Sourcing a signed boot script

[Lukasz Majewski <lukma@denx.de>]

Hi Diego,

> Hi,
> 
> I would like to ask if it is possible to source a script after
> verifying its signature.
> 
> Currently I've been able to source a script from a signed FIT image,
> before doing "bootm", with:
> source <addr>:<name>
> But this way the signature is not checked yet, so the script cannot
> be trusted.
> 
> According to the docs[1] it seems that it's not possible yet to verify
> a FIT image signature without also booting the corresponding image. Is
> that right?

You can look into the "spl" command, which does the FIT parsing (to
prepare data for falcon mode booting).

You may want to re-use such "dry-run" feature to verify the signature,
extract the script and use it.

(And yes, I don't think that checking the signature for script works
out of the box).

> 
> 
> [1]
> https://gitlab.denx.de/u-boot/u-boot/blob/v2019.10/doc/uImage.FIT/signature.txt#L580
> 
> Thank you,
> Diego Rondini




Best regards,

Lukasz Majewski

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