puppet nftables

# @summary Configure nftables

#

# @example allow dns out and do not allow ntp out

#   class{ 'nftables':

#     out_ntp => false,

#     out_dns => true,

#   }

#

# @example do not flush particular tables, fail2ban in this case

#   class{ 'nftables':

#     noflush_tables => ['inet-f2b-table'],

#   }

#

# @param out_all

#   Allow all outbound connections. If `true` then all other

#   out parameters `out_ntp`, `out_dns`, ... will be assuemed

#   false.

#

# @param out_ntp

#   Allow outbound to ntp servers.

#

# @param out_http

#   Allow outbound to http servers.

#

# @param out_dns

#   Allow outbound to dns servers.

#

# @param out_https

#   Allow outbound to https servers.

#

# @param out_icmp

#   Allow outbound ICMPv4/v6 traffic.

#

# @param in_ssh

#   Allow inbound to ssh servers.

#

# @param in_icmp

#   Allow inbound ICMPv4/v6 traffic.

#

# @param inet_filter

#   Add default tables, chains and rules to process traffic.

#

# @param nat

#   Add default tables and chains to process NAT traffic.

#

# @param nat_table_name

#   The name of the 'nat' table.

#

# @param purge_unmanaged_rules

#   Prohibits in-memory rules that are not declared in Puppet

#   code. Setting this to true activates a check that reloads nftables

#   if the rules in memory have been modified without Puppet.

#

# @param inmem_rules_hash_file

#   The name of the file where the hash of the in-memory rules

#   will be stored.

#

# @param sets

#   Allows sourcing set definitions directly from Hiera.

#

# @param log_prefix

#   String that will be used as prefix when logging packets. It can contain

#   two variables using standard sprintf() string-formatting:

#    * chain: Will be replaced by the name of the chain.

#    * comment: Allows chains to add extra comments.

#

# @param log_discarded

#   Allow to log discarded packets

#

# @param log_limit

#  String with the content of a limit statement to be applied

#  to the rules that log discarded traffic. Set to false to

#  disable rate limiting.

#

# @param reject_with

#   How to discard packets not matching any rule. If `false`, the

#   fate of the packet will be defined by the chain policy (normally

#   drop), otherwise the packet will be rejected with the REJECT_WITH

#   policy indicated by the value of this parameter.

#

# @param in_out_conntrack

#   Adds INPUT and OUTPUT rules to allow traffic that's part of an

#   established connection and also to drop invalid packets.

#

# @param in_out_drop_invalid

#   Drops invalid packets in INPUT and OUTPUT

#

# @param fwd_conntrack

#   Adds FORWARD rules to allow traffic that's part of an

#   established connection and also to drop invalid packets.

#

# @param fwd_drop_invalid

#   Drops invalid packets in FORWARD

#

# @param firewalld_enable

#   Configures how the firewalld systemd service unit is enabled. It might be

#   useful to set this to false if you're externaly removing firewalld from

#   the system completely.

#

# @param noflush_tables

#   If specified only other existings tables will be flushed.

#   If left unset all tables will be flushed via a `flush ruleset`

#

# @param rules

#   Specify hashes of `nftables::rule`s via hiera

#

# @param configuration_path

#   The absolute path to the principal nftables configuration file. The default

#   varies depending on the system, and is set in the module's data.

#

# @param nft_path

#   Path to the nft binary

#

# @param echo

#   Path to the echo binary

#

# @param default_config_mode

#   The default file & dir mode for configuration files and directories. The

#   default varies depending on the system, and is set in the module's data.

#

# @param clobber_default_config

#   Should the existing OS provided rules in the `configuration_path` be removed? If

#   they are not being removed this module will add all of its configuration to the end of

#   the existing rules.

#

class nftables (

  Stdlib::Unixpath $echo,

  Stdlib::Unixpath $configuration_path,

  Stdlib::Unixpath $nft_path,

  Stdlib::Filemode $default_config_mode,

  Boolean $clobber_default_config = false,

  Boolean $in_ssh = true,

  Boolean $in_icmp = true,

  Boolean $out_ntp = true,

  Boolean $out_dns = true,

  Boolean $out_http = true,

  Boolean $out_https = true,

  Boolean $out_icmp = true,

  Boolean $out_all = false,

  Boolean $in_out_conntrack = true,

  Boolean $in_out_drop_invalid = $in_out_conntrack,

  Boolean $fwd_conntrack = false,

  Boolean $fwd_drop_invalid = $fwd_conntrack,

  Boolean $inet_filter = true,

  Boolean $nat = true,

  Boolean $purge_unmanaged_rules = false,

  Hash $rules = {},

  Hash $sets = {},

  String $log_prefix = '[nftables] %<chain>s %<comment>s',

  String[1] $nat_table_name = 'nat',

  Stdlib::Unixpath $inmem_rules_hash_file = '/var/tmp/puppet-nft-memhash',

  Boolean $log_discarded = true,

  Variant[Boolean[false], String] $log_limit = '3/minute burst 5 packets',

  Variant[Boolean[false], Pattern[/icmp(v6|x)? type .+|tcp reset/]] $reject_with = 'icmpx type port-unreachable',

  Variant[Boolean[false], Enum['mask']] $firewalld_enable = 'mask',

  Optional[Array[Pattern[/^(ip|ip6|inet|arp|bridge|netdev)-[-a-zA-Z0-9_]+$/],1]] $noflush_tables = undef,

) {

  package { 'nftables':

    ensure => installed,

  }

  # /etc/services file is needed, on newer OSes this is a dependency on nftables

  if $facts['os']['name'] == 'Ubuntu' and $facts['os']['release']['major'] == '20.04' {

    package { 'netbase':

      ensure => present,

    }

  }

  if $clobber_default_config {

    file { $configuration_path:

      ensure  => file,

      owner   => 'root',

      group   => 'root',

      mode    => $default_config_mode,

      content => "#Puppet Managed\ninclude \"/etc/nftables/puppet.nft\"\n",

      require => Package['nftables'],

      before  => File['/etc/nftables'],

      notify  => Service['nftables'],

    }

  } else {

    file_line { 'enable_nftables':

      line    => 'include "/etc/nftables/puppet.nft"',

      path    => $configuration_path,

      require => Package['nftables'],

      before  => File['/etc/nftables'],

      notify  => Service['nftables'],

    }

  }

  file {

    default:

      owner => 'root',

      group => 'root',

      mode  => $default_config_mode;

    '/etc/nftables':

      ensure => directory,

      mode   => $default_config_mode;

    '/etc/nftables/puppet-preflight':

      ensure  => directory,

      mode    => $default_config_mode,

      purge   => true,

      force   => true,

      recurse => true;

    '/etc/nftables/puppet-preflight.nft':

      ensure  => file,

      content => epp('nftables/config/puppet.nft.epp', {

          'inet_filter' => $inet_filter,

          'nat'         => $nat,

          'noflush'     => $noflush_tables

        }

      );

  } ~> exec {

    'nft validate':

      refreshonly => true,

      command     => "${nft_path} -I /etc/nftables/puppet-preflight -c -f /etc/nftables/puppet-preflight.nft || ( ${echo} '#CONFIG BROKEN' >> /etc/nftables/puppet-preflight.nft && /bin/false)"; # lint:ignore:check_unsafe_interpolations

  } -> file {

    default:

      owner => 'root',

      group => 'root',

      mode  => $default_config_mode;

    '/etc/nftables/puppet.nft':

      ensure  => file,

      content => epp('nftables/config/puppet.nft.epp', {

          'inet_filter' => $inet_filter,

          'nat'         => $nat,

          'noflush'     => $noflush_tables

        }

      );

    '/etc/nftables/puppet':

      ensure  => directory,

      mode    => $default_config_mode,

      purge   => true,

      force   => true,

      recurse => true;

  } ~> service { 'nftables':

    ensure     => running,

    enable     => true,

    hasrestart => true,

    restart    => 'PATH=/usr/bin:/bin systemctl reload nftables',

  }

  if $purge_unmanaged_rules {

    # Reload nftables ruleset from disk if running state not match last service change hash, or is absent (-s required to ignore counters)

    exec { 'nftables_memory_state_check':

      command  => ['echo', 'reloading_nftables'],

      path     => $facts['path'],

      provider => shell,

      unless   => ["test -s ${inmem_rules_hash_file} -a \"$(nft -s list ruleset | sha1sum)\" = \"$(cat ${inmem_rules_hash_file})\""],

      notify   => Service['nftables'],

    }

    # Generate nftables hash upon changes to the nftables service

    exec { 'nftables_generate_hash':

      command     => ["nft -s list ruleset | sha1sum > ${inmem_rules_hash_file}"],

      path        => $facts['path'],

      provider    => shell,

      subscribe   => Service['nftables'],

      refreshonly => true,

    }

  }

  systemd::dropin_file { 'puppet_nft.conf':

    ensure  => present,

    unit    => 'nftables.service',

    content => epp('nftables/systemd/puppet_nft.conf.epp', {

        'configuration_path' => $configuration_path,

        'nft_path'           => $nft_path,

    }),

    notify  => Service['nftables'],

  }

  # firewalld.enable can be mask or false depending upon if firewalld is installed or not

  # https://tickets.puppetlabs.com/browse/PUP-10814

  service { 'firewalld':

    ensure => stopped,

    enable => $firewalld_enable,

  }

  if $inet_filter {

    include nftables::inet_filter

  }

  if $nat {

    include nftables::ip_nat

  }

  # inject custom rules e.g. from hiera

  $rules.each |$n,$v| {

    nftables::rule {

      $n:

        * => $v,

    }

  }

  # inject custom sets e.g. from hiera

  $sets.each |$n,$v| {

    nftables::set {

      $n:

        * => $v,

    }

  }

}