F401 Enabling ROP?

[mwp]

Posted on May 14, 2018 at 20:27

Hi all,

I'm trying to get ROP enabled by my bootloader.

This function is run first up by main().

I'm finding that it get stuck in a loop, as ROP never seems to become enabled (always reads back as being set at level 0).

Any ideas what im doing wrong here?

Thanks.

void BL_ROPL1(){ FLASH_OBProgramInitTypeDef OBInit; //check ROP status HAL_FLASHEx_OBGetConfig(&OBInit); if (OBInit.RDPLevel == OB_RDP_LEVEL_0) {  //no read out protection is active, enable it  OBInit.OptionType = OPTIONBYTE_RDP;  OBInit.RDPLevel = OB_RDP_LEVEL_1;

  HAL_FLASH_Unlock();

  HAL_FLASH_OB_Unlock();  HAL_FLASHEx_OBProgram(&OBInit);  HAL_FLASH_OB_Lock();  HAL_FLASH_OB_Launch();  NVIC_SystemReset(); //shouldnt get to here }}#rop #security #stm32 #stm32f401 #protection

[Tesla DeLorean]

Posted on May 14, 2018 at 20:39

You should perhaps unlock the Flash/OB first, and pay attention to status returned.

[mwp]

Posted on May 15, 2018 at 19:27

Okay, here is the full thing.

All i ever see is a flickering green LED (flickering due to the boot loop).

Never a red LED indicating an issue.

void

BL_Flash_Protect() {

#ifndef BL_DONT_PROTECT

    FLASH_OBProgramInitTypeDef OBInit;     

//get ROP status

    

if

(HAL_FLASH_Unlock() != HAL_OK)         

goto

ferror;     

if

(HAL_FLASH_OB_Unlock() != HAL_OK)         

goto

ferror;     HAL_FLASHEx_OBGetConfig(&OBInit);     

if

(OBInit.RDPLevel == OB_RDP_LEVEL_0)     {         

//no read out protection is active

        

//disable flash read out to external devices

        LL_GPIO_SetOutputPin(LED3_GRN_PIN);         OBInit.OptionType = OPTIONBYTE_RDP;         OBInit.RDPLevel = OB_RDP_LEVEL_1;         

if

(HAL_FLASHEx_OBProgram(&OBInit) != HAL_OK)             

goto

ferror;         HAL_FLASH_OB_Lock();         HAL_FLASH_Lock();         HAL_FLASH_OB_Launch();

//restarts

        NVIC_SystemReset();

//shouldnt get to here

    }     HAL_FLASH_OB_Lock();     HAL_FLASH_Lock();     

return

;     ferror:

while

(1)     {         LL_GPIO_SetOutputPin(LED3_RED_PIN);         __BKPT(0);     }

#endif

}

[mwp]

Posted on May 15, 2018 at 21:06

Solved!

I misunderstood the function of HAL_FLASH_OB_Launch().

The correct working order is:

HAL_FLASHEx_OBGetConfig(&OBInit);

OBInit.OptionType = OPTIONBYTE_RDP;

OBInit.RDPLevel = OB_RDP_LEVEL_1;

HAL_FLASH_OB_Unlock();

HAL_FLASH_Unlock();

HAL_FLASHEx_OBProgram(&OBInit);

HAL_FLASH_OB_Launch();

HAL_FLASH_OB_Lock();

HAL_FLASH_Lock();

NVIC_SystemReset();