# # Shorewall-perl 4.0 -- /usr/share/shorewall-perl/Shorewall/Actions.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 # # This module contains the code for dealing with actions (built-in, # standard and user-defined) and Macros. # package Shorewall::Actions; require Exporter; use Shorewall::Config; use Shorewall::Zones; use Shorewall::Chains; use strict; our @ISA = qw(Exporter); our @EXPORT = qw( merge_levels isolate_basic_target add_requiredby createlogactionchain createactionchain find_logactionchain process_actions1 process_actions2 process_actions3 find_macro split_action substitute_param merge_macro_source_dest merge_macro_column %usedactions %default_actions %actions %macros ); our @EXPORT_OK = qw( initialize ); our $VERSION = 4.00; # # Used Actions. Each action that is actually used has an entry with value 1. # our %usedactions; # # Default actions for each policy. # our %default_actions; # Action Table # # %actions{ => { requires => { = 1, # = 1, # ... # } , # actchain => # Used for generating unique chain names for each : pair. # our %actions; # # Contains an entry for each used :[:] that maps to the associated chain. # our %logactionchains; our %macros; # # 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() { %usedactions = (); %default_actions = ( DROP => 'none' , REJECT => 'none' , ACCEPT => 'none' , QUEUE => 'none' ); %actions = (); %logactionchains = (); } INIT { initialize; } # # This function determines the logging for a subordinate action or a rule within a superior action # sub merge_levels ($$) { my ( $superior, $subordinate ) = @_; my @supparts = split /:/, $superior; my @subparts = split /:/, $subordinate; my $subparts = @subparts; my $target = $subparts[0]; # # Try to find a macro file -- RETURNS false if the file doesn't exist or MACRO if it does. # If the file exists, the macro is entered into the 'targets' table and the fully-qualified # name of the file is stored in the 'macro' table. # sub find_macro( $ ) { my $macro = $_[0]; my $macrofile = find_file "macro.$macro"; if ( -f $macrofile ) { $macros{$macro} = $macrofile; $targets{$macro} = MACRO; } else { 0; } } # # Return ( action, level[:tag] ) from passed full action # sub split_action ( $ ) { my $action = $_[0]; my @a = split( /:/ , $action, 4 ); fatal_error "Invalid ACTION ($action)" if ( $action =~ /::/ ) || ( @a > 3 ); ( shift @a, join ":", @a ); } # # This function substitutes the second argument for the first part of the first argument up to the first colon (":") # # Example: # # substitute_param DNAT PARAM:info:FTP # # produces "DNAT:info:FTP" # sub substitute_param( $$ ) { my ( $param, $action ) = @_; if ( $action =~ /:/ ) { my $logpart = (split_action $action)[1]; $logpart =~ s!/$!!; return "$param:$logpart"; } $param; } # # Combine fields from a macro body with one from the macro invocation # sub merge_macro_source_dest( $$ ) { my ( $body, $invocation ) = @_; if ( $invocation ) { if ( $body ) { return $body if $invocation eq '-'; return "$body:$invocation" if $invocation =~ /.*?\.*?\.|^\+|^~|^!~/; return "$invocation:$body"; } return $invocation; } $body || ''; } sub merge_macro_column( $$ ) { my ( $body, $invocation ) = @_; if ( defined $invocation && $invocation ne '' && $invocation ne '-' ) { $invocation; } else { $body; } } push @subparts, '' while @subparts < 3; #Avoid undefined values my $level = $supparts[1]; my $tag = $supparts[2]; if ( @supparts == 3 ) { return "$target:none!:$tag" if $level eq 'none!'; return "$target:$level:$tag" if $level =~ /!$/; return $subordinate if $subparts >= 2; return "$target:$level:$tag"; } if ( @supparts == 2 ) { return "$target:none!" if $level eq 'none!'; return "$target:$level" if ($level =~ /!$/) || ($subparts < 2); } $subordinate; } # # Get Macro Name -- strips away trailing /* and :* from the first column in a rule, macro or action. # sub isolate_basic_target( $ ) { ( split '[/:]', $_[0])[0]; } # # Define an Action # sub new_action( $ ) { my $action = $_[0]; $actions{$action} = { actchain => '', requires => {} }; } # # Record a 'requires' relationship between a pair of actions. # sub add_requiredby ( $$ ) { my ($requiredby , $requires ) = @_; $actions{$requires}{requires}{$requiredby} = 1; } # # Create and record a log action chain -- Log action chains have names # that are formed from the action name by prepending a "%" and appending # a 1- or 2-digit sequence number. In the functions that follow, # the CHAIN, LEVEL and TAG variable serves as arguments to the user's # exit. We call the exit corresponding to the name of the action but we # set CHAIN to the name of the iptables chain where rules are to be added. # Similarly, LEVEL and TAG contain the log level and log tag respectively. # # The maximum length of a chain name is 30 characters -- since the log # action chain name is 2-3 characters longer than the base chain name, # this function truncates the original chain name where necessary before # it adds the leading "%" and trailing sequence number. # sub createlogactionchain( $$ ) { my ( $action, $level ) = @_; my $chain = $action; my $actionref = $actions{$action}; my $chainref; $chain = substr $chain, 0, 28 if ( length $chain ) > 28; while ( $chain_table{'%' . $chain . $actionref->{actchain}} ) { $chain = substr $chain, 0, 27 if $actionref->{actchain} == 10 and length $chain == 28; } $actionref = new_action $action unless $actionref; $level = 'none' unless $level; $logactionchains{"$action:$level"} = $chainref = new_chain 'filter', '%' . $chain . $actionref->{actchain}++; mark_referenced $chainref; # Just in case the action body is empty. unless ( $targets{$action} & STANDARD ) { my $file = find_file $chain; if ( -f $file ) { progress_message "Processing $file..."; ( $level, my $tag ) = split /:/, $level; $tag = $tag || ''; unless ( my $return = eval `cat $file` ) { fatal_error "Couldn't parse $file: $@" if $@; fatal_error "Couldn't do $file: $!" unless defined $return; fatal_error "Couldn't run $file" unless $return; } } } } sub createsimpleactionchain( $ ) { my $action = shift; my $chainref = new_chain 'filter', $action; $logactionchains{"$action:none"} = $chainref; mark_referenced $chainref; # Just in case the action body is empty. unless ( $targets{$action} & STANDARD ) { my $file = find_file $action; if ( -f $file ) { progress_message "Processing $file..."; my ( $level, $tag ) = ( '', '' ); unless ( my $return = eval `cat $file` ) { fatal_error "Couldn't parse $file: $@" if $@; fatal_error "Couldn't do $file: $!" unless defined $return; fatal_error "Couldn't run $file" unless $return; } } } } # # Create an action chain and run it's associated user exit # sub createactionchain( $ ) { my ( $action , $level ) = split_action $_[0]; my $chainref; if ( defined $level && $level ne '' ) { if ( $level eq 'none' ) { createsimpleactionchain $action; } else { createlogactionchain $action , $level; } } else { createsimpleactionchain $action; } } # # Find the chain that handles the passed action. If the chain cannot be found, # a fatal error is generated and the function does not return. # sub find_logactionchain( $ ) { my $fullaction = $_[0]; my ( $action, $level ) = split_action $fullaction; $level = 'none' unless $level; fatal_error "Fatal error in find_logactionchain" unless $logactionchains{"$action:$level"}; } # # The functions process_actions1-3() implement the three phases of action processing. # # The first phase (process_actions1) occurs before the rules file is processed. ${SHAREDIR}/actions.std # and ${CONFDIR}/actions are scanned (in that order) and for each action: # # a) The related action definition file is located and scanned. # b) Forward and unresolved action references are trapped as errors. # c) A dependency graph is created using the 'requires' field in the 'actions' table. # # As the rules file is scanned, each action[:level[:tag]] is merged onto the 'usedactions' hash. When an # is merged into the hash, its action chain is created. Where logging is specified, a chain with the name # %n is used where the name is truncated on the right where necessary to ensure that the total # length of the chain name does not exceed 30 characters. # # The second phase (process_actions2) occurs after the rules file is scanned. The transitive closure of # %usedactions is generated; again, as new actions are merged into the hash, their action chains are created. # # The final phase (process_actions3) is to traverse the keys of %usedactions populating each chain appropriately # by reading the action definition files and creating rules. Note that a given action definition file is # processed once for each unique [:level[:tag]] applied to an invocation of the action. # sub process_macro1 ( $$ ) { my ( $action, $macrofile ) = @_; progress_message " ..Expanding Macro $macrofile..."; push_open( $macrofile ); while ( read_a_line ) { my ( $mtarget, $msource, $mdest, $mproto, $mports, $msports, $ mrate, $muser ) = split_line 1, 8, 'macro file'; $mtarget =~ s/:.*$//; my $targettype = $targets{$mtarget}; $targettype = 0 unless defined $targettype; fatal_error "Invalid target ($mtarget)" unless ( $targettype == STANDARD ) || ( $mtarget eq 'PARAM' ) || ( $mtarget eq 'LOG' ); } progress_message " ..End Macro $macrofile"; pop_open; } sub process_action1 ( $$ ) { my ( $action, $wholetarget ) = @_; my ( $target, $level ) = split_action $wholetarget; $level = 'none' unless $level; my $targettype = $targets{$target}; if ( defined $targettype ) { return if ( $targettype == STANDARD ) || ( $targettype == MACRO ) || ( $targettype & LOGRULE ); fatal_error "Invalid TARGET ($target)" if $targettype & STANDARD; fatal_error "An action may not invoke itself" if $target eq $action; add_requiredby $wholetarget, $action if $targettype & ACTION; } elsif ( $target eq 'COMMENT' ) { fatal_error "Invalid TARGET ($wholetarget)" unless $wholetarget eq $target; } else { ( $target, my $param ) = split '/', $target; if ( defined $param ) { my $paramtype = $targets{$param} || 0; fatal_error "Parameter value not allowed in action files ($param)" if $paramtype & NATRULE; } fatal_error "Invalid or missing ACTION ($wholetarget)" unless defined $target; if ( find_macro $target ) { process_macro1( $action, $macros{$target} ); } else { fatal_error "Invalid TARGET ($target)"; } } } sub process_actions1() { progress_message2 "Preprocessing Action Files..."; for my $act ( grep $targets{$_} & ACTION , keys %targets ) { new_action $act; } for my $file ( qw/actions.std actions/ ) { open_file $file; while ( read_a_line ) { my ( $action ) = split_line 1, 1, 'action file'; if ( $action =~ /:/ ) { warning_message 'Default Actions are now specified in /etc/shorewall/shorewall.conf'; $action =~ s/:.*$//; } next unless $action; if ( $targets{$action} ) { next if $targets{$action} & ACTION; fatal_error "Invalid Action Name ($action)"; } $targets{$action} = ACTION; fatal_error "Invalid Action Name ($action)" unless "\L$action" =~ /^[a-z]\w*$/; new_action $action; my $actionfile = find_file "action.$action"; fatal_error "Missing Action File ($actionfile)" unless -f $actionfile; progress_message2 " Pre-processing $actionfile..."; push_open( $actionfile ); while ( read_a_line ) { my ($wholetarget, $source, $dest, $proto, $ports, $sports, $rate, $users ) = split_line 1, 8, 'action file'; process_action1( $action, $wholetarget ); } pop_open; } } } sub process_actions2 () { progress_message2 'Generating Transitive Closure of Used-action List...'; my $changed = 1; while ( $changed ) { $changed = 0; for my $target (keys %usedactions) { my ($action, $level) = split_action $target; my $actionref = $actions{$action}; fatal_error "Null Action Reference in process_actions2" unless $actionref; for my $action1 ( keys %{$actionref->{requires}} ) { my $action2 = merge_levels $target, $action1; unless ( $usedactions{ $action2 } ) { $usedactions{ $action2 } = 1; createactionchain $action2; $changed = 1; } } } } } # # This function is called to process each rule generated from an action file. # sub process_action( $$$$$$$$$$ ) { my ($chainref, $actionname, $target, $source, $dest, $proto, $ports, $sports, $rate, $user ) = @_; my ( $action , $level ) = split_action $target; expand_rule ( $chainref , NO_RESTRICT , do_proto( $proto, $ports, $sports ) . do_ratelimit( $rate, $action ) . do_user $user , $source , $dest , '', #Original Dest '-j ' . ($action eq 'REJECT' ? 'reject' : $action eq 'CONTINUE' ? 'RETURN' : $action), $level , $action , '' ); } # # Expand Macro in action file4s. # sub process_macro3( $$$$$$$$$$$ ) { my ( $fn, $param, $chainref, $action, $source, $dest, $proto, $ports, $sports, $rate, $user ) = @_; progress_message "..Expanding Macro $fn..."; push_open $fn; my $standard = ( $fn =~ /^($globals{SHAREDIR})/ ); while ( read_a_line ) { my ( $mtarget, $msource, $mdest, $mproto, $mports, $msports, $mrate, $muser ) = split_line 1, 8, 'macro file'; if ( $mtarget =~ /^PARAM:?/ ) { fatal_error 'PARAM requires that a parameter be supplied in macro invocation' unless $param; $mtarget = substitute_param $param, $mtarget; } if ( $msource ) { if ( ( $msource eq '-' ) || ( $msource eq 'SOURCE' ) ) { $msource = $source || ''; } elsif ( $msource eq 'DEST' ) { $msource = $dest || ''; } else { $msource = merge_macro_source_dest $msource, $source; } } else { $msource = ''; } $msource = '' if $msource eq '-'; if ( $mdest ) { if ( ( $mdest eq '-' ) || ( $mdest eq 'DEST' ) ) { $mdest = $dest || ''; } elsif ( $mdest eq 'SOURCE' ) { $mdest = $source || ''; } else { $mdest = merge_macro_source_dest $mdest, $dest; } } else { $mdest = ''; } $mdest = '' if $mdest eq '-'; $mproto = merge_macro_column $mproto, $proto; $mports = merge_macro_column $mports, $ports; $msports = merge_macro_column $msports, $sports; $mrate = merge_macro_column $mrate, $rate; $muser = merge_macro_column $muser, $user; process_action $chainref, $action, $mtarget, $msource, $mdest, $mproto, $mports, $msports, $mrate, $muser; } pop_open; progress_message '..End Macro' } # # Generate chain for non-builtin action invocation # sub process_action3( $$$$$ ) { my ( $chainref, $wholeaction, $action, $level, $tag ) = @_; my $actionfile = find_file "action.$action"; my $standard = ( $actionfile =~ /^$globals{SHAREDIR}/ ); fatal_error "Missing Action File ($actionfile)" unless -f $actionfile; progress_message2 "Processing $actionfile for chain $chainref->{name}..."; open_file $actionfile; while ( read_a_line ) { my ($target, $source, $dest, $proto, $ports, $sports, $rate, $user ) = split_line1 1, 8, 'action file'; if ( $target eq 'COMMENT' ) { process_comment; next; } my $target2 = merge_levels $wholeaction, $target; my ( $action2 , $level2 ) = split_action $target2; my $action2type = $targets{isolate_basic_target $action2}; unless ( $action2type == STANDARD ) { if ( $action2type & ACTION ) { $target2 = (find_logactionchain ( $target = $target2 ))->{name}; } else { die "Internal Error" unless $action2type == MACRO || $action2type & LOGRULE; } } if ( $action2type == MACRO ) { ( $action2, my $param ) = split '/', $action2; fatal_error "Null Macro" unless my $fn = $macros{$action2}; process_macro3( $fn, $param, $chainref, $action, $source, $dest, $proto, $ports, $sports, $rate, $user ); } else { process_action $chainref, $action, $target2, $source, $dest, $proto, $ports, $sports, $rate, $user; } } $comment = ''; } sub process_actions3 () { # # The following small functions generate rules for the builtin actions of the same name # sub dropBcast( $$$ ) { my ($chainref, $level, $tag) = @_; if ( $capabilities{ADDRTYPE} ) { if ( $level ne '' ) { log_rule_limit $level, $chainref, 'dropBcast' , 'DROP', '', $tag, 'add', ' -m addrtype --dst-type BROADCAST'; log_rule_limit $level, $chainref, 'dropBcast' , 'DROP', '', $tag, 'add', ' -d 224.0.0.0/4'; } add_rule $chainref, '-m addrtype --dst-type BROADCAST -j DROP'; } else { add_command $chainref, 'for address in $ALL_BCASTS; do'; push_cmd_mode $chainref; log_rule_limit $level, $chainref, 'dropBcast' , 'DROP', '', $tag, 'add', ' -d $address' if $level ne ''; add_rule $chainref, '-d $address -j DROP'; pop_cmd_mode $chainref; add_command $chainref, 'done'; log_rule_limit $level, $chainref, 'dropBcast' , 'DROP', '', $tag, 'add', ' -d 224.0.0.0/4' if $level ne ''; } add_rule $chainref, '-d 224.0.0.0/4 -j DROP'; } sub allowBcast( $$$ ) { my ($chainref, $level, $tag) = @_; if ( $capabilities{ADDRTYPE} ) { if ( $level ne '' ) { log_rule_limit $level, $chainref, 'allowBcast' , 'ACCEPT', '', $tag, 'add', ' -m addrtype --dst-type BROADCAST'; log_rule_limit $level, $chainref, 'allowBcast' , 'ACCEPT', '', $tag, 'add', ' -d 224.0.0.0/4'; } add_rule $chainref, '-m addrtype --dst-type BROADCAST -j ACCEPT'; } else { add_command $chainref, 'for address in $ALL_BCASTS; do'; push_cmd_mode $chainref; log_rule_limit $level, $chainref, 'allowBcast' , 'ACCEPT', '', $tag, 'add', ' -d $address' if $level ne ''; add_rule $chainref, '-d $address -j ACCEPT'; pop_cmd_mode $chainref; add_command $chainref, 'done'; log_rule_limit $level, $chainref, 'allowBcast' , 'ACCEPT', '', $tag, 'add', ' -d 224.0.0.0/4' if $level ne ''; } add_rule $chainref, '-d 224.0.0.0/4 -j ACCEPT'; } sub dropNotSyn ( $$$ ) { my ($chainref, $level, $tag) = @_; log_rule_limit $level, $chainref, 'dropNotSyn' , 'DROP', '', $tag, 'add', '-p tcp ! --syn ' if $level ne ''; add_rule $chainref , '-p tcp ! --syn -j DROP'; } sub rejNotSyn ( $$$ ) { my ($chainref, $level, $tag) = @_; log_rule_limit $level, $chainref, 'rejNotSyn' , 'REJECT', '', $tag, 'add', '-p tcp ! --syn ' if $level ne ''; add_rule $chainref , '-p tcp ! --syn -j REJECT --reject-with tcp-reset'; } sub dropInvalid ( $$$ ) { my ($chainref, $level, $tag) = @_; log_rule_limit $level, $chainref, 'dropInvalid' , 'DROP', '', $tag, 'add', '-m state --state INVALID ' if $level ne ''; add_rule $chainref , '-m state --state INVALID -j DROP'; } sub allowInvalid ( $$$ ) { my ($chainref, $level, $tag) = @_; log_rule_limit $level, $chainref, 'allowInvalid' , 'ACCEPT', '', $tag, 'add', '-m state --state INVALID ' if $level ne ''; add_rule $chainref , '-m state --state INVALID -j ACCEPT'; } sub forwardUPnP ( $$$ ) { } sub allowinUPnP ( $$$ ) { my ($chainref, $level, $tag) = @_; if ( $level ne '' ) { log_rule_limit $level, $chainref, 'allowinUPnP' , 'ACCEPT', '', $tag, 'add', '-p udp --dport 1900 '; log_rule_limit $level, $chainref, 'allowinUPnP' , 'ACCEPT', '', $tag, 'add', '-p tcp --dport 49152 '; } add_rule $chainref, '-p udp --dport 1900 -j ACCEPT'; add_rule $chainref, '-p tcp --dport 49152 -j ACCEPT'; } sub Limit( $$$ ) { my ($chainref, $level, $tag) = @_; my @tag = split /,/, $tag; fatal_error 'Limit rules must include ,, as the log tag (' . join( ':', 'Limit', $level eq '' ? 'none' : $level , $tag ) . ')' unless @tag == 3; my $set = $tag[0]; for ( @tag[1,2] ) { fatal_error 'Max connections and interval in Limit rules must be numeric (' . join( ':', 'Limit', $level eq '' ? 'none' : $level, $tag ) . ')' unless /^\d+$/ } my $count = $tag[1] + 1; require_capability( 'RECENT_MATCH' , 'Limit rules' , '' ); add_rule $chainref, "-m recent --name $set --set"; if ( $level ne '' ) { my $xchainref = new_chain 'filter' , "$chainref->{name}%"; log_rule_limit $level, $xchainref, $tag[0], 'DROP', '', '', 'add', ''; add_rule $xchainref, '-j DROP'; add_rule $chainref, "-m recent --name $set --update --seconds $tag[2] --hitcount $count -j $xchainref->{name}"; } else { add_rule $chainref, "-m recent --update --name $set --seconds $tag[2] --hitcount $count -j DROP"; } add_rule $chainref, '-j ACCEPT'; } my %builtinops = ( 'dropBcast' => \&dropBcast, 'allowBcast' => \&allowBcast, 'dropNotSyn' => \&dropNotSyn, 'rejNotSyn' => \&rejNotSyn, 'dropInvalid' => \&dropInvalid, 'allowInvalid' => \&allowInvalid, 'allowinUPnP' => \&allowinUPnP, 'forwardUPnP' => \&forwardUPnP, 'Limit' => \&Limit, ); for my $wholeaction ( keys %usedactions ) { my $chainref = find_logactionchain $wholeaction; my ( $action, $level, $tag ) = split /:/, $wholeaction; $level = '' unless defined $level; $tag = '' unless defined $tag; if ( $targets{$action} & BUILTIN ) { $level = '' if $level =~ /none!?/; $builtinops{$action}->($chainref, $level, $tag); } else { process_action3 $chainref, $wholeaction, $action, $level, $tag; } } } 1;