Hello, This is more of a user question but I didn't find any other suitable forum to ask.
I want to install a server that should have an encrypted root but be able to reboot unattended. systemd-cryptenroll with TPM2 looks like a viable option. I'm concerned about which PCRs to pin so that an average attacker won't be able to decrypt the volume having physical possession of the server. This means I'm not concerned about cracking the TPM chip or reading out life memory. To me it is acceptable to pin a lot of them so that adding/changing devices would prevent automatic decryption. Also 5 looks good about changed GPT partitions. I'm concerned though about an attacker replacing the encrypted root volume with a non-encrypted one. Which may result in system booting an attacker controlled environment while PCRs may be in a state that allows decryption of the original root volume. Would anything prevent the system from booting with a replaced root volume? If it can boot in such a way, which PCRs need to be pinned to remove the ability to decrypt the original root volume? If there is presently no such PCR, can some custom validation be added in the process to take care of that? Thank you!
