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In the UEFI setup, I see options to clear the secure boot keys, to install the default secure boot keys, and to install an Intel-owned PK. I don't see any option to load keys from storage. That's not the end of the world, in fact I prefer to manage secure boot from the OS anyway. I cleared the secure boot keys and rebooted. However, I found that I cannot install a PK via the EFI variable filesystem from linux.
Initial state:
* Secure Boot: Enabled (checked)
* Clear Secure Boot Variables on next boot (checked)
After one reboot:
* Secure Boot: Enabled (checked)
* Secure Boot Mode: Custom
* PK,KEK,db,dbx: Not Installed
Commands:
$ od --address-radix=n --format=u1 /sys/firmware/efi/efivars/SecureBoot*
6 0 0 0 0
$ ls /sys/firmware/efi/efivars/{PK-*,KEK-*,db-*,dbx-*}
ls: cannot access '/sys/firmware/efi/efivars/PK-*': Invalid argument
ls: cannot access '/sys/firmware/efi/efivars/KEK-*': Invalid argument
ls: cannot access '/sys/firmware/efi/efivars/db-*': Invalid argument
ls: cannot access '/sys/firmware/efi/efivars/dbx-*': Invalid argument
$ sbkeysync --verbose --pk --dry-run --keystore /tmp/sb
Filesystem keystore:
/tmp/sb/db/db.signed [2196 bytes]
/tmp/sb/KEK/KEK.signed [2201 bytes]
/tmp/sb/PK/PK.signed [2196 bytes]
firmware keys:
PK:
KEK:
db:
dbx:
filesystem keys:
PK:
/CN=.....
from /tmp/sb/PK/PK.signed
KEK:
/CN=......
from /tmp/sb/KEK/KEK.signed
db:
/CN=....
from /tmp/sb/db/db.signed
dbx:
New keys in filesystem:
/tmp/sb/db/db.signed
/tmp/sb/KEK/KEK.signed
/tmp/sb/PK/PK.signed
$ sudo sbkeysync --verbose --pk --keystore /tmp/sb
....same as above, not not a dry run this time...
New keys in filesystem:
/tmp/sb/db/db.signed
/tmp/sb/KEK/KEK.signed
/tmp/sb/PK/PK.signed
Inserting key update /tmp/sb/db/db.signed into db
Inserting key update /tmp/sb/KEK/KEK.signed into KEK
Error writing key update: Invalid argument
Error syncing keystore file /tmp/sb/KEK/KEK.signed
$ sudo lsattr /sys/firmware/efi/efivars/PK-8be4df61-93ca-11d2-aa0d-00e098032b8c /sys/firmware/efi/efivars/KEK-8be4df61-93ca-11d2-aa0d-00e098032b8c /sys/firmware/efi/efivars/db-d719b2cb-3d3a-4596-a3bc-dad00e67656f /sys/firmware/efi/efivars/dbx-d719b2cb-3d3a-4596-a3bc-dad00e67656f
lsattr: No such file or directory while trying to stat /sys/firmware/efi/efivars/PK-8be4df61-93ca-11d2-aa0d-00e098032b8c
----i--------------- /sys/firmware/efi/efivars/KEK-8be4df61-93ca-11d2-aa0d-00e098032b8c
----i--------------- /sys/firmware/efi/efivars/db-d719b2cb-3d3a-4596-a3bc-dad00e67656f
lsattr: No such file or directory while trying to stat /sys/firmware/efi/efivars/dbx-d719b2cb-3d3a-4596-a3bc-dad00e67656f
$ sudo chattr -i /sys/firmware/efi/efivars/PK-8be4df61-93ca-11d2-aa0d-00e098032b8c /sys/firmware/efi/efivars/KEK-8be4df61-93ca-11d2-aa0d-00e098032b8c
chattr: No such file or directory while trying to stat /sys/firmware/efi/efivars/PK-8be4df61-93ca-11d2-aa0d-00e098032b8c
$ sudo sbkeysync --verbose --pk --keystore /tmp/sb
...
firmware keys:
PK:
KEK:
db:
/CN=...
dbx:
...
New keys in filesystem:
/tmp/sb/KEK/KEK.signed
/tmp/sb/PK/PK.signed
Inserting key update /tmp/sb/KEK/KEK.signed into KEK
Error writing key update: Invalid argument
Error syncing keystore file /tmp/sb/KEK/KEK.signed
For whatever reason, I can't install the KEK or PK from the operating system and I don't see an option to do it from the UEFI setup either.
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What is the model number of your NUC?
Doc
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$ sudo dmidecode
...
BIOS Information
Vendor: Intel Corp.
Version: PYBSWCEL.86A.0055.2016.0812.1130
...
Base Board Information
Manufacturer: Intel Corporation
Product Name: NUC5PPYB
Version: H76558-107
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Hi HuckBerry,
Welcome to our new community platform.
The Intel® NUC Kit NUC5PPYH has been discontinued and we no longer offer interactive support for this product but other community members may collaborate on this request.
I would also recommend that you review the documentation that I am attaching to this post.
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Thanks for the response. I don't suspect this is specific to the model NUC I have, but rather to the firmware that is likely shared among several models. I subscribed to Michael M's thread as I suspect it's the same question. If you could provide documentation on how to load a custom PK key into the newest model NUC, I could try working backwards from there to see if it works on my NUC.
The documentation you linked is a good guide for developing, but it only illustrates testing the signing keys on a virtual machine. My question is how to load the keys into a real NUC.

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