#!/usr/bin/env bash
#
# JbTecWiz Support Centre -- generated fix script
#
# Fault : Automatic updates broke something, or are not running at all
# Fix   : Confirm updates are actually being applied
# Source: https://jbtecwiz.com/support/lnx-sec-unattended
#
# Run as     : Root shell
# Expect     : 25 minutes
# Risk       : medium
# Reversible : yes
#
# WHEN THIS IS THE RIGHT FIX
#   Nothing appears to be patched.
#
# HOW TO UNDO IT
#   Disable the timer to stop automatic updates.
#
# Walks the fix one step at a time and asks before each. Steps with no
# command are yours to do -- it prints those and waits. DRYRUN=1 prints
# without executing; UNATTENDED=1 does not ask.
#
# --------------------------------------------------------------------
# NO WARRANTY - USE AT YOUR OWN RISK
#
# This script is provided by JbTecWiz as-is and with no warranty of any
# kind, express or implied. You run it entirely at your own risk.
#
# JbTecWiz accepts no liability for any loss or damage arising from its
# use, including but not limited to data loss, downtime, or configuration
# changes that turn out to be wrong for your system.
#
# You are responsible for reading this script before running it, for
# satisfying yourself that it suits the machine in front of you, and for
# having a working backup first. Some steps cannot be undone.
# --------------------------------------------------------------------

set -uo pipefail
DRYRUN="${DRYRUN:-0}"
UNATTENDED="${UNATTENDED:-0}"
failed=0

if [ "$(id -u)" -ne 0 ]; then
  echo "  This fix is documented as needing root. Re-run with sudo." >&2
  exit 3
fi

rule() { printf "\n%s\n" "$(printf '-%.0s' $(seq 1 70))"; if [ $# -gt 0 ]; then echo "$1"; fi; }
prose() { echo "$1" | fold -s -w 74 | sed "s/^/  /"; }

# Returns 0 when the caller should run the command, 1 when it should not.
# A manual step always returns 1 -- there is nothing for the caller to run.
step() {  # step <n> <do> <why> <manual|cmd> [command lines...]
  local n="$1" dotext="$2" why="$3" mode="$4"; shift 4
  rule "  Step $n of 5"
  prose "$dotext"
  if [ -n "$why" ]; then echo; prose "$why"; fi
  if [ "$mode" = "manual" ]; then
    echo; echo "  -> Do this yourself, then press Enter to carry on."
    if [ "$UNATTENDED" = "0" ] && [ "$DRYRUN" = "0" ]; then read -r _; fi
    return 1
  fi
  echo; printf "    %s\n" "$@"; echo
  if [ "$DRYRUN" = "1" ]; then echo "  (dry run -- not executed)"; return 1; fi
  if [ "$UNATTENDED" = "0" ]; then
    read -r -p "  Run this step? [Y]es / [S]kip / [Q]uit " a
    case "$a" in
      [Qq]*) echo "  Stopped at your request."; exit 0 ;;
      [Ss]*) echo "  Skipped."; return 1 ;;
    esac
  fi
  return 0
}

rule
echo "  Automatic updates broke something, or are not running at all"
echo "  Confirm updates are actually being applied"
echo
echo "  Risk: medium   Reversible   25 minutes"
echo
prose 'No warranty. Use at your own risk - JbTecWiz accepts no liability. Read it before you run it, and have a backup.'
rule
echo
if [ "$UNATTENDED" = "0" ] && [ "$DRYRUN" = "0" ]; then
  read -r -p "  Ready? [y/N] " go
  case "$go" in [Yy]*) ;; *) echo "  Nothing was changed."; exit 0;; esac
fi

if step 1 'Check whether it is enabled and when it last ran.' '' cmd 'systemctl list-timers apt-daily* dnf-makecache* dnf-automatic* --all' 'sudo tail -20 /var/log/unattended-upgrades/unattended-upgrades.log 2>/dev/null'; then
  systemctl list-timers apt-daily* dnf-makecache* dnf-automatic* --all
  sudo tail -20 /var/log/unattended-upgrades/unattended-upgrades.log 2>/dev/null
  if [ $? -ne 0 ]; then
    failed=$((failed+1))
    echo "  Step 1 failed. The rest of the fix may depend on it." >&2
  fi
fi

if step 2 'Check the configuration is actually turning it on. Installing the package does not enable it on every distribution.' '' cmd 'cat /etc/apt/apt.conf.d/20auto-upgrades 2>/dev/null' 'grep -vE '\''^\s*(#|$)'\'' /etc/dnf/automatic.conf 2>/dev/null'; then
  cat /etc/apt/apt.conf.d/20auto-upgrades 2>/dev/null
  grep -vE '^\s*(#|$)' /etc/dnf/automatic.conf 2>/dev/null
  if [ $? -ne 0 ]; then
    failed=$((failed+1))
    echo "  Step 2 failed. The rest of the fix may depend on it." >&2
  fi
fi

if step 3 'Enable it for security updates.' '' cmd 'sudo dpkg-reconfigure -plow unattended-upgrades' 'sudo systemctl enable --now dnf-automatic-install.timer'; then
  sudo dpkg-reconfigure -plow unattended-upgrades
  sudo systemctl enable --now dnf-automatic-install.timer
  if [ $? -ne 0 ]; then
    failed=$((failed+1))
    echo "  Step 3 failed. The rest of the fix may depend on it." >&2
  fi
fi

if step 4 'Check what is running with libraries that have since been replaced -- this is the gap that makes a patched machine still vulnerable.' 'A library updated on disk does not affect a process that already mapped the old one. Until those services are restarted, the vulnerability is still present in memory and no package list will show it.' cmd 'sudo needrestart -b 2>/dev/null || sudo dnf needs-restarting -r'; then
  sudo needrestart -b 2>/dev/null || sudo dnf needs-restarting -r
  if [ $? -ne 0 ]; then
    failed=$((failed+1))
    echo "  Step 4 failed. The rest of the fix may depend on it." >&2
  fi
fi

if step 5 'Restart the affected services, or schedule a reboot where the kernel has been updated.' '' cmd 'sudo needrestart -r a'; then
  sudo needrestart -r a
  if [ $? -ne 0 ]; then
    failed=$((failed+1))
    echo "  Step 5 failed. The rest of the fix may depend on it." >&2
  fi
fi

rule "  Confirm it worked"
prose 'The timer is active, the log shows recent installs, and nothing needs restarting.'
if [ "$DRYRUN" = "0" ]; then
  systemctl list-timers | grep -Ei 'unattended|dnf-automatic'
  sudo needrestart -b 2>/dev/null | tail -5
fi

rule
if [ "$failed" -gt 0 ]; then
  echo "  Finished with $failed failed step(s)."
  echo "  Read the full write-up at https://jbtecwiz.com/support/lnx-sec-unattended"
else
  echo "  Finished."
fi
echo
prose 'To undo: Disable the timer to stop automatic updates.'
rule