refactor(core): improve NFC driver for better compatibility across various ST chips
What the developer wrote
Authored by tychovrahe
refactor(core): improve NFC driver for better compatibility across various ST chips
[no changelog]
What changed, and why it matters
This commit renames an NFC driver to be chip-agnostic and reorders its startup steps so the interrupt line is configured before the NFC controller is initialized, then cleared again after. It also swaps a flag-clearing macro for a more correct interrupt-clearing macro. These are defensive housekeeping changes that reduce the chance of a stale interrupt firing at the wrong moment during startup. There is no direct evidence this fixes an exploitable security bug.
Treat as a normal driver robustness improvement. No urgent security action is indicated by the diff alone. If this commit is part of a larger release, verify whether the vendor release notes describe it as a security fix.
Security signals we found
Interrupt line configuration moved before controller initialization
Pending interrupt flags cleared before and after rfalNfcInitialize()
__HAL_GPIO_EXTI_CLEAR_FLAG replaced with __HAL_GPIO_EXTI_CLEAR_IT
rfal_initialized flag set later in the init sequence
Evidence from the diff
The patch refactors core/embed/io/nfc/st25/nfc.c: the driver struct and global are renamed from st25r3916b_ to st25_ for broader ST chip compatibility. Functionally, nfc_init() now configures the EXTI/NVIC interrupt path before calling rfalNfcInitialize(), clears pending interrupt bits both before and after rfal initialization, and uses __HAL_GPIO_EXTI_CLEAR_IT() instead of __HAL_GPIO_EXTI_CLEAR_FLAG(). The rfal_initialized flag is set only after interrupts are enabled. These changes harden the init sequence against stale or spurious NFC IRQs during controller bring-up, but the diff itself does not demonstrate a reachable vulnerability.
Changed components
core/embed/io/nfc/st25/nfc.cNFC EXTI interrupt handlingST25R3916B / ST25 NFC driver initializationInspect captured patch +33 / −30
diff --git a/core/embed/io/nfc/st25/nfc.c b/core/embed/io/nfc/st25/nfc.c
index 61928a38..a09d6ff9 100644
--- a/core/embed/io/nfc/st25/nfc.c
+++ b/core/embed/io/nfc/st25/nfc.c
@@ -68,9 +68,9 @@ typedef struct {
rfalNfcDiscoverParam disc_params;
bool rfal_initialized;
nfc_state_t last_nfc_state;
-} st25r3916b_driver_t;
+} st25_driver_t;
-static st25r3916b_driver_t g_st25r3916b_driver = {
+static st25_driver_t g_st25_driver = {
.initialized = false,
.rfal_initialized = false,
};
@@ -129,13 +129,13 @@ static nfc_status_t nfc_transcieve_blocking(uint8_t *tx_buf,
static void nfc_card_emulator_loop(rfalNfcDevice *nfc_dev);
nfc_status_t nfc_init() {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
if (drv->initialized) {
return NFC_OK;
}
- memset(drv, 0, sizeof(st25r3916b_driver_t));
+ memset(drv, 0, sizeof(st25_driver_t));
// Enable clock of relevant peripherals
// SPI + GPIO ports
@@ -200,18 +200,6 @@ nfc_status_t nfc_init() {
goto cleanup;
}
- ReturnCode ret;
- ret = rfalNfcInitialize();
-
- // Set default discovery parameters
- rfalNfcDefaultDiscParams(&drv->disc_params);
-
- if (ret != RFAL_ERR_NONE) {
- goto cleanup;
- }
-
- drv->rfal_initialized = true;
-
// Initialize EXTI for NFC IRQ pin
EXTI_ConfigTypeDef EXTI_Config = {0};
EXTI_Config.GPIOSel = NFC_EXTI_INTERRUPT_GPIOSEL;
@@ -225,10 +213,25 @@ nfc_status_t nfc_init() {
}
NVIC_SetPriority(NFC_EXTI_INTERRUPT_NUM, IRQ_PRI_NORMAL);
- __HAL_GPIO_EXTI_CLEAR_FLAG(NFC_INT_PIN);
+ __HAL_GPIO_EXTI_CLEAR_IT(NFC_INT_PIN);
+ NVIC_ClearPendingIRQ(NFC_EXTI_INTERRUPT_NUM);
+
+ ReturnCode ret;
+ ret = rfalNfcInitialize();
+
+ // Set default discovery parameters
+ rfalNfcDefaultDiscParams(&drv->disc_params);
+
+ if (ret != RFAL_ERR_NONE) {
+ goto cleanup;
+ }
+
+ __HAL_GPIO_EXTI_CLEAR_IT(NFC_INT_PIN);
NVIC_ClearPendingIRQ(NFC_EXTI_INTERRUPT_NUM);
NVIC_EnableIRQ(NFC_EXTI_INTERRUPT_NUM);
+ drv->rfal_initialized = true;
+
drv->initialized = true;
drv->last_nfc_state = NFC_STATE_NOT_ACTIVE;
@@ -240,7 +243,7 @@ cleanup:
}
void nfc_deinit(void) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
if (drv->rfal_initialized) {
// Deactivate rfal STM (Disconnects active devices)
@@ -266,11 +269,11 @@ void nfc_deinit(void) {
HAL_GPIO_DeInit(NFC_SPI_NSS_PORT, NFC_SPI_NSS_PIN);
HAL_GPIO_DeInit(NFC_INT_PORT, NFC_INT_PIN);
- memset(drv, 0, sizeof(st25r3916b_driver_t));
+ memset(drv, 0, sizeof(st25_driver_t));
}
nfc_status_t nfc_register_tech(const nfc_tech_t tech) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
if (drv->initialized == false) {
return NFC_NOT_INITIALIZED;
@@ -343,7 +346,7 @@ nfc_status_t nfc_register_tech(const nfc_tech_t tech) {
}
nfc_status_t nfc_activate_stm(void) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
if (!drv->initialized) {
return NFC_NOT_INITIALIZED;
@@ -359,7 +362,7 @@ nfc_status_t nfc_activate_stm(void) {
}
nfc_status_t nfc_deactivate_stm(void) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
if (!drv->initialized) {
return NFC_OK;
@@ -378,7 +381,7 @@ nfc_status_t nfc_deactivate_stm(void) {
}
nfc_status_t nfc_get_event(nfc_event_t *event) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
*event = NFC_NO_EVENT;
@@ -481,7 +484,7 @@ nfc_status_t nfc_get_event(nfc_event_t *event) {
}
nfc_status_t nfc_dev_deactivate(void) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
if (!drv->initialized) {
return NFC_NOT_INITIALIZED;
@@ -494,7 +497,7 @@ nfc_status_t nfc_dev_deactivate(void) {
nfc_status_t nfc_transceive(const uint8_t *tx_data, uint16_t tx_data_len,
uint8_t *rx_data, uint16_t *rx_data_len) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
if (drv->initialized == false) {
return NFC_NOT_INITIALIZED;
@@ -516,7 +519,7 @@ nfc_status_t nfc_transceive(const uint8_t *tx_data, uint16_t tx_data_len,
}
nfc_status_t nfc_dev_write_ndef_uri(void) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
if (!drv->initialized) {
return NFC_NOT_INITIALIZED;
@@ -585,7 +588,7 @@ nfc_status_t nfc_dev_read_info(nfc_dev_info_t *dev_info) {
HAL_StatusTypeDef nfc_spi_transmit_receive(const uint8_t *tx_data,
uint8_t *rx_data, uint16_t length) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
HAL_StatusTypeDef status;
if ((tx_data != NULL) && (rx_data == NULL)) {
@@ -601,16 +604,16 @@ HAL_StatusTypeDef nfc_spi_transmit_receive(const uint8_t *tx_data,
}
void nfc_ext_irq_set_callback(void (*cb)(void)) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
drv->nfc_irq_callback = cb;
}
void NFC_EXTI_INTERRUPT_HANDLER(void) {
- st25r3916b_driver_t *drv = &g_st25r3916b_driver;
+ st25_driver_t *drv = &g_st25_driver;
// Clear the EXTI line pending bit
- __HAL_GPIO_EXTI_CLEAR_FLAG(NFC_INT_PIN);
+ __HAL_GPIO_EXTI_CLEAR_IT(NFC_INT_PIN);
if (drv->nfc_irq_callback != NULL) {
drv->nfc_irq_callback();
}
Why this scored 16/100
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