shorewall_code/Shorewall-perl/Shorewall/Chains.pm
2007-04-17 15:37:32 +00:00

1592 lines
36 KiB
Perl

#
# Shorewall-perl 3.9 -- /usr/share/shorewall-perl/Shorewall/Chains.pm
#
# This program is under GPL [http://www.gnu.org/copyleft/gpl.htm]
#
# (c) 2007 - Tom Eastep (teastep@shorewall.net)
#
# Complete documentation is available at http://shorewall.net
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of Version 2 of the GNU General Public License
# as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA
#
#
package Shorewall::Chains;
require Exporter;
use Shorewall::Common;
use Shorewall::Config;
use Shorewall::Zones;
use Shorewall::Interfaces;
use strict;
our @ISA = qw(Exporter);
our @EXPORT = qw( STANDARD
NATRULE
BUILTIN
NONAT
NATONLY
REDIRECT
ACTION
MACRO
LOGRULE
NO_RESTRICT
PREROUTE_RESTRICT
INPUT_RESTRICT
OUTPUT_RESTRICT
POSTROUTE_RESTRICT
ALL_RESTRICT
add_command
add_file
add_rule
insert_rule
chain_base
forward_chain
input_chain
output_chain
masq_chain
syn_chain
mac_chain
macrecent_target
dynamic_fwd
dynamic_in
dynamic_out
dynamic_chains
dnat_chain
snat_chain
ecn_chain
first_chains
new_chain
ensure_chain
ensure_filter_chain
ensure_mangle_chain
new_standard_chain
new_builtin_chain
initialize_chain_table
finish_section
newexclusionchain
clearrule
do_proto
mac_match
numeric_value
verify_mark
verify_small_mark
validate_mark
do_test
do_ratelimit
do_user
do_tos
iprange_match
match_source_net
match_dest_net
match_orig_dest
match_ipsec_in
match_ipsec_out
log_rule_limit
log_rule
expand_rule
addnatjump
insertnatjump
get_interface_addresses
create_netfilter_load
@policy_chains
%chain_table
$nat_table
$mangle_table
$filter_table
$section
%sections
$comment
%targets
);
our @EXPORT_OK = ();
our @VERSION = 1.00;
#
# Chain Table
#
# @policy_chains is a list of references to policy chains in the filter table
#
# %chain_table { <table> => { <chain1> => { name => <chain name>
# table => <table name>
# is_policy => 0|1
# is_optionsl => 0|1
# referenced => 0|1
# policy => <policy>
# loglevel => <level>
# synparams => <burst/limit>
# default => <default action>
# policy_chain => <ref to policy chain -- self-reference if this is a policy chain>
# rules => [ <rule1>
# <rule2>
# ...
# ]
# } ,
# <chain2> => ...
# }
# }
#
# 'is_optional' only applies to policy chains; when true, indicates that this is a provisional policy chain which might be
# replaced. Policy chains created under the IMPLICIT_CONTINUE=Yes option are optional.
#
# Only 'referenced' chains get written to the iptables-restore input.
#
# 'loglevel', 'synparams' and 'default' only apply to policy chains.
#
our @policy_chains;
our %chain_table = ( raw => {} ,
mangle => {},
nat => {},
filter => {} );
our $nat_table = $chain_table{nat};
our $mangle_table = $chain_table{mangle};
our $filter_table = $chain_table{filter};
#
# These get set to 1 as sections are encountered.
#
our %sections = ( ESTABLISHED => 0,
RELATED => 0,
NEW => 0
);
#
# Current rules file section.
#
our $section = 'ESTABLISHED';
#
# Contents of last COMMENT line.
#
our $comment = '';
# Target Table. Each entry maps a target to a set of flags defined as follows.
#
use constant { STANDARD => 1, #defined by Netfilter
NATRULE => 2, #Involved NAT
BUILTIN => 4, #A built-in action
NONAT => 8, #'NONAT' or 'ACCEPT+'
NATONLY => 16, #'DNAT-' or 'REDIRECT-'
REDIRECT => 32, #'REDIRECT'
ACTION => 64, #An action
MACRO => 128, #A Macro
LOGRULE => 256, #'LOG'
};
#
# As new targets (Actions and Macros) are discovered, they are added to the table
#
our %targets = ('ACCEPT' => STANDARD,
'ACCEPT+' => STANDARD + NONAT,
'ACCEPT!' => STANDARD,
'NONAT' => STANDARD + NONAT,
'DROP' => STANDARD,
'DROP!' => STANDARD,
'REJECT' => STANDARD,
'REJECT!' => STANDARD,
'DNAT' => NATRULE,
'DNAT-' => NATRULE + NATONLY,
'REDIRECT' => NATRULE + REDIRECT,
'REDIRECT-' => NATRULE + REDIRECT + NATONLY,
'LOG' => STANDARD + LOGRULE,
'CONTINUE' => STANDARD,
'QUEUE' => STANDARD,
'SAME' => NATRULE,
'SAME-' => NATRULE + NATONLY,
'dropBcast' => BUILTIN + ACTION,
'allowBcast' => BUILTIN + ACTION,
'dropNotSyn' => BUILTIN + ACTION,
'rejNotSyn' => BUILTIN + ACTION,
'dropInvalid' => BUILTIN + ACTION,
'allowInvalid' => BUILTIN + ACTION,
'allowinUPnP' => BUILTIN + ACTION,
'forwardUPnP' => BUILTIN + ACTION,
'Limit' => BUILTIN + ACTION,
);
#
# expand_rule() restrictions
#
use constant { NO_RESTRICT => 0,
PREROUTE_RESTRICT => 1,
INPUT_RESTRICT => 4,
OUTPUT_RESTRICT => 8,
POSTROUTE_RESTRICT => 16,
ALL_RESTRICT => 12
};
#
# Used to sequence 'exclusion' chains with names 'excl0', 'excl1', ...
#
my $exclseq = 0;
#
# Used to suppress duplicate match specifications.
#
my $iprangematch = 0;
#
# Sequence for naming temporary chains
#
my $chainseq;
#
# Add a run-time command to a chain. Arguments are:
#
# Chain reference , Command
#
#
# Count of the number of unclosed loops in generated shell code. We insert shell code
# into the Chain tables 'rules' array (proceeded by '~'). create_netfilter_load()
# emits that code inline for execution at run-time.
#
my $loopcount = 0;
sub add_command($$)
{
my ($chainref, $command) = @_;
push @{$chainref->{rules}}, join ('', '~', ' ' x $loopcount, $command );
$chainref->{referenced} = 1;
}
#
# Copy a file into a chain's rules as a set of run-time commands
#
sub add_file( $$ ) {
my $chainref = $_[0];
my $file = find_file $_[1];
if ( -f $file ) {
open EF , '<', $file or fatal_error "Unable to open $file";
add_command $chainref, qq(progress_message "Processing $file...");
add_command $chainref, '';
while ( $line = <EF> ) {
chomp $line;
add_command $chainref, $line;
}
add_command $chainref, '';
close EF;
}
}
#
# Add a rule to a chain. Arguments are:
#
# Chain reference , Rule
#
sub add_rule($$)
{
my ($chainref, $rule) = @_;
$rule .= " -m comment --comment \"$comment\"" if $comment;
if ( $loopcount ) {
add_command $chainref , qq(echo "-A $chainref->{name} $rule" >&3);
} else {
push @{$chainref->{rules}}, $rule;
$chainref->{referenced} = 1;
}
$iprangematch = 0;
}
#
# Insert a rule into a chain. Arguments are:
#
# Table , Chain , Rule Number, Rule
#
sub insert_rule($$$)
{
my ($chainref, $number, $rule) = @_;
fatal_error 'Internal Error in insert_rule()' if $loopcount;
$rule .= "-m comment --comment \"$comment\"" if $comment;
splice @{$chainref->{rules}}, $number - 1, 0, $rule;
$chainref->{referenced} = 1;
$iprangematch = 0;
}
#
# Form the name of a chain.
#
sub chain_base($) {
my $chain = $_[0];
$chain =~ s/^@/at_/;
$chain =~ tr/[.\-%@]/_/;
$chain =~ s/\+$//;
$chain;
}
#
# Forward Chain for an interface
#
sub forward_chain($)
{
chain_base( $_[0] ) . '_fwd';
}
#
# Input Chain for an interface
#
sub input_chain($)
{
chain_base( $_[0] ) . '_in';
}
#
# Output Chain for an interface
#
sub output_chain($)
{
chain_base( $_[0] ) . '_out';
}
#
# Masquerade Chain for an interface
#
sub masq_chain($)
{
chain_base( $_[0] ) . '_masq';
}
#
# Syn_chain
#
sub syn_chain ( $ ) {
'@' . $_[0];
}
#
# MAC Verification Chain for an interface
#
sub mac_chain( $ )
{
chain_base( $_[0] ) . '_mac';
}
sub macrecent_target($)
{
$config{MACLIST_TTL} ? chain_base( $_[0] ) . '_rec' : 'RETURN';
}
#
# Functions for creating dynamic zone rules
#
sub dynamic_fwd( $ )
{
chain_base( $_[0] ) . '_dynf';
}
sub dynamic_in( $ )
{
chain_base( $_[0] ) . '_dyni';
}
sub dynamic_out( $ ) # $1 = interface
{
chain_base( $_[0] ) . '_dyno';
}
sub dynamic_chains( $ ) #$1 = interface
{
my $c = chain_base( $_[0] );
[ $c . '_dyni' , $c . '_dynf' , $c . '_dyno' ];
}
#
# DNAT Chain from a zone
#
sub dnat_chain( $ )
{
chain_base( $_[0] ) . '_dnat';
}
#
# SNAT Chain to an interface
#
sub snat_chain( $ )
{
chain_base( $_[0] ) . '_snat';
}
#
# ECN Chain to an interface
#
sub ecn_chain( $ )
{
chain_base( $_[0] ) . '_ecn';
}
#
# First chains for an interface
#
sub first_chains( $ ) #$1 = interface
{
my $c = chain_base $_[0];
[ $c . '_fwd', $c . '_in' ];
}
#
# Create a new chain and return a reference to it.
#
sub new_chain($$)
{
my ($table, $chain) = @_;
my %ch;
my @rules;
$ch{name} = $chain;
$ch{log} = 1 if $globals{LOGRULENUMBERS};
$ch{rules} = \@rules;
$ch{table} = $table;
$chain_table{$table}{$chain} = \%ch;
\%ch;
}
#
# Create an anonymous chain
#
sub new_anon_chain( $ ) {
my $chainref = $_[0];
my $seq = $chainseq++;
new_chain( $chainref->{table}, 'chain' . "$seq" );
}
#
#
# Create a chain if it doesn't exist already
#
sub ensure_chain($$)
{
my ($table, $chain) = @_;
my $ref = $chain_table{$table}{$chain};
return $ref if $ref;
new_chain $table, $chain;
}
sub finish_chain_section( $$ );
#
# Create a filter chain if necessary. Optionally populate it with the appropriate ESTABLISHED,RELATED rule(s) and perform SYN rate limiting.
#
sub ensure_filter_chain( $$ )
{
my ($chain, $populate) = @_;
my $chainref = $filter_table->{$chain};
$chainref = new_chain 'filter' , $chain unless $chainref;
if ( $populate and ! $chainref->{referenced} ) {
if ( $section eq 'NEW' or $section eq 'DONE' ) {
finish_chain_section $chainref , 'ESTABLISHED,RELATED';
} elsif ( $section eq 'ESTABLISHED' ) {
finish_chain_section $chainref , 'ESTABLISHED';
}
}
$chainref->{referenced} = 1;
$chainref;
}
sub ensure_mangle_chain($) {
my $chain = $_[0];
my $chainref = ensure_chain 'mangle', $chain;
$chainref->{referenced} = 1;
$chainref;
}
#
# Add a builtin chain
#
sub new_builtin_chain($$$)
{
my ( $table, $chain, $policy ) = @_;
my $chainref = new_chain $table, $chain;
$chainref->{referenced} = 1;
$chainref->{policy} = $policy;
$chainref->{builtin} = 1;
}
sub new_standard_chain($) {
my $chainref = new_chain 'filter' ,$_[0];
$chainref->{referenced} = 1;
$chainref;
}
#
# Add all builtin chains to the chain table
#
#
sub initialize_chain_table()
{
for my $chain qw/OUTPUT PREROUTING/ {
new_builtin_chain 'raw', $chain, 'ACCEPT';
}
for my $chain qw/INPUT OUTPUT FORWARD/ {
new_builtin_chain 'filter', $chain, 'DROP';
}
for my $chain qw/PREROUTING POSTROUTING OUTPUT/ {
new_builtin_chain 'nat', $chain, 'ACCEPT';
}
for my $chain qw/PREROUTING INPUT FORWARD OUTPUT POSTROUTING/ {
new_builtin_chain 'mangle', $chain, 'ACCEPT';
}
if ( $capabilities{MANGLE_FORWARD} ) {
for my $chain qw/ FORWARD POSTROUTING / {
new_builtin_chain 'mangle', $chain, 'ACCEPT';
}
}
}
#
# Add ESTABLISHED,RELATED rules and synparam jumps to the passed chain
#
sub finish_chain_section ($$) {
my ($chainref, $state ) = @_;
my $chain = $chainref->{name};
add_rule $chainref, "-m state --state $state -j ACCEPT" unless $config{FASTACCEPT};
if ($sections{RELATED} ) {
if ( $chainref->{is_policy} ) {
if ( $chainref->{synparams} ) {
my $synchainref = ensure_chain 'filter', "\@$chain";
if ( $section eq 'DONE' ) {
if ( $chainref->{policy} =~ /^(ACCEPT|CONTINUE|QUEUE)$/ ) {
add_rule $chainref, "-p tcp --syn -j $synchainref->{name}";
}
} else {
add_rule $chainref, "-p tcp --syn -j $synchainref->{name}";
}
}
} else {
my $policychainref = $chainref->{policychain};
if ( $policychainref->{synparams} ) {
my $synchainref = ensure_chain 'filter', "\@$policychainref->{name}";
add_rule $synchainref, "-p tcp --syn -j $synchainref->{name}";
}
}
}
}
#
# Do section-end processing
#
sub finish_section ( $ ) {
my $sections = $_[0];
for my $zone ( @zones ) {
for my $zone1 ( @zones ) {
my $chainref = $chain_table{'filter'}{"$zone}2${zone1}"};
if ( $chainref->{referenced} ) {
finish_chain_section $chainref, $sections;
}
}
}
}
sub newexclusionchain() {
my $seq = $exclseq++;
"excl${seq}";
}
sub clearrule() {
$iprangematch = 0;
}
#
# Handle parsing of PROTO, DEST PORT(S) , SOURCE PORTS(S). Returns the appropriate match string.
#
sub do_proto( $$$ )
{
my ($proto, $ports, $sports ) = @_;
my $output = '';
$proto = '' if $proto eq '-';
$ports = '' if $ports eq '-';
$sports = '' if $sports eq '-';
if ( $proto ) {
if ( $proto =~ /^(tcp|udp|6|17)$/i ) {
$output = "-p $proto ";
if ( $ports ) {
my @ports = split /,/, $ports;
my $count = @ports;
if ( $count > 1 ) {
fatal_error "Port list requires Multiport support in your kernel/iptables: $ports" unless $capabilities{MULTIPORT};
for my $port ( @ports ) {
if ( $port =~ /:/ ) {
fatal_error "Port range in a list requires Extended Multiport Support in your kernel/iptables: $ports" unless $capabilities{XMULTIPORT};
$count++;
}
}
fatal_error "Too many entries in port list: $ports" if $count > 15;
$output .= "-m multiport --dports $ports ";
} else {
$output .= "--dport $ports ";
}
}
if ( $sports ) {
my @ports = split /,/, $sports;
my $count = @ports;
if ( $count > 1 ) {
fatal_error "Port list requires Multiport support in your kernel/iptables: $sports" unless $capabilities{MULTIPORT};
for my $port ( @ports ) {
if ( $port =~ /:/ ) {
fatal_error "Port range in a list requires Extended Multiport Support in your kernel/iptables: $sports" unless $capabilities{XMULTIPORT};
$count++;
}
}
fatal_error "Too many entries in port list: $sports" if $count > 15;
$output .= "-m multiport --sports $sports ";
} else {
$output .= "--sport $sports ";
}
}
} elsif ( $proto =~ /^(icmp|1)$/i ) {
my @ports = split /,/, $ports;
my $count = @ports;
fatal_error 'Multiple ICMP types are not permitted' if $count > 1;
$output .= "-p icmp ";
$output .= "--icmp-type $ports " if $count;
fatal_error 'SOURCE PORT(S) not permitted with ICMP' if $sports ne "";
} elsif ( $proto =~ /^(ipp2p(:(tcp|udp|all)))?$/i ) {
require_capability( 'IPP2P' , 'PROTO = ipp2p' );
$proto = $2 ? $3 : 'tcp';
$ports = 'ipp2p' unless $ports;
$output .= "-p $proto -m ipp2p --$ports ";
} else {
$output .= "-p $proto ";
}
} elsif ( $ports || $sports ) {
fatal_error "SOURCE/DEST PORT(S) not allowed without PROTO, rule \"$line\""
}
$output;
}
sub mac_match( $ ) {
my $mac = $_[0];
$mac =~ s/^(!?)~//;
$mac =~ s/^!// if my $invert = ( $1 ? '! ' : '');
$mac =~ s/-/:/g;
"--match mac --mac-source ${invert}$mac ";
}
#
# Convert value to decimal number
#
sub numeric_value ( $ ) {
my $mark = $_[0];
fatal_error "Invalid Numeric Value" unless "\L$mark" =~ /^(0x[a-f0-9]+|0[0-7]*|[1-9]\d*)$/;
$mark =~ /^0x/ ? hex $mark : $mark =~ /^0/ ? oct $mark : $mark;
}
#
# Mark validatation functions
#
sub verify_mark( $ ) {
my $mark = $_[0];
my $limit = $config{HIGH_ROUTE_MARKS} ? 0xFFFF : 0xFF;
fatal_error "Invalid Mark or Mask value: $mark"
unless numeric_value( $mark ) <= $limit;
}
sub verify_small_mark( $ ) {
verify_mark ( (my $mark) = $_[0] );
fatal_error "Mark value ($mark) too large" if numeric_value( $mark ) > 0xFF;
}
sub validate_mark( $ ) {
for ( split '/', $_[0] ) {
verify_mark $_;
}
}
#
# Generate an appropriate -m [conn]mark match string for the contents of a MARK column
#
sub do_test ( $$ )
{
my ($testval, $mask) = @_;
return '' unless $testval and $testval ne '-';
my $invert = $testval =~ s/^!// ? '! ' : '';
my $match = $testval =~ s/:C$// ? '-m connmark ' : '-m mark ';
$testval .= '/0xFF' unless ( $testval =~ '/' );
"${invert}$match $testval ";
}
#
# Create a "-m limit" match for the passed LIMIT/BURST
#
sub do_ratelimit( $ ) {
my $rate = $_[0];
return '' unless $rate and $rate ne '-';
if ( $rate =~ /^([^:]+):([^:]+)$/ ) {
"-m limit --limit $1 --limit-burst $2 ";
} else {
"-m limit --limit $rate ";
}
}
#
# Create a "-m owner" match for the passed USER/GROUP
#
sub do_user( $ ) {
my $user = $_[0];
my $rule = ' -m owner';
return '' unless $user and $user ne '-';
if ( $user =~ /^(!)?(.*)\+(.*)$/ ) {
$rule .= "! --cmd-owner $2 " if $2;
$user = "!$1";
} elsif ( $user =~ /^(.*)\+(.*)$/ ) {
$rule .= "--cmd-owner $2 " if $2;
$user = $1;
}
if ( $user =~ /^!(.*):(.*)$/ ) {
$rule .= "! --uid-owner $1 " if $1;
$rule .= "! --gid-owner $2 " if $2;
} elsif ( $user =~ /^(.*):(.*)$/ ) {
$rule .= "--uid-owner $1 " if $1;
$rule .= "--gid-owner $2 " if $2;
} elsif ( $user =~ /^!/ ) {
$rule .= "! --uid-owner $user ";
} else {
$rule .= "--uid-owner $user ";
}
$rule;
}
#
# Create a "-m tos" match for the passed TOS
#
sub do_tos( $ ) {
my $tos = $_[0];
$tos ne '-' ? "-m tos --tos $tos " : '';
}
#
# Avoid generating a second '-m iprange' in a single rule.
#
sub iprange_match() {
my $match = '';
require_capability( 'IPRANGE_MATCH' , 'Address Ranges' );
unless ( $iprangematch ) {
$match = '-m iprange ';
$iprangematch = 1;
}
$match;
}
#
# Get set flags (ipsets).
#
sub get_set_flags( $$ ) {
my ( $setname, $option ) = @_;
my $options = $option;
fatal_error "Your kernel and/or iptables does not include ipset match: $setname" unless $capabilities{IPSET_MATCH};
if ( $setname =~ /(.*)\[([1-6])\]$/ ) {
$setname = $1;
my $count = $2;
$options .= ",$option" while --$count > 0;
} elsif ( $setname =~ /(.+)\[(.*)\]$/ ) {
$setname = $1;
$options = $2;
}
$setname =~ s/^\+//;
"--set $setname $options"
}
#
# Match a Source. Currently only handles IP addresses and ranges
#
sub match_source_net( $ ) {
my $net = $_[0];
if ( $net =~ /^(!?).*\..*\..*\..*-.*\..*\..*\..*/ ) {
$net =~ s/!// if my $invert = $1 ? '! ' : '';
iprange_match . "${invert}--src-range $net ";
} elsif ( $net =~ /^(!?)~(.*)$/ ) {
( $net = $2 ) =~ s/-/:/g;
"-m mac --mac-source $1 $net ";
} elsif ( $net =~ /^(!?)\+/ ) {
require_capability( 'IPSET_MATCH' , 'ipset names in Shorewall configuration files' );
join( '', '-m set ', $1 ? '! ' : '', get_set_flags( $net, 'src' ) );
} elsif ( $net =~ /^!/ ) {
$net =~ s/!//;
"-s ! $net ";
} else {
$net eq ALLIPv4 ? '' : "-s $net ";
}
}
#
# Match a Source. Currently only handles IP addresses and ranges
#
sub match_dest_net( $ ) {
my $net = $_[0];
if ( $net =~ /^(!?).*\..*\..*\..*-.*\..*\..*\..*/ ) {
$net =~ s/!// if my $invert = $1 ? '! ' : '';
iprange_match . "${invert}--dst-range $net ";
} elsif ( $net =~ /^(!?)\+/ ) {
require_capability( 'IPSET_MATCH' , 'ipset names in Shorewall configuration files' );
join( '', '-m set ', $1 ? '! ' : '', get_set_flags( $net, 'dst' ) );
} elsif ( $net =~ /^!/ ) {
$net =~ s/!//;
"-d ! $net ";
} else {
$net eq ALLIPv4 ? '' : "-d $net ";
}
}
#
# Match original destination
#
sub match_orig_dest ( $ ) {
my $net = $_[0];
return '' if $net eq ALLIPv4;
return '' unless $capabilities{CONNTRACK_MATCH};
if ( $net =~ /^!/ ) {
$net =~ s/!//;
"-m conntrack --ctorigdst ! $net ";
} else {
$net eq ALLIPv4 ? '' : "-m conntrack --ctorigdst $net ";
}
}
#
# Match Source IPSEC
#
sub match_ipsec_in( $$ ) {
my ( $zone , $hostref ) = @_;
my $match = '-m policy --dir in --pol ';
my $zoneref = $zones{$zone};
my $optionsref = $zoneref->{options};
if ( $zoneref->{type} eq 'ipsec4' ) {
$match .= "ipsec $optionsref->{in_out}{ipsec}$optionsref->{in}{ipsec}";
} elsif ( $capabilities{POLICY_MATCH} ) {
$match .= "$hostref->{ipsec} $optionsref->{in_out}{ipsec}$optionsref->{in}{ipsec}";
} else {
'';
}
}
#
# Match Dest IPSEC
#
sub match_ipsec_out( $$ ) {
my ( $zone , $hostref ) = @_;
my $match = '-m policy --dir out --pol ';
my $zoneref = $zones{$zone};
my $optionsref = $zoneref->{options};
if ( $zoneref->{type} eq 'ipsec4' ) {
$match .= "ipsec $optionsref->{in_out}{ipsec}$optionsref->{out}{ipsec}";
} elsif ( $capabilities{POLICY_MATCH} ) {
$match .= "$hostref->{ipsec} $optionsref->{in_out}{ipsec}$optionsref->{out}{ipsec}"
} else {
'';
}
}
#
# Generate a log message
#
sub log_rule_limit( $$$$$$$$ ) {
my ($level, $chainref, $chain, $disposition, $limit, $tag, $command, $predicates ) = @_;
my $prefix;
$limit = $globals{LOGLIMIT} unless $limit;
if ( $tag ) {
if ( $config{LOGTAGONLY} ) {
$chain = $tag;
$tag = '';
} else {
$tag .= ' ';
}
} else {
$tag = '' unless defined $tag;
}
if ( $globals{LOGRULENUMBERS} ) {
$prefix = (sprintf $config{LOGFORMAT} , $chain , $chainref->{log}++, $disposition ) . $tag;
} else {
$prefix = (sprintf $config{LOGFORMAT} , $chain , $disposition) . $tag;
}
if ( length $prefix > 29 ) {
$prefix = substr $prefix, 0, 29;
warning_message "Log Prefix shortened to \"$prefix\"";
}
if ( $level eq 'ULOG' ) {
$prefix = "-j ULOG $globals{LOGPARMS} --ulog-prefix \"$prefix\" ";
} else {
$prefix = "-j LOG $globals{LOGPARMS} --log-level $level --log-prefix \"$prefix\" ";
}
if ( $command eq 'add' ) {
add_rule ( $chainref, $predicates . $prefix );
} else {
insert_rule ( $chainref , 1 , $predicates . $prefix );
}
}
sub log_rule( $$$$ ) {
my ( $level, $chainref, $disposition, $predicates ) = @_;
log_rule_limit $level, $chainref, $chainref->{name} , $disposition, $globals{LOGLIMIT}, '', 'add', $predicates;
}
#
# Split a comma-separated source or destination host list but keep [...] together.
#
sub mysplit( $ ) {
my @input = split /,/, $_[0];
return @input unless $_[0] =~ /\[/;
my @result;
while ( @input ) {
my $element = shift @input;
if ( $element =~ /\[/ ) {
while ( ! ( $element =~ /\]/ ) ) {
last unless @input;
$element .= ( ',' . shift @input );
}
fatal_error "Invalid Host List ($_[0])" unless substr( $element, -1, 1 ) eq ']';
}
push @result, $element;
}
@result;
}
#
# Keep track of which interfaces have active 'address', 'addresses' and 'networks' variables
#
my %interfaceaddr;
my %interfaceaddrs;
my %interfacenets;
#
# Returns the name of the shell variable holding the first address of the passed interface
#
sub interface_address( $ ) {
chain_base( $_[0] ) . '_address';
}
#
# Record that the ruleset requires the first IP address on the passed interface
#
sub get_interface_address ( $ ) {
my ( $interface ) = $_[0];
my $variable = interface_address( $interface );
$interfaceaddr{$interface} = "$variable=\$(find_first_interface_address $interface)";
"\$$variable";
}
#
# Returns the name of the shell variable holding the addresses of the passed interface
#
sub interface_addresses( $ ) {
chain_base( $_[0] ) . '_addresses';
}
#
# Record that the ruleset requires the IP addresses on the passed interface
#
sub get_interface_addresses ( $ ) {
my ( $interface ) = $_[0];
my $variable = interface_addresses( $interface );
$interfaceaddr{$interface} = qq($variable=\$(get_interface_addresses $interface)
[ -n "\$$variable" ] || fatal_error "Unable to determine the IP address(es) of $interface"
);
"\$$variable";
}
#
# Returns the name of the shell variable holding the networks routed out of the passed interface
#
sub interface_nets( $ ) {
chain_base( $_[0] ) . '_networks';
}
#
# Record that the ruleset requires the first IP address on the passed interface
#
sub get_interface_nets ( $ ) {
my ( $interface ) = $_[0];
my $variable = interface_nets( $interface );
$interfaceaddr{$interface} = qq($variable=\$(get_routed_networks $interface)
[ -n "\$$variable" ] || fatal_error "Unable to determine the routes through interface \\"$interface\\""
);
"\$$variable";
}
#
# This function provides a uniform way to generate rules (something the original Shorewall sorely needed).
#
sub expand_rule( $$$$$$$$$$ )
{
my ($chainref , $restriction, $rule, $source, $dest, $origdest, $target, $loglevel , $disposition, $exceptionrule ) = @_;
my ($iiface, $diface, $inets, $dnets, $iexcl, $dexcl, $onets , $oexcl );
my $chain = $chainref->{name};
#
# Handle Log Level
#
my $logtag;
if ( $loglevel ) {
( $loglevel, $logtag ) = split /:/, $loglevel;
if ( $loglevel =~ /^none!?$/i ) {
return if $disposition eq 'LOG';
$loglevel = $logtag = '';
}
}
#
# Isolate Source Interface, if any
#
if ( $source ) {
if ( $source eq '-' ) {
$source = '';
} elsif ( $source =~ /^([^:]+):([^:]+)$/ ) {
$iiface = $1;
$inets = $2;
} elsif ( $source =~ /\+|~|\..*\./ ) {
$inets = $source;
} else {
$iiface = $source;
}
} else {
$source = '';
}
#
# Verify Inteface, if any
#
if ( $iiface ) {
fatal_error "Unknown Interface ($iiface): \"$line\"" unless known_interface $iiface;
if ( $restriction & POSTROUTE_RESTRICT ) {
#
# An interface in the SOURCE column of a masq file
#
my $networks = get_interface_nets ( $iiface );
add_command( $chainref , join( '', 'for source in ', $networks, '; do' ) );
$rule .= '-s $source ';
#
# While $loopcount > 0, calls to 'add_rule()' will be converted to calls to 'add_command()'
#
$loopcount++;
} else {
fatal_error "Source Interface ( $iiface ) not allowed when the source zone is $firewall_zone: $line"
if $restriction & OUTPUT_RESTRICT;
$rule .= "-i $iiface ";
}
}
#
# Isolate Destination Interface, if any
#
if ( $dest ) {
if ( $dest eq '-' ) {
$dest = '';
} elsif ( ( $restriction & PREROUTE_RESTRICT ) && $dest =~ /^detect:(.*)$/ ) {
#
# DETECT_DNAT_IPADDRS=Yes and we're generating the nat rule
#
my @interfaces = split /\s+/, $1;
if ( @interfaces > 1 ) {
my $list = "";
for my $interface ( @interfaces ) {
$list = join( ' ', $list , get_interface_address( $interface ) );
}
add_command( $chainref , "for address in $list; do" );
$rule .= '-d $address ';
$loopcount++;
} else {
$rule .= join ( '', '-d ', get_interface_address( $interfaces[0] ), ' ' );
}
$dest = '';
} elsif ( $dest =~ /^([^:]+):([^:]+)$/ ) {
$diface = $1;
$dnets = $2;
} elsif ( $dest =~ /\+|~|\..*\./ ) {
$dnets = $dest;
} else {
$diface = $dest;
}
} else {
$dest = '';
}
#
# Verify Destination Interface, if any
#
if ( $diface ) {
fatal_error "Unknown Interface ($diface) in rule \"$line\"" unless known_interface $diface;
if ( $restriction & PREROUTE_RESTRICT ) {
#
# ADDRESS 'detect' in the masq file.
#
add_command $chainref , "dests=\$(find_interface_addresses $diface)";
add_command $chainref , qq([ -z "\$dests" ] && fatal_error "Unable to determine the address(es) of interface \"$diface\"");
add_command $chainref , 'for dest in $dests; do';
$rule .= '-d $dest';
$loopcount++;
} else {
fatal_error "Destination Interface ( $diface ) not allowed when the destination zone is $firewall_zone: $line"
if $restriction & INPUT_RESTRICT;
$rule .= "-o $diface ";
}
}
if ( $origdest ) {
if ( $origdest eq '-' || ! $capabilities{CONNTRACK_MATCH} ) {
$origdest = '';
} elsif ( $origdest =~ /^detect:(.*)$/ ) {
#
# Either the filter part of a DNAT rule or 'detect' was given in the ORIG DEST column
#
my @interfaces = split /\s+/, $1;
if ( @interfaces > 1 ) {
my $list = "";
for my $interface ( @interfaces ) {
$list = join( ' ', $list , get_interface_address( $interface ) );
}
add_command( $chainref , "for address in $list; do" );
$rule .= '-m conntrack --ctorigdst $address ';
$loopcount++;
} else {
get_interface_address $interfaces[0];
$rule .= join( '', '-m conntrack --ctorigdst $', interface_address ( $interfaces[0] ), ' ' );
}
$origdest = '';
} else {
if ( $origdest =~ /^([^!]+)?!([^!]+)$/ ) {
#
# Exclusion
#
$onets = $1;
$oexcl = $2;
} else {
$oexcl = '';
$onets = $origdest;
}
unless ( $onets ) {
my @oexcl = mysplit $oexcl;
if ( @oexcl == 1 ) {
$rule .= "-m conntrack --ctorigdst ! $oexcl ";
$oexcl = '';
}
}
}
} else {
$oexcl = '';
}
#
# Determine if there is Source Exclusion
#
if ( $inets ) {
if ( $inets =~ /^([^!]+)?!([^!]+)$/ ) {
$inets = $1;
$iexcl = $2;
} else {
$iexcl = '';
}
unless ( $inets ) {
my @iexcl = mysplit $iexcl;
if ( @iexcl == 1 ) {
$rule .= match_source_net "!$iexcl ";
$iexcl = '';
}
}
} else {
$iexcl = '';
}
#
# Determine if there is Destination Exclusion
#
if ( $dnets ) {
if ( $dnets =~ /^([^!]+)?!([^!]+)$/ ) {
$dnets = $1;
$dexcl = $2;
} else {
$dexcl = '';
}
unless ( $dnets ) {
my @dexcl = mysplit $dexcl;
if ( @dexcl == 1 ) {
$rule .= match_dest_net "!$dexcl ";
$dexcl = '';
}
}
} else {
$dexcl = '';
}
$inets = ALLIPv4 unless $inets;
$dnets = ALLIPv4 unless $dnets;
$onets = ALLIPv4 unless $onets;
if ( $iexcl || $dexcl || $oexcl ) {
#
# We have non-trivial exclusion -- need to create an exclusion chain
#
my $echain = newexclusionchain;
#
# Use the current rule and sent all possible matches to the exclusion chain
#
for my $onet ( mysplit $onets ) {
$onet = match_orig_dest $onet;
for my $inet ( mysplit $inets ) {
$inet = match_source_net $inet;
for my $dnet ( mysplit $dnets ) {
add_rule $chainref, join( '', $rule, $inet, match_dest_net( $dnet ), $onet, "-j $echain" );
}
}
}
#
# The final rule in the exclusion chain will not qualify the source or destination
#
$inets = ALLIPv4;
$dnets = ALLIPv4;
#
# Create the Exclusion Chain
#
my $echainref = new_chain $chainref->{table}, $echain;
#
# Generate RETURNs for each exclusion
#
for my $net ( mysplit $iexcl ) {
add_rule $echainref, ( match_source_net $net ) . '-j RETURN';
}
for my $net ( mysplit $dexcl ) {
add_rule $echainref, ( match_dest_net $net ) . '-j RETURN';
}
for my $net ( mysplit $oexcl ) {
add_rule $echainref, ( match_orig_dest $net ) . '-j RETURN';
}
#
# Log rule
#
log_rule_limit $loglevel , $echainref , $chain, $disposition , '', $logtag , 'add' , '' if $loglevel;
#
# Generate Final Rule
#
add_rule $echainref, $exceptionrule . $target unless $disposition eq 'LOG';
} else {
#
# No exclusions
#
for my $onet ( mysplit $onets ) {
$onet = match_orig_dest $onet;
for my $inet ( mysplit $inets ) {
$inet = match_source_net $inet;
for my $dnet ( mysplit $dnets ) {
if ( $loglevel ) {
log_rule_limit
$loglevel ,
$chainref ,
$chain,
$disposition ,
'' ,
$logtag ,
'add' ,
join( '', $rule, $inet, match_dest_net( $dnet ), $onet );
}
unless ( $disposition eq 'LOG' ) {
add_rule
$chainref,
join( '', $rule, $inet, match_dest_net( $dnet ), $onet, $target );
}
}
}
}
}
while ( $loopcount > 0 ) {
$loopcount--;
add_command $chainref, 'done';
}
}
#
# If the destination chain exists, then at the end of the source chain add a jump to the destination.
#
sub addnatjump( $$$ ) {
my ( $source , $dest, $predicates ) = @_;
my $destref = $nat_table->{$dest} || {};
if ( $destref->{referenced} ) {
add_rule $nat_table->{$source} , $predicates . "-j $dest";
} else {
clearrule;
}
}
#
# If the destination chain exists, then at the position in the source chain given by $$countref, add a jump to the destination.
#
sub insertnatjump( $$$$ ) {
my ( $source, $dest, $countref, $predicates ) = @_;
my $destref = $nat_table->{$dest} || {};
if ( $destref->{referenced} ) {
insert_rule $nat_table->{$source} , ($$countref)++, $predicates . "-j $dest";
} else {
clearrule;
}
}
#
# What follows is the code that generates the input to iptables-restore
#
my @builtins = qw(PREROUTING INPUT FORWARD OUTPUT POSTROUTING);
#
# State of the generator.
#
use constant { NULL_STATE => 0 , # Generating neither shell commands nor iptables-restore input
CAT_STATE => 1 , # Generating iptables-restore input
CMD_STATE => 2 }; # Generating shell commands.
my $state = NULL_STATE;
#
# Emits the passed 'rule'
#
sub emitr( $ ) {
my $rule = $_[0];
if ( substr( $rule, 0, 1 ) eq '~' ) {
#
# A command
#
unless ( $state == CMD_STATE ) {
emit_unindented "__EOF__\n" if $state == CAT_STATE;
$state = CMD_STATE;
}
$rule = substr( $rule, 1 );
emit $rule;
} else {
unless ( $state == CAT_STATE ) {
emit '';
emit 'cat >&3 << __EOF__';
$state = CAT_STATE;
}
emit_unindented $rule;
}
}
#
# Generate the netfilter input
#
sub create_netfilter_load() {
emitj( 'setup_netfilter()',
'{'
);
push_indent;
#
# Establish the values of shell variables used in the following shell commands and/or 'here documents' input.
#
for ( values %interfaceaddr ) {
emit $_;
}
for ( values %interfaceaddrs ) {
emit $_;
}
for ( values %interfacenets ) {
emit $_;
}
emit '';
#
# We always write the input into a file then pass the file to iptables-restore. That way, if things go wrong,
# the user (and Shorewall support) has something to look at to determine the error
#
emit 'exec 3>${VARDIR}/.iptables-restore-input';
for my $table ( qw/raw nat mangle filter/ ) {
emitr "*$table";
my @chains;
#
# iptables-restore seems to be quite picky about the order of the builtin chains
#
for my $chain ( @builtins ) {
my $chainref = $chain_table{$table}{$chain};
if ( $chainref ) {
emitr ":$chain $chainref->{policy} [0:0]";
push @chains, $chainref;
}
}
#
# First create the chains in the current table
#
for my $chain ( grep $chain_table{$table}{$_}->{referenced} , ( sort keys %{$chain_table{$table}} ) ) {
my $chainref = $chain_table{$table}{$chain};
unless ( $chainref->{builtin} ) {
emitr ":$chainref->{name} - [0:0]";
push @chains, $chainref;
}
}
#
# then emit the rules
#
for my $chainref ( @chains ) {
my $name = $chainref->{name};
for my $rule ( @{$chainref->{rules}} ) {
$rule = "-A $name $rule" unless substr( $rule, 0, 1) eq '~';
emitr $rule;
}
}
#
# Commit the changes to the table
#
emitr 'COMMIT';
}
emit_unindented '__EOF__' unless $state == CMD_STATE;
emit '';
#
# Now generate the actual iptabes-restore command
#
emitj( ' exec 3>&-',
'',
'iptables-restore < ${VARDIR}/.iptables-restore-input'
);
emitj( 'if [ $? != 0 ]; then',
' fatal_error "iptables-restore Failed. Input is in ${VARDIR}/.iptables-restore-input"',
"fi\n"
);
pop_indent;
emit "}\n";
}
1;