I plan to provide a Linux appliance to several users. These users are tech savvy and can easily reset the root password on a standard linux system.
How can I create a running Linux system that keeps even the root user out of the filesystem once protected? (I looked at disk encryption like LUKS but in all cases the root user can gain access to an automounted partition).
How do I solve this problem? Stack exchange questions like this assume the attacker does NOT have root access, but it seems simple to reset root password by booting into single user/recovery mode.
I've read about LUKS but FDE requires rolling the keyfile into the initramfs (as shown here) but I think you can easily unroll the initramfs and extract the key. So I don't think this solves the problem