RNode_Firmware_CE/Device.h
2024-09-12 20:32:54 +01:00

331 lines
10 KiB
C

// Copyright (C) 2023, Mark Qvist
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
#include <Ed25519.h>
#if MCU_VARIANT == MCU_ESP32
#include "mbedtls/md.h"
#include "esp_ota_ops.h"
#include "esp_flash_partitions.h"
#include "esp_partition.h"
#elif MCU_VARIANT == MCU_NRF52
#include "Adafruit_nRFCrypto.h"
// size of chunk to retrieve from flash sector
#define CHUNK_SIZE 128
#define END_SECTION_SIZE 256
#if defined(NRF52840_XXAA)
// https://learn.adafruit.com/introducing-the-adafruit-nrf52840-feather/hathach-memory-map
// each section follows along from one another, in this order
// this is always at the start of the memory map
#define APPLICATION_START 0x26000
#define USER_DATA_START 0xED000
#endif
#endif
// Forward declaration from Utilities.h
void eeprom_update(int mapped_addr, uint8_t byte);
uint8_t eeprom_read(uint32_t addr);
void hard_reset(void);
#if !HAS_EEPROM && MCU_VARIANT == MCU_NRF52
void eeprom_flush();
#endif
const uint8_t dev_keys [] PROGMEM = {
0x0f, 0x15, 0x86, 0x74, 0xa0, 0x7d, 0xf2, 0xde, 0x32, 0x11, 0x29, 0xc1, 0x0d, 0xda, 0xcc, 0xc3,
0xe1, 0x9b, 0xac, 0xf2, 0x27, 0x06, 0xee, 0x89, 0x1f, 0x7a, 0xfc, 0xc3, 0x6a, 0xf5, 0x38, 0x08
};
#define DEV_SIG_LEN 64
uint8_t dev_sig[DEV_SIG_LEN];
#define DEV_KEY_LEN 32
uint8_t dev_k_prv[DEV_KEY_LEN];
uint8_t dev_k_pub[DEV_KEY_LEN];
#define DEV_HASH_LEN 32
uint8_t dev_hash[DEV_HASH_LEN];
uint8_t dev_partition_table_hash[DEV_HASH_LEN];
uint8_t dev_bootloader_hash[DEV_HASH_LEN];
uint8_t dev_firmware_hash[DEV_HASH_LEN];
uint8_t dev_firmware_hash_target[DEV_HASH_LEN];
#define EEPROM_SIG_LEN 128
uint8_t dev_eeprom_signature[EEPROM_SIG_LEN];
bool dev_signature_validated = false;
bool fw_signature_validated = true;
#define DEV_SIG_OFFSET EEPROM_SIZE-EEPROM_RESERVED-DEV_SIG_LEN
#define dev_sig_addr(a) (a+DEV_SIG_OFFSET)
#define DEV_FWHASH_OFFSET EEPROM_SIZE-EEPROM_RESERVED-DEV_SIG_LEN-DEV_HASH_LEN
#define dev_fwhash_addr(a) (a+DEV_FWHASH_OFFSET)
bool device_signatures_ok() {
return dev_signature_validated && fw_signature_validated;
}
void device_validate_signature() {
int n_keys = sizeof(dev_keys)/DEV_KEY_LEN;
bool valid_signature_found = false;
for (int i = 0; i < n_keys; i++) {
memcpy(dev_k_pub, dev_keys+DEV_KEY_LEN*i, DEV_KEY_LEN);
if (Ed25519::verify(dev_sig, dev_k_pub, dev_hash, DEV_HASH_LEN)) {
valid_signature_found = true;
}
}
if (valid_signature_found) {
dev_signature_validated = true;
} else {
dev_signature_validated = false;
}
}
void device_save_signature() {
device_validate_signature();
if (dev_signature_validated) {
for (uint8_t i = 0; i < DEV_SIG_LEN; i++) {
eeprom_update(dev_sig_addr(i), dev_sig[i]);
}
}
}
void device_load_signature() {
for (uint8_t i = 0; i < DEV_SIG_LEN; i++) {
#if HAS_EEPROM
dev_sig[i] = EEPROM.read(dev_sig_addr(i));
#elif MCU_VARIANT == MCU_NRF52
dev_sig[i] = eeprom_read(dev_sig_addr(i));
#endif
}
}
void device_load_firmware_hash() {
for (uint8_t i = 0; i < DEV_HASH_LEN; i++) {
#if HAS_EEPROM
dev_firmware_hash_target[i] = EEPROM.read(dev_fwhash_addr(i));
#elif MCU_VARIANT == MCU_NRF52
dev_firmware_hash_target[i] = eeprom_read(dev_fwhash_addr(i));
#endif
}
}
void device_save_firmware_hash() {
for (uint8_t i = 0; i < DEV_HASH_LEN; i++) {
eeprom_update(dev_fwhash_addr(i), dev_firmware_hash_target[i]);
}
#if !HAS_EEPROM && MCU_VARIANT == MCU_NRF52
eeprom_flush();
#endif
if (!fw_signature_validated) hard_reset();
}
#if MCU_VARIANT == MCU_NRF52
void calculate_region_hash(unsigned long long start, unsigned long long end, uint8_t* return_hash) {
// this function calculates the hash digest of a region of memory,
// currently it is only designed to work for the application region
uint8_t chunk[CHUNK_SIZE] = {0};
// to store potential last chunk of program
uint8_t chunk_next[CHUNK_SIZE] = {0};
nRFCrypto_Hash hash;
hash.begin(CRYS_HASH_SHA256_mode);
bool finish = false;
uint8_t size;
bool application = true;
int end_count = 0;
unsigned long length = 0;
while (start < end - 1 ) {
const void* src = (const void*)start;
if (start + CHUNK_SIZE >= end) {
size = (end - 1) - start;
}
else {
size = CHUNK_SIZE;
}
memcpy(chunk, src, CHUNK_SIZE);
// check if we've reached the end of the program
// if we're checking the application region
if (application) {
for (int i = 0; i < CHUNK_SIZE; i++) {
if (chunk[i] == 0xFF) {
bool matched = true;
end_count = 1;
// check if rest of chunk is FFs as well, only if FF is not
// at the end of chunk
if (i < CHUNK_SIZE - 1) {
for (int x = 0; x < CHUNK_SIZE - i; x++) {
if (chunk[i+x] != 0xFF) {
matched = false;
break;
}
end_count++;
}
}
if (matched) {
while (end_count < END_SECTION_SIZE) {
// check if bytes in next chunk up to total
// required are also FFs
for (int x = 1; x <= ceil(END_SECTION_SIZE / CHUNK_SIZE); x++) {
const void* src_next = (const void*)start + CHUNK_SIZE*x;
if ((END_SECTION_SIZE - end_count) > CHUNK_SIZE) {
size = CHUNK_SIZE;
} else {
size = END_SECTION_SIZE - end_count;
}
memcpy(chunk_next, src_next, size);
for (int y = 0; y < size; y++) {
if (chunk_next[y] != 0xFF) {
matched = false;
break;
}
end_count++;
}
if (!matched) {
break;
}
}
if (!matched) {
break;
}
}
if (matched) {
finish = true;
size = i;
break;
}
}
}
}
}
if (finish) {
hash.update(chunk, size);
length += size;
break;
} else {
hash.update(chunk, size);
}
start += CHUNK_SIZE;
length += CHUNK_SIZE;
}
hash.end(return_hash);
}
#endif
void device_validate_partitions() {
device_load_firmware_hash();
#if MCU_VARIANT == MCU_ESP32
esp_partition_t partition;
partition.address = ESP_PARTITION_TABLE_OFFSET;
partition.size = ESP_PARTITION_TABLE_MAX_LEN;
partition.type = ESP_PARTITION_TYPE_DATA;
esp_partition_get_sha256(&partition, dev_partition_table_hash);
partition.address = ESP_BOOTLOADER_OFFSET;
partition.size = ESP_PARTITION_TABLE_OFFSET;
partition.type = ESP_PARTITION_TYPE_APP;
esp_partition_get_sha256(&partition, dev_bootloader_hash);
esp_partition_get_sha256(esp_ota_get_running_partition(), dev_firmware_hash);
#elif MCU_VARIANT == MCU_NRF52
// todo, add bootloader, partition table, or softdevice?
calculate_region_hash(APPLICATION_START, USER_DATA_START, dev_firmware_hash);
#endif
for (uint8_t i = 0; i < DEV_HASH_LEN; i++) {
if (dev_firmware_hash_target[i] != dev_firmware_hash[i]) {
fw_signature_validated = false;
break;
}
}
}
bool device_firmware_ok() {
return fw_signature_validated;
}
#if MCU_VARIANT == MCU_ESP32 || MCU_VARIANT == MCU_NRF52
bool device_init() {
#if VALIDATE_FIRMWARE
if (bt_ready) {
#if MCU_VARIANT == MCU_ESP32
for (uint8_t i=0; i<EEPROM_SIG_LEN; i++){dev_eeprom_signature[i]=EEPROM.read(eeprom_addr(ADDR_SIGNATURE+i));}
mbedtls_md_context_t ctx;
mbedtls_md_type_t md_type = MBEDTLS_MD_SHA256;
mbedtls_md_init(&ctx);
mbedtls_md_setup(&ctx, mbedtls_md_info_from_type(md_type), 0);
mbedtls_md_starts(&ctx);
#if HAS_BLUETOOTH == true || HAS_BLE == true
mbedtls_md_update(&ctx, dev_bt_mac, BT_DEV_ADDR_LEN);
#else
// TODO: Get from BLE stack instead
// mbedtls_md_update(&ctx, dev_bt_mac, BT_DEV_ADDR_LEN);
#endif
mbedtls_md_update(&ctx, dev_eeprom_signature, EEPROM_SIG_LEN);
mbedtls_md_finish(&ctx, dev_hash);
mbedtls_md_free(&ctx);
#elif MCU_VARIANT == MCU_NRF52
for (uint8_t i=0; i<EEPROM_SIG_LEN; i++){dev_eeprom_signature[i]=eeprom_read(eeprom_addr(ADDR_SIGNATURE+i));}
nRFCrypto.begin();
nRFCrypto_Hash hash;
hash.begin(CRYS_HASH_SHA256_mode);
#if HAS_BLUETOOTH == true || HAS_BLE == true
hash.update(dev_bt_mac, BT_DEV_ADDR_LEN);
#else
// TODO: Get from BLE stack instead
// hash.update(dev_bt_mac, BT_DEV_ADDR_LEN);
#endif
hash.update(dev_eeprom_signature, EEPROM_SIG_LEN);
hash.end(dev_hash);
#endif
device_load_signature();
device_validate_signature();
device_validate_partitions();
#if MCU_VARIANT == MCU_NRF52
nRFCrypto.end();
#endif
device_init_done = true;
return device_init_done && fw_signature_validated;
} else {
return false;
}
#else
// Skip hash comparison and checking BT
return true;
#endif
}
#endif