esp-idf/components/nvs_flash/include/nvs_flash.h
Laukik Hase c1bed366ba
nvs_flash: Add support for HMAC-based NVS encryption keys protection scheme
- This features allows the NVS encryption keys to be derived and protected using
  the HMAC peripheral. Since the encryption keys are derived at runtime, they
  are not stored anywhere in the flash and hence this feature does not require
  a separate `nvs_keys` partition.
2023-05-23 13:55:52 +05:30

324 lines
12 KiB
C

/*
* SPDX-FileCopyrightText: 2015-2023 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef nvs_flash_h
#define nvs_flash_h
#ifdef __cplusplus
extern "C" {
#endif
#include "nvs.h"
#include "esp_partition.h"
#define NVS_KEY_SIZE 32 // AES-256
/**
* @brief Key for encryption and decryption
*/
typedef struct {
uint8_t eky[NVS_KEY_SIZE]; /*!< XTS encryption and decryption key*/
uint8_t tky[NVS_KEY_SIZE]; /*!< XTS tweak key */
} nvs_sec_cfg_t;
/**
* @brief Callback function prototype for generating the NVS encryption keys
*/
typedef esp_err_t (*nvs_flash_generate_keys_t) (const void *scheme_data, nvs_sec_cfg_t* cfg);
/**
* @brief Callback function prototype for reading the NVS encryption keys
*/
typedef esp_err_t (*nvs_flash_read_cfg_t) (const void *scheme_data, nvs_sec_cfg_t* cfg);
/**
* @brief NVS encryption: Security scheme configuration structure
*/
typedef struct
{
int scheme_id; /*!< Security Scheme ID (E.g. HMAC) */
void *scheme_data; /*!< Scheme-specific data (E.g. eFuse block for HMAC-based key generation) */
nvs_flash_generate_keys_t nvs_flash_key_gen; /*!< Callback for the nvs_flash_key_gen implementation */
nvs_flash_read_cfg_t nvs_flash_read_cfg; /*!< Callback for the nvs_flash_read_keys implementation */
} nvs_sec_scheme_t;
/**
* @brief Initialize the default NVS partition.
*
* This API initialises the default NVS partition. The default NVS partition
* is the one that is labeled "nvs" in the partition table.
*
* When "NVS_ENCRYPTION" is enabled in the menuconfig, this API enables
* the NVS encryption for the default NVS partition as follows
* 1. Read security configurations from the first NVS key
* partition listed in the partition table. (NVS key partition is
* any "data" type partition which has the subtype value set to "nvs_keys")
* 2. If the NVS key partiton obtained in the previous step is empty,
* generate and store new keys in that NVS key partiton.
* 3. Internally call "nvs_flash_secure_init()" with
* the security configurations obtained/generated in the previous steps.
*
* Post initialization NVS read/write APIs
* remain the same irrespective of NVS encryption.
*
* @return
* - ESP_OK if storage was successfully initialized.
* - ESP_ERR_NVS_NO_FREE_PAGES if the NVS storage contains no empty pages
* (which may happen if NVS partition was truncated)
* - ESP_ERR_NOT_FOUND if no partition with label "nvs" is found in the partition table
* - ESP_ERR_NO_MEM in case memory could not be allocated for the internal structures
* - one of the error codes from the underlying flash storage driver
* - error codes from nvs_flash_read_security_cfg API (when "NVS_ENCRYPTION" is enabled).
* - error codes from nvs_flash_generate_keys API (when "NVS_ENCRYPTION" is enabled).
* - error codes from nvs_flash_secure_init_partition API (when "NVS_ENCRYPTION" is enabled) .
*/
esp_err_t nvs_flash_init(void);
/**
* @brief Initialize NVS flash storage for the specified partition.
*
* @param[in] partition_label Label of the partition. Must be no longer than 16 characters.
*
* @return
* - ESP_OK if storage was successfully initialized.
* - ESP_ERR_NVS_NO_FREE_PAGES if the NVS storage contains no empty pages
* (which may happen if NVS partition was truncated)
* - ESP_ERR_NOT_FOUND if specified partition is not found in the partition table
* - ESP_ERR_NO_MEM in case memory could not be allocated for the internal structures
* - one of the error codes from the underlying flash storage driver
*/
esp_err_t nvs_flash_init_partition(const char *partition_label);
/**
* @brief Initialize NVS flash storage for the partition specified by partition pointer.
*
* @param[in] partition pointer to a partition obtained by the ESP partition API.
*
* @return
* - ESP_OK if storage was successfully initialized
* - ESP_ERR_NVS_NO_FREE_PAGES if the NVS storage contains no empty pages
* (which may happen if NVS partition was truncated)
* - ESP_ERR_INVALID_ARG in case partition is NULL
* - ESP_ERR_NO_MEM in case memory could not be allocated for the internal structures
* - one of the error codes from the underlying flash storage driver
*/
esp_err_t nvs_flash_init_partition_ptr(const esp_partition_t *partition);
/**
* @brief Deinitialize NVS storage for the default NVS partition
*
* Default NVS partition is the partition with "nvs" label in the partition table.
*
* @return
* - ESP_OK on success (storage was deinitialized)
* - ESP_ERR_NVS_NOT_INITIALIZED if the storage was not initialized prior to this call
*/
esp_err_t nvs_flash_deinit(void);
/**
* @brief Deinitialize NVS storage for the given NVS partition
*
* @param[in] partition_label Label of the partition
*
* @return
* - ESP_OK on success
* - ESP_ERR_NVS_NOT_INITIALIZED if the storage for given partition was not
* initialized prior to this call
*/
esp_err_t nvs_flash_deinit_partition(const char* partition_label);
/**
* @brief Erase the default NVS partition
*
* Erases all contents of the default NVS partition (one with label "nvs").
*
* @note If the partition is initialized, this function first de-initializes it. Afterwards, the partition has to
* be initialized again to be used.
*
* @return
* - ESP_OK on success
* - ESP_ERR_NOT_FOUND if there is no NVS partition labeled "nvs" in the
* partition table
* - different error in case de-initialization fails (shouldn't happen)
*/
esp_err_t nvs_flash_erase(void);
/**
* @brief Erase specified NVS partition
*
* Erase all content of a specified NVS partition
*
* @note If the partition is initialized, this function first de-initializes it. Afterwards, the partition has to
* be initialized again to be used.
*
* @param[in] part_name Name (label) of the partition which should be erased
*
* @return
* - ESP_OK on success
* - ESP_ERR_NOT_FOUND if there is no NVS partition with the specified name
* in the partition table
* - different error in case de-initialization fails (shouldn't happen)
*/
esp_err_t nvs_flash_erase_partition(const char *part_name);
/**
* @brief Erase custom partition.
*
* Erase all content of specified custom partition.
*
* @note
* If the partition is initialized, this function first de-initializes it.
* Afterwards, the partition has to be initialized again to be used.
*
* @param[in] partition pointer to a partition obtained by the ESP partition API.
*
* @return
* - ESP_OK on success
* - ESP_ERR_NOT_FOUND if there is no partition with the specified
* parameters in the partition table
* - ESP_ERR_INVALID_ARG in case partition is NULL
* - one of the error codes from the underlying flash storage driver
*/
esp_err_t nvs_flash_erase_partition_ptr(const esp_partition_t *partition);
/**
* @brief Initialize the default NVS partition.
*
* This API initialises the default NVS partition. The default NVS partition
* is the one that is labeled "nvs" in the partition table.
*
* @param[in] cfg Security configuration (keys) to be used for NVS encryption/decryption.
* If cfg is NULL, no encryption is used.
*
* @return
* - ESP_OK if storage has been initialized successfully.
* - ESP_ERR_NVS_NO_FREE_PAGES if the NVS storage contains no empty pages
* (which may happen if NVS partition was truncated)
* - ESP_ERR_NOT_FOUND if no partition with label "nvs" is found in the partition table
* - ESP_ERR_NO_MEM in case memory could not be allocated for the internal structures
* - one of the error codes from the underlying flash storage driver
*/
esp_err_t nvs_flash_secure_init(nvs_sec_cfg_t* cfg);
/**
* @brief Initialize NVS flash storage for the specified partition.
*
* @param[in] partition_label Label of the partition. Note that internally, a reference to
* passed value is kept and it should be accessible for future operations
*
* @param[in] cfg Security configuration (keys) to be used for NVS encryption/decryption.
* If cfg is null, no encryption/decryption is used.
* @return
* - ESP_OK if storage has been initialized successfully.
* - ESP_ERR_NVS_NO_FREE_PAGES if the NVS storage contains no empty pages
* (which may happen if NVS partition was truncated)
* - ESP_ERR_NOT_FOUND if specified partition is not found in the partition table
* - ESP_ERR_NO_MEM in case memory could not be allocated for the internal structures
* - one of the error codes from the underlying flash storage driver
*/
esp_err_t nvs_flash_secure_init_partition(const char *partition_label, nvs_sec_cfg_t* cfg);
/**
* @brief Generate and store NVS keys in the provided esp partition
*
* @param[in] partition Pointer to partition structure obtained using
* esp_partition_find_first or esp_partition_get.
* Must be non-NULL.
* @param[out] cfg Pointer to nvs security configuration structure.
* Pointer must be non-NULL.
* Generated keys will be populated in this structure.
*
*
* @return
* - ESP_OK, if cfg was read successfully;
* - ESP_ERR_INVALID_ARG, if partition or cfg is NULL;
* - or error codes from esp_partition_write/erase APIs.
*/
esp_err_t nvs_flash_generate_keys(const esp_partition_t* partition, nvs_sec_cfg_t* cfg);
/**
* @brief Read NVS security configuration from a partition.
*
* @param[in] partition Pointer to partition structure obtained using
* esp_partition_find_first or esp_partition_get.
* Must be non-NULL.
* @param[out] cfg Pointer to nvs security configuration structure.
* Pointer must be non-NULL.
*
* @note Provided partition is assumed to be marked 'encrypted'.
*
* @return
* - ESP_OK, if cfg was read successfully;
* - ESP_ERR_INVALID_ARG, if partition or cfg is NULL
* - ESP_ERR_NVS_KEYS_NOT_INITIALIZED, if the partition is not yet written with keys.
* - ESP_ERR_NVS_CORRUPT_KEY_PART, if the partition containing keys is found to be corrupt
* - or error codes from esp_partition_read API.
*/
esp_err_t nvs_flash_read_security_cfg(const esp_partition_t* partition, nvs_sec_cfg_t* cfg);
/**
* @brief Registers the given security scheme for NVS encryption
* The scheme registered with sec_scheme_id by this API be used as
* the default security scheme for the "nvs" partition.
* Users will have to call this API explicitly in their application.
*
* @param[in] scheme_cfg Pointer to the security scheme configuration structure
* that the user (or the nvs_key_provider) wants to register.
*
* @return
* - ESP_OK, if security scheme registration succeeds;
* - ESP_ERR_INVALID_ARG, if scheme_cfg is NULL;
* - ESP_FAIL, if security scheme registration fails
*/
esp_err_t nvs_flash_register_security_scheme(nvs_sec_scheme_t *scheme_cfg);
/**
* @brief Fetch the configuration structure for the default active
* security scheme for NVS encryption
*
* @return Pointer to the default active security scheme configuration
* (NULL if no scheme is registered yet i.e. active)
*/
nvs_sec_scheme_t *nvs_flash_get_default_security_scheme(void);
/**
* @brief Generate (and store) the NVS keys using the specified key-protection scheme
*
* @param[in] scheme_cfg Security scheme specific configuration
*
* @param[out] cfg Security configuration (encryption keys)
*
* @return
* - ESP_OK, if cfg was populated successfully with generated encryption keys;
* - ESP_ERR_INVALID_ARG, if scheme_cfg or cfg is NULL;
* - ESP_FAIL, if the key generation process fails
*/
esp_err_t nvs_flash_generate_keys_v2(nvs_sec_scheme_t *scheme_cfg, nvs_sec_cfg_t* cfg);
/**
* @brief Read NVS security configuration set by the specified security scheme
*
* @param[in] scheme_cfg Security scheme specific configuration
*
* @param[out] cfg Security configuration (encryption keys)
*
* @return
* - ESP_OK, if cfg was read successfully;
* - ESP_ERR_INVALID_ARG, if scheme_cfg or cfg is NULL;
* - ESP_FAIL, if the key reading process fails
*/
esp_err_t nvs_flash_read_security_cfg_v2(nvs_sec_scheme_t *scheme_cfg, nvs_sec_cfg_t* cfg);
#ifdef __cplusplus
}
#endif
#endif /* nvs_flash_h */