#!/bin/bash
# SPDX-Version: 3.0
# SPDX-CreationInfo: 2025-02-13; WEIDNER, Marc S.; <cendev@coresecret.eu>
# SPDX-ExternalRef: GIT https://cendev.eu/marc.weidner/CISS.2025.debian.installer.git
# SPDX-FileContributor: WEIDNER, Marc S.; Centurion Intelligence Consulting Agency
# SPDX-FileCopyrightText: 2024-2025; WEIDNER, Marc S.; <cendev@coresecret.eu>
# SPDX-FileType: SOURCE
# SPDX-License-Identifier: EUPL-1.2 OR LicenseRef-CCLA-1.0
# SPDX-LicenseComment: This file is part of the CISS.2025.hardened.installer framework.
# SPDX-PackageName: CISS.2025.hardened.installer
# SPDX-Security-Contact: security@coresecret.eu

###########################################################################################
# 3.8.2. Functions - installation - setup ssh                                             #
###########################################################################################

###########################################################################################
# Setup ssh server
# Globals:
#   DIR_BAK
#   DIR_LOG
#   FINAL_FQDN
#   FINAL_IPV4_ADDRESS
#   FINAL_IPV6_ADDRESS
#   MODULE_ERR
#   MODULE_TXT
#   PATH_ABS
#   TARGET
#   accounts_ssh
#   accounts_user_login
#   accounts_user_name
# Arguments:
#   None
###########################################################################################
3_8_2_functions_installation_setup_ssh() {
  declare -g -x MODULE_ERR="3_8_2_functions_installation_setup_ssh"
  declare -g -x MODULE_TXT="Setup ssh"
  do_show_header "${MODULE_TXT}"

  do_in_target "${TARGET}" apt-get install -y ssh
  do_log "info" "false" "Command: 'apt-get install -y ssh' executed in: '${TARGET}'."

  rm -rf "${TARGET}"/etc/ssh/ssh_host_*key*

  do_in_target "${TARGET}" ssh-keygen -o -a "${accounts_ssh-keyrounds}" -N "" -t ed25519 -f /etc/ssh/ssh_host_ed25519_key -C "root@${FINAL_FQDN}-$(date -I)"
  do_log "info" "false" "Generated ed25519 SSH Key, executed in: '${TARGET}'."

  do_in_target "${TARGET}" ssh-keygen -o -a "${accounts_ssh-keyrounds}" -N "" -t rsa -b 4096 -f /etc/ssh/ssh_host_rsa_key -C "root@${FINAL_FQDN}-$(date -I)"
  do_log "info" "false" "Generated RSA4096 SSH Key, executed in chroot."

  declare TIMESTAMP
  TIMESTAMP=$(do_get_timestamp)

  echo "${TIMESTAMP}" >> "${DIR_LOG}"sshd_config.log && sshd -T >> "${DIR_LOG}"sshd_config.log
  echo "${TIMESTAMP}" >> "${DIR_LOG}"ssh.log && ssh-keygen -r @ >> "${DIR_LOG}"ssh.log

  cp -u "${TARGET}"/etc/ssh/sshd_config "${DIR_BAK}"sshd_config.bak
  chmod 0644 "${DIR_BAK}"sshd_config.bak
  cp -u "${TARGET}"/etc/ssh/ssh_config "${DIR_BAK}"ssh_config.bak
  chmod 0644 "${DIR_BAK}"ssh_config.bak

  rm "${TARGET}"/etc/ssh/sshd_config

  cp "${PATH_ABS}"/.assets/sshd_config "${TARGET}"/etc/ssh/sshd_config

  sed -i "s/ListenAddress				0.0.0.0/ListenAddress				${FINAL_IPV4_ADDRESS}/" "${TARGET}"/etc/ssh/sshd_config

  if [[ -n ${FINAL_IPV6_ADDRESS} ]]; then
    sed -i "s/ListenAddress				::/ListenAddress				${FINAL_IPV6_ADDRESS}/" "${TARGET}"/etc/ssh/sshd_config
  else
    sed -i "/^\s*ListenAddress\s*::/d" "${TARGET}"/etc/ssh/sshd_config
  fi

  sed -i "s/Port					22/Port					${accounts_ssh-port}/" "${TARGET}"/etc/ssh/sshd_config

  if [[ ${accounts_user_login,,} == "true"  ]]; then
    sed -i "s/AllowUsers				DUMMYSTRING/AllowUsers				root ${accounts_user_name}/" "${TARGET}"/etc/ssh/sshd_config
  else
    sed -i "s/AllowUsers				DUMMYSTRING/AllowUsers				root/" "${TARGET}"/etc/ssh/sshd_config
  fi

  chmod 0600 "${TARGET}"/etc/ssh/sshd_config "${TARGET}"/etc/ssh/ssh_config
  TIMESTAMP=$(do_get_timestamp)
  echo "${TIMESTAMP}" >> "${DIR_LOG}"ssh.log
  do_in_target "${TARGET}" /bin/bash -c "sshd -T >> ${DIR_LOG}ssh.log"

  ###########################################################################################
  # Remarks: The file /etc/profile.d/idle-users.sh is created to set two read-only          #
  # environment variables: TMOUT and HISTFILE.                                              #
  # TMOUT=14400 ensures that users are automatically logged out after 4 hours of inactivity.#
  # readonly HISTFILE ensures that the command history cannot be changed.                   #
  # The chmod +x command ensures that the file is executed in every shell session.          #
  ###########################################################################################
  echo "readonly TMOUT=14400" >> "${TARGET}"/etc/profile.d/idle-users.sh
  echo "readonly HISTFILE" >> "${TARGET}"/etc/profile.d/idle-users.sh
  chmod +x "${TARGET}"/etc/profile.d/idle-users.sh

  do_show_footer "${MODULE_TXT}"
}
# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=sh: