lunaryorn

secureboot

#archlinux #systemd #tpm2 #secureboot #dracut #luks #sbctl

This article describes my Arch Linux setup which combines Secure Boot with custom keys, TPM2-based full disk encryption and systemd-homed into a fully encrypted and authenticated, yet convenient Linux system.

This setup draws inspiration from Authenticated Boot and Disk Encryption on Linux and Unlocking LUKS2 volumes with TPM2, FIDO2, PKCS#11 Security Hardware on systemd 248 by Lennart Poettering, and combines my previous posts Unlock LUKS rootfs with TPM2 key, Secure boot on Arch Linux with sbctl and dracut, and Arch Linux with LUKS and (almost) no configuration.

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#archlinux #systemd #tpm2 #secureboot #dracut #luks #sbctl

Historically cryptsetup and LUKS only supported good old passwords; however recent systemd versions extend cryptsetup with additional key types such as FIDO tokens and TPM devices.

I like the idea of encrypting the rootfs with a TPM2 key; it allows booting without ugly LUKS password prompts but still it keeps data encrypted at rest, and when combined with secure boot also still protects the running system against unauthorized access.

Secure boot will prevent others from placing custom kernels on the unencrypted EFI system partition and booting these, or changing the kernel cmdline, in order to obtain root access to the unlocked rootfs. LUKS encryption with a TPM-based key bound to secure boot state protects the data if someone removes the hard disk and attempts to access it offline, or tries to disable secure boot in order to boot a custom kernel.

I’ve covered secure boot setup in a past article; this article talks about the TPM2-based encryption.

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#archlinux #secureboot #dracut #sbctl

I started playing around with secure boot, with the ultimately goal of setting it up on my laptop. I experimented in a libvirt/qemu VM and to my surprise a custom secure boot is rather easy (the Secure Boot page on the Arch Wiki suggests quite the contrary), thanks to dracut and a fairly recent tool named sbctl which just recently had it’s first release.

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