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20eee55d9d45b68d36929914bba40ea8adb3065d
mbedtls/library/psa_crypto_storage.c
Gilles Peskine 7fad3ef3b5 Switch key slots to psa_key_attributes_t 
Switch `psa_key_slot_t` to the full `psa_key_attributes_t`, now that this
structure only has psa_core_key_attributes_t`.

To minimize the diff without breaking the build much, temporarily make
`psa_key_attributes_t` contain either the `core` field or all the fields.
This allows both things like `slot->attr.core.type` and `slot->attr.type`
to exist. The build breaks with compilers that don't support anonymous
unions and structs, which are only standard C since C11.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
2024-02-28 01:30:24 +01:00

482 lines
16 KiB
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/*
* PSA persistent key storage
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#include "common.h"
#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
#include <stdlib.h>
#include <string.h>
#include "psa/crypto.h"
#include "psa_crypto_storage.h"
#include "mbedtls/platform_util.h"
#if defined(MBEDTLS_PSA_ITS_FILE_C)
#include "psa_crypto_its.h"
#else /* Native ITS implementation */
#include "psa/error.h"
#include "psa/internal_trusted_storage.h"
#endif
#include "mbedtls/platform.h"
/****************************************************************/
/* Key storage */
/****************************************************************/
/* Determine a file name (ITS file identifier) for the given key identifier.
* The file name must be distinct from any file that is used for a purpose
* other than storing a key. Currently, the only such file is the random seed
* file whose name is PSA_CRYPTO_ITS_RANDOM_SEED_UID and whose value is
* 0xFFFFFF52. */
static psa_storage_uid_t psa_its_identifier_of_slot(mbedtls_svc_key_id_t key)
{
#if defined(MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER)
/* Encode the owner in the upper 32 bits. This means that if
* owner values are nonzero (as they are on a PSA platform),
* no key file will ever have a value less than 0x100000000, so
* the whole range 0..0xffffffff is available for non-key files. */
uint32_t unsigned_owner_id = MBEDTLS_SVC_KEY_ID_GET_OWNER_ID(key);
return ((uint64_t) unsigned_owner_id << 32) |
MBEDTLS_SVC_KEY_ID_GET_KEY_ID(key);
#else
/* Use the key id directly as a file name.
* psa_is_key_id_valid() in psa_crypto_slot_management.c
* is responsible for ensuring that key identifiers do not have a
* value that is reserved for non-key files. */
return key;
#endif
}
/**
* \brief Load persistent data for the given key slot number.
*
* This function reads data from a storage backend and returns the data in a
* buffer.
*
* \param key Persistent identifier of the key to be loaded. This
* should be an occupied storage location.
* \param[out] data Buffer where the data is to be written.
* \param data_size Size of the \c data buffer in bytes.
*
* \retval #PSA_SUCCESS \emptydescription
* \retval #PSA_ERROR_DATA_INVALID \emptydescription
* \retval #PSA_ERROR_DATA_CORRUPT \emptydescription
* \retval #PSA_ERROR_STORAGE_FAILURE \emptydescription
* \retval #PSA_ERROR_DOES_NOT_EXIST \emptydescription
*/
static psa_status_t psa_crypto_storage_load(
const mbedtls_svc_key_id_t key, uint8_t *data, size_t data_size)
{
psa_status_t status;
psa_storage_uid_t data_identifier = psa_its_identifier_of_slot(key);
struct psa_storage_info_t data_identifier_info;
size_t data_length = 0;
status = psa_its_get_info(data_identifier, &data_identifier_info);
if (status != PSA_SUCCESS) {
return status;
}
status = psa_its_get(data_identifier, 0, (uint32_t) data_size, data, &data_length);
if (data_size != data_length) {
return PSA_ERROR_DATA_INVALID;
}
return status;
}
int psa_is_key_present_in_storage(const mbedtls_svc_key_id_t key)
{
psa_status_t ret;
psa_storage_uid_t data_identifier = psa_its_identifier_of_slot(key);
struct psa_storage_info_t data_identifier_info;
ret = psa_its_get_info(data_identifier, &data_identifier_info);
if (ret == PSA_ERROR_DOES_NOT_EXIST) {
return 0;
}
return 1;
}
/**
* \brief Store persistent data for the given key slot number.
*
* This function stores the given data buffer to a persistent storage.
*
* \param key Persistent identifier of the key to be stored. This
* should be an unoccupied storage location.
* \param[in] data Buffer containing the data to be stored.
* \param data_length The number of bytes
* that make up the data.
*
* \retval #PSA_SUCCESS \emptydescription
* \retval #PSA_ERROR_INSUFFICIENT_STORAGE \emptydescription
* \retval #PSA_ERROR_ALREADY_EXISTS \emptydescription
* \retval #PSA_ERROR_STORAGE_FAILURE \emptydescription
* \retval #PSA_ERROR_DATA_INVALID \emptydescription
*/
static psa_status_t psa_crypto_storage_store(const mbedtls_svc_key_id_t key,
const uint8_t *data,
size_t data_length)
{
psa_status_t status;
psa_storage_uid_t data_identifier = psa_its_identifier_of_slot(key);
struct psa_storage_info_t data_identifier_info;
if (psa_is_key_present_in_storage(key) == 1) {
return PSA_ERROR_ALREADY_EXISTS;
}
status = psa_its_set(data_identifier, (uint32_t) data_length, data, 0);
if (status != PSA_SUCCESS) {
return PSA_ERROR_DATA_INVALID;
}
status = psa_its_get_info(data_identifier, &data_identifier_info);
if (status != PSA_SUCCESS) {
goto exit;
}
if (data_identifier_info.size != data_length) {
status = PSA_ERROR_DATA_INVALID;
goto exit;
}
exit:
if (status != PSA_SUCCESS) {
/* Remove the file in case we managed to create it but something
* went wrong. It's ok if the file doesn't exist. If the file exists
* but the removal fails, we're already reporting an error so there's
* nothing else we can do. */
(void) psa_its_remove(data_identifier);
}
return status;
}
psa_status_t psa_destroy_persistent_key(const mbedtls_svc_key_id_t key)
{
psa_status_t ret;
psa_storage_uid_t data_identifier = psa_its_identifier_of_slot(key);
struct psa_storage_info_t data_identifier_info;
ret = psa_its_get_info(data_identifier, &data_identifier_info);
if (ret == PSA_ERROR_DOES_NOT_EXIST) {
return PSA_SUCCESS;
}
if (psa_its_remove(data_identifier) != PSA_SUCCESS) {
return PSA_ERROR_DATA_INVALID;
}
ret = psa_its_get_info(data_identifier, &data_identifier_info);
if (ret != PSA_ERROR_DOES_NOT_EXIST) {
return PSA_ERROR_DATA_INVALID;
}
return PSA_SUCCESS;
}
/**
* \brief Get data length for given key slot number.
*
* \param key Persistent identifier whose stored data length
* is to be obtained.
* \param[out] data_length The number of bytes that make up the data.
*
* \retval #PSA_SUCCESS \emptydescription
* \retval #PSA_ERROR_STORAGE_FAILURE \emptydescription
* \retval #PSA_ERROR_DOES_NOT_EXIST \emptydescription
* \retval #PSA_ERROR_DATA_CORRUPT \emptydescription
*/
static psa_status_t psa_crypto_storage_get_data_length(
const mbedtls_svc_key_id_t key,
size_t *data_length)
{
psa_status_t status;
psa_storage_uid_t data_identifier = psa_its_identifier_of_slot(key);
struct psa_storage_info_t data_identifier_info;
status = psa_its_get_info(data_identifier, &data_identifier_info);
if (status != PSA_SUCCESS) {
return status;
}
*data_length = (size_t) data_identifier_info.size;
return PSA_SUCCESS;
}
/**
* Persistent key storage magic header.
*/
#define PSA_KEY_STORAGE_MAGIC_HEADER "PSA\0KEY"
#define PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH (sizeof(PSA_KEY_STORAGE_MAGIC_HEADER))
typedef struct {
uint8_t magic[PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH];
uint8_t version[4];
uint8_t lifetime[sizeof(psa_key_lifetime_t)];
uint8_t type[2];
uint8_t bits[2];
uint8_t policy[sizeof(psa_key_policy_t)];
uint8_t data_len[4];
uint8_t key_data[];
} psa_persistent_key_storage_format;
void psa_format_key_data_for_storage(const uint8_t *data,
const size_t data_length,
const psa_key_attributes_t *attr,
uint8_t *storage_data)
{
psa_persistent_key_storage_format *storage_format =
(psa_persistent_key_storage_format *) storage_data;
memcpy(storage_format->magic, PSA_KEY_STORAGE_MAGIC_HEADER,
PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH);
MBEDTLS_PUT_UINT32_LE(0, storage_format->version, 0);
MBEDTLS_PUT_UINT32_LE(attr->lifetime, storage_format->lifetime, 0);
MBEDTLS_PUT_UINT16_LE((uint16_t) attr->type, storage_format->type, 0);
MBEDTLS_PUT_UINT16_LE((uint16_t) attr->bits, storage_format->bits, 0);
MBEDTLS_PUT_UINT32_LE(attr->policy.usage, storage_format->policy, 0);
MBEDTLS_PUT_UINT32_LE(attr->policy.alg, storage_format->policy, sizeof(uint32_t));
MBEDTLS_PUT_UINT32_LE(attr->policy.alg2, storage_format->policy, 2 * sizeof(uint32_t));
MBEDTLS_PUT_UINT32_LE(data_length, storage_format->data_len, 0);
memcpy(storage_format->key_data, data, data_length);
}
static psa_status_t check_magic_header(const uint8_t *data)
{
if (memcmp(data, PSA_KEY_STORAGE_MAGIC_HEADER,
PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH) != 0) {
return PSA_ERROR_DATA_INVALID;
}
return PSA_SUCCESS;
}
psa_status_t psa_parse_key_data_from_storage(const uint8_t *storage_data,
size_t storage_data_length,
uint8_t **key_data,
size_t *key_data_length,
psa_key_attributes_t *attr)
{
psa_status_t status;
const psa_persistent_key_storage_format *storage_format =
(const psa_persistent_key_storage_format *) storage_data;
uint32_t version;
if (storage_data_length < sizeof(*storage_format)) {
return PSA_ERROR_DATA_INVALID;
}
status = check_magic_header(storage_data);
if (status != PSA_SUCCESS) {
return status;
}
version = MBEDTLS_GET_UINT32_LE(storage_format->version, 0);
if (version != 0) {
return PSA_ERROR_DATA_INVALID;
}
*key_data_length = MBEDTLS_GET_UINT32_LE(storage_format->data_len, 0);
if (*key_data_length > (storage_data_length - sizeof(*storage_format)) ||
*key_data_length > PSA_CRYPTO_MAX_STORAGE_SIZE) {
return PSA_ERROR_DATA_INVALID;
}
if (*key_data_length == 0) {
*key_data = NULL;
} else {
*key_data = mbedtls_calloc(1, *key_data_length);
if (*key_data == NULL) {
return PSA_ERROR_INSUFFICIENT_MEMORY;
}
memcpy(*key_data, storage_format->key_data, *key_data_length);
}
attr->lifetime = MBEDTLS_GET_UINT32_LE(storage_format->lifetime, 0);
attr->type = MBEDTLS_GET_UINT16_LE(storage_format->type, 0);
attr->bits = MBEDTLS_GET_UINT16_LE(storage_format->bits, 0);
attr->policy.usage = MBEDTLS_GET_UINT32_LE(storage_format->policy, 0);
attr->policy.alg = MBEDTLS_GET_UINT32_LE(storage_format->policy, sizeof(uint32_t));
attr->policy.alg2 = MBEDTLS_GET_UINT32_LE(storage_format->policy, 2 * sizeof(uint32_t));
return PSA_SUCCESS;
}
psa_status_t psa_save_persistent_key(const psa_key_attributes_t *attr,
const uint8_t *data,
const size_t data_length)
{
size_t storage_data_length;
uint8_t *storage_data;
psa_status_t status;
/* All keys saved to persistent storage always have a key context */
if (data == NULL || data_length == 0) {
return PSA_ERROR_INVALID_ARGUMENT;
}
if (data_length > PSA_CRYPTO_MAX_STORAGE_SIZE) {
return PSA_ERROR_INSUFFICIENT_STORAGE;
}
storage_data_length = data_length + sizeof(psa_persistent_key_storage_format);
storage_data = mbedtls_calloc(1, storage_data_length);
if (storage_data == NULL) {
return PSA_ERROR_INSUFFICIENT_MEMORY;
}
psa_format_key_data_for_storage(data, data_length, attr, storage_data);
status = psa_crypto_storage_store(attr->id,
storage_data, storage_data_length);
mbedtls_zeroize_and_free(storage_data, storage_data_length);
return status;
}
void psa_free_persistent_key_data(uint8_t *key_data, size_t key_data_length)
{
mbedtls_zeroize_and_free(key_data, key_data_length);
}
psa_status_t psa_load_persistent_key(psa_key_attributes_t *attr,
uint8_t **data,
size_t *data_length)
{
psa_status_t status = PSA_SUCCESS;
uint8_t *loaded_data;
size_t storage_data_length = 0;
mbedtls_svc_key_id_t key = attr->id;
status = psa_crypto_storage_get_data_length(key, &storage_data_length);
if (status != PSA_SUCCESS) {
return status;
}
loaded_data = mbedtls_calloc(1, storage_data_length);
if (loaded_data == NULL) {
return PSA_ERROR_INSUFFICIENT_MEMORY;
}
status = psa_crypto_storage_load(key, loaded_data, storage_data_length);
if (status != PSA_SUCCESS) {
goto exit;
}
status = psa_parse_key_data_from_storage(loaded_data, storage_data_length,
data, data_length, attr);
/* All keys saved to persistent storage always have a key context */
if (status == PSA_SUCCESS &&
(*data == NULL || *data_length == 0)) {
status = PSA_ERROR_STORAGE_FAILURE;
}
exit:
mbedtls_zeroize_and_free(loaded_data, storage_data_length);
return status;
}
/****************************************************************/
/* Transactions */
/****************************************************************/
#if defined(PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS)
psa_crypto_transaction_t psa_crypto_transaction;
psa_status_t psa_crypto_save_transaction(void)
{
struct psa_storage_info_t p_info;
psa_status_t status;
status = psa_its_get_info(PSA_CRYPTO_ITS_TRANSACTION_UID, &p_info);
if (status == PSA_SUCCESS) {
/* This shouldn't happen: we're trying to start a transaction while
* there is still a transaction that hasn't been replayed. */
return PSA_ERROR_CORRUPTION_DETECTED;
} else if (status != PSA_ERROR_DOES_NOT_EXIST) {
return status;
}
return psa_its_set(PSA_CRYPTO_ITS_TRANSACTION_UID,
sizeof(psa_crypto_transaction),
&psa_crypto_transaction,
0);
}
psa_status_t psa_crypto_load_transaction(void)
{
psa_status_t status;
size_t length;
status = psa_its_get(PSA_CRYPTO_ITS_TRANSACTION_UID, 0,
sizeof(psa_crypto_transaction),
&psa_crypto_transaction, &length);
if (status != PSA_SUCCESS) {
return status;
}
if (length != sizeof(psa_crypto_transaction)) {
return PSA_ERROR_DATA_INVALID;
}
return PSA_SUCCESS;
}
psa_status_t psa_crypto_stop_transaction(void)
{
psa_status_t status = psa_its_remove(PSA_CRYPTO_ITS_TRANSACTION_UID);
/* Whether or not updating the storage succeeded, the transaction is
* finished now. It's too late to go back, so zero out the in-memory
* data. */
memset(&psa_crypto_transaction, 0, sizeof(psa_crypto_transaction));
return status;
}
#endif /* PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS */
/****************************************************************/
/* Random generator state */
/****************************************************************/
#if defined(MBEDTLS_PSA_INJECT_ENTROPY)
psa_status_t mbedtls_psa_storage_inject_entropy(const unsigned char *seed,
size_t seed_size)
{
psa_status_t status;
struct psa_storage_info_t p_info;
status = psa_its_get_info(PSA_CRYPTO_ITS_RANDOM_SEED_UID, &p_info);
if (PSA_ERROR_DOES_NOT_EXIST == status) { /* No seed exists */
status = psa_its_set(PSA_CRYPTO_ITS_RANDOM_SEED_UID, seed_size, seed, 0);
} else if (PSA_SUCCESS == status) {
/* You should not be here. Seed needs to be injected only once */
status = PSA_ERROR_NOT_PERMITTED;
}
return status;
}
#endif /* MBEDTLS_PSA_INJECT_ENTROPY */
/****************************************************************/
/* The end */
/****************************************************************/
#endif /* MBEDTLS_PSA_CRYPTO_STORAGE_C */
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