Split the mkinitcpio-only remote-LUKS-unlock path into an InitramfsBackend
ABC with a get_backend() dispatch, and add the initramfs-tools backend for
Debian / Raspberry Pi OS.
- base.py: six-step backend contract; encryption.py becomes a thin,
distro-neutral sequencer (get_backend by distribution).
- initramfs_tools.py: crypttab `none luks,initramfs`, cmdline rewritten to
root=/dev/mapper + ip=::::host:eth0:dhcp, dropbear-initramfs
authorized_keys, update-initramfs -k all (no build-host uname leak).
- shipped hooks (configuration/initramfs-tools/*): single-hop non-anonymous
onion, libnss DNS baking, sed-not-source DHCP, kill-tor-before-pivot.
- shared offline onion keygen in keygen.py; tor.py removed (logic moved to
mkinitcpio.py).
- raspios added to the apt distro family (session.py, raspberry.py).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Encrypted image setups can now bake a Tor onion service into the initramfs
so the dropbear unlock shell stays reachable behind NAT or a dynamic IP.
When the user opts in, configure_encryption installs tor + busybox, drops
the mkinitcpio hooks (ordered `netconf tor dropbear encryptssh`), generates
the v3 onion keys offline in the image chroot, and prints the stable
.onion address. Unlock with `torsocks ssh root@<onion-address>`.
The runtime hook syncs the clock via NTP first (RTC-less boards boot at
1970, which Tor's consensus checks reject) and starts the onion service
pointing at dropbear on 127.0.0.1:22.
Hardening baked in from an adversarial review of the shipped path:
- cmdline.txt boot path (RPi4-class firmware boot) now sets the same
ip=::::<host>:eth0:dhcp net.ifnames=0 params as the boot.txt path, so
the initramfs actually gets a network and the onion can publish.
- the initramfs bakes in libnss_dns.so.2 so the NTP hostname resolves.
- the hook extracts DHCP DNS with sed instead of sourcing the lease files,
which would run attacker-controlled DHCP option strings as root pre-boot.
- NTP is attempted unconditionally (bounded), not gated on DHCP-provided DNS.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
