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shorewall_code/Shorewall-perl/Shorewall/Chains.pm
teastep f1567e6e3d Beta 1 prep 
git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@8492 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
2008-05-04 00:18:47 +00:00

2488 lines
64 KiB
Perl
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#
# Shorewall-perl 4.2 -- /usr/share/shorewall-perl/Shorewall/Chains.pm
#
# This program is under GPL [http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt]
#
# (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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# This is the low-level iptables module. It provides the basic services
# of chain and rule creation. It is used by the higher level modules such
# as Rules to create iptables-restore input.
#
package Shorewall::Chains;
require Exporter;
use Scalar::Util 'reftype';
use Shorewall::Config qw(:DEFAULT :internal);
use Shorewall::Zones;
use Shorewall::IPAddrs;
use strict;
our @ISA = qw(Exporter);
our @EXPORT = qw(
add_rule
add_jump
insert_rule
new_chain
new_manual_chain
ensure_manual_chain
log_rule_limit
%chain_table
$nat_table
$mangle_table
$filter_table
);
our %EXPORT_TAGS = (
internal => [ qw( STANDARD
NATRULE
BUILTIN
NONAT
NATONLY
REDIRECT
ACTION
MACRO
LOGRULE
NFQ
CHAIN
NO_RESTRICT
PREROUTE_RESTRICT
INPUT_RESTRICT
OUTPUT_RESTRICT
POSTROUTE_RESTRICT
ALL_RESTRICT
add_command
add_commands
move_rules
process_comment
no_comment
macro_comment
clear_comment
incr_cmd_level
decr_cmd_level
chain_base
forward_chain
zone_forward_chain
use_forward_chain
input_chain
zone_input_chain
use_input_chain
output_chain
zone_output_chain
use_output_chain
masq_chain
syn_flood_chain
mac_chain
macrecent_target
dynamic_fwd
dynamic_in
dynamic_out
dynamic_chains
zone_dynamic_chain
dnat_chain
snat_chain
ecn_chain
first_chains
ensure_chain
ensure_accounting_chain
ensure_mangle_chain
ensure_nat_chain
new_standard_chain
new_builtin_chain
new_nat_chain
ensure_filter_chain
initialize_chain_table
finish_section
setup_zone_mss
newexclusionchain
clearrule
do_proto
mac_match
verify_mark
verify_small_mark
validate_mark
do_test
do_ratelimit
do_user
do_tos
do_connbytes
match_source_dev
match_dest_dev
iprange_match
match_source_net
match_dest_net
match_orig_dest
match_ipsec_in
match_ipsec_out
log_rule
expand_rule
addnatjump
get_interface_address
get_interface_addresses
get_interface_bcasts
get_interface_gateway
get_interface_mac
set_global_variables
create_netfilter_load
create_chainlist_reload
$section
%sections
%targets
) ],
);
Exporter::export_ok_tags('internal');
our $VERSION = 4.1.5;
#
# Chain Table
#
# %chain_table { <table> => { <chain1> => { name => <chain name>
# table => <table name>
# is_policy => undef|1 -- if 1, this is a policy chain
# is_optional => undef|1 -- See below.
# referenced => undef|1 -- If 1, will be written to the iptables-restore-input.
# builtin => undef|1 -- If 1, one of Netfilter's built-in chains.
# manual => undef|1 -- If 1, a manual chain.
# accounting => undef|1 -- If 1, an accounting chain
# log => <logging rule number for use when LOGRULENUMBERS>
# policy => <policy>
# policychain => <name of policy chain> -- self-reference if this is a policy chain
# policypair => [ <policy source>, <policy dest> ] -- Used for reporting duplicated policies
# loglevel => <level>
# synparams => <burst/limit>
# synchain => <name of synparam chain>
# default => <default action>
# cmdlevel => <number of open loops or blocks in runtime commands>
# 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 marked with is_optional == 1.
#
# Only 'referenced' chains get written to the iptables-restore input.
#
# 'loglevel', 'synparams', 'synchain' and 'default' only apply to policy chains.
#
our %chain_table;
our $nat_table;
our $mangle_table;
our $filter_table;
#
# It is a layer violation to keep information about the rules file sections in this module but in Shorewall, the rules file
# and the filter table are very closely tied. By keeping the information here, we avoid making several other modules dependent
# on Shorewall::Rules.
#
our %sections;
our $section;
our $comment;
use constant { STANDARD => 1, #defined by Netfilter
NATRULE => 2, #Involves NAT
BUILTIN => 4, #A built-in action
NONAT => 8, #'NONAT' or 'ACCEPT+'
NATONLY => 16, #'DNAT-' or 'REDIRECT-'
REDIRECT => 32, #'REDIRECT'
ACTION => 64, #An action (may be built-in)
MACRO => 128, #A Macro
LOGRULE => 256, #'LOG'
NFQ => 512, #'NFQUEUE'
CHAIN => 1024, #Manual Chain
};
our %targets;
#
# expand_rule() restrictions
#
use constant { NO_RESTRICT => 0, # FORWARD chain rule - Both -i and -o may be used in the rule
PREROUTE_RESTRICT => 1, # PREROUTING chain rule - -o converted to -d <address list> using main routing table
INPUT_RESTRICT => 4, # INPUT chain rule - -o not allowed
OUTPUT_RESTRICT => 8, # OUTPUT chain rule - -i not allowed
POSTROUTE_RESTRICT => 16, # POSTROUTING chain rule - -i converted to -s <address list> using main routing table
ALL_RESTRICT => 12 # fw->fw rule - neither -i nor -o allowed
};
our $exclseq;
our $iprangematch;
our $chainseq;
our %interfaceaddr;
our %interfaceaddrs;
our %interfacenets;
our %interfacemacs;
our %interfacebcasts;
our %interfacegateways;
our @builtins = qw(PREROUTING INPUT FORWARD OUTPUT POSTROUTING);
#
# Mode of the generator.
#
use constant { NULL_MODE => 0 , # Generating neither shell commands nor iptables-restore input
CAT_MODE => 1 , # Generating iptables-restore input
CMD_MODE => 2 }; # Generating shell commands.
our $mode;
#
# Initialize globals -- we take this novel approach to globals initialization to allow
# the compiler to run multiple times in the same process. The
# initialize() function does globals initialization for this
# module and is called from an INIT block below. The function is
# also called by Shorewall::Compiler::compiler at the beginning of
# the second and subsequent calls to that function.
#
sub initialize() {
%chain_table = ( raw => {} ,
mangle => {},
nat => {},
filter => {} );
$nat_table = $chain_table{nat};
$mangle_table = $chain_table{mangle};
$filter_table = $chain_table{filter};
#
# These get set to 1 as sections are encountered.
#
%sections = ( ESTABLISHED => 0,
RELATED => 0,
NEW => 0
);
#
# Current rules file section.
#
$section = 'ESTABLISHED';
#
# Contents of last COMMENT line.
#
$comment = '';
#
# As new targets (Actions and Macros) are discovered, they are added to the table
#
%targets = ('ACCEPT' => STANDARD,
'ACCEPT+' => STANDARD + NONAT,
'ACCEPT!' => STANDARD,
'NONAT' => STANDARD + NONAT + NATONLY,
'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,
'CONTINUE!' => STANDARD,
'QUEUE' => STANDARD,
'QUEUE!' => STANDARD,
'NFQUEUE' => STANDARD + NFQ,
'NFQUEUE!' => STANDARD + NFQ,
'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,
);
#
# Used to sequence 'exclusion' chains with names 'excl0', 'excl1', ...
#
$exclseq = 0;
#
# Used to suppress duplicate match specifications.
#
$iprangematch = 0;
#
# Sequence for naming temporary chains
#
$chainseq = undef;
#
# Keep track of which interfaces have active 'address', 'addresses', 'networks', etc. variables
#
%interfaceaddr = ();
%interfaceaddrs = ();
%interfacenets = ();
%interfacemacs = ();
%interfacebcasts = ();
%interfacegateways = ();
}
INIT {
initialize;
}
#
# Add a run-time command to a chain. Arguments are:
#
# Chain reference , Command
#
#
# Process a COMMENT line (in $currentline)
#
sub process_comment() {
if ( $capabilities{COMMENTS} ) {
( $comment = $currentline ) =~ s/^\s*COMMENT\s*//;
$comment =~ s/\s*$//;
} else {
warning_message "COMMENT ignored -- requires comment support in iptables/Netfilter";
}
}
#
# Returns True if there is a current COMMENT or if COMMENTS are not available.
#
sub no_comment() {
$comment ? 1 : $capabilities{COMMENTS} ? 0 : 1;
}
#
# Clear the $comment variable
#
sub clear_comment() {
$comment = '';
}
#
# Set $comment to the passed unless there is a current comment
#
sub macro_comment( $ ) {
my $macro = $_[0];
$comment = $macro unless $comment || ! ( $capabilities{COMMENTS} && $config{AUTO_COMMENT} );
}
#
# Functions to manipulate cmdlevel
#
sub incr_cmd_level( $ ) {
$_[0]->{cmdlevel}++;
}
sub decr_cmd_level( $ ) {
fatal_error "Internal error in decr_cmd_level()" if --$_[0]->{cmdlevel} < 0;
}
sub add_command($$)
{
my ($chainref, $command) = @_;
push @{$chainref->{rules}}, join ('', ' ' x $chainref->{cmdlevel} , $command );
$chainref->{referenced} = 1;
}
sub add_commands {
my $chainref = shift @_;
for my $command ( @_ ) {
push @{$chainref->{rules}}, join ('', ' ' x $chainref->{cmdlevel} , $command );
}
$chainref->{referenced} = 1;
}
sub push_rule( $$ ) {
my ($chainref, $rule) = @_;
$rule .= qq( -m comment --comment "$comment") if $comment;
if ( $chainref->{cmdlevel} ) {
$rule =~ s/"/\\"/g; #Must preserve quotes in the rule
add_command $chainref , qq(echo "-A $chainref->{name} $rule" >&3);
} else {
push @{$chainref->{rules}}, join( ' ', '-A' , $chainref->{name}, $rule );
$chainref->{referenced} = 1;
}
}
#
# Add a rule to a chain. Arguments are:
#
# Chain reference , Rule [, Expand-long-dest-port-lists ]
#
sub add_rule($$;$)
{
my ($chainref, $rule, $expandports) = @_;
fatal_error 'Internal Error in add_rule()' if reftype $rule;
$iprangematch = 0;
#
# Pre-processing the port lists as was done in Shorewall-shell results in port-list
# processing driving the rest of rule generation.
#
# By post-processing each rule generated by expand_rule(), we avoid all of that
# messiness and replace it with the following localized messiness.
#
# Because source ports are seldom specified and source port lists are rarer still,
# we only worry about the destination ports.
#
if ( $expandports && $rule =~ '^(.* --dports\s+)([^ ]+)(.*)$' ) {
#
# Rule has a --dports specification
#
my ($first, $ports, $rest) = ( $1, $2, $3 );
if ( ( $ports =~ tr/:,/:,/ ) > 15 ) {
#
# More than 15 ports specified
#
my @ports = split '([,:])', $ports;
while ( @ports ) {
my $count = 0;
my $newports = '';
while ( @ports && $count < 15 ) {
my ($port, $separator) = ( shift @ports, shift @ports );
$separator ||= '';
if ( ++$count == 15 ) {
if ( $separator eq ':' ) {
unshift @ports, $port, ':';
chop $newports;
last;
} else {
$newports .= $port;
}
} else {
$newports .= "${port}${separator}";
}
}
push_rule ( $chainref, join( '', $first, $newports, $rest ) );
}
} else {
push_rule ( $chainref, $rule );
}
} else {
push_rule ( $chainref, $rule );
}
}
#
# Add a jump from the chain represented by the reference in the first argument to
# the target in the second argument. The optional third argument specifies any
# matches to be included in the rule and must end with a space character if it is non-null.
#
sub add_jump( $$;$ ) {
my ( $fromref, $to, $predicate ) = @_;
$predicate |= '';
my $toref;
#
# The second argument may be a scalar (chain name or builtin target) or a chain reference
#
if ( reftype $to ) {
$toref = $to;
$to = $toref->{name};
} else {
#
# Ensure that we have the chain unless it is a builtin like 'ACCEPT'
#
$toref = ensure_chain( $fromref->{table} , $to ) unless ( $targets{$to} || 0 ) & STANDARD;
}
#
# If the destination is a chain, mark it referenced
#
$toref->{referenced} = 1 if $toref;
add_rule ($fromref, join( '', $predicate, "-j $to" ) );
}
#
# Insert a rule into a chain. Arguments are:
#
# Chain reference , Rule Number, Rule
#
sub insert_rule($$$)
{
my ($chainref, $number, $rule) = @_;
fatal_error 'Internal Error in insert_rule()' if $chainref->{cmdlevel};
$rule .= "-m comment --comment \"$comment\"" if $comment;
splice( @{$chainref->{rules}}, $number - 1, 0, join( ' ', '-A', $chainref->{name}, $rule ) );
$iprangematch = 0;
$chainref->{referenced} = 1;
}
#
# Move the rules from one chain to another
#
# The rules generated by interface options are added to the interfaces's input chain and
# forward chain. Shorewall::Rules::generate_matrix() may decide to move those rules to
# a zone-oriented chain, hence this function.
#
# The source chain must not have any run-time code included in its rules.
#
sub move_rules( $$ ) {
my ($chain1, $chain2 ) = @_;
if ( $chain1->{referenced} ) {
my @rules = @{$chain1->{rules}};
for ( @rules ) {
fatal_error "Internal Error in move_rules()" unless /^-A/;
s/ $chain1->{name} / $chain2->{name} /;
}
splice @{$chain2->{rules}}, 0, 0, @rules;
$chain2->{referenced} = 1;
$chain1->{referenced} = 0;
$chain1->{rules} = [];
}
}
#
# Form the name of a chain.
#
sub chain_base($) {
my $chain = $_[0];
$chain =~ s/^@/at_/;
$chain =~ tr/[.\-%@]/_/;
$chain =~ s/\+$//;
$chain;
}
sub chain_base_cond($) {
$config{DYNAMIC_ZONES} ? chain_base($_[0]) : $_[0];
}
#
# Forward Chain for an interface
#
sub forward_chain($)
{
chain_base_cond($_[0]) . '_fwd';
}
#
# Forward Chain for a zone
#
sub zone_forward_chain($) {
chain_base($_[0]) . '_frwd';
}
#
# Returns true if we're to use the interface's forward chain
#
sub use_forward_chain($) {
my $interface = $_[0];
my $interfaceref = find_interface($interface);
#
# We must use the interfaces's chain if the interface is associated with multiple zone nets
#
$interfaceref->{nets} > 1;
}
#
# Input Chain for an interface
#
sub input_chain($)
{
chain_base_cond($_[0]) . '_in';
}
#
# Input Chain for a zone
#
sub zone_input_chain($) {
chain_base($_[0]) . '_input';
}
#
# Returns true if we're to use the interface's input chain
#
sub use_input_chain($) {
my $interface = $_[0];
my $interfaceref = find_interface($interface);
my $nets = $interfaceref->{nets};
#
# We must use the interfaces's chain if the interface is associated with multiple zone nets
#
return 1 if $nets > 1;
#
# Don't need it if it isn't associated with any zone
#
return 0 unless $nets;
#
# Interface associated with a single zone -- use the zone's input chain if it has one
#
my $chainref = $filter_table->{zone_input_chain $interfaceref->{zone}};
return 0 if $chainref;
#
# Use the '<zone>2fw' chain if it is referenced.
#
$chainref = $filter_table->{join( '' , $interfaceref->{zone} , '2' , firewall_zone )};
! $chainref->{referenced};
}
#
# Output Chain for an interface
#
sub output_chain($)
{
chain_base_cond($_[0]) . '_out';
}
#
# Output Chain for a zone
#
sub zone_output_chain($) {
chain_base($_[0]) . '_output';
}
#
# Returns true if we're to use the interface's output chain
#
sub use_output_chain($) {
my $interface = $_[0];
my $interfaceref = find_interface($interface);
my $nets = $interfaceref->{nets};
#
# We must use the interfaces's chain if the interface is associated with multiple zone nets
#
return 1 if $nets > 1;
#
# Don't need it if it isn't associated with any zone
#
return 0 unless $nets;
#
# Interface associated with a single zone -- use the zone's output chain if it has one
#
my $chainref = $filter_table->{zone_output_chain $interfaceref->{zone}};
return 0 if $chainref;
#
# Use the 'fw2<zone>' chain if it is referenced.
#
$chainref = $filter_table->{join( '', firewall_zone , '2', $interfaceref->{zone} )};
! $chainref->{referenced};
}
#
# Masquerade Chain for an interface
#
sub masq_chain($)
{
chain_base_cond($_[0]) . '_masq';
}
#
# Syn_flood_chain -- differs from the other _chain functions in that the argument is a chain table reference
#
sub syn_flood_chain ( $ ) {
'@' . $_[0]->{synchain};
}
#
# MAC Verification Chain for an interface
#
sub mac_chain( $ )
{
chain_base_cond($_[0]) . '_mac';
}
sub macrecent_target($)
{
$config{MACLIST_TTL} ? chain_base_cond($_[0]) . '_rec' : 'RETURN';
}
#
# Functions for creating dynamic zone rules
#
sub dynamic_fwd( $ )
{
chain_base_cond($_[0]) . '_dynf';
}
sub dynamic_in( $ )
{
chain_base_cond($_[0]) . '_dyni';
}
sub dynamic_out( $ ) # $1 = interface
{
chain_base_cond($_[0]) . '_dyno';
}
sub dynamic_chains( $ ) #$1 = interface
{
my $c = chain_base_cond($_[0]);
( $c . '_dyni' , $c . '_dynf' , $c . '_dyno' );
}
sub zone_dynamic_chain( $ ) # $1 = zone
{
$_[0] . '_dyn';
}
#
# DNAT Chain from a zone
#
sub dnat_chain( $ )
{
chain_base_cond($_[0]) . '_dnat';
}
#
# SNAT Chain to an interface
#
sub snat_chain( $ )
{
chain_base_cond($_[0]) . '_snat';
}
#
# ECN Chain to an interface
#
sub ecn_chain( $ )
{
chain_base_cond($_[0]) . '_ecn';
}
#
# First chains for an interface
#
sub first_chains( $ ) #$1 = interface
{
my $c = chain_base_cond($_[0]);
( $c . '_fwd', $c . '_in' );
}
#
# Create a new chain and return a reference to it.
#
sub new_chain($$)
{
my ($table, $chain) = @_;
warning_message "Internal error in new_chain()" if $chain_table{$table}{$chain};
$chain_table{$table}{$chain} = { name => $chain,
rules => [],
table => $table,
loglevel => '',
log => 1,
cmdlevel => 0 };
}
#
# Create a chain if it doesn't exist already
#
sub ensure_chain($$)
{
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 'RELATED' ) {
finish_chain_section $chainref , 'ESTABLISHED';
}
}
$chainref->{referenced} = 1;
$chainref;
}
#
# Create an accounting chain if necessary.
#
sub ensure_accounting_chain( $ )
{
my ($chain) = @_;
my $chainref = $filter_table->{$chain};
if ( $chainref ) {
fatal_error "Non-accounting chain ($chain) used in accounting rule" if ! $chainref->{accounting};
} else {
$chainref = new_chain 'filter' , $chain unless $chainref;
$chainref->{accounting} = 1;
$chainref->{referenced} = 1;
}
$chainref;
}
sub ensure_mangle_chain($) {
my $chain = $_[0];
my $chainref = ensure_chain 'mangle', $chain;
$chainref->{referenced} = 1;
$chainref;
}
sub ensure_nat_chain($) {
my $chain = $_[0];
my $chainref = ensure_chain 'nat', $chain;
$chainref->{referenced} = 1;
$chainref;
}
#
# Add a builtin chain
#
sub new_builtin_chain($$$)
{
my ( $table, $chain, $policy ) = @_;
my $chainref = new_chain $table, $chain;
$chainref->{referenced} = 1;
$chainref->{policy} = $policy;
$chainref->{builtin} = 1;
}
sub new_standard_chain($) {
my $chainref = new_chain 'filter' ,$_[0];
$chainref->{referenced} = 1;
$chainref;
}
sub new_nat_chain($) {
my $chainref = new_chain 'nat' ,$_[0];
$chainref->{referenced} = 1;
$chainref;
}
sub new_manual_chain($) {
my $chain = $_[0];
fatal_error "Duplicate Chain Name ($chain)" if $targets{$chain} || $filter_table->{$chain};
$targets{$chain} = CHAIN;
( my $chainref = ensure_filter_chain( $chain, 0) )->{manual} = 1;
$chainref->{referenced} = 1;
$chainref;
}
sub ensure_manual_chain($) {
my $chain = $_[0];
my $chainref = $filter_table->{$chain} || new_manual_chain($chain);
fatal_error "$chain exists and is not a manual chain" unless $chainref->{manual};
$chainref;
}
#
# Add all builtin chains to the chain table
#
#
sub initialize_chain_table()
{
for my $chain qw(OUTPUT PREROUTING) {
new_builtin_chain 'raw', $chain, 'ACCEPT';
}
for my $chain qw(INPUT OUTPUT FORWARD) {
new_builtin_chain 'filter', $chain, 'DROP';
}
for my $chain qw(PREROUTING POSTROUTING OUTPUT) {
new_builtin_chain 'nat', $chain, 'ACCEPT';
}
for my $chain qw(PREROUTING INPUT OUTPUT ) {
new_builtin_chain 'mangle', $chain, 'ACCEPT';
}
if ( $capabilities{MANGLE_FORWARD} ) {
for my $chain qw( FORWARD POSTROUTING ) {
new_builtin_chain 'mangle', $chain, 'ACCEPT';
}
}
}
#
# Add ESTABLISHED,RELATED rules and synparam jumps to the passed chain
#
sub finish_chain_section ($$) {
my ($chainref, $state ) = @_;
my $chain = $chainref->{name};
my $savecomment = $comment;
$comment = '';
add_rule $chainref, "-m state --state $state -j ACCEPT" unless $config{FASTACCEPT};
if ($sections{NEW} ) {
if ( $chainref->{is_policy} ) {
if ( $chainref->{synparams} ) {
my $synchainref = ensure_chain 'filter', syn_flood_chain $chainref;
if ( $section eq 'DONE' ) {
if ( $chainref->{policy} =~ /^(ACCEPT|CONTINUE|QUEUE|NFQUEUE)/ ) {
add_rule $chainref, "-p tcp --syn -j $synchainref->{name}";
}
} else {
add_rule $chainref, "-p tcp --syn -j $synchainref->{name}";
}
}
} else {
my $policychainref = $filter_table->{$chainref->{policychain}};
if ( $policychainref->{synparams} ) {
my $synchainref = ensure_chain 'filter', syn_flood_chain $policychainref;
add_rule $chainref, "-p tcp --syn -j $synchainref->{name}";
}
}
}
$comment = $savecomment;
}
#
# Do section-end processing
#
sub finish_section ( $ ) {
my $sections = $_[0];
for my $section ( split /,/, $sections ) {
$sections{$section} = 1;
}
for my $zone ( all_zones ) {
for my $zone1 ( all_zones ) {
my $chainref = $chain_table{'filter'}{"${zone}2${zone1}"};
if ( $chainref->{referenced} ) {
finish_chain_section $chainref, $sections;
}
}
}
}
#
# Helper for set_mss
#
sub set_mss1( $$ ) {
my ( $chain, $mss ) = @_;
my $chainref = ensure_chain 'filter', $chain;
if ( $chainref->{policy} ne 'NONE' ) {
my $match = $capabilities{TCPMSS_MATCH} ? "-m tcpmss --mss $mss: " : '';
insert_rule $chainref, 1, "-p tcp --tcp-flags SYN,RST SYN ${match}-j TCPMSS --set-mss $mss"
}
}
#
# Set up rules to set MSS to and/or from zone "$zone"
#
sub set_mss( $$$ ) {
my ( $zone, $mss, $direction) = @_;
for my $z ( all_zones ) {
if ( $direction eq '_in' ) {
set_mss1 "${zone}2${z}" , $mss;
} elsif ( $direction eq '_out' ) {
set_mss1 "${z}2${zone}", $mss;
} else {
set_mss1 "${z}2${zone}", $mss;
set_mss1 "${zone}2${z}", $mss;
}
}
}
#
# Interate over non-firewall zones and interfaces with 'mss=' setting adding TCPMSS rules as appropriate.
#
sub setup_zone_mss() {
for my $zone ( all_zones ) {
my $zoneref = find_zone( $zone );
set_mss( $zone, $zoneref->{options}{in_out}{mss}, '' ) if $zoneref->{options}{in_out}{mss};
set_mss( $zone, $zoneref->{options}{in}{mss}, '_in' ) if $zoneref->{options}{in}{mss};
set_mss( $zone, $zoneref->{options}{out}{mss}, '_out' ) if $zoneref->{options}{out}{mss};
}
}
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 ) = @_;
#
# Return the number of ports represented by the passed list
#
sub port_count( $ ) {
( $_[0] =~ tr/,:/,:/ ) + 1;
}
my $output = '';
$proto = '' if $proto eq '-';
$ports = '' if $ports eq '-';
$sports = '' if $sports eq '-';
if ( $proto ne '' ) {
my $synonly = ( $proto =~ s/:syn$//i );
my $protonum = resolve_proto $proto;
if ( defined $protonum ) {
#
# Protocol is numeric and <= 65535 or is defined in /etc/protocols or NSS equivalent
#
my $pname = proto_name( $proto = $protonum );
#
# $proto now contains the protocol number and $pname contains the canonical name of the protocol
#
unless ( $synonly ) {
$output = "-p $proto ";
} else {
fatal_error '":syn" is only allowed with tcp' unless $proto == TCP;
$output = "-p $proto --syn ";
}
PROTO:
{
if ( $proto == TCP || $proto == UDP || $proto == SCTP ) {
my $multiport = 0;
if ( $ports ne '' ) {
if ( $ports =~ tr/,/,/ > 0 || $sports =~ tr/,/,/ > 0 ) {
fatal_error "Port lists require Multiport support in your kernel/iptables" unless $capabilities{MULTIPORT};
fatal_error "Multiple ports not supported with SCTP" if $proto == SCTP;
$ports = validate_port_list $pname , $ports;
$output .= "-m multiport --dports $ports ";
$multiport = 1;
} else {
$ports = validate_portpair $pname , $ports;
$output .= "--dport $ports ";
}
} else {
$multiport = ( ( $sports =~ tr/,/,/ ) > 0 );
}
if ( $sports ne '' ) {
if ( $multiport ) {
fatal_error "Too many entries in SOURCE PORT(S) list" if port_count( $sports ) > 15;
$sports = validate_port_list $pname , $sports;
$output .= "-m multiport --sports $sports ";
} else {
$sports = validate_portpair $pname , $sports;
$output .= "--sport $sports ";
}
}
last PROTO; }
if ( $proto == ICMP ) {
if ( $ports ne '' ) {
fatal_error 'Multiple ICMP types are not permitted' if $ports =~ /,/;
$ports = validate_icmp $ports;
$output .= "--icmp-type $ports ";
}
fatal_error 'SOURCE PORT(S) not permitted with ICMP' if $sports ne '';
last PROTO; }
fatal_error "SOURCE/DEST PORT(S) not allowed with PROTO $pname" if $ports ne '' || $sports ne '';
} # PROTO
} else {
fatal_error '":syn" is only allowed with tcp' if $synonly;
if ( $proto =~ /^(ipp2p(:(tcp|udp|all))?)$/i ) {
my $p = $2 ? lc $3 : 'tcp';
require_capability( 'IPP2P_MATCH' , "PROTO = $proto" , 's' );
$proto = '-p ' . proto_name($p) . ' ';
$ports = 'ipp2p' unless $ports;
$output .= "${proto}-m ipp2p --$ports ";
} else {
fatal_error "Invalid/Unknown protocol ($proto)"
}
}
} else {
#
# No protocol
#
fatal_error "SOURCE/DEST PORT(S) not allowed without PROTO" if $ports ne '' || $sports ne '';
}
$output;
}
sub mac_match( $ ) {
my $mac = $_[0];
$mac =~ s/^(!?)~//;
my $invert = ( $1 ? '! ' : '');
$mac =~ tr/-/:/;
fatal_error "Invalid MAC address ($mac)" unless $mac =~ /^(?:[0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}$/;
"--match mac --mac-source ${invert}$mac ";
}
#
# Mark validatation functions
#
sub verify_mark( $ ) {
my $mark = $_[0];
my $limit = $config{HIGH_ROUTE_MARKS} ? 0xFFFF : 0xFF;
my $value = numeric_value( $mark );
fatal_error "Invalid Mark or Mask value ($mark)"
unless defined( $value ) && $value <= $limit;
fatal_error "Invalid High Mark or Mask value ($mark)"
if ( $value > 0xFF && $value & 0xFF );
}
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) = @_;
my $originaltestval = $testval;
return '' unless defined $testval and $testval ne '-';
$mask = '' unless defined $mask;
my $invert = $testval =~ s/^!// ? '! ' : '';
my $match = $testval =~ s/:C$// ? "-m connmark ${invert}--mark" : "-m mark ${invert}--mark";
fatal_error "Invalid MARK value ($originaltestval)" if $testval eq '/';
validate_mark $testval;
$testval = join( '/', $testval, in_hex($mask) ) unless ( $testval =~ '/' );
"$match $testval ";
}
my %norate = ( DROP => 1, REJECT => 1 );
#
# Create a "-m limit" match for the passed LIMIT/BURST
#
sub do_ratelimit( $$ ) {
my ( $rate, $action ) = @_;
return '' unless $rate and $rate ne '-';
fatal_error "Rate Limiting not available with $action" if $norate{$action};
if ( $rate =~ /^(\d+(\/(sec|min|hour|day))?):(\d+)$/ ) {
"-m limit --limit $1 --limit-burst $4 ";
} elsif ( $rate =~ /^(\d+)(\/(sec|min|hour|day))?$/ ) {
"-m limit --limit $rate ";
} else {
fatal_error "Invalid rate ($rate)";
}
}
#
# Create a "-m owner" match for the passed USER/GROUP
#
sub do_user( $ ) {
my $user = $_[0];
my $rule = '-m owner ';
return '' unless defined $user and $user ne '-';
if ( $user =~ /^(!)?(.*)\+(.*)$/ ) {
$rule .= "! --cmd-owner $2 " if defined $2 && $2 ne '';
$user = "!$1";
} elsif ( $user =~ /^(.*)\+(.*)$/ ) {
$rule .= "--cmd-owner $2 " if defined $2 && $2 ne '';
$user = $1;
}
if ( $user =~ /^!(.*):(.*)$/ ) {
$rule .= "! --uid-owner $1 " if defined $1 && $1 ne '';
$rule .= "! --gid-owner $2 " if defined $2 && $2 ne '';
} elsif ( $user =~ /^(.*):(.*)$/ ) {
$rule .= "--uid-owner $1 " if defined $1 && $1 ne '';
$rule .= "--gid-owner $2 " if defined $2 && $2 ne '';
} elsif ( $user =~ /^!(.*)$/ ) {
fatal_error "Invalid USER/GROUP (!)" if $1 eq '';
$rule .= "! --uid-owner $1 ";
} 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 " : '';
}
my %dir = ( O => 'original' ,
R => 'reply' ,
B => 'both' );
my %mode = ( P => 'packets' ,
B => 'bytes' ,
A => 'avgpkt' );
#
# Create a "-m connbytes" match for the passed argument
#
sub do_connbytes( $ ) {
my $connbytes = $_[0];
return '' if $connbytes eq '-';
# 1 2 3 5 6
fatal_error "Invalid CONNBYTES ($connbytes)" unless $connbytes =~ /^(!)? (\d+): (\d+)? ((:[ORB]) (:[PBA])?)?$/x;
my $invert = $1 || ''; $invert = '! ' if $invert;
my $min = $2; $min = 0 unless defined $min;
my $max = $3 || ''; fatal_error "Invalid byte range ($min:$max)" if $max ne '' and $min > $max;
my $dir = $5 || 'B';
my $mode = $6 || 'B';
$dir =~ s/://;
$mode =~ s/://;
"${invert}-m connbytes --connbytes $min:$max --connbytes-dir $dir{$dir} --connbytes-mode $mode{$mode} ";
}
#
# Match Source Interface
#
sub match_source_dev( $ ) {
my $interface = shift;
my $interfaceref = known_interface( $interface );
if ( $interfaceref && $interfaceref->{options}{port} ) {
"-i $interfaceref->{bridge} -m physdev --physdev-in $interface ";
} else {
"-i $interface ";
}
}
#
# Match Dest device
#
sub match_dest_dev( $ ) {
my $interface = shift;
my $interfaceref = known_interface( $interface );
if ( $interfaceref && $interfaceref->{options}{port} ) {
if ( $capabilities{PHYSDEV_BRIDGE} ) {
"-o $interfaceref->{bridge} -m physdev --physdev-is-bridged --physdev-out $interface ";
} else {
"-o $interfaceref->{bridge} -m physdev --physdev-out $interface ";
}
} else {
"-o $interface ";
}
}
#
# 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 unless $capabilities{KLUDGEFREE};
}
$match;
}
#
# Get set flags (ipsets).
#
sub get_set_flags( $$ ) {
my ( $setname, $option ) = @_;
my $options = $option;
if ( $setname =~ /^(.*)\[([1-6])\]$/ ) {
$setname = $1;
my $count = $2;
$options .= ",$option" while --$count > 0;
} elsif ( $setname =~ /^(.*)\[(.*)\]$/ ) {
$setname = $1;
$options = $2;
}
$setname =~ s/^\+//;
fatal_error "Invalid ipset name ($setname)" unless $setname =~ /^[a-zA-Z]\w*/;
"--set $setname $options "
}
#
# Match a Source. Handles IP addresses and ranges and MAC addresses
#
sub match_source_net( $;$ ) {
my ( $net, $restriction) = @_;
$restriction |= NO_RESTRICT;
if ( $net =~ /^(!?)(\d+\.\d+\.\d+\.\d+)-(\d+\.\d+\.\d+\.\d+)$/ ) {
my ($addr1, $addr2) = ( $2, $3 );
$net =~ s/!// if my $invert = $1 ? '! ' : '';
validate_range $addr1, $addr2;
iprange_match . "${invert}--src-range $net ";
} elsif ( $net =~ /^!?~/ ) {
fatal_error "MAC address cannot be used in this context" if $restriction >= OUTPUT_RESTRICT;
mac_match $net;
} elsif ( $net =~ /^(!?)\+/ ) {
require_capability( 'IPSET_MATCH' , 'ipset names in Shorewall configuration files' , '' );
join( '', '-m set ', $1 ? '! ' : '', get_set_flags( $net, 'src' ) );
} elsif ( $net =~ s/^!// ) {
validate_net $net, 1;
"-s ! $net ";
} else {
validate_net $net, 1;
$net eq ALLIPv4 ? '' : "-s $net ";
}
}
#
# Match a Source. Currently only handles IP addresses and ranges
#
sub match_dest_net( $ ) {
my $net = $_[0];
if ( $net =~ /^(!?)(\d+\.\d+\.\d+\.\d+)-(\d+\.\d+\.\d+\.\d+)$/ ) {
my ($addr1, $addr2) = ( $2, $3 );
$net =~ s/!// if my $invert = $1 ? '! ' : '';
validate_range $addr1, $addr2;
iprange_match . "${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/!//;
validate_net $net, 1;
"-d ! $net ";
} else {
validate_net $net, 1;
$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 =~ s/^!// ) {
validate_net $net, 1;
"-m conntrack --ctorigdst ! $net ";
} else {
validate_net $net, 1;
$net eq ALLIPv4 ? '' : "-m conntrack --ctorigdst $net ";
}
}
#
# Match Source IPSEC
#
sub match_ipsec_in( $$ ) {
my ( $zone , $hostref ) = @_;
my $match = '-m policy --dir in --pol ';
my $zoneref = find_zone( $zone );
my $optionsref = $zoneref->{options};
if ( $zoneref->{type} eq 'ipsec4' ) {
$match .= "ipsec $optionsref->{in_out}{ipsec}$optionsref->{in}{ipsec}";
} elsif ( $capabilities{POLICY_MATCH} ) {
$match .= "$hostref->{ipsec} $optionsref->{in_out}{ipsec}$optionsref->{in}{ipsec}";
} else {
'';
}
}
#
# Match Dest IPSEC
#
sub match_ipsec_out( $$ ) {
my ( $zone , $hostref ) = @_;
my $match = '-m policy --dir out --pol ';
my $zoneref = find_zone( $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( $$$$$$$$ ) {
my ($level, $chainref, $chain, $disposition, $limit, $tag, $command, $predicates ) = @_;
my $prefix = '';
$level = validate_level $level; # Do this here again because this function can be called directly from user exits.
return 1 if $level eq '';
$predicates .= ' ' if $predicates && substr( $predicates, -1, 1 ) ne ' ';
unless ( $predicates =~ /-m limit / ) {
$limit = $globals{LOGLIMIT} unless $limit && $limit ne '-';
$predicates .= $limit if $limit;
}
if ( $config{LOGFORMAT} =~ /^\s*$/ ) {
if ( $level =~ '^ULOG' ) {
$prefix = "-j $level ";
} elsif ( $level =~ /^NFLOG/ ) {
$prefix = "-j $level ";
} else {
$prefix = "-j LOG $globals{LOGPARMS}--log-level $level ";
}
} else {
if ( $tag ) {
if ( $config{LOGTAGONLY} ) {
$chain = $tag;
$tag = '';
} else {
$tag .= ' ';
}
} else {
$tag = '' unless defined $tag;
}
$disposition =~ s/\s+.*//;
if ( $globals{LOGRULENUMBERS} ) {
$prefix = (sprintf $config{LOGFORMAT} , $chain , $chainref->{log}++, $disposition ) . $tag;
} else {
$prefix = (sprintf $config{LOGFORMAT} , $chain , $disposition) . $tag;
}
if ( length $prefix > 29 ) {
$prefix = substr( $prefix, 0, 28 ) . ' ';
warning_message "Log Prefix shortened to \"$prefix\"";
}
if ( $level =~ '^ULOG' ) {
$prefix = "-j $level --ulog-prefix \"$prefix\" ";
} elsif ( $level =~ /^NFLOG/ ) {
$prefix = "-j $level --nflog-prefix \"$prefix\" ";
} else {
$prefix = "-j LOG $globals{LOGPARMS}--log-level $level --log-prefix \"$prefix\" ";
}
}
if ( $command eq 'add' ) {
add_rule ( $chainref, $predicates . $prefix , 1 );
} else {
insert_rule ( $chainref , 1 , $predicates . $prefix );
}
}
sub log_rule( $$$$ ) {
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_list $_[0], 'host';
return @input unless $_[0] =~ /\[/;
my @result;
while ( @input ) {
my $element = shift @input;
if ( $element =~ /\[/ ) {
while ( substr( $element, -1, 1 ) ne ']' ) {
last unless @input;
$element .= ( ',' . shift @input );
}
fatal_error "Invalid Host List ($_[0])" unless substr( $element, -1, 1 ) eq ']';
}
push @result, $element;
}
@result;
}
#
# Returns the name of the shell variable holding the first address of the passed interface
#
sub interface_address( $ ) {
my $variable = chain_base( $_[0] ) . '_address';
uc $variable;
}
#
# 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 );
my $function = interface_is_optional( $interface ) ? 'find_first_interface_address_if_any' : 'find_first_interface_address';
$interfaceaddr{$interface} = "$variable=\$($function $interface)\n";
"\$$variable";
}
#
# Returns the name of the shell variable holding the broadcast addresses of the passed interface
#
sub interface_bcasts( $ ) {
my $variable = chain_base( $_[0] ) . '_bcasts';
uc $variable;
}
#
# Record that the ruleset requires the broadcast addresses on the passed interface
#
sub get_interface_bcasts ( $ ) {
my ( $interface ) = $_[0];
my $variable = interface_bcasts( $interface );
$interfacebcasts{$interface} = qq($variable="\$(get_interface_bcasts $interface) 255.255.255.255");
"\$$variable";
}
#
# Returns the name of the shell variable holding the gateway through the passed interface
#
sub interface_gateway( $ ) {
my $variable = chain_base( $_[0] ) . '_gateway';
uc $variable;
}
#
# Record that the ruleset requires the gateway address on the passed interface
#
sub get_interface_gateway ( $ ) {
my ( $interface ) = $_[0];
my $variable = interface_gateway( $interface );
if ( interface_is_optional $interface ) {
$interfacegateways{$interface} = qq([ -n "\$$variable" ] || $variable=\$(detect_gateway $interface)\n);
} else {
$interfacegateways{$interface} = qq([ -n "\$$variable" ] || $variable=\$(detect_gateway $interface)
[ -n "\$$variable" ] || fatal_error "Unable to detect the gateway through interface $interface"
);
}
"\$$variable";
}
#
# Returns the name of the shell variable holding the addresses of the passed interface
#
sub interface_addresses( $ ) {
my $variable = chain_base( $_[0] ) . '_addresses';
uc $variable;
}
#
# Record that the ruleset requires the IP addresses on the passed interface
#
sub get_interface_addresses ( $ ) {
my ( $interface ) = $_[0];
my $variable = interface_addresses( $interface );
if ( interface_is_optional $interface ) {
$interfaceaddrs{$interface} = qq($variable=\$(find_interface_addresses $interface)\n);
} else {
$interfaceaddrs{$interface} = qq($variable=\$(find_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( $ ) {
my $variable = chain_base( $_[0] ) . '_networks';
uc $variable;
}
#
# Record that the ruleset requires the networks routed out of the passed interface
#
sub get_interface_nets ( $ ) {
my ( $interface ) = $_[0];
my $variable = interface_nets( $interface );
if ( interface_is_optional $interface ) {
$interfacenets{$interface} = qq($variable=\$(get_routed_networks $interface)\n);
} else {
$interfacenets{$interface} = qq($variable=\$(get_routed_networks $interface)
[ -n "\$$variable" ] || fatal_error "Unable to determine the routes through interface \\"$interface\\""
);
}
"\$$variable";
}
#
# Returns the name of the shell variable holding the MAC address of the gateway for the passed provider out of the passed interface
#
sub interface_mac( $$ ) {
my $variable = join( '_' , chain_base( $_[0] ) , chain_base( $_[1] ) , 'mac' );
uc $variable;
}
#
# Record the fact that the ruleset requires MAC address of the passed gateway IP routed out of the passed interface for the passed provider number
#
sub get_interface_mac( $$$ ) {
my ( $ipaddr, $interface , $table ) = @_;
my $variable = interface_mac( $interface , $table );
if ( interface_is_optional $interface ) {
$interfacemacs{$table} = qq($variable=\$(find_mac $ipaddr $interface)\n);
} else {
$interfacemacs{$table} = qq($variable=\$(find_mac $ipaddr $interface)
[ -n "\$$variable" ] || fatal_error "Unable to determine the MAC address of $ipaddr through interface \\"$interface\\""
);
}
"\$$variable";
}
#
# This function provides a uniform way to generate rules (something the original Shorewall sorely needed).
#
# Returns the destination interface specified in the rule, if any.
#
sub expand_rule( $$$$$$$$$$ )
{
my ($chainref , # Chain
$restriction, # Determines what to do with interface names in the SOURCE or DEST
$rule, # Caller's matches that don't depend on the SOURCE, DEST and ORIGINAL DEST
$source, # SOURCE
$dest, # DEST
$origdest, # ORIGINAL DEST
$target, # Target ('-j' part of the rule)
$loglevel , # Log level (and tag)
$disposition, # Primative part of the target (RETURN, ACCEPT, ...)
$exceptionrule # Caller's matches used in exclusion case
) = @_;
my ($iiface, $diface, $inets, $dnets, $iexcl, $dexcl, $onets , $oexcl );
my $chain = $chainref->{name};
our @ends = ();
#
# In the generated rules, we sometimes need run-time loops or conditional blocks. This function is used
# to define such a loop or block.
#
# $chainref = Reference to the chain
# $command = The shell command that begins the loop or conditional
# $end = The shell keyword ('done' or 'fi') that ends the loop or conditional
#
# All open loops and conditionals are closed just before expand_rule() exits
#
sub push_command( $$$ ) {
my ( $chainref, $command, $end ) = @_;
add_command $chainref, $command;
incr_cmd_level $chainref;
push @ends, $end;
}
#
# Handle Log Level
#
my $logtag;
if ( $loglevel ne '' ) {
( $loglevel, $logtag, my $remainder ) = split( /:/, $loglevel, 3 );
fatal_error "Invalid log tag" if defined $remainder;
if ( $loglevel =~ /^none!?$/i ) {
return if $disposition eq 'LOG';
$loglevel = $logtag = '';
} else {
$loglevel = validate_level( $loglevel );
$logtag = '' unless defined $logtag;
}
} elsif ( $disposition eq 'LOG' ) {
fatal_error "LOG requires a level";
}
#
# Mark Target as referenced, if it's a chain
#
if ( $disposition ) {
my $targetref = $chain_table{$chainref->{table}}{$disposition};
$targetref->{referenced} = 1 if $targetref;
}
#
# 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 Interface, if any
#
if ( $iiface ) {
fatal_error "Unknown Interface ($iiface)" unless known_interface $iiface;
if ( $restriction & POSTROUTE_RESTRICT ) {
#
# An interface in the SOURCE column of a masq file
#
fatal_error "Bridge ports may not appear in the SOURCE column of this file" if port_to_bridge( $iiface );
my $networks = get_interface_nets ( $iiface );
push_command $chainref, join( '', 'for source in ', $networks, '; do' ), 'done';
$rule .= '-s $source ';
} else {
fatal_error "Source Interface ($iiface) not allowed when the source zone is the firewall zone" if $restriction & OUTPUT_RESTRICT;
$rule .= match_source_dev( $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 = "";
my $optional;
for my $interface ( @interfaces ) {
$optional++ if interface_is_optional $interface;
$list = join( ' ', $list , get_interface_address( $interface ) );
}
push_command( $chainref , "for address in $list; do" , 'done' );
push_command( $chainref , 'if [ $address != 0.0.0.0 ]; then' , 'fi' ) if $optional;
$rule .= '-d $address ';
} else {
my $interface = $interfaces[0];
my $variable = get_interface_address( $interface );
push_command( $chainref , "if [ $variable != 0.0.0.0 ]; then" , 'fi') if interface_is_optional( $interface );
$rule .= "-d $variable ";
}
$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)" unless known_interface $diface;
if ( $restriction & PREROUTE_RESTRICT ) {
#
# ADDRESS 'detect' in the masq file.
#
fatal_error "Bridge port ($diface) not allowed" if port_to_bridge( $diface );
push_command( $chainref , 'for dest in ' . get_interface_addresses( $diface) . '; do', 'done' );
$rule .= '-d $dest ';
} else {
fatal_error "Bridge Port ($diface) not allowed in OUTPUT or POSTROUTING rules" if ( $restriction & ( POSTROUTE_RESTRICT + OUTPUT_RESTRICT ) ) && port_to_bridge( $diface );
fatal_error "Destination Interface ($diface) not allowed when the destination zone is the firewall zone" if $restriction & INPUT_RESTRICT;
if ( $iiface ) {
my $bridge = port_to_bridge( $diface );
fatal_error "Source interface ($iiface) is not a port on the same bridge as the destination interface ( $diface )" if $bridge && $bridge ne source_port_to_bridge( $iiface );
}
$rule .= match_dest_dev( $diface );
}
} else {
$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 = "";
my $optional;
for my $interface ( @interfaces ) {
$optional++ if interface_is_optional $interface;
$list = join( ' ', $list , get_interface_address( $interface ) );
}
push_command( $chainref , "for address in $list; do" , 'done' );
push_command( $chainref , 'if [ $address != 0.0.0.0 ]; then' , 'fi' ) if $optional;
$rule .= '-m conntrack --ctorigdst $address ';
} else {
my $interface = $interfaces[0];
my $variable = get_interface_address( $interface );
push_command( $chainref , "if [ $variable != 0.0.0.0 ]; then" , 'fi' ) if interface_is_optional( $interface );
$rule .= "-m conntrack --ctorigdst $variable ";
}
$origdest = '';
} else {
fatal_error "Invalid ORIGINAL DEST" if $origdest =~ /^([^!]+)?,!([^!]+)$/ || $origdest =~ /.*!.*!/;
if ( $origdest =~ /^([^!]+)?!([^!]+)$/ ) {
#
# Exclusion
#
$onets = $1;
$oexcl = $2;
} else {
$oexcl = '';
$onets = $origdest;
}
unless ( $onets ) {
my @oexcl = mysplit $oexcl;
if ( @oexcl == 1 ) {
$rule .= match_orig_dest( "!$oexcl" );
$oexcl = '';
}
}
}
} else {
$oexcl = '';
}
#
# Determine if there is Source Exclusion
#
if ( $inets ) {
fatal_error "Invalid SOURCE" if $inets =~ /^([^!]+)?,!([^!]+)$/ || $inets =~ /.*!.*!/;
if ( $inets =~ /^([^!]+)?!([^!]+)$/ ) {
$inets = $1;
$iexcl = $2;
} else {
$iexcl = '';
}
unless ( $inets || ( $iiface && $restriction & POSTROUTE_RESTRICT ) ) {
my @iexcl = mysplit $iexcl;
if ( @iexcl == 1 ) {
$rule .= match_source_net "!$iexcl" , $restriction;
$iexcl = '';
}
}
} else {
$iexcl = '';
}
#
# Determine if there is Destination Exclusion
#
if ( $dnets ) {
fatal_error "Invalid DEST" if $dnets =~ /^([^!]+)?,!([^!]+)$/ || $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;
fatal_error "Input interface may not be specified with a source IP address in the POSTROUTING chain" if $restriction == POSTROUTE_RESTRICT && $iiface && $inets ne ALLIPv4;
fatal_error "Output interface may not be specified with a destination IP address in the PREROUTING chain" if $restriction == PREROUTE_RESTRICT && $diface && $dnets ne ALLIPv4;
if ( $iexcl || $dexcl || $oexcl ) {
#
# We have non-trivial exclusion -- need to create an exclusion chain
#
fatal_error "Exclusion is not possible in ACCEPT+/CONTINUE/NONAT rules" if $disposition eq 'RETURN';
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 ) {
for my $dnet ( mysplit $dnets ) {
#
# We evaluate the source net match in the inner loop to accomodate systems without $capabilities{KLUDGEFREE}
#
add_rule( $chainref, join( '', $rule, match_source_net( $inet, $restriction ), match_dest_net( $dnet ), $onet, "-j $echain" ), 1 );
}
}
}
#
# Create the Exclusion Chain
#
my $echainref = new_chain $chainref->{table}, $echain;
#
# Generate RETURNs for each exclusion
#
add_rule $echainref, ( match_source_net $_ , $restriction ) . '-j RETURN' for ( mysplit $iexcl );
add_rule $echainref, ( match_dest_net $_ ) . '-j RETURN' for ( mysplit $dexcl );
add_rule $echainref, ( match_orig_dest $_ ) . '-j RETURN' for ( mysplit $oexcl );
#
# Log rule
#
log_rule_limit $loglevel , $echainref , $chain, $disposition , '', $logtag , 'add' , '' if $loglevel;
#
# Generate Final Rule
#
add_rule( $echainref, $exceptionrule . $target, 1 ) unless $disposition eq 'LOG';
} else {
#
# No exclusions
#
for my $onet ( mysplit $onets ) {
$onet = match_orig_dest $onet;
for my $inet ( mysplit $inets ) {
#
# We defer evaluating the source net match to accomodate system without $capabilities{KLUDGEFREE}
#
for my $dnet ( mysplit $dnets ) {
if ( $loglevel ne '' ) {
log_rule_limit
$loglevel ,
$chainref ,
$chain,
$disposition ,
'' ,
$logtag ,
'add' ,
join( '', $rule, match_source_net( $inet , $restriction ) , match_dest_net( $dnet ), $onet );
}
unless ( $disposition eq 'LOG' ) {
add_rule(
$chainref,
join( '', $rule, match_source_net ($inet , $restriction ), match_dest_net( $dnet ), $onet, $target ) ,
1 );
}
}
}
}
}
while ( @ends ) {
decr_cmd_level $chainref;
add_command $chainref, pop @ends;
}
$diface;
}
#
# 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;
}
}
sub emit_comment() {
emit ( '#',
'# Establish the values of shell variables used in the following function calls',
'#' );
our $emitted_comment = 1;
}
sub emit_test() {
emit ( 'if [ "$COMMAND" != restore ]; then' ,
'' );
push_indent;
our $emitted_test = 1;
}
#
# Generate setting of global variables
#
sub set_global_variables() {
our ( $emitted_comment, $emitted_test ) = (0, 0);
for ( values %interfaceaddr ) {
emit_comment unless $emitted_comment;
emit $_;
}
for ( values %interfacegateways ) {
emit_comment unless $emitted_comment;
emit $_;
}
for ( values %interfacemacs ) {
emit_comment unless $emitted_comment;
emit $_;
}
for ( values %interfaceaddrs ) {
emit_comment unless $emitted_comment;
emit_test unless $emitted_test;
emit $_;
}
for ( values %interfacenets ) {
emit_comment unless $emitted_comment;
emit_test unless $emitted_test;
emit $_;
}
unless ( $capabilities{ADDRTYPE} ) {
emit_comment unless $emitted_comment;
emit_test unless $emitted_test;
emit 'ALL_BCASTS="$(get_all_bcasts) 255.255.255.255"';
for ( values %interfacebcasts ) {
emit $_;
}
}
pop_indent, emit "fi\n" if $emitted_test;
}
#
# What follows is the code that generates the input to iptables-restore
#
# We always write the iptables-restore input into a file then pass the
# file to iptables-restore. That way, if things go wrong, the user (and Shorewall support)
# has (have) something to look at to determine the error
#
# We may have to generate part of the input at run-time. The rules array in each chain
# table entry may contain rules (begin with '-A') or shell source. We alternate between
# writing the rules ('-A') into the temporary file to be bassed to iptables-restore
# (CAT_MODE) and and writing shell source into the generated script (CMD_MODE).
#
# The following two functions are responsible for the mode transitions.
#
sub enter_cat_mode() {
emit '';
emit 'cat >&3 << __EOF__';
$mode = CAT_MODE;
}
sub enter_cmd_mode() {
emit_unindented "__EOF__\n" if $mode == CAT_MODE;
$mode = CMD_MODE;
}
#
# Emits the passed rule (input to iptables-restore) or command
#
sub emitr( $ ) {
my $rule = $_[0];
if ( $rule && substr( $rule, 0, 2 ) eq '-A' ) {
#
# A rule
#
enter_cat_mode unless $mode == CAT_MODE;
emit_unindented $rule;
} else {
#
# A command
#
enter_cmd_mode unless $mode == CMD_MODE;
emit $rule;
}
}
#
# Generate the netfilter input
#
sub create_netfilter_load() {
my @table_list;
push @table_list, 'raw' if $capabilities{RAW_TABLE};
push @table_list, 'nat' if $capabilities{NAT_ENABLED};
push @table_list, 'mangle' if $capabilities{MANGLE_ENABLED} && $config{MANGLE_ENABLED};
push @table_list, 'filter';
$mode = NULL_MODE;
emit ( 'setup_netfilter()',
'{'
);
push_indent;
save_progress_message "Preparing iptables-restore input...";
emit '';
emit 'exec 3>${VARDIR}/.iptables-restore-input';
enter_cat_mode;
for my $table ( @table_list ) {
emit_unindented "*$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 ) {
fatal_error "Internal error in create_netfilter_load()" if $chainref->{cmdlevel};
emit_unindented ":$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} ) {
fatal_error "Internal error in create_netfilter_load()" if $chainref->{cmdlevel};
emit_unindented ":$chainref->{name} - [0:0]";
push @chains, $chainref;
}
}
#
# Then emit the rules
#
for my $chainref ( @chains ) {
emitr $_ for ( @{$chainref->{rules}} );
}
#
# Commit the changes to the table
#
enter_cat_mode unless $mode == CAT_MODE;
emit_unindented 'COMMIT';
}
enter_cmd_mode;
#
# Now generate the actual iptables-restore command
#
emit( 'exec 3>&-',
'',
'[ -n "$DEBUG" ] && command=debug_restore_input || command=$IPTABLES_RESTORE',
'',
'progress_message2 "Running $command..."',
'',
'cat ${VARDIR}/.iptables-restore-input | $command # Use this nonsensical form to appease SELinux',
'if [ $? != 0 ]; then',
' fatal_error "iptables-restore Failed. Input is in ${VARDIR}/.iptables-restore-input"',
"fi\n"
);
pop_indent;
emit "}\n";
}
#
# Generate the netfilter input for refreshing a list of chains
#
sub create_chainlist_reload($) {
my $chains = $_[0];
my @chains = split_list $chains, 'chain';
unless ( @chains ) {
@chains = qw( blacklst ) if $filter_table->{blacklst};
push @chains, 'mangle:' if $capabilities{MANGLE_ENABLED} && $config{MANGLE_ENABLED};
$chains = join( ',', @chains ) if @chains;
}
$mode = NULL_MODE;
emit( 'chainlist_reload()',
'{'
);
push_indent;
if ( @chains ) {
if ( @chains == 1 ) {
progress_message2 "Compiling iptables-restore input for chain @chains...";
save_progress_message "Preparing iptables-restore input for chain @chains...";
} else {
progress_message2 "Compiling iptables-restore input for chains $chains...";
save_progress_message "Preparing iptables-restore input for chains $chains...";
}
emit '';
my $table = 'filter';
my %chains;
for my $chain ( @chains ) {
( $table , $chain ) = split ':', $chain if $chain =~ /:/;
fatal_error "Invalid table ( $table )" unless $table =~ /^(nat|mangle|filter)$/;
$chains{$table} = [] unless $chains{$table};
if ( $chain ) {
fatal_error "No $table chain found with name $chain" unless $chain_table{$table}{$chain};
fatal_error "Built-in chains may not be refreshed" if $chain_table{table}{$chain}{builtin};
push @{$chains{$table}}, $chain;
} else {
while ( my ( $chain, $chainref ) = each %{$chain_table{$table}} ) {
push @{$chains{$table}}, $chain if $chainref->{referenced} && ! $chainref->{builtin};
}
}
}
emit 'exec 3>${VARDIR}/.iptables-restore-input';
enter_cat_mode;
for $table qw(nat mangle filter) {
next unless $chains{$table};
emit_unindented "*$table";
my $tableref=$chain_table{$table};
@chains = sort @{$chains{$table}};
for my $chain ( @chains ) {
my $chainref = $tableref->{$chain};
emit_unindented ":$chainref->{name} - [0:0]";
}
for my $chain ( @chains ) {
my $chainref = $tableref->{$chain};
my @rules = @{$chainref->{rules}};
@rules = () unless @rules;
#
# Emit the chain rules
#
emitr $_ for ( @rules );
}
#
# Commit the changes to the table
#
enter_cat_mode unless $mode == CAT_MODE;
emit_unindented 'COMMIT';
}
enter_cmd_mode;
#
# Now generate the actual iptables-restore command
#
emit( 'exec 3>&-',
'',
'progress_message2 "Running iptables-restore..."',
'',
'cat ${VARDIR}/.iptables-restore-input | $IPTABLES_RESTORE -n # Use this nonsensical form to appease SELinux',
'if [ $? != 0 ]; then',
' fatal_error "iptables-restore Failed. Input is in ${VARDIR}/.iptables-restore-input"',
"fi\n"
);
} else {
emit('true');
}
pop_indent;
emit "}\n";
}
1;
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