[U-Boot] RFC: Secure boot framework

[Fernandes, Joel A]

Hi,

Can anyone comment on what has been discussed about a framework for secure boot and authentication, if there has been such a discussion, in the community?

I have some U-boot code that is based off of a slightly older U-boot which does authentication and/or decryption. The main code that does the cryptography is in the ROM of the SoC. However, I'm sure there will be other U-boot developers requiring the crypto algorithms itself to be supported.

My questions are :
(1) Would a general framework for performing authentication and/or decryption of signed and/or encrypted images be useful for U-boot? These operations seem to make a lot of sense for a bootloader.

(2) Does such a framework make sense for any of your usecase(s)?

(3) Has there been any work or discussions of coming up with such a framework for U-boot?

I imagine a framework like this will atleast consist of: 

1. General purposes cryptographic functions in a library (which we might not need for our case), some light weight crypto library.
2. Hooks for board/Soc-specific functions that call into the general crypto lib and do any other board/SoC-specific stuff.
3. General commands (in a cmd_crpto.c) that calls into the callbacks mentioned in 2. for encryption and verification of an image already in memory. (making it commands can allow us to leave bootm alone and do the inplace decryption/verification independently - however for SPL, we don't need the commands and call into 2. directly).
4. Abstract any other change(s) to common boot code in a common place.

Let me know your suggestions, thanks.

Regards,
Joel