Injecting public keys into FTDs for FIT verification

[Jan Kiszka]

On 05.11.21 13:42, Jan Kiszka wrote:
> On 05.11.21 11:28, Rasmus Villemoes wrote:
>> On 05/11/2021 11.16, Jan Kiszka wrote:
>>> Hi all,
>>>
>>> in order to use CONFIG_FIT_SIGNATURE and also
>>> CONFIG_SPL_FIT_SIGNATURE, a public key needs to be placed into the
>>> control FDT. So far, I only found mkimage being able to do that during
>>> FIT image signing. That is fairly unhandy and often incompatible with
>>> how firmware is built & signed vs. how the lifecycle of the artifacts to
>>> be loaded and verified look like. Is there really no other way than
>>> mkimage -K?
>>>
>>> I'm currently considering to derive a tool that, given a public key
>>> (which is easy to hand around, compared to the private key needed for
>>> signing), injects them into a FDT. Then I would hook that up as generic
>>> feature for U-Boot builds, enriching all control FTDs already during the
>>> first build with this when requested.
>>>
>>> Am I missing an even simpler approach?
>>
>> You're not missing an existing upstream simpler approach, but it's
>> certainly an itch that others have had [1] [2]. My latest attempt
>>
>> https://lore.kernel.org/u-boot/20210928085651.619892-1-rasmus.villemoes@prevas.dk/
>>

Looking at this path: I would also need it for SPL, so that SPL can
validate the container for the main U-Boot. Seems that is missing here,
isn't it?

Jan

>> does now have an R-b by Simon, so now I'm just waiting for that to
>> actually make it into master. I have the script(s) that will convert a
>> public key to a .dtsi fragment, and I'm happy to share that.
>>
> 
> Cool, that would be very welcome!
> 
> Jan
> 
>> Rasmus
>>
>> [1]
>> https://lore.kernel.org/u-boot/CAO5Uq5TyTMacERo01weTEda-5X4Fx-VUoYFHa=mBYhW-RvmVSQ@mail.gmail.com/
>> [2]
>> https://lore.kernel.org/u-boot/94d75c521aed46dbb54a8275be2f529e@kaspersky.com/
>>
> 

-- 
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux