#!/bin/sh
# bashsupport disable=BP5007
# shellcheck disable=SC2249
# shellcheck shell=sh

# SPDX-Version: 3.0
# SPDX-CreationInfo: 2025-11-12; WEIDNER, Marc S.; <msw@coresecret.dev>
# SPDX-ExternalRef: GIT https://git.coresecret.dev/msw/CISS.debian.live.builder.git
# SPDX-FileContributor: WEIDNER, Marc S.; Centurion Intelligence Consulting Agency
# SPDX-FileCopyrightText: 2024-2025; WEIDNER, Marc S.; <msw@coresecret.dev>
# SPDX-FileType: SOURCE
# SPDX-License-Identifier: EUPL-1.2 OR LicenseRef-CCLA-1.0
# SPDX-LicenseComment: This file is part of the CISS.debian.installer.secure framework.
# SPDX-PackageName: CISS.debian.live.builder
# SPDX-Security-Contact: security@coresecret.eu

# Purpose: Open /live/ciss_rootfs.crypt (LUKS) and present its SquashFS as /run/live/rootfs
# Phase  : premount (executed by live-boot inside the initramfs)

set -eu

printf "\e[95m[INFO] Starting: [/usr/lib/live/boot/0024-ciss-crypt-squash] ... \n\e[0m"

#######################################
# Premount logging helper.
# Globals:
#   None
# Arguments:
#   *: String to log.
#######################################
log() {
  msg="$*"
  if [ -w /dev/kmsg ]; then
    printf '<6>%s: %s\n' '0024-ciss-crypt-squash' "${msg}" > /dev/kmsg
  else
    printf '%s: %s\n' '0024-ciss-crypt-squash' "${msg}"
  fi
}

### Declare variables. ---------------------------------------------------------------------------------------------------------
export CDLB_ISO_LABEL="CISS.debian.live"
export CDLB_LUKS_FS="/live/ciss_rootfs.crypt"
export CDLB_MAPPER_NAME="crypt_liveiso"
export CDLB_MAPPER_DEV="/dev/mapper/${CDLB_MAPPER_NAME}"
CDLB_REMOTE_WAIT_SECS="${CDLB_REMOTE_WAIT_SECS:-10}"
CDLB_MAX_TRIES="${CDLB_MAX_TRIES:-3}"
MNT_MEDIUM="/run/live/medium"
MNT_ROOTFS="/run/live/rootfs"
_PARAMETER=""
_dev=""

### Read the kernel cmdline once. ----------------------------------------------------------------------------------------------
CMDLINE="$(cat /proc/cmdline 2>/dev/null || printf '')"

for _PARAMETER in ${CMDLINE}; do

  case "${_PARAMETER}" in

    ciss_crypt_path=*) export CDLB_LUKS_FS="${_PARAMETER#ciss_crypt_path=}";;
    ciss_iso_label=* ) export CDLB_ISO_LABEL="${_PARAMETER#ciss_iso_label=}";;

  esac

done

printf "\e[92m[INFO] CDLB_LUKS_FS   : [%s] \n\e[0m" "${CDLB_LUKS_FS}"
printf "\e[92m[INFO] CDLB_ISO_LABEL : [%s] \n\e[0m" "${CDLB_ISO_LABEL}"

mkdir -p "${MNT_MEDIUM}" "${MNT_ROOTFS}"

### Mount the live medium (ISO) read-only, unless already mounted. -------------------------------------------------------------
if ! mountpoint -q "${MNT_MEDIUM}"; then

  if [ -n "${CDLB_ISO_LABEL}" ] && [ -e "/dev/disk/by-label/${CDLB_ISO_LABEL}" ]; then

    mount -r -t iso9660 "/dev/disk/by-label/${CDLB_ISO_LABEL}" "${MNT_MEDIUM}" 2>/dev/null \
      || mount -r -t udf "/dev/disk/by-label/${CDLB_ISO_LABEL}" "${MNT_MEDIUM}" 2>/dev/null \
      || log "could not mount label=${CDLB_ISO_LABEL} (iso9660/udf)"

  fi

fi

if ! mountpoint -q "${MNT_MEDIUM}"; then

  ### Fallback scan (covers SR drives and loop-mounted ISOs that udev exposed).
  for _dev in /dev/sr* /dev/cdrom /dev/disk/by-label/*; do

    ### Skip non-block entries early.
    [ -b "${_dev}" ] || continue

    ### Try ISO9660 first, then UDF; only unmount on failure.
    if mount -r -t iso9660 "${_dev}" "${MNT_MEDIUM}" 2>/dev/null || mount -r -t udf   "${_dev}" "${MNT_MEDIUM}" 2>/dev/null; then

      mountpoint -q "${MNT_MEDIUM}" 2>/dev/null && break

    else

      umount "${MNT_MEDIUM}" 2>/dev/null || true

    fi

  done

fi

if ! mountpoint -q "${MNT_MEDIUM}"; then

  log "No live medium mounted, defer to default live-boot path."
  printf "\e[91m[FATAL] No live medium mounted, defer to default live-boot path. \n\e[0m"
  exit 0

fi

printf "\e[92m[INFO] MNT_MEDIUM     : [%s] \n\e[0m" "${MNT_MEDIUM}"

### Locate the encrypted root container on the medium. -------------------------------------------------------------------------
if [ ! -f "${MNT_MEDIUM}${CDLB_LUKS_FS}" ]; then

  log "Encrypted root not found at: [${MNT_MEDIUM}/${CDLB_LUKS_FS}]"
  printf "\e[91m[FATAL] Encrypted root not found at: [%s%s] \n\e[0m" "${MNT_MEDIUM}" "${CDLB_LUKS_FS}"
  exit 0

fi

printf "\e[92m[INFO] CISS LUKS FS   : [%s%s] \n\e[0m" "${MNT_MEDIUM}" "${CDLB_LUKS_FS}"

### Attach a loop device read-only to the encrypted file. ----------------------------------------------------------------------
LOOP="$(losetup -f --show -r "${MNT_MEDIUM}${CDLB_LUKS_FS}")" || { log "losetup failed"; exit 42; }

### Expose the loop device for unlock-wrapper.sh, dropbear forced-command. -----------------------------------------------------
mkdir -p /run 2>/dev/null || true
echo "${LOOP}" >| /run/ciss-loopdev 2>/dev/null || true
chmod 0600 /run/ciss-loopdev 2>/dev/null || true

### Wait briefly for the LUKS container to open via dropbear. ------------------------------------------------------------------
if [ ! -b "${CDLB_MAPPER_DEV}" ]; then

  REMAINING="${CDLB_REMOTE_WAIT_SECS}"

  while [ "${REMAINING}" -gt 0 ]; do

    if [ -b "${CDLB_MAPPER_DEV}" ]; then

      log "LUKS mapping [${CDLB_MAPPER_DEV}] opened remotely by dropbear unlock_wrapper.sh."
      printf "\e[92m[INFO] LUKS mapping   : [%s] opened remotely by dropbear unlock_wrapper.sh. \n\e[0m" "${CDLB_MAPPER_DEV}"
      break

    fi

    sleep 1
    REMAINING=$((REMAINING - 1))

  done

fi

### Fallback: interactive password entry on the console. -----------------------------------------------------------------------
if [ ! -b "${CDLB_MAPPER_DEV}" ]; then

  attempts=0

  while [ "${attempts}" -lt "${CDLB_MAX_TRIES}" ] && [ ! -b "${LUKS_MAPPER_DEV}" ]; do

    attempts=$((attempts + 1))

    printf "\e[93m[INFO] Unlock         : [%s] Attempts: [%s/%s] Enter Passphrase on console: \n\e[0m" \
      "${CDLB_LUKS_FS}" "${attempts}" "${CDLB_MAX_TRIES}" >/dev/console 2>/dev/null || true

    ### Let cryptsetup handle the prompt on /dev/console; no keyfile, no FIFO.
    if cryptsetup open --type luks --readonly "${LOOP}" "${LUKS_MAPPER_NAME}"; then

      log "LUKS mapping [${CDLB_MAPPER_DEV}] opened via local console."
      printf "\e[92m[INFO] LUKS mapping   : [%s] Opened via local console. \n\e[0m" "${CDLB_MAPPER_DEV}"
      break

    fi

  done

fi

### Final sanity check. --------------------------------------------------------------------------------------------------------
if [ ! -b "${CDLB_MAPPER_DEV}" ]; then

  log "Failed to unlock encrypted root [${CDLB_LUKS_FS}] via dropbear and console."
  printf "\e[91m[WARN] Failed unlock  : [%s] via dropbear and console. \n\e[0m" "${CDLB_LUKS_FS}"
  exit 42

fi

### Expose the decrypted root device for live-boot overlay. The live-boot components will pick this up in '9990-overlay.sh'. ---
echo "${CDLB_MAPPER_DEV}" >| /run/ciss-rootdev

chmod 0644 /run/ciss-rootdev 2>/dev/null || true

export CISS_ROOT_DEV="${CDLB_MAPPER_DEV}"
export CISS_ROOT_DIR=""

log "Decrypted root device exposed at [/run/ciss-rootdev] -> [${CDLB_MAPPER_DEV}]"

printf "\e[92m[INFO] Decrypted root device exposed at: [/run/ciss-rootdev] -> [%s] \n\e[0m" "${CDLB_MAPPER_DEV}"

printf "\e[92m[INFO] Successfully applied: [/usr/lib/live/boot/0024-ciss-crypt-squash] \n\e[0m"

# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=sh