Read Out Protect - Only a section?

mwp · ‎2013-01-31

Posted on January 31, 2013 at 13:48

Hi all,

Is it possible to read out protect only one specific area of flash?

I want to use a bootloader that can program both encrypted and un-encrypted programs.

I need to protect the bootloader from being read so un-encrypted (non-trusted) programs cannot access the encryption method/keys in the bootloader.

Is this possible somehow?

Thanks in advance!

mwp · ‎2013-01-31

Posted on January 31, 2013 at 14:53

Ok... so obviously ROP is of no use here as non-trusted firmware can still access the bootloader even if ROP could only be enabled for that section of flash.

So... is there any other way of doing what im after?

Tesla DeLorean · ‎2013-01-31

Posted on January 31, 2013 at 15:52

Code running in FLASH, and copied out of flash into RAM, can read the entire memory space.

You could copy data to RAM from a ROP'd device and then reset with BOOTx pins set to execute from RAM, such code would not be able to read the ROM or FLASH.

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mwp · ‎2013-01-31

Posted on January 31, 2013 at 16:04

Hardware is in production, so i guess it cant be done.

Thanks.