mirror of
https://github.com/kuhyx/scripts.git
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453 lines
14 KiB
Bash
Executable File
453 lines
14 KiB
Bash
Executable File
#!/bin/bash
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# One-shot installer for hosts guard + psychological friction + read-only bind mount
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# Layers implemented:
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# - Canonical snapshot of /etc/hosts at /usr/local/share/locked-hosts
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# - Enforcement script (/usr/local/sbin/enforce-hosts.sh)
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# - Systemd path-based auto-revert (hosts-guard.path + hosts-guard.service)
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# - Read-only bind mount (hosts-bind-mount.service)
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# - Delayed edit workflow (/usr/local/sbin/unlock-hosts)
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#
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# This script is idempotent. Re-running updates installed artifacts safely.
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#
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# Usage:
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# sudo ./setup_hosts_guard.sh [options]
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# Options:
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# --force-snapshot Overwrite canonical snapshot even if it exists
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# --no-snapshot Skip creating canonical snapshot (assume already present)
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# --skip-bind Do not enable read-only bind mount service
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# --skip-path-watch Do not enable path watch auto-revert
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# --delay N Set unlock delay seconds (default 45)
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# --dry-run Show actions without performing changes
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# --uninstall Remove installed units/scripts (does NOT restore original hosts)
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# -h|--help Show help
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#
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# Exit codes:
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# 0 success, 1 generic failure, 2 argument error
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set -euo pipefail
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######################################################################
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# Defaults / Config
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######################################################################
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FORCE_SNAPSHOT=0
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DO_SNAPSHOT=1
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ENABLE_BIND=1
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ENABLE_PATH=1
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ENABLE_NSSWITCH=1
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UNINSTALL=0
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DELAY=45
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DRY_RUN=0
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INSTALL_SHELL_HOOKS=1
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INSTALL_AUDIT_RULE=1
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ADD_ALIAS_STUB=1
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######################################################################
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# Helpers
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######################################################################
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msg() { printf '\e[1;32m[+]\e[0m %s\n' "$*"; }
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note() { printf '\e[1;34m[i]\e[0m %s\n' "$*"; }
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warn() { printf '\e[1;33m[!]\e[0m %s\n' "$*"; }
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err() { printf '\e[1;31m[x]\e[0m %s\n' "$*" >&2; }
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run() {
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if [[ $DRY_RUN -eq 1 ]]; then
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printf 'DRY-RUN:'
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if [ "$#" -gt 0 ]; then
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printf ' %q' "$@"
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fi
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printf '\n'
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else
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"$@"
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fi
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}
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require_root() { if [[ $EUID -ne 0 ]]; then exec sudo -E bash "$0" "$@"; fi; }
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usage() { sed -n '1,/^set -euo pipefail/p' "$0" | sed 's/^# \{0,1\}//'; }
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######################################################################
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# Parse args
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######################################################################
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while [[ $# -gt 0 ]]; do
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case "$1" in
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--force-snapshot)
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FORCE_SNAPSHOT=1
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shift
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;;
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--no-snapshot)
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DO_SNAPSHOT=0
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shift
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;;
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--skip-bind)
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ENABLE_BIND=0
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shift
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;;
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--skip-path-watch)
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ENABLE_PATH=0
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shift
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;;
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--skip-nsswitch)
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ENABLE_NSSWITCH=0
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shift
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;;
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--delay)
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DELAY=${2:-}
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[[ -z ${DELAY} ]] && {
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err '--delay requires value'
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exit 2
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}
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shift 2
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;;
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--dry-run)
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DRY_RUN=1
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shift
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;;
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--no-shell-hooks)
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INSTALL_SHELL_HOOKS=0
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shift
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;;
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--shell-hooks)
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INSTALL_SHELL_HOOKS=1
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shift
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;;
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--no-audit)
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INSTALL_AUDIT_RULE=0
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shift
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;;
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--audit)
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INSTALL_AUDIT_RULE=1
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shift
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;;
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--no-alias-stub)
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ADD_ALIAS_STUB=0
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shift
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;;
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--alias-stub)
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ADD_ALIAS_STUB=1
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shift
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;;
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--uninstall)
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UNINSTALL=1
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shift
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;;
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-h | --help)
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usage
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exit 0
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;;
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*)
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err "Unknown argument: $1"
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usage
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exit 2
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;;
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esac
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done
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require_root "$@"
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######################################################################
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# Paths
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######################################################################
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SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
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REPO_ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"
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TEMPLATE_ENFORCE="$SCRIPT_DIR/enforce-hosts.sh"
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TEMPLATE_UNLOCK="$SCRIPT_DIR/psychological/unlock-hosts.sh"
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UNIT_GUARD_SERVICE="$SCRIPT_DIR/hosts-guard.service"
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UNIT_GUARD_PATH="$SCRIPT_DIR/hosts-guard.path"
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UNIT_BIND_SERVICE="$SCRIPT_DIR/hosts-bind-mount.service"
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TEMPLATE_ENFORCE_NSSWITCH="$SCRIPT_DIR/enforce-nsswitch.sh"
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UNIT_NSSWITCH_SERVICE="$SCRIPT_DIR/nsswitch-guard.service"
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UNIT_NSSWITCH_PATH="$SCRIPT_DIR/nsswitch-guard.path"
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INSTALL_ENFORCE="/usr/local/sbin/enforce-hosts.sh"
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INSTALL_UNLOCK="/usr/local/sbin/unlock-hosts"
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INSTALL_ENFORCE_NSSWITCH="/usr/local/sbin/enforce-nsswitch.sh"
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CANON="/usr/local/share/locked-hosts"
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CANON_NSSWITCH="/usr/local/share/locked-nsswitch.conf"
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HOSTS="/etc/hosts"
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NSSWITCH="/etc/nsswitch.conf"
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# Shell hook destinations (user agnostic system-wide skeleton + etc profile.d)
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ZSH_FILTER_SNIPPET="/etc/zsh/hosts_guard_history_filter.zsh"
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BASH_FILTER_SNIPPET="/etc/profile.d/hosts_guard_history_filter.sh"
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SYSTEMD_DIR="/etc/systemd/system"
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######################################################################
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# Uninstall flow
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######################################################################
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if [[ $UNINSTALL -eq 1 ]]; then
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note "Uninstalling hosts guard components ( protections removed )"
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for u in hosts-guard.path hosts-guard.service hosts-bind-mount.service nsswitch-guard.path nsswitch-guard.service; do
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if systemctl list-unit-files | grep -q "^$u"; then
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run systemctl disable --now "$u" || true
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fi
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done
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for f in \
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"$INSTALL_ENFORCE" \
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"$INSTALL_UNLOCK" \
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"$INSTALL_ENFORCE_NSSWITCH" \
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"$SYSTEMD_DIR/hosts-guard.service" \
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"$SYSTEMD_DIR/hosts-guard.path" \
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"$SYSTEMD_DIR/hosts-bind-mount.service" \
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"$SYSTEMD_DIR/nsswitch-guard.service" \
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"$SYSTEMD_DIR/nsswitch-guard.path" \
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"$ZSH_FILTER_SNIPPET" \
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"$BASH_FILTER_SNIPPET"; do
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if [[ -e $f ]]; then run rm -f "$f"; fi
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done
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note "Leaving canonical snapshots at $CANON and $CANON_NSSWITCH (remove manually if undesired)."
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if [[ $DRY_RUN -eq 0 ]]; then systemctl daemon-reload; fi
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msg "Uninstall complete"
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exit 0
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fi
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######################################################################
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# Pre-flight checks
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######################################################################
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note "Script directory: $SCRIPT_DIR"
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note "Repository root: $REPO_ROOT"
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for req in "$TEMPLATE_ENFORCE" "$TEMPLATE_UNLOCK" "$UNIT_GUARD_SERVICE"; do
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[[ -f $req ]] || {
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err "Missing template: $req"
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exit 1
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}
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done
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if [[ ! -f $HOSTS ]]; then
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err "$HOSTS does not exist. Run your hosts/install.sh first."
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exit 1
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fi
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######################################################################
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# Snapshot
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######################################################################
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if [[ $DO_SNAPSHOT -eq 1 ]]; then
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if [[ -f $CANON && $FORCE_SNAPSHOT -eq 0 ]]; then
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note "Canonical snapshot exists (use --force-snapshot to overwrite)"
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else
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msg "Creating canonical snapshot at $CANON"
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run install -m 644 -D "$HOSTS" "$CANON"
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fi
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else
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note "Skipping snapshot creation (--no-snapshot)"
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fi
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######################################################################
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# Install scripts
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######################################################################
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msg "Installing enforcement script -> $INSTALL_ENFORCE"
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run install -m 755 "$TEMPLATE_ENFORCE" "$INSTALL_ENFORCE"
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msg "Installing unlock script -> $INSTALL_UNLOCK"
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run install -m 755 "$TEMPLATE_UNLOCK" "$INSTALL_UNLOCK"
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# Adjust delay in unlock script if different from default
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if [[ $DELAY -ne 45 ]]; then
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msg "Adjusting unlock delay to $DELAY seconds"
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if [[ $DRY_RUN -eq 1 ]]; then
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echo "DRY-RUN: would patch $INSTALL_UNLOCK"
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else
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# Replace DELAY_SECONDS=... line
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sed -i -E "s/^(DELAY_SECONDS=).*/\\1$DELAY/" "$INSTALL_UNLOCK" || warn "Failed to adjust delay"
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fi
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fi
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######################################################################
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# Install shell history filters (optional)
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######################################################################
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if [[ $INSTALL_SHELL_HOOKS -eq 1 ]]; then
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msg "Installing shell history suppression hooks for unlock command"
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# Pattern matches commands invoking unlock-hosts (with or without sudo) & setup script force snapshot
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# Zsh: use zshaddhistory function
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if command -v zsh >/dev/null 2>&1; then
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if [[ $DRY_RUN -eq 1 ]]; then
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echo "DRY-RUN: would create $ZSH_FILTER_SNIPPET"
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else
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cat >"$ZSH_FILTER_SNIPPET" <<'ZEOF'
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# Added by hosts guard setup – suppress unlock-hosts commands from Zsh history
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autoload -Uz add-zsh-hook 2>/dev/null || true
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_hosts_guard_history_filter() {
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emulate -L zsh
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setopt extendedglob
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local line="$1"
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local _pattern='(^|;|&&|\|\|)\s*(sudo\s+)?(/usr/local/sbin/)?unlock-hosts(\s|;|$)'
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if [[ $line =~ ${_pattern} ]]; then
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return 1
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fi
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return 0
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}
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if typeset -f add-zsh-hook >/dev/null 2>&1; then
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add-zsh-hook zshaddhistory _hosts_guard_history_filter 2>/dev/null || true
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else
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zshaddhistory() { _hosts_guard_history_filter "$1"; }
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fi
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ZEOF
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chmod 644 "$ZSH_FILTER_SNIPPET"
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fi
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fi
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# Bash: rely on HISTCONTROL and PROMPT_COMMAND filter
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if command -v bash >/dev/null 2>&1; then
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if [[ $DRY_RUN -eq 1 ]]; then
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echo "DRY-RUN: would create $BASH_FILTER_SNIPPET"
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else
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cat >"$BASH_FILTER_SNIPPET" <<'BEOF'
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# Added by hosts guard setup – suppress unlock-hosts commands from Bash history
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export HISTCONTROL=ignoredups:erasedups
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_hosts_guard_hist_filter() {
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local last_cmd
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local _pattern='(^|;|&&|\|\|)\s*(sudo\s+)?(/usr/local/sbin/)?unlock-hosts(\s|;|$)'
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last_cmd=$(history 1 2>/dev/null | sed -E 's/^ *[0-9]+ +//')
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if [[ -n $last_cmd && $last_cmd =~ ${_pattern} ]]; then
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local id
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id=$(history 1 2>/dev/null | awk '{print $1}')
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if [[ -n $id ]]; then history -d $id 2>/dev/null || true; fi
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history -w 2>/dev/null || true
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history -c || true
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history -r 2>/dev/null || true
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fi
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}
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case :${PROMPT_COMMAND-}: in
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*:_hosts_guard_hist_filter:* ) ;;
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* ) PROMPT_COMMAND="_hosts_guard_hist_filter${PROMPT_COMMAND:+;${PROMPT_COMMAND}}" ;;
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esac
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BEOF
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chmod 644 "$BASH_FILTER_SNIPPET"
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fi
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fi
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else
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note "Skipping shell history hooks (--no-shell-hooks)"
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fi
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######################################################################
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# Add alias stub to discourage raw invocation (shell-level friction)
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######################################################################
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if [[ $ADD_ALIAS_STUB -eq 1 ]]; then
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PROFILE_STUB="/etc/profile.d/hosts_guard_alias_stub.sh"
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if [[ $DRY_RUN -eq 1 ]]; then
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echo "DRY-RUN: would create $PROFILE_STUB"
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else
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cat >"$PROFILE_STUB" <<'ASTUB'
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# Added by hosts guard setup – discourages casual use of unlock-hosts name
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if command -v unlock-hosts >/dev/null 2>&1; then
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alias unlock-hosts='command_not_found_handle 2>/dev/null || echo "Use: sudo /usr/local/sbin/unlock-hosts (logged & delayed)"'
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fi
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ASTUB
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chmod 644 "$PROFILE_STUB"
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fi
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fi
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######################################################################
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# Audit rule to record executions (requires auditd)
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######################################################################
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if [[ $INSTALL_AUDIT_RULE -eq 1 ]]; then
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if command -v auditctl >/dev/null 2>&1; then
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audit_rule_str="-w /usr/local/sbin/unlock-hosts -p x -k hosts_unlock"
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audit_rule_args=(-w /usr/local/sbin/unlock-hosts -p x -k hosts_unlock)
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if auditctl -l 2>/dev/null | grep -Fq "/usr/local/sbin/unlock-hosts"; then
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note "Audit rule already present"
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else
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run auditctl "${audit_rule_args[@]}" || warn "Failed to add audit rule (runtime)"
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if [[ $DRY_RUN -eq 1 ]]; then
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echo "DRY-RUN: would create /etc/audit/rules.d/hosts_unlock.rules"
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else
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echo "$audit_rule_str" >/etc/audit/rules.d/hosts_unlock.rules
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fi
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fi
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else
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warn "auditctl not found; skipping audit rule (install auditd to enable)"
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fi
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fi
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######################################################################
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# Install systemd units
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######################################################################
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msg "Deploying systemd units"
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run install -m 644 "$UNIT_GUARD_SERVICE" "$SYSTEMD_DIR/hosts-guard.service"
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run install -m 644 "$UNIT_GUARD_PATH" "$SYSTEMD_DIR/hosts-guard.path"
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run install -m 644 "$UNIT_BIND_SERVICE" "$SYSTEMD_DIR/hosts-bind-mount.service"
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run install -m 644 "$UNIT_NSSWITCH_SERVICE" "$SYSTEMD_DIR/nsswitch-guard.service"
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run install -m 644 "$UNIT_NSSWITCH_PATH" "$SYSTEMD_DIR/nsswitch-guard.path"
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if [[ $DRY_RUN -eq 0 ]]; then systemctl daemon-reload; fi
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######################################################################
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# Enable / Start
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######################################################################
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if [[ $ENABLE_PATH -eq 1 ]]; then
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msg "Enabling path watch (auto-revert)"
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run systemctl enable --now hosts-guard.path
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else
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note "Skipping path watch (--skip-path-watch)"
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fi
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if [[ $ENABLE_BIND -eq 1 ]]; then
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msg "Enabling read-only bind mount"
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run systemctl enable --now hosts-bind-mount.service
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else
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note "Skipping bind mount (--skip-bind)"
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fi
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if [[ $ENABLE_NSSWITCH -eq 1 ]]; then
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msg "Enabling nsswitch.conf protection (hosts bypass prevention)"
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msg "Installing nsswitch enforcement script -> $INSTALL_ENFORCE_NSSWITCH"
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run install -m 755 "$TEMPLATE_ENFORCE_NSSWITCH" "$INSTALL_ENFORCE_NSSWITCH"
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# Create nsswitch canonical snapshot if needed
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if [[ -f "$NSSWITCH" ]]; then
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if [[ ! -f "$CANON_NSSWITCH" ]]; then
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msg "Creating canonical nsswitch.conf snapshot at $CANON_NSSWITCH"
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run cp "$NSSWITCH" "$CANON_NSSWITCH"
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run chmod 644 "$CANON_NSSWITCH"
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chattr +i "$CANON_NSSWITCH" 2>/dev/null || warn "Failed to protect canonical nsswitch copy"
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fi
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fi
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run systemctl enable --now nsswitch-guard.path
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# Perform initial nsswitch enforcement
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if [[ $DRY_RUN -eq 1 ]]; then
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echo "DRY-RUN: would run $INSTALL_ENFORCE_NSSWITCH"
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else
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"$INSTALL_ENFORCE_NSSWITCH" || warn "nsswitch enforcement returned non-zero"
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fi
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else
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note "Skipping nsswitch protection (--skip-nsswitch)"
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fi
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msg "Performing initial hosts enforcement"
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if [[ $DRY_RUN -eq 1 ]]; then
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echo "DRY-RUN: would run $INSTALL_ENFORCE"
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else
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"$INSTALL_ENFORCE" || warn "Enforcement returned non-zero"
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fi
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######################################################################
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# Summary
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######################################################################
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echo
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msg "Hosts guard setup complete"
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echo "Canonical hosts copy: $CANON"
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echo "Canonical nsswitch copy: $CANON_NSSWITCH"
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echo "Enforce script: $INSTALL_ENFORCE"
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echo "nsswitch enforce: $INSTALL_ENFORCE_NSSWITCH"
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echo "Unlock command: sudo $INSTALL_UNLOCK"
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echo "Delay (seconds): $DELAY"
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echo "Auto-revert path watch: $([[ $ENABLE_PATH -eq 1 ]] && echo enabled || echo disabled)"
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echo "Read-only bind mount: $([[ $ENABLE_BIND -eq 1 ]] && echo enabled || echo disabled)"
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echo "nsswitch protection: $([[ $ENABLE_NSSWITCH -eq 1 ]] && echo enabled || echo disabled)"
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echo "Shell history suppression: $([[ $INSTALL_SHELL_HOOKS -eq 1 ]] && echo enabled || echo disabled)"
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echo "Audit rule: $([[ $INSTALL_AUDIT_RULE -eq 1 ]] && echo enabled || echo disabled)"
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echo "Alias stub: $([[ $ADD_ALIAS_STUB -eq 1 ]] && echo enabled || echo disabled)"
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echo
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echo "Test flow:"
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echo " sudo sed -i '1s/.*/# tamper test/' /etc/hosts # Should revert automatically"
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echo " sudo $INSTALL_UNLOCK # Intentional edit workflow"
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echo
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echo "Uninstall:"
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echo " sudo $0 --uninstall"
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echo "(Optional) Skip shell history hooks: --no-shell-hooks"
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echo
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exit 0
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