User:Pjones/SecureBootSelfSigning

Self Signing For Secure Boot

Here's how to do your own signing for use with Secure Boot!

Stuff you need

• software that needs to be signed
  • shim - https://github.com/mjg59/shim/releases/download/0.8/shim-0.8.tar.bz2
  • grub2 - upstream from gnu.org or your distro, plus these patches if your distro doesn't have them:
    • 70e7bfb, acc83cf, fe7b32a
  • the linux kernel from whatever distro you're using.
  • pesign - https://github.com/vathpela/pesign/releases/download/0.110/pesign-0.110.tar.bz2

Create signing keys

This is pretty easy on a modern Linux distro when you've got pesign installed, though it is recommended to use a hardware security mechanism like a smart card or USB FIPS 140 Level 2 conforming device to generate and store the cryptographic keys. There's a short tutorial on that <a href="https://fedoraproject.org/wiki/User:Pjones/SecureBootSmartCardDeployment">here</a>, though for these purposes you don't really need a CA key. Assuming you've got the device itself set up and its modules added to the nss db in /etc/pki/pesign, and it is represented with a token in your pesign nss database named "fred", you need to create the keypaid and certificates:

efikeygen -t fred -S -n jrh-signer -c "CN=J.Random Hacker's Code Signing Authority and Amalgamated Distillates, Inc." -u "https://example.com/jrh-signer-info"

Build shim with your key built in to it

At the least, you need some things from shim signed, and you need to build it with your keys built in. Basically this:

jrh-machine:~/shim-0.8$ certutil -d /etc/pki/pesign -h fred -L -n jrh-signer -r > jrh-signer.cer
jrh-machine:~/shim-0.8$ make 'DEFAULT_LOADER=\\\\grubx64.efi' VENDOR_CERT_FILE=jrh-signer.cer shim.efi MokManager.efi fallback.efi
jrh-machine:~/shim-0.8$ pesign -t fred -c jrh-signer -s -i shim.efi -o shim-signed.efi
jrh-machine:~/shim-0.8$ pesign -t fred -c jrh-signer -s -i fallback.efi -o fallback-signed.efi
jrh-machine:~/shim-0.8$ pesign -t fred -c jrh-signer -s -i MokManager.efi -o MokManager-signed.efi

Assuming the EFI system partition is mounted on /boot/efi/, you'll also need to copy the files into place. Don't just change -o above to point there; you may hit <a href="https://github.com/vathpela/fuzzy-lana">this problem</a> and find yourself having a very confusing week.

mkdir -p /boot/efi/EFI/jrh/ /boot/efi/EFI/BOOT
cp shim-signed.efi /boot/efi/EFI/jrh/shim.efi
cp MokManager-signed.efi /boot/efi/EFI/jrh/MokManager.efi
cp shim-signed.efi /boot/efi/EFI/BOOTX64.EFI
cp fallback.efi /boot/efi/EFI/BOOT/fallback.efi

You'll also want to make a BOOT.CSV for fallback to find in EFI\jrh\ ; it's a UCS-2 LE file, so do something like:

echo -n "shim.efi,JRH-OS,,This is the boot entry for JRH-OS" | ( printf "\xff\xfe" ; sed 's/./&\x00/g') > /boot/efi/EFI/jrh/BOOT.CSV

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