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As someone who uses systemd, "boot security" is pointless. If someone has enough access to your hardware to try booting a different kernel, they have time to lo
by swe02 2y ago
As someone who uses systemd, "boot security" is pointless. If someone has enough access to your hardware to try booting a different kernel, they have time to load a signed shim that passes secure boot and launches unsigned code.
The only boot security real users need is disk encryption.
- fc417fc802 2y agoThere are multiple possible configurations. Only the most basic will permit an arbitrary payload as you describe. I've never been entirely clear about the security model when the signed shim is permitted. I assume I'm missing some nuance. Disk encryption alone won't protect you from either persistent malware (remote) or evil maids (local).
- viraptor 2y ago"on a system not configured for boot security, you get no boot security" is indeed correct. If you care about boot security, your local platform doesn't give you the chance to boot custom kernels and not passing secure boot doesn't give you decryption keys.
- craftkiller 2y ago> signed shim How would they sign such a shim without my keys? I don't leave Microsoft keys enrolled on my laptop.
- bigfatkitten 1y ago> The only boot security real users need is disk encryption. Which becomes easy to bypass without boot security. If an adversary can modify code that executes in the boot process, they can steal your keys.
- teddyh 1y agoAn adversary can usually only modify code that executes in the boot process if they already have root privileges, or if they have physical access. In either of those cases the game is already over anyway.
- bigfatkitten 1y ago> or if they have physical access. If you're not worried about physical access, then why would you encrypt your disk at all?
- teddyh 1y agoEncrypted disks saves you from an unsophisticated attacker. Also, full disk encryption enables the feature of using a power plug switch as a ”lockdown mode” button.