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linux-image-manager/lim/configuration/initcpio/tor_hook

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#!/usr/bin/ash
# mkinitcpio runtime hook: start Tor so the dropbear unlock shell is
# reachable as an onion service while encryptssh waits for the passphrase.
# Installed to /etc/initcpio/hooks/tor by linux-image-manager.
# netconf's ipconfig drops its DHCP lease data (incl. DNS) into
# /tmp/net-*.conf; busybox's resolver only reads /etc/resolv.conf.
_tor_write_resolv_conf() {
[ -s /etc/resolv.conf ] && return 0
local conf dns
for conf in /tmp/net-*.conf; do
[ -f "$conf" ] || continue
# Extract ONLY the DNS fields with sed; never source these files —
# they hold attacker-controllable DHCP option strings (hostname,
# domain, rootpath), and sourcing would run them as root pre-boot.
for dns in $(sed -n 's/^IPV4DNS[01]=//p' "$conf"); do
[ -n "$dns" ] && [ "$dns" != "0.0.0.0" ] \
&& echo "nameserver $dns" >> /etc/resolv.conf
done
done
[ -s /etc/resolv.conf ]
}
run_hook() {
# Tor rejects consensus documents when the clock is far off; boards
# without an RTC boot in 1970, so sync before starting Tor. Bounded:
# a failed sync must never block the boot.
msg "tor: syncing clock via NTP..."
# Best-effort DNS; a tor_ntp IP literal needs none, so never gate on it.
_tor_write_resolv_conf || msg "tor: no DNS from DHCP (fine if tor_ntp is an IP)"
/usr/local/bin/busybox timeout 30 \
/usr/local/bin/busybox ntpd -n -q -p "${tor_ntp:-pool.ntp.org}" \
|| msg "tor: NTP sync failed, keeping current clock"
msg "tor: starting onion service for remote unlock..."
mkdir -p /var/lib/tor
chmod 0700 /var/lib/tor /etc/tor/onion
chmod 0600 /etc/tor/onion/hs_ed25519_secret_key
tor -f /etc/tor/torrc --RunAsDaemon 1 --Log "notice file /tmp/tor.log" \
|| msg "tor: failed to start, unlock stays reachable via direct IP"
}
run_cleanuphook() {
# Nothing from the initramfs may keep running after the pivot.
/usr/local/bin/busybox killall tor 2>/dev/null
return 0
}