#!/bin/bash

LOGGER='logger -t C3_VPS_INIT '
OS_RELEASE='/etc/os-release'

function set_init() {
    create_swapfile
    start_sshd
    update_packages
}

function create_swapfile() {
    SWAPFILE_SIZE="2048M"
    SWAPFILE_DIRECTORY="/var/spool/swap"
    SWAPFILE_NAME="swapfile"
    SWAPFILE_PATH="${SWAPFILE_DIRECTORY}/${SWAPFILE_NAME}"
    FSTAB_PATH="/etc/fstab"

    if [ "$(grep --count "swap" "${FSTAB_PATH}")" -ge 1 ]; then
        return 0
    else
        if [ ! -e ${SWAPFILE_DIRECTORY} ]; then
            mkdir -p ${SWAPFILE_DIRECTORY}
        fi

        if [ ! -e ${SWAPFILE_PATH} ]; then
            fallocate -l ${SWAPFILE_SIZE} ${SWAPFILE_PATH}
            chmod 600 ${SWAPFILE_PATH}
            mkswap ${SWAPFILE_PATH}
            swapon ${SWAPFILE_PATH}

            echo "${SWAPFILE_PATH}    none    swap    defaults    0 0" >> ${FSTAB_PATH}
        fi
    fi

    return 0
}

function start_sshd() {
    systemctl reset-failed sshd
    systemctl start sshd
}

function update_packages() {
    function failed_to_detect() {
        ${LOGGER} 'Failed to identify distribution name or version.Updating will be skipped .'
        return 1
    }

    function CVE_2024_6387_RHEL_family(){
        ${LOGGER} 'Start: Update openssh package.'
        dnf --assumeyes --refresh upgrade openssh
	      systemctl restart sshd.service
        ${LOGGER} 'Complete: Update openssh package.'
    }

    function CVE_2024_6387_debian(){
        ${LOGGER} 'Start: Update openssh package.'
        apt-get update && DEBIAN_FRONTEND=noninteractive  apt-get upgrade --assume-yes
	      systemctl restart ssh.service
        ${LOGGER} 'Complete: Update openssh package.'
    }

    function CVE_2024_6387_ubuntu(){
        ${LOGGER} 'Start: Update openssh package.'
        systemctl start apt-daily.service && systemctl start apt-daily-upgrade.service
	      systemctl restart ssh.service
        ${LOGGER} 'Complete: Update openssh package.'
    }

    function CVE_2024_6387_archlinux(){
        ${LOGGER} 'Start: Update openssh package.'
        pacman -Sy --noconfirm archlinux-keyring && pacman -Syu --noconfirm "openssh>=9.8p1-1"
	      systemctl restart sshd.service
        ${LOGGER} 'Complete: Update openssh package.'
    }


    if [ -e "${OS_RELEASE}" ]; then
        local DISTRIBUTION_NAME
        DISTRIBUTION_NAME=$(grep "^ID=" "${OS_RELEASE}" | cut -d '=' -f 2 | sed -e 's/"//g')
        local DISTRIBUTION_VERSION
        DISTRIBUTION_VERSION=$(grep "^VERSION_ID=" "${OS_RELEASE}" | cut -d "=" -f 2 | sed -e 's/"//g' | sed -e 's/"//g')

        case ${DISTRIBUTION_NAME} in
            "centos" )
                case ${DISTRIBUTION_VERSION} in
                    "9" )
                        CVE_2024_6387_RHEL_family
                        ;;

                    * )
                        ;;

                esac
                ;;

            "almalinux" )
                CVE_2024_6387_RHEL_family
                ;;

            "rocky" )
                CVE_2024_6387_RHEL_family
                ;;

            "ol" )
                CVE_2024_6387_RHEL_family
                ;;

            "miraclelinux" )
                CVE_2024_6387_RHEL_family
                ;;

            "ubuntu" )
                case ${DISTRIBUTION_VERSION} in
                    "24.04" )
                        CVE_2024_6387_ubuntu
                        ;;

                    "22.04" )
                        ;;

                    "20.04" )
                        ;;

                    * )
                        failed_to_detect
                        ;;

                esac
                ;;

            "debian" )
                case ${DISTRIBUTION_VERSION} in
                    "12" )
                        CVE_2024_6387_debian
                        ;;

                    "11" )
                        CVE_2024_6387_debian
                        ;;

                    * )
                        failed_to_detect
                        ;;

                esac
                ;;

            "fedora" )
                ;;

            "opensuse-leap" )
                ;;

            "arch" )
                CVE_2024_6387_archlinux
                ;;

            * )
                failed_to_detect
                ;;

        esac

        return 0
    fi

    failed_to_detect
}

set_init