Re: [OE-core] [PATCH] kernel-fitimage: generate openssl RSA keys for signing fitimage

["Usama Arif" <usama.arif@arm.com>]

On 21/09/2020 14:03, Richard Purdie wrote:
> On Tue, 2020-09-08 at 13:28 +0100, Usama Arif wrote:
>> The keys are only generated if they dont exist. The key
>> generation can be turned off by setting FIT_GENERATE_KEYS to "0".
>> The default key length for private keys is 2048 and the default
>> format for public key certificate is x.509.
>>
>> Signed-off-by: Usama Arif <usama.arif@arm.com>
>> ---
>>   meta/classes/kernel-fitimage.bbclass | 44 ++++++++++++++++++++++++++++
>>   1 file changed, 44 insertions(+)
> 
> I'm worried about this as keys are generally something the user needs
> to handle carefully. Making it all "magic" means that a missing key
> might not throw an error when it should and also, someone might not
> save the keys when they might need to.
> 
To make sure the keys exists, we could check in step 7 of 
fitimage_assemble that ${UBOOT_SIGN_KEYDIR}/${UBOOT_SIGN_KEYNAME}".key 
and ${UBOOT_SIGN_KEYDIR}/${UBOOT_SIGN_KEYNAME}".crt exist if 
UBOOT_SIGN_ENABLE is set to 1?

> Perhaps this code should need to be explicitly enabled?

By explicitly enable do you mean change the ?= to = in the below line?

FIT_GENERATE_KEYS ?= "${@bb.utils.contains('UBOOT_SIGN_ENABLE', '1', 
'1', '0', d)}"

I actually think that keeping ?= is a good idea as users might want to 
use some other key not generated by oe-core, so they can choose to 
disable FIT_GENERATE_KEYS.

Thanks for the review!
Usama

> 
> Cheers,
> 
> Richard
>