#!/bin/sh
#
# PROVIDE: ossec_hids
# REQUIRE: DAEMON
# BEFORE:  LOGIN
# KEYWORD: shutdown

# ossec_hids_enable (bool):             Set it to YES to enable %%PORTNAME%%.
#                                       Default: NO
# ossec_hids_clear_log (bool):          Set it to YES to clear ossec.log before %%PORTNAME%% startup.
#                                       Default: NO
# ossec_hids_clear_ar_log (bool):       Set it to YES to clear active-responses.log before %%PORTNAME%% startup.
#                                       Default: NO
# ossec_hids_fetch_connect_time (int):  Time in seconds to wait for the download of the shared configuration to start.
#                                       Used only by agent installation.
#                                       Default: 40
# ossec_hids_fetch_read_time (int):     Time in seconds to wait for subsequent download chunks of the shared configuration.
#                                       Used only by agent installation.
#                                       Default: 10

. /etc/rc.subr

name="ossec_hids"
rcvar=ossec_hids_enable

load_rc_config $name

: ${ossec_hids_enable="NO"}
: ${ossec_hids_clear_log="NO"}
: ${ossec_hids_clear_ar_log="NO"}
: ${ossec_hids_fetch_connect_time=40}
: ${ossec_hids_fetch_read_time=10}

ossec_type="%%OSSEC_TYPE%%"
ossec_home="%%OSSEC_HOME%%"

if [ -z "${ossec_hids_user}" ]; then
    ossec_hids_user=$(stat -f '%Su' "${ossec_home}")
fi

ossec_conf="${ossec_home}/etc/ossec.conf"
ossec_conf_dir="${ossec_home}/etc/ossec.conf.d"
ossec_conf_bin="${ossec_home}/bin/config/ossec-conf"

agent_conf="${ossec_home}/etc/shared/agent.conf"
agent_conf_dir="${ossec_home}/etc/agent.conf.d"
agent_conf_bin="${ossec_home}/bin/config/agent-conf"

ossec_client_keys="${ossec_home}/etc/client.keys"
ossec_ar_tmp="${ossec_home}/active-response"
ossec_log="${ossec_home}/logs/ossec.log"
ossec_ar_log="${ossec_home}/logs/active-responses.log"
ossec_merged="${ossec_home}/etc/shared/merged.mg"

ossec_local_time="/etc/localtime"
ossec_resolv_conf="/etc/resolv.conf"

extra_commands="help status reload ossec_conf"
case ${ossec_type} in
    server)
        extra_commands="${extra_commands} agent_conf manage_agent reset_counter"
        ;;
    agent)
        extra_commands="${extra_commands} agent_conf manage_agent reset_counter config_profile fetch_config"
        ;;
esac
if [ -x "${ossec_conf_bin}" ]; then
    extra_commands="${extra_commands} merge_config"
fi

ossec_rc_command=$1
shift 1

help_cmd="ossec_hids_help $@"
start_cmd="ossec_hids_command start $@"
stop_cmd="ossec_hids_command stop $@"
restart_cmd="ossec_hids_command restart $@"
status_cmd="ossec_hids_command status $@"
reload_cmd="ossec_hids_command reload $@"
manage_agent_cmd="ossec_hids_manage_agent $@"
reset_counter_cmd="ossec_hids_reset_counter $@"
config_profile_cmd="ossec_hids_config_profile $@"
fetch_config_cmd="ossec_hids_fetch_config $@"
merge_config_cmd="ossec_hids_create_config force $@"
ossec_conf_cmd="ossec_hids_ossec_conf $@"
agent_conf_cmd="ossec_hids_agent_conf $@"

start_precmd="ossec_hids_create_env && ossec_hids_create_config && ossec_hids_clean && ossec_hids_check"
restart_precmd="${start_precmd}"
reload_precmd="ossec_hids_create_env && ossec_hids_create_config"
config_profile_precmd="ossec_hids_check"
fetch_config_precmd="${start_precmd}"

agent_ids_cmd="${ossec_home}/bin/manage_agents -l | sed -En -e 's|.*ID:[[:space:]]*([[:digit:]]+).*|\1|p'"
agent_names_cmd="${ossec_home}/bin/manage_agents -l | sed -En -e 's|.*Name:[[:space:]]*([^,]+).*|\1|p'"

ossec_hids_help() {
    local indent="    "

    echo "Additional commands:"
    echo

    for command in ${extra_commands}; do
        case ${command} in
            ossec_conf)
                echo "${command}"
                if [ -x "${ossec_conf_bin}" ]; then
                    echo "${indent}Displays the \"ossec.conf\" as it would have been produced"
                    echo "${indent}by merging files from \"ossec.conf.d\" directory."
                    echo "${indent}Does not overwrite the actual \"ossec.conf\"."
                else
                    echo "${indent}Displays the current \"ossec.conf\"."
                fi
                echo
            ;;
            agent_conf)
                echo "${command}"
                if [ -x "${agent_conf_bin}" ]; then
                    echo "${indent}Displays the \"agent.conf\" as it would have been produced"
                    echo "${indent}by merging files from \"agent.conf.d\" directory."
                    echo "${indent}Does not overwrite the actual \"agent.conf\"."
                else
                    echo "${indent}Displays the current \"agent.conf\"."
                fi
                echo
            ;;
            manage_agent)
                echo "${command} [...]"
                echo "${indent}Executes OSSEC Agent Manager."
                echo "${indent}Any additional arguments will be passed along (-h for help)."
                echo "${indent}Use this command to export and import agent keys."
                echo
            ;;
            reset_counter)
                case ${ossec_type} in
                    server)
                        echo "${command} <agent_name>"
                        echo "${indent}Stops the OSSEC and resets (removes) the replay attack prevention counter(s)."
                        echo "${indent}Only the counter for the given <agent_name> is reset."
                        echo "${indent}If the <agent_name> is \"-\", then counters for all agents are reset."
                    ;;
                    agent)
                        echo "${command}"
                        echo "${indent}Stops the OSSEC and resets (removes) the replay attack prevention counter."
                    ;;
                esac
                echo "${indent}Use this command on both the server and the agent to bring back connectivity."
                echo "${indent}The typical scenario for desynchronization of counters is one of the OSSEC"
                echo "${indent}instances has been restored from backup."
                echo "${indent}Use the following procedure:"
                echo "${indent}1. Reset counter on the agent."
                echo "${indent}2. Reset counter on the server for that specific agent."
                echo "${indent}3. Start the server."
                echo "${indent}4. Start the agent."
                echo
            ;;
            config_profile)
                echo "${command}"
                echo "${indent}Displays a list (i.e. union of sets) of applicable (to this agent) configuration"
                echo "${indent}profiles sent by the server (current \"agent.conf\") merged with configuration"
                echo "${indent}profiles enabled on this agent (current \"ossec.conf\"). Each entry on the list"
                echo "${indent}is marked with one of the following markers:"
                echo "${indent}(+) - The profile is sent by the server and is enabled on this agent."
                echo "${indent}(-) - The profile is sent by the server and is applicable for this agent, but is"
                echo "${indent}      not enabled in the \"ossec.conf\"."
                echo "${indent}(?) - The profile is enabled on this agent, but is not sent by the server or is"
                echo "${indent}      not applicable to this agent."
                echo
            ;;
            fetch_config)
                echo "${command}"
                echo "${indent}(Re)starts the agent with a fresh copy of server shared configuration (including"
                echo "${indent}\"agent.conf\"). Command can also be used to ensure server connectivity."
                echo
            ;;
            merge_config)
                echo "${command}"
                echo "${indent}Creates \"ossec.conf\" by merging files from \"ossec.conf.d\" directory."
                case ${ossec_type} in
                    server)
                        echo "${indent}Creates \"agent.conf\" by merging files from \"agent.conf.d\" directory."
                    ;;
                esac
                echo "${indent}Usually you do not need to run this command, because configuration files will"
                echo "${indent}be merged before OSSEC startup if any of them has been modified/created/deleted"
                echo "${indent}since the last merging. This command, however, does merging unconditionally."
                echo
            ;;
        esac
    done

    echo "To avoid problems with this script and the port in general, keep your XML-like"
    echo "configuration pretty printed. Place element tags in single and separate lines."
    echo "Comments can span on multiple but still separate lines."
    echo "Do NOT use the following formatting:"
    echo
    echo "${indent}<elementA"
    echo "${indent}${indent}attribute=\"value\"><!-- I am a long and"
    echo "${indent}${indent}${indent}descriptive comment -->"
    echo "${indent}${indent}<elementB>"
    echo "${indent}${indent}${indent}Some content"
    echo "${indent}${indent}</elementB><elementC>"
    echo "${indent}${indent}${indent}Another content</elementC>"
    echo "${indent}</elementA>"
    echo
    echo "Use instead:"
    echo
    echo "${indent}<elementA attribute=\"value\">"
    echo "${indent}${indent}<!-- I am a long and"
    echo "${indent}${indent}descriptive comment -->"
    echo "${indent}${indent}<elementB>Some content</elementB>"
    echo "${indent}${indent}<elementC>Another content</elementC>"
    echo "${indent}</elementA>"
    echo
}

ossec_hids_create_file() {
    local path=$1
    local owner=$2
    local mode=$3

    if [ ! -e "${path}" ]; then
        touch "${path}" && chown ${owner} "${path}" && chmod ${mode} "${path}"
    fi
}

ossec_hids_check() {
    case ${ossec_type} in
        server)
            if [ ! -s "${ossec_client_keys}" ]; then
                echo "WARNING: There are no client keys created - remote connections will be disabled."
                echo
            fi
            ;;
        agent)
            if [ ! -s "${ossec_client_keys}" ]; then
                echo "WARNING: There are is no client key imported - connection to server not possible."
                echo
            else
                if [ $(eval ${agent_ids_cmd} | wc -l) -gt 1 ]; then
                    echo "ERROR: There are multiple client keys imported - only one is allowed."
                    echo
                    return 1
                fi
            fi
            ;;
    esac

    return 0
}

ossec_hids_inline_content() {
    local element="$1"
    sed -En "s|.*<${element}>(.*)</${element}>.*|\1|p"
}

ossec_hids_remove_comments() {
    # Comments must be on separate lines i.e. not next to uncommented code
    awk '/<!--/ {off=1} /-->/ {off=2} /([\s\S]*)/ {if (off==0) print; if (off==2) off=0}'
}

ossec_hids_config_profile() {
    if [ ! -f "${ossec_conf}" ]; then
        echo -n "ERROR: The \"${ossec_conf}\" is missing."
        if [ -x "${ossec_conf_bin}" ]; then
            echo " Run:"
            echo "$(realpath $0) merge_config"
        else
            echo
        fi
        echo
        return 1
    fi
    if [ ! -f "${agent_conf}" ]; then
        echo "ERROR: The \"${agent_conf}\" is missing. Run:"
        echo "$(realpath $0) fetch_config"
        echo
        return 1
    fi

    local os="FreeBSD"
    local name=$(eval ${agent_names_cmd})

    local server_profiles=`ossec_hids_remove_comments < "${agent_conf}" | sed -En \
        -e "s|.*<agent_config[[:space:]]+profile=\"([^\"]+)\"[[:space:]]*>.*|\1|p" \
        -e "s|.*<agent_config[[:space:]]+profile=\"([^\"]+)\"[[:space:]]+os=\"${os}\"[[:space:]]*>.*|\1|p" \
        -e "s|.*<agent_config[[:space:]]+os=\"${os}\"[[:space:]]+profile=\"([^\"]+)\"[[:space:]]*>.*|\1|p" \
        -e "s|.*<agent_config[[:space:]]+profile=\"([^\"]+)\"[[:space:]]+name=\"${name}\"[[:space:]]*>.*|\1|p" \
        -e "s|.*<agent_config[[:space:]]+name=\"${name}\"[[:space:]]+profile=\"([^\"]+)\"[[:space:]]*>.*|\1|p" \
        -e "s|.*<agent_config[[:space:]]+profile=\"([^\"]+)\"[[:space:]]+os=\"${os}\"[[:space:]]+name=\"${name}\"[[:space:]]*>.*|\1|p" \
        -e "s|.*<agent_config[[:space:]]+profile=\"([^\"]+)\"[[:space:]]+name=\"${name}\"[[:space:]]+os=\"${os}\"[[:space:]]*>.*|\1|p" \
        -e "s|.*<agent_config[[:space:]]+os=\"${os}\"[[:space:]]+profile=\"([^\"]+)\"[[:space:]]+name=\"${name}\"[[:space:]]*>.*|\1|p" \
        -e "s|.*<agent_config[[:space:]]+os=\"${os}\"[[:space:]]+name=\"${name}\"[[:space:]]+profile=\"([^\"]+)\"[[:space:]]*>.*|\1|p" \
        -e "s|.*<agent_config[[:space:]]+name=\"${name}\"[[:space:]]+profile=\"([^\"]+)\"[[:space:]]+os=\"${os}\"[[:space:]]*>.*|\1|p" \
        -e "s|.*<agent_config[[:space:]]+name=\"${name}\"[[:space:]]+os=\"${os}\"[[:space:]]+profile=\"([^\"]+)\"[[:space:]]*>.*|\1|p" \
        | sort -u`

    local agent_profiles=$(ossec_hids_remove_comments < "${ossec_conf}" | ossec_hids_inline_content "config-profile" | sed -E 's|[[:space:]]*,[[:space:]]*| |g')

    local output=""
    for server_profile in ${server_profiles}; do
        local matching_profile=""
        for agent_profile in ${agent_profiles}; do
            if [ "${agent_profile}" == "${server_profile}" ]; then
                matching_profile="${agent_profile}"
                break
            fi
        done
        if [ -n "${matching_profile}" ]; then
            output="${output}(+) ${server_profile}
"
        else
            output="${output}(-) ${server_profile}
"
        fi
    done
    for agent_profile in ${agent_profiles}; do
        local matching_profile=""
        for server_profile in ${server_profiles}; do
            if [ "${server_profile}" == "${agent_profile}" ]; then
                matching_profile="${server_profile}"
                break
            fi
        done
        if [ -z "${matching_profile}" ]; then
            output="${output}(?) ${agent_profile}
"
        fi
    done

    echo -n "${output}" | sort -k 2
}

ossec_hids_config_is_outdated() {
    local dst_file="$1"
    local src_dir="$2"

    if [ ! -e "${dst_file}" ]; then
        return 0
    fi

    if [ "${src_dir}" -nt "${dst_file}" ]; then
        return 0
    fi

    for src_file in $(find "${src_dir}" -maxdepth 1 -type f -name "*.conf"); do
        if [ "${src_file}" -nt "${dst_file}" ]; then
            return 0
        fi
    done

    return 1
}

ossec_hids_create_config() {
    case ${ossec_type} in
        server)
            if [ -x "${agent_conf_bin}" ]; then
                # Merge agent.conf.d files into agent.conf
                if [ "$1" == "force" ] || ossec_hids_config_is_outdated "${agent_conf}" "${agent_conf_dir}"; then
                    ossec_hids_create_file "${agent_conf}" ${ossec_hids_user}:%%OSSEC_GROUP%% 0640
                    "${agent_conf_bin}" > "${agent_conf}"
                fi
            fi
            ;;
    esac

    if [ -x "${ossec_conf_bin}" ]; then
        # Merge ossec.conf.d files into ossec.conf
        if [ "$1" == "force" ] || ossec_hids_config_is_outdated "${ossec_conf}" "${ossec_conf_dir}"; then
            ossec_hids_create_file "${ossec_conf}" ${ossec_hids_user}:%%OSSEC_GROUP%% 0640
            "${ossec_conf_bin}" > "${ossec_conf}"
        fi
    fi

    return 0
}

ossec_hids_create_env() {
    # Copy required files from outside of home directory
    if [ ! -e "${ossec_local_time}" ]; then
        echo "ERROR: Missing \"${ossec_local_time}\". Run command \"tzsetup\"."
        echo
        return 1
    fi
    if [ ! -e "${ossec_resolv_conf}" ]; then
        echo "ERROR: Missing \"${ossec_resolv_conf}\"."
        echo
        return 1
    fi
    install -o ${ossec_hids_user} -g %%OSSEC_GROUP%% -m 0440 "${ossec_local_time}" "${ossec_home}${ossec_local_time}"
    install -o ${ossec_hids_user} -g %%OSSEC_GROUP%% -m 0440 "${ossec_resolv_conf}" "${ossec_home}${ossec_resolv_conf}"

    return 0
}

ossec_hids_clean() {
    if [ "${ossec_type}" == "server" ]; then
        rm -f "${ossec_merged}"
    fi

    if checkyesno ossec_hids_clear_log && [ -e "${ossec_log}" ]; then
        echo -n > "${ossec_log}"
    fi

    if checkyesno ossec_hids_clear_ar_log && [ -e "${ossec_ar_log}" ]; then
        echo -n > "${ossec_ar_log}"
    fi

    return 0
}

ossec_hids_reset_counter() {
    local agent_name="$1"

    ossec_hids_command stop
    sleep 1
    echo

    case ${ossec_type} in
        server)
            if [ -z "${agent_name}" ]; then
                echo "ERROR: Specify agent name to reset counter for this agent or \"-\" to reset counters for all agents."
                echo
                return 1
            fi
            local agent_counter=0
            if [ "${agent_name}" == "-" ]; then
                for agent_id in $(eval ${agent_ids_cmd}); do
                    if [ -e "${ossec_home}/queue/rids/${agent_id}" ]; then
                        rm "${ossec_home}/queue/rids/${agent_id}" && agent_counter=$((agent_counter + 1))
                    fi
                done
            else
                local agent_id=`${ossec_home}/bin/manage_agents -l | sed -En -e "s|.*ID:[[:space:]]*([[:digit:]]+),[[:space:]]*Name:[[:space:]]${agent_name},.*|\1|p"`
                if [ -n "${agent_id}" ]; then
                    if [ -e "${ossec_home}/queue/rids/${agent_id}" ]; then
                        rm "${ossec_home}/queue/rids/${agent_id}" && agent_counter=$((agent_counter + 1))
                    fi
                fi
            fi
            echo "Removed ${agent_counter} counter(s)."
            echo
            ;;
        agent)
            local agent_counter=0
            for agent_id in $(eval ${agent_ids_cmd}); do
                # Should be executed only once
                if [ -e "${ossec_home}/queue/rids/${agent_id}" ]; then
                    rm "${ossec_home}/queue/rids/${agent_id}" && agent_counter=$((agent_counter + 1))
                fi
            done
            echo "Removed ${agent_counter} counter(s)."
            echo
            ;;
    esac

    return 0
}

ossec_hids_fetch_config() {
    ossec_hids_command stop
    sleep 1
    echo
    rm -f "${ossec_merged}"
    ossec_hids_command start || return 1
    echo
    echo "Waiting ${ossec_hids_fetch_connect_time} seconds for the shared configuration download to start."
    sleep ${ossec_hids_fetch_connect_time}
    if [ ! -s "${ossec_merged}" ]; then
        echo "ERROR: Failed to download shared configuration from the OSSEC server."
        echo
        local ossec_log_tail=$(tail "${ossec_log}")
        echo "Portion of the \"${ossec_log}\":"
        echo "${ossec_log_tail}"
        echo
        if echo "${ossec_log_tail}" | grep -q "ERROR: Unable to send message to"; then
            echo "Check if your configuration contains the correct server address in \"server-ip\" option."
            echo
        else
            local ossec_rc_path="$(realpath $0)"
            echo "Is the imported agent key correct? To import it run:"
            echo "${ossec_rc_path} manage_agent"
            echo
            echo "If you are certain the imported agent key is correct, then run:"
            echo "${ossec_rc_path} reset_counter"
            echo "${ossec_rc_path} fetch_config"
            echo
            echo "If this doesn't help, you need to reset counter on the server."
            echo "If the server runs FreeBSD port of OSSEC, run:"
            echo "On the agent:"
            echo "${ossec_rc_path} reset_counter"
            echo "On the server:"
            echo "${ossec_rc_path} reset_counter $(eval ${agent_names_cmd})"
            echo "${ossec_rc_path} start"
            echo "On the agent:"
            echo "${ossec_rc_path} fetch_config"
            echo
        fi
        ossec_hids_command stop
        return 1
    else
        # The download has started
        while true; do
            local current_time=$(date +%s)
            local modification_time=$(stat -f %m "${ossec_merged}")
            if [ $((current_time - modification_time)) -gt ${ossec_hids_fetch_read_time} ]; then
                echo "Download finished."
                echo
                ossec_hids_command restart || return 1
                break;
            else
                echo "Download in progress..."
                sleep ${ossec_hids_fetch_read_time}
            fi
        done
    fi

    return 0
}

ossec_hids_ossec_conf() {
    if [ -x "${ossec_conf_bin}" ]; then
        "${ossec_conf_bin}"
    elif [ -f "${ossec_conf}" ]; then
        cat "${ossec_conf}"
    fi
}

ossec_hids_agent_conf() {
    if [ -x "${agent_conf_bin}" ]; then
        "${agent_conf_bin}"
    elif [ -f "${agent_conf}" ]; then
        cat "${agent_conf}"
    fi
}

ossec_hids_manage_agent() {
    "${ossec_home}/bin/manage_agents" $@
    return $?
}

ossec_hids_command() {
    "${ossec_home}/bin/ossec-control" $1
    return $?
}

run_rc_command "${ossec_rc_command}"