
status = psa_get_transparent_key( source_key, &source_slot, status = psa_get_and_lock_transparent_key_slot_with_policy(
PSA_KEY_USAGE_COPY, 0 ); source_key, &source_slot, PSA_KEY_USAGE_COPY, 0 );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
goto exit; goto exit;
@ -2390,9 +2392,9 @@ exit:
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
psa_fail_key_creation( target_slot, driver ); psa_fail_key_creation( target_slot, driver );
decrement_status = psa_decrement_key_slot_access_count( source_slot ); unlock_status = psa_unlock_key_slot( source_slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
@ -3179,7 +3181,7 @@ static psa_status_t psa_mac_setup( psa_mac_operation_t *operation,
int is_sign ) int is_sign )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
size_t key_bits; size_t key_bits;
psa_key_usage_t usage = psa_key_usage_t usage =
@ -3199,7 +3201,8 @@ static psa_status_t psa_mac_setup( psa_mac_operation_t *operation,
if( is_sign ) if( is_sign )
operation->is_sign = 1; operation->is_sign = 1;
status = psa_get_transparent_key( key, &slot, usage, alg ); status = psa_get_and_lock_transparent_key_slot_with_policy(
key, &slot, usage, alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
goto exit; goto exit;
key_bits = psa_get_key_slot_bits( slot ); key_bits = psa_get_key_slot_bits( slot );
@ -3289,9 +3292,9 @@ exit:
operation->key_set = 1; operation->key_set = 1;
} }
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
psa_status_t psa_mac_sign_setup( psa_mac_operation_t *operation, psa_status_t psa_mac_sign_setup( psa_mac_operation_t *operation,
@ -3789,7 +3792,7 @@ psa_status_t psa_sign_hash( mbedtls_svc_key_id_t key,
size_t *signature_length ) size_t *signature_length )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
*signature_length = signature_size; *signature_length = signature_size;
@ -3800,7 +3803,9 @@ psa_status_t psa_sign_hash( mbedtls_svc_key_id_t key,
if( signature_size == 0 ) if( signature_size == 0 )
return( PSA_ERROR_BUFFER_TOO_SMALL ); return( PSA_ERROR_BUFFER_TOO_SMALL );
status = psa_get_key_from_slot( key, &slot, PSA_KEY_USAGE_SIGN_HASH, alg ); status = psa_get_and_lock_key_slot_with_policy( key, &slot,
PSA_KEY_USAGE_SIGN_HASH,
alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
goto exit; goto exit;
if( ! PSA_KEY_TYPE_IS_KEY_PAIR( slot->attr.type ) ) if( ! PSA_KEY_TYPE_IS_KEY_PAIR( slot->attr.type ) )
@ -3897,9 +3902,9 @@ exit:
/* If signature_size is 0 then we have nothing to do. We must not call /* If signature_size is 0 then we have nothing to do. We must not call
* memset because signature may be NULL in this case. */ * memset because signature may be NULL in this case. */
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
psa_status_t psa_verify_hash( mbedtls_svc_key_id_t key, psa_status_t psa_verify_hash( mbedtls_svc_key_id_t key,
@ -3910,11 +3915,12 @@ psa_status_t psa_verify_hash( mbedtls_svc_key_id_t key,
size_t signature_length ) size_t signature_length )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
status = psa_get_key_from_slot( key, &slot, status = psa_get_and_lock_key_slot_with_policy( key, &slot,
PSA_KEY_USAGE_VERIFY_HASH, alg ); PSA_KEY_USAGE_VERIFY_HASH,
alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
@ -3985,9 +3991,9 @@ psa_status_t psa_verify_hash( mbedtls_svc_key_id_t key,
} }
exit: exit:
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
#if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_PKCS1_V21) #if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_PKCS1_V21)
@ -4012,7 +4018,7 @@ psa_status_t psa_asymmetric_encrypt( mbedtls_svc_key_id_t key,
size_t *output_length ) size_t *output_length )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
(void) input; (void) input;
@ -4026,7 +4032,8 @@ psa_status_t psa_asymmetric_encrypt( mbedtls_svc_key_id_t key,
if( ! PSA_ALG_IS_RSA_OAEP( alg ) && salt_length != 0 ) if( ! PSA_ALG_IS_RSA_OAEP( alg ) && salt_length != 0 )
return( PSA_ERROR_INVALID_ARGUMENT ); return( PSA_ERROR_INVALID_ARGUMENT );
status = psa_get_transparent_key( key, &slot, PSA_KEY_USAGE_ENCRYPT, alg ); status = psa_get_and_lock_transparent_key_slot_with_policy(
key, &slot, PSA_KEY_USAGE_ENCRYPT, alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
if( ! ( PSA_KEY_TYPE_IS_PUBLIC_KEY( slot->attr.type ) || if( ! ( PSA_KEY_TYPE_IS_PUBLIC_KEY( slot->attr.type ) ||
@ -4100,9 +4107,9 @@ rsa_exit:
} }
exit: exit:
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
psa_status_t psa_asymmetric_decrypt( mbedtls_svc_key_id_t key, psa_status_t psa_asymmetric_decrypt( mbedtls_svc_key_id_t key,
@ -4116,7 +4123,7 @@ psa_status_t psa_asymmetric_decrypt( mbedtls_svc_key_id_t key,
size_t *output_length ) size_t *output_length )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
(void) input; (void) input;
@ -4130,7 +4137,8 @@ psa_status_t psa_asymmetric_decrypt( mbedtls_svc_key_id_t key,
if( ! PSA_ALG_IS_RSA_OAEP( alg ) && salt_length != 0 ) if( ! PSA_ALG_IS_RSA_OAEP( alg ) && salt_length != 0 )
return( PSA_ERROR_INVALID_ARGUMENT ); return( PSA_ERROR_INVALID_ARGUMENT );
status = psa_get_transparent_key( key, &slot, PSA_KEY_USAGE_DECRYPT, alg ); status = psa_get_and_lock_transparent_key_slot_with_policy(
key, &slot, PSA_KEY_USAGE_DECRYPT, alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
if( ! PSA_KEY_TYPE_IS_KEY_PAIR( slot->attr.type ) ) if( ! PSA_KEY_TYPE_IS_KEY_PAIR( slot->attr.type ) )
@ -4203,9 +4211,9 @@ rsa_exit:
} }
exit: exit:
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
@ -4220,7 +4228,7 @@ static psa_status_t psa_cipher_setup( psa_cipher_operation_t *operation,
mbedtls_operation_t cipher_operation ) mbedtls_operation_t cipher_operation )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
int ret = 0; int ret = 0;
psa_key_slot_t *slot; psa_key_slot_t *slot;
size_t key_bits; size_t key_bits;
@ -4238,7 +4246,7 @@ static psa_status_t psa_cipher_setup( psa_cipher_operation_t *operation,
return( PSA_ERROR_INVALID_ARGUMENT ); return( PSA_ERROR_INVALID_ARGUMENT );
/* Fetch key material from key storage. */ /* Fetch key material from key storage. */
status = psa_get_key_from_slot( key, &slot, usage, alg ); status = psa_get_and_lock_key_slot_with_policy( key, &slot, usage, alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
goto exit; goto exit;
@ -4366,9 +4374,9 @@ exit:
else else
psa_cipher_abort( operation ); psa_cipher_abort( operation );
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
psa_status_t psa_cipher_encrypt_setup( psa_cipher_operation_t *operation, psa_status_t psa_cipher_encrypt_setup( psa_cipher_operation_t *operation,
@ -4768,7 +4776,7 @@ static void psa_aead_abort_internal( aead_operation_t *operation )
#endif /* MBEDTLS_GCM_C */ #endif /* MBEDTLS_GCM_C */
} }
psa_decrement_key_slot_access_count( operation->slot ); psa_unlock_key_slot( operation->slot );
} }
static psa_status_t psa_aead_setup( aead_operation_t *operation, static psa_status_t psa_aead_setup( aead_operation_t *operation,
@ -4780,7 +4788,8 @@ static psa_status_t psa_aead_setup( aead_operation_t *operation,
size_t key_bits; size_t key_bits;
mbedtls_cipher_id_t cipher_id; mbedtls_cipher_id_t cipher_id;
status = psa_get_transparent_key( key, &operation->slot, usage, alg ); status = psa_get_and_lock_transparent_key_slot_with_policy(
key, &operation->slot, usage, alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
@ -5910,11 +5919,11 @@ psa_status_t psa_key_derivation_input_key(
mbedtls_svc_key_id_t key ) mbedtls_svc_key_id_t key )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
status = psa_get_transparent_key( key, &slot, status = psa_get_and_lock_transparent_key_slot_with_policy(
PSA_KEY_USAGE_DERIVE, operation->alg ); key, &slot, PSA_KEY_USAGE_DERIVE, operation->alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
{ {
psa_key_derivation_abort( operation ); psa_key_derivation_abort( operation );
@ -5931,9 +5940,9 @@ psa_status_t psa_key_derivation_input_key(
slot->data.key.data, slot->data.key.data,
slot->data.key.bytes ); slot->data.key.bytes );
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
@ -6082,13 +6091,13 @@ psa_status_t psa_key_derivation_key_agreement( psa_key_derivation_operation_t *o
size_t peer_key_length ) size_t peer_key_length )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot; psa_key_slot_t *slot;
if( ! PSA_ALG_IS_KEY_AGREEMENT( operation->alg ) ) if( ! PSA_ALG_IS_KEY_AGREEMENT( operation->alg ) )
return( PSA_ERROR_INVALID_ARGUMENT ); return( PSA_ERROR_INVALID_ARGUMENT );
status = psa_get_transparent_key( private_key, &slot, status = psa_get_and_lock_transparent_key_slot_with_policy(
PSA_KEY_USAGE_DERIVE, operation->alg ); private_key, &slot, PSA_KEY_USAGE_DERIVE, operation->alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
status = psa_key_agreement_internal( operation, step, status = psa_key_agreement_internal( operation, step,
@ -6104,9 +6113,9 @@ psa_status_t psa_key_derivation_key_agreement( psa_key_derivation_operation_t *o
operation->can_output_key = 1; operation->can_output_key = 1;
} }
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }
psa_status_t psa_raw_key_agreement( psa_algorithm_t alg, psa_status_t psa_raw_key_agreement( psa_algorithm_t alg,
@ -6118,7 +6127,7 @@ psa_status_t psa_raw_key_agreement( psa_algorithm_t alg,
size_t *output_length ) size_t *output_length )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t decrement_status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_slot_t *slot = NULL; psa_key_slot_t *slot = NULL;
if( ! PSA_ALG_IS_KEY_AGREEMENT( alg ) ) if( ! PSA_ALG_IS_KEY_AGREEMENT( alg ) )
@ -6126,8 +6135,8 @@ psa_status_t psa_raw_key_agreement( psa_algorithm_t alg,
status = PSA_ERROR_INVALID_ARGUMENT; status = PSA_ERROR_INVALID_ARGUMENT;
goto exit; goto exit;
} }
status = psa_get_transparent_key( private_key, &slot, status = psa_get_and_lock_transparent_key_slot_with_policy(
PSA_KEY_USAGE_DERIVE, alg ); private_key, &slot, PSA_KEY_USAGE_DERIVE, alg );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
goto exit; goto exit;
@ -6150,9 +6159,9 @@ exit:
*output_length = output_size; *output_length = output_size;
} }
decrement_status = psa_decrement_key_slot_access_count( slot ); unlock_status = psa_unlock_key_slot( slot );
return( ( status == PSA_SUCCESS ) ? decrement_status : status ); return( ( status == PSA_SUCCESS ) ? unlock_status : status );
} }

18
library/psa_crypto_core.h
View file

@ -38,8 +38,7 @@ typedef struct
psa_core_key_attributes_t attr; psa_core_key_attributes_t attr;
/* /*
* Number of on-going accesses, read and/or write, to the key slot by the * Number of locks, read and/or write, to the key slot by the library.
* library.
* *
* This counter is incremented by one each time a library function * This counter is incremented by one each time a library function
* retrieves through one of the dedicated internal API a pointer to the * retrieves through one of the dedicated internal API a pointer to the
@ -47,7 +46,7 @@ typedef struct
* *
* This counter is decremented by one each time a library function stops * This counter is decremented by one each time a library function stops
* accessing to the key slot and states it by calling the * accessing to the key slot and states it by calling the
* psa_decrement_key_slot_access_count() API. * psa_unlock_key_slot() API.
* *
* This counter is used to prevent resetting the key slot while the library * This counter is used to prevent resetting the key slot while the library
* may access it. For example, such control is needed in the following * may access it. For example, such control is needed in the following
@ -61,7 +60,7 @@ typedef struct
* or purge or destroy a key while it is in used by the library through * or purge or destroy a key while it is in used by the library through
* another thread. * another thread.
*/ */
size_t access_count; size_t lock_count;
union union
{ {
@ -101,18 +100,17 @@ static inline int psa_is_key_slot_occupied( const psa_key_slot_t *slot )
return( slot->attr.type != 0 ); return( slot->attr.type != 0 );
} }
/** Test whether a key slot is accessed. /** Test whether a key slot is locked.
* *
* A key slot is accessed iff its access counter is strickly greater than * A key slot is locked iff its lock counter is strickly greater than 0.
* 0.
* *
* \param[in] slot The key slot to test. * \param[in] slot The key slot to test.
* *
* \return 1 if the slot is accessed, 0 otherwise. * \return 1 if the slot is locked, 0 otherwise.
*/ */
static inline int psa_is_key_slot_accessed( const psa_key_slot_t *slot ) static inline int psa_is_key_slot_locked( const psa_key_slot_t *slot )
{ {
return( slot->access_count > 0 ); return( slot->lock_count > 0 );
} }
/** Retrieve flags from psa_key_slot_t::attr::core::flags. /** Retrieve flags from psa_key_slot_t::attr::core::flags.

92
library/psa_crypto_slot_management.c
View file

@ -68,25 +68,23 @@ psa_status_t psa_validate_key_id(
return( PSA_ERROR_INVALID_HANDLE ); return( PSA_ERROR_INVALID_HANDLE );
} }
/** Search for the description of a key given its identifier. /** Get the description in memory of a key given its identifier and lock it.
* *
* The descriptions of volatile keys and loaded persistent keys are * The descriptions of volatile keys and loaded persistent keys are
* stored in key slots. This function returns a pointer to the key slot * stored in key slots. This function returns a pointer to the key slot
* containing the description of a key given its identifier. * containing the description of a key given its identifier.
* *
* The function searches the key slots containing the description of the key * The function searches the key slots containing the description of the key
* with \p key identifier. The function does only read accesses to the key * with \p key identifier. The function does only read accesses to the key
* slots. The function does not load any persistent key thus does not access * slots. The function does not load any persistent key thus does not access
* any storage. * any storage.
* *
* For volatile key identifiers, only one key slot is queried as a volatile * For volatile key identifiers, only one key slot is queried as a volatile
* key with identifier key_id can only be stored in slot of index * key with identifier key_id can only be stored in slot of index
* ( key_id - #PSA_KEY_ID_VOLATILE_MIN ). * ( key_id - #PSA_KEY_ID_VOLATILE_MIN ).
* *
* On success, the access counter of the returned key slot is incremented by * On success, the function locks the key slot. It is the responsibility of
* one. It is the responsibility of the caller to call * the caller to unlock the key slot when it does not access it anymore.
* psa_decrement_key_slot_access_count() when it does not access the key slot
* anymore.
* *
* \param key Key identifier to query. * \param key Key identifier to query.
* \param[out] p_slot On success, `*p_slot` contains a pointer to the * \param[out] p_slot On success, `*p_slot` contains a pointer to the
@ -101,7 +99,7 @@ psa_status_t psa_validate_key_id(
* \retval #PSA_ERROR_DOES_NOT_EXIST * \retval #PSA_ERROR_DOES_NOT_EXIST
* There is no key with key identifier \p key in the key slots. * There is no key with key identifier \p key in the key slots.
*/ */
static psa_status_t psa_search_key_in_slots( static psa_status_t psa_get_and_lock_key_slot_in_memory(
mbedtls_svc_key_id_t key, psa_key_slot_t **p_slot ) mbedtls_svc_key_id_t key, psa_key_slot_t **p_slot )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
@ -133,7 +131,7 @@ static psa_status_t psa_search_key_in_slots(
if( status == PSA_SUCCESS ) if( status == PSA_SUCCESS )
{ {
status = psa_increment_key_slot_access_count( slot ); status = psa_lock_key_slot( slot );
if( status == PSA_SUCCESS ) if( status == PSA_SUCCESS )
*p_slot = slot; *p_slot = slot;
} }
@ -157,7 +155,7 @@ void psa_wipe_all_key_slots( void )
for( slot_idx = 0; slot_idx < PSA_KEY_SLOT_COUNT; slot_idx++ ) for( slot_idx = 0; slot_idx < PSA_KEY_SLOT_COUNT; slot_idx++ )
{ {
psa_key_slot_t *slot = &global_data.key_slots[ slot_idx ]; psa_key_slot_t *slot = &global_data.key_slots[ slot_idx ];
slot->access_count = 1; slot->lock_count = 1;
(void) psa_wipe_key_slot( slot ); (void) psa_wipe_key_slot( slot );
} }
global_data.key_slots_initialized = 0; global_data.key_slots_initialized = 0;
@ -168,7 +166,7 @@ psa_status_t psa_get_empty_key_slot( psa_key_id_t *volatile_key_id,
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
size_t slot_idx; size_t slot_idx;
psa_key_slot_t *selected_slot, *unaccessed_persistent_key_slot; psa_key_slot_t *selected_slot, *unlocked_persistent_key_slot;
if( ! global_data.key_slots_initialized ) if( ! global_data.key_slots_initialized )
{ {
@ -176,7 +174,7 @@ psa_status_t psa_get_empty_key_slot( psa_key_id_t *volatile_key_id,
goto error; goto error;
} }
selected_slot = unaccessed_persistent_key_slot = NULL; selected_slot = unlocked_persistent_key_slot = NULL;
for( slot_idx = 0; slot_idx < PSA_KEY_SLOT_COUNT; slot_idx++ ) for( slot_idx = 0; slot_idx < PSA_KEY_SLOT_COUNT; slot_idx++ )
{ {
psa_key_slot_t *slot = &global_data.key_slots[ slot_idx ]; psa_key_slot_t *slot = &global_data.key_slots[ slot_idx ];
@ -186,30 +184,30 @@ psa_status_t psa_get_empty_key_slot( psa_key_id_t *volatile_key_id,
break; break;
} }
if( ( unaccessed_persistent_key_slot == NULL ) && if( ( unlocked_persistent_key_slot == NULL ) &&
( ! PSA_KEY_LIFETIME_IS_VOLATILE( slot->attr.lifetime ) ) && ( ! PSA_KEY_LIFETIME_IS_VOLATILE( slot->attr.lifetime ) ) &&
( ! psa_is_key_slot_accessed( slot ) ) ) ( ! psa_is_key_slot_locked( slot ) ) )
unaccessed_persistent_key_slot = slot; unlocked_persistent_key_slot = slot;
} }
/* /*
* If there is no unused key slot and there is at least one unaccessed key * If there is no unused key slot and there is at least one unlocked key
* slot containing the description of a permament key, recycle the first * slot containing the description of a permament key, recycle the first
* such key slot we encountered. If we need later on to operate on the * such key slot we encountered. If we need later on to operate on the
* persistent key we evict now, we will reload its description from * persistent key we evict now, we will reload its description from
* storage. * storage.
*/ */
if( ( selected_slot == NULL ) && if( ( selected_slot == NULL ) &&
( unaccessed_persistent_key_slot != NULL ) ) ( unlocked_persistent_key_slot != NULL ) )
{ {
selected_slot = unaccessed_persistent_key_slot; selected_slot = unlocked_persistent_key_slot;
selected_slot->access_count = 1; selected_slot->lock_count = 1;
psa_wipe_key_slot( selected_slot ); psa_wipe_key_slot( selected_slot );
} }
if( selected_slot != NULL ) if( selected_slot != NULL )
{ {
status = psa_increment_key_slot_access_count( selected_slot ); status = psa_lock_key_slot( selected_slot );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
goto error; goto error;
@ -267,8 +265,8 @@ exit:
} }
#endif /* MBEDTLS_PSA_CRYPTO_STORAGE_C */ #endif /* MBEDTLS_PSA_CRYPTO_STORAGE_C */
psa_status_t psa_get_key_slot( mbedtls_svc_key_id_t key, psa_status_t psa_get_and_lock_key_slot( mbedtls_svc_key_id_t key,
psa_key_slot_t **p_slot ) psa_key_slot_t **p_slot )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
@ -278,9 +276,9 @@ psa_status_t psa_get_key_slot( mbedtls_svc_key_id_t key,
/* /*
* On success, the pointer to the slot is passed directly to the caller * On success, the pointer to the slot is passed directly to the caller
* thus no need to decrement the key slot access counter here. * thus no need to unlock the key slot here.
*/ */
status = psa_search_key_in_slots( key, p_slot ); status = psa_get_and_lock_key_slot_in_memory( key, p_slot );
if( status != PSA_ERROR_DOES_NOT_EXIST ) if( status != PSA_ERROR_DOES_NOT_EXIST )
return( status ); return( status );
@ -305,26 +303,26 @@ psa_status_t psa_get_key_slot( mbedtls_svc_key_id_t key,
} }
psa_status_t psa_decrement_key_slot_access_count( psa_key_slot_t *slot ) psa_status_t psa_unlock_key_slot( psa_key_slot_t *slot )
{ {
if( slot == NULL ) if( slot == NULL )
return( PSA_SUCCESS ); return( PSA_SUCCESS );
if( slot->access_count > 0 ) if( slot->lock_count > 0 )
{ {
slot->access_count--; slot->lock_count--;
return( PSA_SUCCESS ); return( PSA_SUCCESS );
} }
/* /*
* As the return error code may not be handled in case of multiple errors, * As the return error code may not be handled in case of multiple errors,
* do our best to report if the access counter is equal to zero: if * do our best to report if the lock counter is equal to zero: if
* available call MBEDTLS_PARAM_FAILED that may terminate execution (if * available call MBEDTLS_PARAM_FAILED that may terminate execution (if
* called as part of the execution of a unit test suite this will stop the * called as part of the execution of a unit test suite this will stop the
* test suite execution). * test suite execution).
*/ */
#ifdef MBEDTLS_CHECK_PARAMS #ifdef MBEDTLS_CHECK_PARAMS
MBEDTLS_PARAM_FAILED( slot->access_count > 0 ); MBEDTLS_PARAM_FAILED( slot->lock_count > 0 );
#endif #endif
return( PSA_ERROR_CORRUPTION_DETECTED ); return( PSA_ERROR_CORRUPTION_DETECTED );
@ -379,7 +377,7 @@ psa_status_t psa_open_key( mbedtls_svc_key_id_t key, psa_key_handle_t *handle )
psa_status_t status; psa_status_t status;
psa_key_slot_t *slot; psa_key_slot_t *slot;
status = psa_get_key_slot( key, &slot ); status = psa_get_and_lock_key_slot( key, &slot );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
{ {
*handle = PSA_KEY_HANDLE_INIT; *handle = PSA_KEY_HANDLE_INIT;
@ -388,7 +386,7 @@ psa_status_t psa_open_key( mbedtls_svc_key_id_t key, psa_key_handle_t *handle )
*handle = key; *handle = key;
return( psa_decrement_key_slot_access_count( slot ) ); return( psa_unlock_key_slot( slot ) );
#else /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */ #else /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */
(void) key; (void) key;
@ -405,14 +403,14 @@ psa_status_t psa_close_key( psa_key_handle_t handle )
if( psa_key_handle_is_null( handle ) ) if( psa_key_handle_is_null( handle ) )
return( PSA_SUCCESS ); return( PSA_SUCCESS );
status = psa_search_key_in_slots( handle, &slot ); status = psa_get_and_lock_key_slot_in_memory( handle, &slot );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
if( slot->access_count <= 1 ) if( slot->lock_count <= 1 )
return( psa_wipe_key_slot( slot ) ); return( psa_wipe_key_slot( slot ) );
else else
return( psa_decrement_key_slot_access_count( slot ) ); return( psa_unlock_key_slot( slot ) );
} }
psa_status_t psa_purge_key( mbedtls_svc_key_id_t key ) psa_status_t psa_purge_key( mbedtls_svc_key_id_t key )
@ -420,15 +418,15 @@ psa_status_t psa_purge_key( mbedtls_svc_key_id_t key )
psa_status_t status; psa_status_t status;
psa_key_slot_t *slot; psa_key_slot_t *slot;
status = psa_search_key_in_slots( key, &slot ); status = psa_get_and_lock_key_slot_in_memory( key, &slot );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
if( ( ! PSA_KEY_LIFETIME_IS_VOLATILE( slot->attr.lifetime ) ) && if( ( ! PSA_KEY_LIFETIME_IS_VOLATILE( slot->attr.lifetime ) ) &&
( slot->access_count <= 1 ) ) ( slot->lock_count <= 1 ) )
return( psa_wipe_key_slot( slot ) ); return( psa_wipe_key_slot( slot ) );
else else
return( psa_decrement_key_slot_access_count( slot ) ); return( psa_unlock_key_slot( slot ) );
} }
void mbedtls_psa_get_stats( mbedtls_psa_stats_t *stats ) void mbedtls_psa_get_stats( mbedtls_psa_stats_t *stats )
@ -440,9 +438,9 @@ void mbedtls_psa_get_stats( mbedtls_psa_stats_t *stats )
for( slot_idx = 0; slot_idx < PSA_KEY_SLOT_COUNT; slot_idx++ ) for( slot_idx = 0; slot_idx < PSA_KEY_SLOT_COUNT; slot_idx++ )
{ {
const psa_key_slot_t *slot = &global_data.key_slots[ slot_idx ]; const psa_key_slot_t *slot = &global_data.key_slots[ slot_idx ];
if( ! psa_is_key_slot_accessed( slot ) ) if( ! psa_is_key_slot_locked( slot ) )
{ {
++stats->unaccessed_slots; ++stats->unlocked_slots;
} }
if( ! psa_is_key_slot_occupied( slot ) ) if( ! psa_is_key_slot_occupied( slot ) )
{ {

53
library/psa_crypto_slot_management.h
View file

@ -61,19 +61,17 @@ static inline int psa_key_id_is_volatile( psa_key_id_t key_id )
( key_id <= PSA_KEY_ID_VOLATILE_MAX ) ); ( key_id <= PSA_KEY_ID_VOLATILE_MAX ) );
} }
/** Retrieve the description of a key given its identifier. /** Get the description of a key given its identifier and lock it.
* *
* The descriptions of volatile keys and loaded persistent keys are * The descriptions of volatile keys and loaded persistent keys are stored in
* stored in key slots. This function returns a pointer to the key slot * key slots. This function returns a pointer to the key slot containing the
* containing the description of a key given its identifier. * description of a key given its identifier.
* *
* In case of a persistent key, the function loads the description of the key * In case of a persistent key, the function loads the description of the key
* into a key slot if not already done. * into a key slot if not already done.
* *
* On success, the access counter of the returned key slot is incremented by * On success, the returned key slot is locked. It is the responsibility of
* one. It is the responsibility of the caller to call * the caller to unlock the key slot when it does not access it anymore.
* psa_decrement_key_slot_access_count() when it does not access the slot
* anymore.
* *
* \param key Key identifier to query. * \param key Key identifier to query.
* \param[out] p_slot On success, `*p_slot` contains a pointer to the * \param[out] p_slot On success, `*p_slot` contains a pointer to the
@ -98,8 +96,8 @@ static inline int psa_key_id_is_volatile( psa_key_id_t key_id )
* \retval #PSA_ERROR_STORAGE_FAILURE * \retval #PSA_ERROR_STORAGE_FAILURE
* \retval #PSA_ERROR_DATA_CORRUPT * \retval #PSA_ERROR_DATA_CORRUPT
*/ */
psa_status_t psa_get_key_slot( mbedtls_svc_key_id_t key, psa_status_t psa_get_and_lock_key_slot( mbedtls_svc_key_id_t key,
psa_key_slot_t **p_slot ); psa_key_slot_t **p_slot );
/** Initialize the key slot structures. /** Initialize the key slot structures.
* *
@ -116,10 +114,9 @@ void psa_wipe_all_key_slots( void );
/** Find a free key slot. /** Find a free key slot.
* *
* This function returns a key slot that is available for use and is in its * This function returns a key slot that is available for use and is in its
* ground state (all-bits-zero). On success, the access counter of the * ground state (all-bits-zero). On success, the key slot is locked. It is
* returned key slot is incremented by one. It is the responsibility of the * the responsibility of the caller to unlock the key slot when it does not
* caller to call psa_decrement_key_slot_access_count() when it does not access * access it anymore.
* the key slot anymore.
* *
* \param[out] volatile_key_id On success, volatile key identifier * \param[out] volatile_key_id On success, volatile key identifier
* associated to the returned slot. * associated to the returned slot.
@ -132,31 +129,31 @@ void psa_wipe_all_key_slots( void );
psa_status_t psa_get_empty_key_slot( psa_key_id_t *volatile_key_id, psa_status_t psa_get_empty_key_slot( psa_key_id_t *volatile_key_id,
psa_key_slot_t **p_slot ); psa_key_slot_t **p_slot );
/** Increment slot access counter. /** Lock a key slot.
* *
* This function increments the slot access counter by one. * This function increments the key slot lock counter by one.
* *
* \param[in] slot The key slot. * \param[in] slot The key slot.
* *
* \retval #PSA_SUCCESS * \retval #PSA_SUCCESS
The access count was incremented. The key slot lock counter was incremented.
* \retval #PSA_ERROR_CORRUPTION_DETECTED * \retval #PSA_ERROR_CORRUPTION_DETECTED
* The access count already reached its maximum value and was not * The lock counter already reached its maximum value and was not
* increased. * increased.
*/ */
static inline psa_status_t psa_increment_key_slot_access_count( psa_key_slot_t *slot ) static inline psa_status_t psa_lock_key_slot( psa_key_slot_t *slot )
{ {
if( slot->access_count >= SIZE_MAX ) if( slot->lock_count >= SIZE_MAX )
return( PSA_ERROR_CORRUPTION_DETECTED ); return( PSA_ERROR_CORRUPTION_DETECTED );
slot->access_count++; slot->lock_count++;
return( PSA_SUCCESS ); return( PSA_SUCCESS );
} }
/** Decrement slot access counter. /** Unlock a key slot.
* *
* This function decrements the slot access counter by one. * This function decrements the key slot lock counter by one.
* *
* \note To ease the handling of errors in retrieving a key slot * \note To ease the handling of errors in retrieving a key slot
* a NULL input pointer is valid, and the function returns * a NULL input pointer is valid, and the function returns
@ -164,13 +161,13 @@ static inline psa_status_t psa_increment_key_slot_access_count( psa_key_slot_t *
* *
* \param[in] slot The key slot. * \param[in] slot The key slot.
* \retval #PSA_SUCCESS * \retval #PSA_SUCCESS
* \p slot is NULL or the key slot access pointer has been * \p slot is NULL or the key slot lock counter has been
* decremented successfully. * decremented successfully.
* \retval #PSA_ERROR_CORRUPTION_DETECTED * \retval #PSA_ERROR_CORRUPTION_DETECTED
* The access counter was equal to 0. * The lock counter was equal to 0.
* *
*/ */
psa_status_t psa_decrement_key_slot_access_count( psa_key_slot_t *slot ); psa_status_t psa_unlock_key_slot( psa_key_slot_t *slot );
/** Test whether a lifetime designates a key in an external cryptoprocessor. /** Test whether a lifetime designates a key in an external cryptoprocessor.
* *

4
tests/include/test/psa_crypto_helpers.h
View file

@ -41,9 +41,9 @@ static int test_helper_is_psa_pristine( int line, const char *file )
msg = "An external slot has not been closed properly."; msg = "An external slot has not been closed properly.";
else if( stats.half_filled_slots != 0 ) else if( stats.half_filled_slots != 0 )
msg = "A half-filled slot has not been cleared properly."; msg = "A half-filled slot has not been cleared properly.";
else if( stats.unaccessed_slots != PSA_KEY_SLOT_COUNT ) else if( stats.unlocked_slots != PSA_KEY_SLOT_COUNT )
{ {
msg = "Some slots are still marked as accessed."; msg = "Some slots are still marked as locked.";
} }
/* If the test has already failed, don't overwrite the failure /* If the test has already failed, don't overwrite the failure