Secure trusted boot mechanism

[Sascha Hauer]

On Mon, Jan 16, 2017 at 09:22:57AM +0000, Dold, Wolfram wrote:
> Hi Sascha,
> thanks for your fast reply.
> 
> On 16.01.2017 09:33, Sascha Hauer wrote:
> > Hi Wolfram,
> > 
> > On Mon, Jan 16, 2017 at 08:26:44AM +0000, Dold, Wolfram wrote:
> >> Hi all,
> >> I wanted to ask if barebox supports any kind of secure boot mechanism like FIT-Image or
> >> any other type of verified secure trusted boot?
> > 
> > Yes, barebox does support FIT images.
> > It also supports HAB on i.MX machines, although this is only for
> > starting trusted bootloaders from the ROM, not for starting trusted
> > kernels.
> We have an TI AM335x Machine. As I understood the only way in such an environment to boot a trusted kernel is FIT?

Yes.

Of course you have to make sure that the Boot ROM only boots trusted
bootloaders. I don't know what the AM335x offers here to do that.

> What we wnat to do is to prevent the device from being hijacked.
> Do you know another way than FIT to do that?

No, at least not with barebox (or U-Boot).

> Is there any documentation available regarding barebox and FIT?

Not really, no. Support is similar to U-Boot though. You have to use
mkimage on a device tree blob describing a FIT image. Additionally
you have to put a public key into the device tree to give barebox
something to verify against. If you decide to give it a try I can guide
you through and in the end we can generate documention from this for the
next one.

Sascha

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