esp-idf/components/bootloader_support/include/esp_flash_encrypt.h

157 lines
5.3 KiB
C
Raw Normal View History

2021-05-09 22:56:51 -04:00
/*
2022-01-17 21:32:56 -05:00
* SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD
2021-05-09 22:56:51 -04:00
*
* SPDX-License-Identifier: Apache-2.0
*/
#pragma once
#include <stdbool.h>
#include "esp_attr.h"
#include "esp_err.h"
#ifndef BOOTLOADER_BUILD
#include "esp_spi_flash.h"
#endif
#include "hal/efuse_ll.h"
#include "sdkconfig.h"
#ifdef __cplusplus
extern "C" {
#endif
/* @brief Flash encryption mode based on efuse values
*/
typedef enum {
ESP_FLASH_ENC_MODE_DISABLED, // flash encryption is not enabled (flash crypt cnt=0)
ESP_FLASH_ENC_MODE_DEVELOPMENT, // flash encryption is enabled but for Development (reflash over UART allowed)
ESP_FLASH_ENC_MODE_RELEASE // flash encryption is enabled for Release (reflash over UART disabled)
} esp_flash_enc_mode_t;
/**
* @file esp_partition.h
* @brief Support functions for flash encryption features
*
* Can be compiled as part of app or bootloader code.
*/
/** @brief Is flash encryption currently enabled in hardware?
*
* Flash encryption is enabled if the FLASH_CRYPT_CNT efuse has an odd number of bits set.
*
* @return true if flash encryption is enabled.
*/
bool esp_flash_encryption_enabled(void);
/* @brief Update on-device flash encryption
*
* Intended to be called as part of the bootloader process if flash
* encryption is enabled in device menuconfig.
*
* If FLASH_CRYPT_CNT efuse parity is 1 (ie odd number of bits set),
* then return ESP_OK immediately (indicating flash encryption is enabled
* and functional).
*
* If FLASH_CRYPT_CNT efuse parity is 0 (ie even number of bits set),
* assume the flash has just been written with plaintext that needs encrypting.
*
* The following regions of flash are encrypted in place:
*
* - The bootloader image, if a valid plaintext image is found.[*]
* - The partition table, if a valid plaintext table is found.
* - Any app partition that contains a valid plaintext app image.
* - Any other partitions with the "encrypt" flag set. [**]
*
* After the re-encryption process completes, a '1' bit is added to the
* FLASH_CRYPT_CNT value (setting the parity to 1) and the EFUSE is re-burned.
*
* [*] If reflashing bootloader with secure boot enabled, pre-encrypt
* the bootloader before writing it to flash or secure boot will fail.
*
* [**] For this reason, if serial re-flashing a previous flashed
* device with secure boot enabled and using FLASH_CRYPT_CNT to
* trigger re-encryption, you must simultaneously re-flash plaintext
* content to all partitions with the "encrypt" flag set or this
* data will be corrupted (encrypted twice).
*
* @note The post-condition of this function is that all
* partitions that should be encrypted are encrypted.
*
* @note Take care not to power off the device while this function
* is running, or the partition currently being encrypted will be lost.
*
* @note RTC_WDT will reset while encryption operations will be performed (if RTC_WDT is configured).
*
* @return ESP_OK if all operations succeeded, ESP_ERR_INVALID_STATE
* if a fatal error occured during encryption of all partitions.
*/
esp_err_t esp_flash_encrypt_check_and_update(void);
/** @brief Encrypt-in-place a block of flash sectors
*
* @note This function resets RTC_WDT between operations with sectors.
* @param src_addr Source offset in flash. Should be multiple of 4096 bytes.
* @param data_length Length of data to encrypt in bytes. Will be rounded up to next multiple of 4096 bytes.
*
* @return ESP_OK if all operations succeeded, ESP_ERR_FLASH_OP_FAIL
* if SPI flash fails, ESP_ERR_FLASH_OP_TIMEOUT if flash times out.
*/
esp_err_t esp_flash_encrypt_region(uint32_t src_addr, size_t data_length);
/** @brief Write protect FLASH_CRYPT_CNT
*
* Intended to be called as a part of boot process if flash encryption
* is enabled but secure boot is not used. This should protect against
* serial re-flashing of an unauthorised code in absence of secure boot.
*
* @note On ESP32 V3 only, write protecting FLASH_CRYPT_CNT will also prevent
* disabling UART Download Mode. If both are wanted, call
* esp_efuse_disable_rom_download_mode() before calling this function.
*
*/
void esp_flash_write_protect_crypt_cnt(void);
/** @brief Return the flash encryption mode
*
* The API is called during boot process but can also be called by
* application to check the current flash encryption mode of ESP32
*
* @return
*/
esp_flash_enc_mode_t esp_get_flash_encryption_mode(void);
/** @brief Check the flash encryption mode during startup
*
* @note This function is called automatically during app startup,
* it doesn't need to be called from the app.
*
* Verifies the flash encryption config during startup:
*
* - Correct any insecure flash encryption settings if hardware
* Secure Boot is enabled.
* - Log warnings if the efuse config doesn't match the project
* config in any way
*/
void esp_flash_encryption_init_checks(void);
/** @brief Set all secure eFuse features related to flash encryption
*
* @return
* - ESP_OK - Successfully
*/
esp_err_t esp_flash_encryption_enable_secure_features(void);
/** @brief Switches Flash Encryption from "Development" to "Release"
*
* If already in "Release" mode, the function will do nothing.
* If flash encryption efuse is not enabled yet then abort.
* It burns:
* - "disable encrypt in dl mode"
* - set FLASH_CRYPT_CNT efuse to max
*/
void esp_flash_encryption_set_release_mode(void);
#ifdef __cplusplus
}
#endif