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Furi: Detect use-after-free #3995

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Furi: Detect use-after-free #3995

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a26631f
Furi: Detect use-after-free
WillyJL Nov 9, 2024
f30f0c1
Furi: Fix Semaphore atomicity
WillyJL Nov 9, 2024
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2 changes: 1 addition & 1 deletion furi/core/memmgr_heap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -527,7 +527,7 @@ void vPortFree(void* pv) {
/* Add this block to the list of free blocks. */
xFreeBytesRemaining += pxLink->xBlockSize;
traceFREE(pv, pxLink->xBlockSize);
memset(pv, 0, pxLink->xBlockSize - xHeapStructSize);
memset(pv, 0xDD, pxLink->xBlockSize - xHeapStructSize);
prvInsertBlockIntoFreeList((BlockLink_t*)pxLink);
}
(void)xTaskResumeAll();
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4 changes: 4 additions & 0 deletions furi/core/semaphore.c
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Original file line number Diff line number Diff line change
Expand Up @@ -104,6 +104,8 @@ FuriStatus furi_semaphore_release(FuriSemaphore* instance) {

stat = FuriStatusOk;

FURI_CRITICAL_ENTER();

if(FURI_IS_IRQ_MODE()) {
yield = pdFALSE;

Expand All @@ -123,6 +125,8 @@ FuriStatus furi_semaphore_release(FuriSemaphore* instance) {
furi_event_loop_link_notify(&instance->event_loop_link, FuriEventLoopEventIn);
}

FURI_CRITICAL_EXIT();

return stat;
}

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47 changes: 46 additions & 1 deletion targets/f7/furi_hal/furi_hal_interrupt.c
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Expand Up @@ -314,7 +314,52 @@ void MemManage_Handler(void) {
}

void BusFault_Handler(void) {
furi_crash("BusFault");
const char* crash_msg = "BusFault";

furi_log_puts("\r\n" _FURI_LOG_CLR_E "Bus fault:\r\n");
if(FURI_BIT(SCB->CFSR, SCB_CFSR_LSPERR_Pos)) {
furi_log_puts(" - lazy stacking for exception entry\r\n");
}

if(FURI_BIT(SCB->CFSR, SCB_CFSR_STKERR_Pos)) {
furi_log_puts(" - stacking for exception entry\r\n");
}

if(FURI_BIT(SCB->CFSR, SCB_CFSR_UNSTKERR_Pos)) {
furi_log_puts(" - unstacking for exception return\r\n");
}

if(FURI_BIT(SCB->CFSR, SCB_CFSR_IMPRECISERR_Pos)) {
furi_log_puts(" - imprecise data access\r\n");
}

if(FURI_BIT(SCB->CFSR, SCB_CFSR_PRECISERR_Pos)) {
furi_log_puts(" - precise data access\r\n");
}

if(FURI_BIT(SCB->CFSR, SCB_CFSR_IBUSERR_Pos)) {
furi_log_puts(" - instruction\r\n");
}

if(FURI_BIT(SCB->CFSR, SCB_CFSR_BFARVALID_Pos)) {
uint32_t busfault_address = SCB->BFAR;
furi_log_puts(" -- at 0x");

char tmp_str[] = "0xFFFFFFFF";
itoa(busfault_address, tmp_str, 16);
furi_log_puts(tmp_str);

furi_log_puts("\r\n");

if(busfault_address == (uint32_t)NULL) {
furi_log_puts(" -- NULL pointer dereference\r\n");
} else if(busfault_address >= 0xDDDDDDDD && busfault_address <= 0xDDDEDDDD) {
crash_msg = "Possible use-after-free";
}
}
furi_log_puts(_FURI_LOG_CLR_RESET);

furi_crash(crash_msg);
}

void UsageFault_Handler(void) {
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