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trezor-firmware
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fix(core): improve bhk handling on STM32U5

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[no changelog]
pull/3590/head
tychovrahe 3 months ago committed by TychoVrahe
parent fb2868d297
commit 6e2f5ff27d
5 changed files with 105 additions and 33 deletions
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44
core/embed/boardloader/main.c
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@ -67,7 +67,7 @@ static const uint8_t * const BOARDLOADER_KEYS[] = {
};
#ifdef STM32U5
void check_bootloader_version(uint8_t bld_version) {
uint8_t get_bootloader_min_version(void) {
const uint8_t *counter_addr =
flash_area_get_address(&SECRET_AREA, SECRET_MONOTONIC_COUNTER_OFFSET,
SECRET_MONOTONIC_COUNTER_LEN);
@ -92,10 +92,12 @@ void check_bootloader_version(uint8_t bld_version) {
}
}
ensure((bld_version >= counter) * sectrue, "BOOTLOADER DOWNGRADED");
return counter;
}
if (bld_version > counter) {
for (int i = 0; i < bld_version; i++) {
void write_bootloader_min_version(uint8_t version) {
if (version > get_bootloader_min_version()) {
for (int i = 0; i < version; i++) {
uint32_t data[4] = {0};
secret_write((uint8_t *)data, SECRET_MONOTONIC_COUNTER_OFFSET + i * 16,
16);
@ -160,6 +162,12 @@ static uint32_t check_sdcard(void) {
return 0;
}
#ifdef STM32U5
if (hdr->monotonic < get_bootloader_min_version()) {
return 0;
}
#endif
return hdr->codelen;
}
@ -255,6 +263,8 @@ int main(void) {
}
trustzone_init_boardloader();
secret_ensure_initialized();
#endif
#ifdef STM32F4
@ -280,6 +290,25 @@ int main(void) {
#if defined USE_SD_CARD
sdcard_init();
#ifdef STM32U5
// If the bootloader is being updated from SD card, we need to preserve the
// monotonic counter from the old bootloader. This is in case that the old
// bootloader did not have the chance yet to write its monotonic counter to
// the secret area - which normally happens later in the flow.
const image_header *old_hdr = read_image_header(
(const uint8_t *)BOOTLOADER_START, BOOTLOADER_IMAGE_MAGIC,
flash_area_get_size(&BOOTLOADER_AREA));
if ((old_hdr != NULL) &&
(sectrue == check_image_header_sig(old_hdr, BOARDLOADER_KEY_M,
BOARDLOADER_KEY_N,
BOARDLOADER_KEYS)) &&
(sectrue ==
check_image_contents(old_hdr, IMAGE_HEADER_SIZE, &BOOTLOADER_AREA))) {
write_bootloader_min_version(old_hdr->monotonic);
}
#endif
if (check_sdcard()) {
return copy_sdcard() == sectrue ? 0 : 3;
}
@ -300,7 +329,12 @@ int main(void) {
"invalid bootloader hash");
#ifdef STM32U5
check_bootloader_version(hdr->monotonic);
uint8_t bld_min_version = get_bootloader_min_version();
ensure((hdr->monotonic >= bld_min_version) * sectrue,
"BOOTLOADER DOWNGRADED");
// Write the bootloader version to the secret area.
// This includes the version of bootloader potentially updated from SD card.
write_bootloader_min_version(hdr->monotonic);
#endif
ensure_compatible_settings();

4
core/embed/bootloader/main.c
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@ -430,6 +430,10 @@ int bootloader_main(void) {
display_reinit();
#ifdef STM32U5
ensure(secret_ensure_initialized(), "secret reinitialized");
#endif
ui_screen_boot_empty(false);
mpu_config_bootloader();

4
core/embed/trezorhal/secret.h
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@ -21,6 +21,10 @@ secbool secret_read(uint8_t* data, uint32_t offset, uint32_t len);
secbool secret_wiped(void);
secbool secret_verify_header(void);
secbool secret_ensure_initialized(void);
void secret_erase(void);
void secret_hide(void);

17
core/embed/trezorhal/stm32f4/secret.c
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@ -7,14 +7,17 @@
static secbool bootloader_locked_set = secfalse;
static secbool bootloader_locked = secfalse;
static secbool verify_header(void) {
uint8_t header[SECRET_HEADER_LEN] = {0};
secbool secret_verify_header(void) {
uint8_t header[sizeof(SECRET_HEADER_MAGIC)] = {0};
memcpy(header, flash_area_get_address(&SECRET_AREA, 0, SECRET_HEADER_LEN),
SECRET_HEADER_LEN);
memcpy(header,
flash_area_get_address(&SECRET_AREA, 0, sizeof(SECRET_HEADER_MAGIC)),
sizeof(SECRET_HEADER_MAGIC));
bootloader_locked =
memcmp(header, SECRET_HEADER_MAGIC, 4) == 0 ? sectrue : secfalse;
memcmp(header, SECRET_HEADER_MAGIC, sizeof(SECRET_HEADER_MAGIC)) == 0
? sectrue
: secfalse;
bootloader_locked_set = sectrue;
return bootloader_locked;
}
@ -22,7 +25,7 @@ static secbool verify_header(void) {
secbool secret_bootloader_locked(void) {
if (bootloader_locked_set != sectrue) {
// Set bootloader_locked.
verify_header();
secret_verify_header();
}
return bootloader_locked;
@ -44,7 +47,7 @@ void secret_write(uint8_t* data, uint32_t offset, uint32_t len) {
}
secbool secret_read(uint8_t* data, uint32_t offset, uint32_t len) {
if (sectrue != verify_header()) {
if (sectrue != secret_verify_header()) {
return secfalse;
}

69
core/embed/trezorhal/stm32u5/secret.c
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@ -3,24 +3,37 @@
#include <string.h>
#include "common.h"
#include "flash.h"
#include "memzero.h"
#include "model.h"
#include "rng.h"
static secbool bootloader_locked_set = secfalse;
static secbool bootloader_locked = secfalse;
static secbool verify_header(void) {
uint8_t header[SECRET_HEADER_LEN] = {0};
secbool secret_verify_header(void) {
uint8_t header[sizeof(SECRET_HEADER_MAGIC)] = {0};
memcpy(header, flash_area_get_address(&SECRET_AREA, 0, SECRET_HEADER_LEN),
SECRET_HEADER_LEN);
memcpy(header,
flash_area_get_address(&SECRET_AREA, 0, sizeof(SECRET_HEADER_MAGIC)),
sizeof(SECRET_HEADER_MAGIC));
bootloader_locked =
memcmp(header, SECRET_HEADER_MAGIC, 4) == 0 ? sectrue : secfalse;
bootloader_locked_set = sectrue;
memcmp(header, SECRET_HEADER_MAGIC, sizeof(SECRET_HEADER_MAGIC)) == 0
? sectrue
: secfalse;
return bootloader_locked;
}
secbool secret_ensure_initialized(void) {
if (sectrue != secret_verify_header()) {
ensure(flash_area_erase_bulk(STORAGE_AREAS, STORAGE_AREAS_COUNT, NULL),
"erase storage failed");
secret_erase();
secret_write_header();
return secfalse;
}
return sectrue;
}
secbool secret_bootloader_locked(void) {
#ifdef FIRMWARE
return TAMP->BKP8R != 0 * sectrue;
@ -46,7 +59,7 @@ void secret_write(uint8_t *data, uint32_t offset, uint32_t len) {
}
secbool secret_read(uint8_t *data, uint32_t offset, uint32_t len) {
if (sectrue != verify_header()) {
if (sectrue != secret_verify_header()) {
return secfalse;
}
@ -69,8 +82,27 @@ secbool secret_bhk_locked(void) {
sectrue;
}
static secbool secret_present(uint32_t offset, uint32_t len) {
uint8_t *optiga_secret =
(uint8_t *)flash_area_get_address(&SECRET_AREA, offset, len);
int optiga_secret_empty_bytes = 0;
for (int i = 0; i < len; i++) {
if (optiga_secret[i] == 0xFF) {
optiga_secret_empty_bytes++;
}
}
return sectrue * (optiga_secret_empty_bytes != len);
}
void secret_bhk_provision(void) {
uint32_t secret[SECRET_BHK_LEN / sizeof(uint32_t)] = {0};
if (sectrue != secret_present(SECRET_BHK_OFFSET, SECRET_BHK_LEN)) {
secret_bhk_regenerate();
}
secbool ok =
secret_read((uint8_t *)secret, SECRET_BHK_OFFSET, SECRET_BHK_LEN);
@ -86,6 +118,8 @@ void secret_bhk_provision(void) {
reg1++;
}
}
memzero(secret, sizeof(secret));
}
void secret_bhk_regenerate(void) {
@ -96,24 +130,16 @@ void secret_bhk_regenerate(void) {
for (int j = 0; j < 4; j++) {
val[j] = rng_get();
}
ensure(flash_area_write_quadword(&BHK_AREA, i * 4 * sizeof(uint32_t), val),
"Failed regenerating BHK");
secbool res =
flash_area_write_quadword(&BHK_AREA, i * 4 * sizeof(uint32_t), val);
memzero(val, sizeof(val));
ensure(res, "Failed regenerating BHK");
}
ensure(flash_lock_write(), "Failed regenerating BHK");
}
secbool secret_optiga_present(void) {
uint8_t *optiga_secret = (uint8_t *)flash_area_get_address(
&SECRET_AREA, SECRET_OPTIGA_KEY_OFFSET, SECRET_OPTIGA_KEY_LEN);
int optiga_secret_empty_bytes = 0;
for (int i = 0; i < SECRET_OPTIGA_KEY_LEN; i++) {
if (optiga_secret[i] == 0xFF) {
optiga_secret_empty_bytes++;
}
}
return sectrue * (optiga_secret_empty_bytes != SECRET_OPTIGA_KEY_LEN);
return secret_present(SECRET_OPTIGA_KEY_OFFSET, SECRET_OPTIGA_KEY_LEN);
}
void secret_optiga_backup(void) {
@ -133,6 +159,7 @@ void secret_optiga_backup(void) {
reg1++;
}
}
memzero(secret, sizeof(secret));
}
secbool secret_optiga_extract(uint8_t *dest) {

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