mirror of
https://github.com/kuhyx/testsAndMisc.git
synced 2026-07-04 15:23:03 +02:00
Krzysztof Rudnicki
6ec85106b7
- Add enforce-resolved.sh: validates ReadEtcHosts=yes, prevents DNSOverTLS bypass, removes drop-in overrides, locks drop-in dir - Add resolved-guard.path/service: watches /etc/systemd/resolved.conf and its drop-in directory for tampering - Update pacman hooks to unlock/relock nsswitch.conf and resolved.conf alongside /etc/hosts during package transactions - Extend setup_hosts_guard.sh with --skip-resolved option, resolved canonical snapshot, drop-in directory locking, and enforcement - Add resolved.conf checks to check_and_enable_services.sh: validates ReadEtcHosts, DNSOverTLS, drop-in overrides, immutable attribute, and resolved-guard.path status with auto-fix capability Fixed on live system: ReadEtcHosts was set to 'no' and nsswitch.conf was missing 'files' in the hosts line, completely bypassing /etc/hosts.
109 lines
2.9 KiB
Bash
Executable File
109 lines
2.9 KiB
Bash
Executable File
#!/usr/bin/env bash
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# Shared functions for hosts-guard pacman hooks
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# This file is sourced by pacman-pre-unlock-hosts.sh and pacman-post-relock-hosts.sh
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TARGET=/etc/hosts
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NSSWITCH=/etc/nsswitch.conf
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RESOLVED_CONF=/etc/systemd/resolved.conf
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RESOLVED_DROPIN=/etc/systemd/resolved.conf.d
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LOGTAG=hosts-guard-hook
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# Check if target has a read-only mount
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is_ro_mount() {
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findmnt -no OPTIONS -T "$TARGET" 2>/dev/null | grep -qw ro
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}
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# Count mount layers for the target
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mount_layers_count() {
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awk '$5=="/etc/hosts"{c++} END{print c+0}' /proc/self/mountinfo 2>/dev/null || echo 0
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}
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# Collapse all bind mount layers
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collapse_mounts() {
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local i=0
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if command -v mountpoint >/dev/null 2>&1; then
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while mountpoint -q "$TARGET"; do
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umount -l "$TARGET" >/dev/null 2>&1 || break
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i=$((i + 1))
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((i > 20)) && break
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done
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else
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local cnt
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cnt=$(mount_layers_count)
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while ((cnt > 1)); do
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umount -l "$TARGET" >/dev/null 2>&1 || break
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i=$((i + 1))
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((i > 20)) && break
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cnt=$(mount_layers_count)
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done
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fi
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}
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# Stop systemd units related to hosts guard
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stop_units_if_present() {
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local units=(hosts-bind-mount.service hosts-guard.path nsswitch-guard.path resolved-guard.path)
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for u in "${units[@]}"; do
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if command -v systemctl >/dev/null 2>&1; then
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if systemctl list-unit-files 2>/dev/null | grep -q "^$u"; then
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systemctl stop "$u" >/dev/null 2>&1 || true
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fi
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fi
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done
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}
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# Remove immutable/append-only attributes from a file
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_remove_attrs_for() {
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local f="$1"
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if [[ -e "$f" ]] && command -v lsattr >/dev/null 2>&1; then
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chattr -ia "$f" >/dev/null 2>&1 || true
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fi
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}
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# Remove immutable/append-only attributes from all guarded files
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remove_host_attrs() {
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_remove_attrs_for "$TARGET"
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}
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remove_all_guard_attrs() {
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_remove_attrs_for "$TARGET"
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_remove_attrs_for "$NSSWITCH"
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_remove_attrs_for "$RESOLVED_CONF"
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_remove_attrs_for "$RESOLVED_DROPIN"
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}
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# Apply immutable attribute to all guarded files
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apply_immutable() {
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if command -v chattr >/dev/null 2>&1; then
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chattr +i "$TARGET" >/dev/null 2>&1 || true
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chattr +i "$NSSWITCH" >/dev/null 2>&1 || true
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chattr +i "$RESOLVED_CONF" >/dev/null 2>&1 || true
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# Lock drop-in dir to prevent creation of override files
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if [[ -d "$RESOLVED_DROPIN" ]]; then
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chattr +i "$RESOLVED_DROPIN" >/dev/null 2>&1 || true
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fi
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fi
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}
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# Apply a single read-only bind mount layer
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apply_ro_bind_mount() {
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mount --bind "$TARGET" "$TARGET" >/dev/null 2>&1 || true
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mount -o remount,ro,bind "$TARGET" >/dev/null 2>&1 || true
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}
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# Start all path watcher services
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start_path_watcher() {
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if command -v systemctl >/dev/null 2>&1; then
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systemctl start hosts-guard.path >/dev/null 2>&1 || true
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systemctl start nsswitch-guard.path >/dev/null 2>&1 || true
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systemctl start resolved-guard.path >/dev/null 2>&1 || true
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fi
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}
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# Log to system logger and run log file
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log_hook() {
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local phase="$1"
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local state="$2"
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logger -t "$LOGTAG" "$phase: $state"
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echo "$(date -Is) $phase-$state" >>/run/hosts-guard-hook.log 2>/dev/null || true
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}
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