Two image-side hardening pieces both small enough to ship together.
deploy/nftables/nftables.conf — single ruleset installed at /etc/nftables.conf.
Default-drop input. Allowed: loopback, established/related, ratelimited
ICMP, kiosk local API :18090 from RFC1918 / RFC4193 / link-local sources
only. SSH stays gated by sshd-disabled (image build sets enable-ssh: 0
and 01-run-chroot masks it); the firewall rule for :22 is left commented
in for triage scenarios. Forward dropped. Output left wide open — kiosk
needs to dial out to arbitrary RTSP cameras + the BF server (which may
live on the public internet) without explicit allowlisting.
deploy/systemd/betterframe-firstboot.{service,sh} — runs once per device
before betterframe-kiosk starts. Generates a 24-char unambiguous-glyph
password, applies via chpasswd, stores at /etc/betterframe/admin-password
(0400 root), and prints a banner to tty1 so an HDMI-attached operator
can transcribe it during the boot window before cage takes over the
screen. Marker at /var/lib/betterframe/.firstboot-complete prevents
re-run on subsequent boots. Without this, every kiosk built from the
same image shipped with bfadmin:betterframe — a single password leak
compromises the entire fleet.
Future follow-up: post the rotated password (encrypted with cluster_key)
to the BF server via heartbeat so admin UI can surface it. Not in this
commit; the local file + tty banner are the only retrieval paths today.
WebView showed a grey/black half-square in the top-left — that's GDK's
"none" cursor rendered by WebKit's own surface, which ignores the
GTK-window CSS we set elsewhere. Inject a WebKit UserStyleSheet that
applies cursor:none !important to every page + frame at User priority,
overriding page-author CSS.
For the boot gap (cage start → first kiosk frame), set XCURSOR_SIZE=1
and WLR_NO_HARDWARE_CURSORS=1 in the systemd unit. SW fallback honors
the 1-pixel size; HW cursors don't, which is why a default arrow leaks
through on some Pi GPUs.
WebKitGTK launches bubblewrap for its web-content process; bwrap refuses
to run when the parent process still carries unexpected CAP_* bits ("but
not setuid, old file caps config?"). Setting CapabilityBoundingSet= +
AmbientCapabilities= empty and NoNewPrivileges=yes gives bwrap a clean
caps slate to drop from, so the sandbox initialises and web/dashboard
cells render instead of crashing the kiosk.
systemd refuses to spawn the unit with code=216/GROUP when any group in
SupplementaryGroups= doesn't exist. Debian's seatd uses -g video — there
is no 'seat' group on the system. Removing it lets cage start; the video
group already covers seatd access.
Replace the user-mode kiosk service with a system unit that runs cage
(single-app Wayland compositor) on tty1 as a dedicated unprivileged
user. No desktop, no display manager, auto-restart on crash via
Restart=always.
setup-pi-kiosk.sh provisions the user, installs cage + seatd, disables
any display manager, points default.target at multi-user, drops the
PAM stack, and enables the service. Idempotent.
Screen wake "auto-login": with no DM and no lockscreen, DPMS-driven
sleep just turns the panel back on — the kiosk process is already
running.
Bind native backend services and Node-RED to loopback so Angie remains the public auth boundary. Keep Docker on an internal compose network and stop kiosk fallback to a layout when display default is none.
