alex/esp-idf
1
0
Fork 0
mirror of https://github.com/espressif/esp-idf.git synced 2025-08-11 04:57:38 +00:00
Code Issues Packages Projects Releases Wiki Activity

efuse(esp32): Deprecate esp_efuse_burn_new_values() & esp_efuse_write_random_key()

Browse Source 
These functions were used only for esp32 in secure_boot and flash encryption.
Use idf efuse APIs instead of efuse regs.
This commit is contained in:
Konstantin Kondrashov
2021-06-17 07:21:36 +08:00
committed by Angus Gratton
parent eca878b37f
commit f339b3fc96
86 changed files with 2785 additions and 2825 deletions
Download Patch File Download Diff File Expand all files Collapse all files

379
components/bootloader_support/src/flash_encryption/flash_encrypt.c Normal file
View File

@@ -0,0 +1,379 @@
/*
* SPDX-FileCopyrightText: 2015-2021 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <strings.h>
#include "bootloader_flash_priv.h"
#include "bootloader_random.h"
#include "esp_image_format.h"
#include "esp_flash_encrypt.h"
#include "esp_flash_partitions.h"
#include "esp_secure_boot.h"
#include "esp_efuse.h"
#include "esp_efuse_table.h"
#include "esp_log.h"
#include "hal/wdt_hal.h"
#ifdef CONFIG_SECURE_FLASH_ENC_ENABLED
#if CONFIG_IDF_TARGET_ESP32
#define CRYPT_CNT ESP_EFUSE_FLASH_CRYPT_CNT
#define WR_DIS_CRYPT_CNT ESP_EFUSE_WR_DIS_FLASH_CRYPT_CNT
#else
#define CRYPT_CNT ESP_EFUSE_SPI_BOOT_CRYPT_CNT
#define WR_DIS_CRYPT_CNT ESP_EFUSE_WR_DIS_SPI_BOOT_CRYPT_CNT
#endif
/* This file implements FLASH ENCRYPTION related APIs to perform
* various operations such as programming necessary flash encryption
* eFuses, detect whether flash encryption is enabled (by reading eFuse)
* and if required encrypt the partitions in flash memory
*/
static const char *TAG = "flash_encrypt";
/* Static functions for stages of flash encryption */
static esp_err_t initialise_flash_encryption(void);
static esp_err_t encrypt_flash_contents(size_t flash_crypt_cnt, bool flash_crypt_wr_dis) __attribute__((unused));
static esp_err_t encrypt_bootloader(void);
static esp_err_t encrypt_and_load_partition_table(esp_partition_info_t *partition_table, int *num_partitions);
static esp_err_t encrypt_partition(int index, const esp_partition_info_t *partition);
esp_err_t esp_flash_encrypt_check_and_update(void)
{
size_t flash_crypt_cnt = 0;
esp_efuse_read_field_cnt(CRYPT_CNT, &flash_crypt_cnt);
bool flash_crypt_wr_dis = esp_efuse_read_field_bit(WR_DIS_CRYPT_CNT);
ESP_LOGV(TAG, "CRYPT_CNT %d, write protection %d", flash_crypt_cnt, flash_crypt_wr_dis);
if (flash_crypt_cnt % 2 == 1) {
/* Flash is already encrypted */
int left = (CRYPT_CNT[0]->bit_count - flash_crypt_cnt) / 2;
if (flash_crypt_wr_dis) {
left = 0; /* can't update FLASH_CRYPT_CNT, no more flashes */
}
ESP_LOGI(TAG, "flash encryption is enabled (%d plaintext flashes left)", left);
return ESP_OK;
} else {
#ifndef CONFIG_SECURE_FLASH_REQUIRE_ALREADY_ENABLED
/* Flash is not encrypted, so encrypt it! */
return encrypt_flash_contents(flash_crypt_cnt, flash_crypt_wr_dis);
#else
ESP_LOGE(TAG, "flash encryption is not enabled, and SECURE_FLASH_REQUIRE_ALREADY_ENABLED "
"is set, refusing to boot.");
return ESP_ERR_INVALID_STATE;
#endif // CONFIG_SECURE_FLASH_REQUIRE_ALREADY_ENABLED
}
}
static esp_err_t check_and_generate_encryption_keys(void)
{
size_t key_size = 32;
#ifdef CONFIG_IDF_TARGET_ESP32
enum { BLOCKS_NEEDED = 1 };
esp_efuse_purpose_t purposes[BLOCKS_NEEDED] = {
ESP_EFUSE_KEY_PURPOSE_FLASH_ENCRYPTION,
};
esp_efuse_coding_scheme_t coding_scheme = esp_efuse_get_coding_scheme(EFUSE_BLK_ENCRYPT_FLASH);
if (coding_scheme != EFUSE_CODING_SCHEME_NONE && coding_scheme != EFUSE_CODING_SCHEME_3_4) {
ESP_LOGE(TAG, "Unknown/unsupported CODING_SCHEME value 0x%x", coding_scheme);
return ESP_ERR_NOT_SUPPORTED;
}
if (coding_scheme == EFUSE_CODING_SCHEME_3_4) {
key_size = 24;
}
#else
#ifdef CONFIG_SECURE_FLASH_ENCRYPTION_AES256
enum { BLOCKS_NEEDED = 2 };
esp_efuse_purpose_t purposes[BLOCKS_NEEDED] = {
ESP_EFUSE_KEY_PURPOSE_XTS_AES_256_KEY_1,
ESP_EFUSE_KEY_PURPOSE_XTS_AES_256_KEY_2,
};
if (esp_efuse_find_purpose(ESP_EFUSE_KEY_PURPOSE_XTS_AES_128_KEY, NULL)) {
ESP_LOGE(TAG, "XTS_AES_128_KEY is already in use, XTS_AES_256_KEY_1/2 can not be used");
return ESP_ERR_INVALID_STATE;
}
#else
enum { BLOCKS_NEEDED = 1 };
esp_efuse_purpose_t purposes[BLOCKS_NEEDED] = {
ESP_EFUSE_KEY_PURPOSE_XTS_AES_128_KEY,
};
#endif // CONFIG_SECURE_FLASH_ENCRYPTION_AES256
#endif // CONFIG_IDF_TARGET_ESP32
esp_efuse_block_t blocks[BLOCKS_NEEDED];
bool has_key = true;
for (unsigned i = 0; i < BLOCKS_NEEDED; i++) {
bool tmp_has_key = esp_efuse_find_purpose(purposes[i], &blocks[i]);
if (tmp_has_key) { // For ESP32: esp_efuse_find_purpose() always returns True, need to check whether the key block is used or not.
tmp_has_key &= !esp_efuse_key_block_unused(blocks[i]);
}
if (i == 1 && tmp_has_key != has_key) {
ESP_LOGE(TAG, "Invalid efuse key blocks: Both AES-256 key blocks must be set.");
return ESP_ERR_INVALID_STATE;
}
has_key &= tmp_has_key;
}
if (!has_key) {
/* Generate key */
uint8_t keys[BLOCKS_NEEDED][32] = { 0 };
ESP_LOGI(TAG, "Generating new flash encryption key...");
for (unsigned i = 0; i < BLOCKS_NEEDED; ++i) {
bootloader_fill_random(keys[i], key_size);
}
ESP_LOGD(TAG, "Key generation complete");
esp_err_t err = esp_efuse_write_keys(purposes, keys, BLOCKS_NEEDED);
if (err != ESP_OK) {
if (err == ESP_ERR_NOT_ENOUGH_UNUSED_KEY_BLOCKS) {
ESP_LOGE(TAG, "Not enough free efuse key blocks (need %d) to continue", BLOCKS_NEEDED);
} else {
ESP_LOGE(TAG, "Failed to write efuse block with purpose (err=0x%x). Can't continue.", err);
}
return err;
}
} else {
for (unsigned i = 0; i < BLOCKS_NEEDED; i++) {
if (!esp_efuse_get_key_dis_write(blocks[i])
|| !esp_efuse_get_key_dis_read(blocks[i])
|| !esp_efuse_get_keypurpose_dis_write(blocks[i])) { // For ESP32: no keypurpose, it returns always True.
ESP_LOGE(TAG, "Invalid key state, check read&write protection for key and keypurpose(if exists)");
return ESP_ERR_INVALID_STATE;
}
}
ESP_LOGI(TAG, "Using pre-loaded flash encryption key in efuse");
}
return ESP_OK;
}
static esp_err_t initialise_flash_encryption(void)
{
esp_efuse_batch_write_begin(); /* Batch all efuse writes at the end of this function */
/* Before first flash encryption pass, need to initialise key & crypto config */
esp_err_t err = check_and_generate_encryption_keys();
if (err != ESP_OK) {
esp_efuse_batch_write_cancel();
return err;
}
err = esp_flash_encryption_enable_secure_features();
if (err != ESP_OK) {
esp_efuse_batch_write_cancel();
return err;
}
err = esp_efuse_batch_write_commit();
if (err != ESP_OK) {
ESP_LOGE(TAG, "Error programming security eFuses (err=0x%x).", err);
return err;
}
return ESP_OK;
}
/* Encrypt all flash data that should be encrypted */
static esp_err_t encrypt_flash_contents(size_t flash_crypt_cnt, bool flash_crypt_wr_dis)
{
esp_err_t err;
esp_partition_info_t partition_table[ESP_PARTITION_TABLE_MAX_ENTRIES];
int num_partitions;
/* If all flash_crypt_cnt bits are burned or write-disabled, the
device can't re-encrypt itself. */
if (flash_crypt_wr_dis || flash_crypt_cnt == CRYPT_CNT[0]->bit_count) {
ESP_LOGE(TAG, "Cannot re-encrypt data CRYPT_CNT %d write disabled %d", flash_crypt_cnt, flash_crypt_wr_dis);
return ESP_FAIL;
}
if (flash_crypt_cnt == 0) {
/* Very first flash of encrypted data: generate keys, etc. */
err = initialise_flash_encryption();
if (err != ESP_OK) {
return err;
}
}
err = encrypt_bootloader();
if (err != ESP_OK) {
return err;
}
err = encrypt_and_load_partition_table(partition_table, &num_partitions);
if (err != ESP_OK) {
return err;
}
/* Now iterate the just-loaded partition table, looking for entries to encrypt
*/
/* Go through each partition and encrypt if necessary */
for (int i = 0; i < num_partitions; i++) {
err = encrypt_partition(i, &partition_table[i]);
if (err != ESP_OK) {
return err;
}
}
ESP_LOGD(TAG, "All flash regions checked for encryption pass");
#ifdef CONFIG_SECURE_FLASH_ENCRYPTION_MODE_RELEASE
// Go straight to max, permanently enabled
ESP_LOGI(TAG, "Setting CRYPT_CNT for permanent encryption");
size_t new_flash_crypt_cnt = CRYPT_CNT[0]->bit_count - flash_crypt_cnt;
#else
/* Set least significant 0-bit in flash_crypt_cnt */
size_t new_flash_crypt_cnt = 1;
#endif
ESP_LOGD(TAG, "CRYPT_CNT %d -> %d", flash_crypt_cnt, new_flash_crypt_cnt);
err = esp_efuse_write_field_cnt(CRYPT_CNT, new_flash_crypt_cnt);
ESP_LOGI(TAG, "Flash encryption completed");
return err;
}
static esp_err_t encrypt_bootloader(void)
{
esp_err_t err;
uint32_t image_length;
/* Check for plaintext bootloader (verification will fail if it's already encrypted) */
if (esp_image_verify_bootloader(&image_length) == ESP_OK) {
ESP_LOGD(TAG, "bootloader is plaintext. Encrypting...");
#if CONFIG_SECURE_BOOT_V2_ENABLED
/* The image length obtained from esp_image_verify_bootloader includes the sector boundary padding and the signature block lengths */
if (ESP_BOOTLOADER_OFFSET + image_length > ESP_PARTITION_TABLE_OFFSET) {
ESP_LOGE(TAG, "Bootloader is too large to fit Secure Boot V2 signature sector and partition table (configured offset 0x%x)", ESP_PARTITION_TABLE_OFFSET);
return ESP_ERR_INVALID_SIZE;
}
#endif // CONFIG_SECURE_BOOT_V2_ENABLED
err = esp_flash_encrypt_region(ESP_BOOTLOADER_OFFSET, image_length);
if (err != ESP_OK) {
ESP_LOGE(TAG, "Failed to encrypt bootloader in place: 0x%x", err);
return err;
}
#ifdef CONFIG_SECURE_BOOT_V1_ENABLED
/* If secure boot is enabled and bootloader was plaintext, also
* need to encrypt secure boot IV+digest.
*/
ESP_LOGD(TAG, "Encrypting secure bootloader IV & digest...");
err = esp_flash_encrypt_region(FLASH_OFFS_SECURE_BOOT_IV_DIGEST, FLASH_SECTOR_SIZE);
if (err != ESP_OK) {
ESP_LOGE(TAG, "Failed to encrypt bootloader IV & digest in place: 0x%x", err);
return err;
}
#endif
ESP_LOGI(TAG, "bootloader encrypted successfully");
} else {
ESP_LOGW(TAG, "no valid bootloader was found");
return ESP_ERR_NOT_FOUND;
}
return ESP_OK;
}
static esp_err_t encrypt_and_load_partition_table(esp_partition_info_t *partition_table, int *num_partitions)
{
esp_err_t err;
/* Check for plaintext partition table */
err = bootloader_flash_read(ESP_PARTITION_TABLE_OFFSET, partition_table, ESP_PARTITION_TABLE_MAX_LEN, false);
if (err != ESP_OK) {
ESP_LOGE(TAG, "Failed to read partition table data");
return err;
}
if (esp_partition_table_verify(partition_table, false, num_partitions) == ESP_OK) {
ESP_LOGD(TAG, "partition table is plaintext. Encrypting...");
esp_err_t err = esp_flash_encrypt_region(ESP_PARTITION_TABLE_OFFSET,
FLASH_SECTOR_SIZE);
if (err != ESP_OK) {
ESP_LOGE(TAG, "Failed to encrypt partition table in place. %x", err);
return err;
}
} else {
ESP_LOGE(TAG, "Failed to read partition table data - not plaintext?");
return ESP_ERR_INVALID_STATE;
}
/* Valid partition table loaded */
ESP_LOGI(TAG, "partition table encrypted and loaded successfully");
return ESP_OK;
}
static esp_err_t encrypt_partition(int index, const esp_partition_info_t *partition)
{
esp_err_t err;
bool should_encrypt = (partition->flags & PART_FLAG_ENCRYPTED);
if (partition->type == PART_TYPE_APP) {
/* check if the partition holds a valid unencrypted app */
esp_image_metadata_t data_ignored;
err = esp_image_verify(ESP_IMAGE_VERIFY,
&partition->pos,
&data_ignored);
should_encrypt = (err == ESP_OK);
} else if ((partition->type == PART_TYPE_DATA && partition->subtype == PART_SUBTYPE_DATA_OTA)
|| (partition->type == PART_TYPE_DATA && partition->subtype == PART_SUBTYPE_DATA_NVS_KEYS)) {
/* check if we have ota data partition and the partition should be encrypted unconditionally */
should_encrypt = true;
}
if (!should_encrypt) {
return ESP_OK;
} else {
/* should_encrypt */
ESP_LOGI(TAG, "Encrypting partition %d at offset 0x%x (length 0x%x)...", index, partition->pos.offset, partition->pos.size);
err = esp_flash_encrypt_region(partition->pos.offset, partition->pos.size);
ESP_LOGI(TAG, "Done encrypting");
if (err != ESP_OK) {
ESP_LOGE(TAG, "Failed to encrypt partition %d", index);
}
return err;
}
}
esp_err_t esp_flash_encrypt_region(uint32_t src_addr, size_t data_length)
{
esp_err_t err;
uint32_t buf[FLASH_SECTOR_SIZE / sizeof(uint32_t)];
if (src_addr % FLASH_SECTOR_SIZE != 0) {
ESP_LOGE(TAG, "esp_flash_encrypt_region bad src_addr 0x%x", src_addr);
return ESP_FAIL;
}
wdt_hal_context_t rtc_wdt_ctx = {.inst = WDT_RWDT, .rwdt_dev = &RTCCNTL};
for (size_t i = 0; i < data_length; i += FLASH_SECTOR_SIZE) {
wdt_hal_write_protect_disable(&rtc_wdt_ctx);
wdt_hal_feed(&rtc_wdt_ctx);
wdt_hal_write_protect_enable(&rtc_wdt_ctx);
uint32_t sec_start = i + src_addr;
err = bootloader_flash_read(sec_start, buf, FLASH_SECTOR_SIZE, false);
if (err != ESP_OK) {
goto flash_failed;
}
err = bootloader_flash_erase_sector(sec_start / FLASH_SECTOR_SIZE);
if (err != ESP_OK) {
goto flash_failed;
}
err = bootloader_flash_write(sec_start, buf, FLASH_SECTOR_SIZE, true);
if (err != ESP_OK) {
goto flash_failed;
}
}
return ESP_OK;
flash_failed:
ESP_LOGE(TAG, "flash operation failed: 0x%x", err);
return err;
}
#endif // CONFIG_SECURE_FLASH_ENC_ENABLED