Setup of external call to bl_validation_fw from my application

[Simon Third]

Hi All,

I'm in the process of implementing the bootloader (NSIB) to support FW upgrades.

This is working well until I added access to call the bootloaders bl_validation_firmware() from my app via the EXT_API feature.  To get the project to compile I had to add

CONFIG_SECURE_BOOT_VALIDATION=y

CONFIG_BL_VALIDATE_FW_EXT_API_ENABLED=y

CONFIG_SECURE_BOOT_CRYPTO=y

CONFIG_SECURE_BOOT_STORAGE=y

EXT_API_REQ(BL_VALIDATE_FW, 1, struct bl_validate_fw_ext_api, bl);

int main(void)
{

        printk("Starting up...\n");

        if (bl->ext_api.bl_validate_firmware(0x9000, 0x9000))
        {
                printk("FW at 0x9000 validated");
        }
        else
                printk("FW at 0x9000 Failed validated");

        printk("Waiting forever...\n");
        while (1)
        {
                ;
        }
        return 0;
}

But then it fails to Link my app, with undefined reference to get_hash().  So am I missing another CONFIG item?

I wouldn't have thought that my app would need to link in bl_crypto in the first place, as this functionality is implemented in the bootloader image? Isn't this the point of the external api to enable calls to the bootloader functions and not having to re-implement them in the user application?

I'm testing this on the nRF52840DK with SDK 2.2.0

Thanks

Simon

[Vidar Berg]

Hello Simon,

It should be possible to utilize the APIs exposed by NSIB (nRF Secure Immutable Bootloader) for image validation without duplicating the crypto dependencies in the application. However, NSIB isn't designed for performing DFU over SMP. For that, you'd need to integrate MCUBoot as your primary or secondary bootloader. If you're looking to get started with DFU, I recommend beginning with the SMP Server Sample. While this sample comes with MCUBoot as the first stage bootloader, you can add CONFIG_SECURE_BOOT=y to the prj.conf if you wish to include NSIB. In this sample, the image validation is taken care of by the bootloader, not the application. The application is only responsible for receiving and storing the image to the secondary slot through the MCUmgr subsystem.

Best regards,

Vidar

[Simon Third]

Hi Vidar,

I have the NSIB working. CONFIG_SECURE_BOOT=y is already included. 

I'm working towards having FW update over a UART using one of our custom protocols (from within my application).  The reason for wanting to call bl_validate_firmware() is to check if the new image programming has worked correctly and signal this status to the master mcu before rebooting. My issue occurs when I add the other CONFIG's as above and add the EXT_API_REQ() helper to enable the call into the bootloader. As far as I can see from the documentation this is the recommended method?

As I test to remove the influence from other CONFIG settings I made a new application with the main() from above but get the same compiler issue with the get_hash() reference.

Could you build my sample application to replicate the issue?

Thanks

S3

[Simon Third]

Hi Vidar,

I've found the solution.

I also need to add

CONFIG_BL_VALIDATE_FW_EXT_API_REQUIRED=y

 

Thanks 

S3