4 # ferm, a firewall setup program that makes firewall rules easy!
6 # Copyright (C) 2001-2007 Auke Kok, Max Kellermann
8 # Comments, questions, greetings and additions to this program
9 # may be sent to <ferm@foo-projects.org>
13 # This program is free software; you can redistribute it and/or modify
14 # it under the terms of the GNU General Public License as published by
15 # the Free Software Foundation; either version 2 of the License, or
16 # (at your option) any later version.
18 # This program is distributed in the hope that it will be useful,
19 # but WITHOUT ANY WARRANTY; without even the implied warranty of
20 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 # GNU General Public License for more details.
23 # You should have received a copy of the GNU General Public License
24 # along with this program; if not, write to the Free Software
25 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
31 eval { require strict
; import strict
; };
34 # we need no vars.pm if there is not even strict.pm
36 *vars
::import
= sub {};
39 eval { require Getopt
::Long
; import Getopt
::Long
; };
43 use vars
qw($has_strict $has_getopt);
45 use vars qw($DATE $VERSION);
47 # subversion keyword magic
48 $DATE = '$Date$' =~ m,(\d{4})-(\d\d)-(\d\d), ? $1.$2.$3 : '';
51 $VERSION .= '~svn' . $DATE;
53 ## interface variables
54 # %option = command line and other options
58 use vars qw(@pre_hooks @post_hooks);
61 # $script: current script file
62 # @stack = ferm's parser stack containing local variables
63 # $auto_chain = index for the next auto-generated chain
64 use vars qw($script %rules @stack $auto_chain);
66 ## netfilter variables
67 # %domains = state information about all domains ("ip" and "ip6")
68 # - initialized: domain initialization is done
69 # - tools: hash providing the paths of the domain's tools
70 # - previous: save file of the previous ruleset, for rollback
71 # - reset: has this domain already been reset?
72 # - tables{$name}: ferm state information about tables
73 # - chains{$chain}: ferm state information about the chains
74 # - builtin: whether this is a built-in chain
75 # - was_created: custom chain has been created
76 # - non_empty: are there rules for this chain?
77 use vars qw(%domains);
80 use vars qw(%deprecated_keywords);
82 # keywords from ferm 1.1 which are deprecated, and the new one; these
83 # are automatically replaced, and a warning is printed
84 %deprecated_keywords = ( goto => 'jump',
87 # these hashes provide the Netfilter module definitions
88 use vars qw(%proto_defs %match_defs %target_defs);
91 # This subsubsystem allows you to support (most) new netfilter modules
92 # in ferm. Add a call to one of the "add_XY_def()" functions below.
94 # Ok, now about the cryptic syntax: the function "add_XY_def()"
95 # registers a new module. There are three kinds of modules: protocol
96 # module (e.g. TCP, ICMP), match modules (e.g. state, physdev) and
97 # target modules (e.g. DNAT, MARK).
99 # The first parameter is always the module name which is passed to
100 # iptables with "-p", "-m" or "-j" (depending on which kind of module
103 # After that, you add an encoded string for each option the module
104 # supports. This is where it becomes tricky.
106 # foo defaults to an option with one argument (which may be a ferm
109 # foo*0 option without any arguments
111 # foo=s one argument which must not be a ferm array ('s' stands for
114 # to-source=a one argument, may be a ferm array ('a'='array'); this forces
115 # ferm to accept arrays, even in a target declaration; example:
116 # to-source (1.2.3.4 5.6.7.8) translates to:
117 # --to-source 1.2.3.4 --to-source 5.6.7.8
119 # ctstate=c one argument, if it's an array, pass it to iptables as a
120 # single comma separated value; example:
121 # ctstate (ESTABLISHED RELATED) translates to:
122 # --ctstate ESTABLISHED,RELATED
124 # foo=sac three arguments: scalar, array, comma separated; you may
125 # concatenate more than one letter code after the '='
127 # foo&bar one argument; call the perl function '&bar()' which parses
130 # !foo negation is allowed and the '!' is written before the keyword
132 # foo! same as above, but '!' is after the keyword and before the
135 # to:=to-destination makes "to" an alias for "to-destination"; you have
136 # to add a declaration for option "to-destination"
139 # add a module definition
142 my $domain_family = shift;
144 die if exists $defs->{$domain_family}{$name};
145 my $def = $defs->{$domain_family}{$name} = {};
151 $params = $1 if $keyword =~ s,\*(\d+)$,,;
152 $params = $1 if $keyword =~ s,=([acs]+)$,,;
153 if ($keyword =~ s,&(\S+)$,,) {
154 $params = eval "\\&$1";
157 $k->{params} = $params if $params;
159 $k->{negation} = $k->{pre_negation} = 1 if $keyword =~ s,^!,,;
160 $k->{negation} = 1 if $keyword =~ s,!$,,;
162 $k->{alias} = $1 if $keyword =~ s,:=(\S+)$,,;
164 $def->{keywords}{$keyword} = $k;
170 # add a protocol module definition
171 sub add_proto_def_x(@) {
172 add_def_x(\%proto_defs, @_);
175 # add a match module definition
176 sub add_match_def_x(@) {
177 add_def_x(\%match_defs, @_);
180 # add a target module definition
181 sub add_target_def_x(@) {
182 add_def_x(\%target_defs, @_);
187 add_def_x($defs, 'ip', @_);
190 # add a protocol module definition
191 sub add_proto_def(@) {
192 add_def(\%proto_defs, @_);
195 # add a match module definition
196 sub add_match_def(@) {
197 add_def(\%match_defs, @_);
200 # add a target module definition
201 sub add_target_def(@) {
202 add_def(\%target_defs, @_);
205 add_proto_def 'dccp', qw(dccp-types!=c dccp-option!);
206 add_proto_def
'mh', qw(mh-type!);
207 add_proto_def
'icmp', qw(icmp-type!);
208 add_proto_def
'icmpv6', qw(icmpv6-type! icmp-type:=icmpv6-type);
209 add_proto_def
'sctp', qw(chunk-types!=sc);
210 add_proto_def
'tcp', qw(tcp-flags!=cc !syn*0 tcp-option! mss);
211 add_proto_def
'udp', qw();
215 qw(protocol! proto:=protocol),
216 # --source, --destination
217 qw(source! saddr:=source destination! daddr:=destination),
219 qw(in-interface! interface:=in-interface if:=in-interface),
221 qw(out-interface! outerface:=out-interface of:=out-interface),
224 add_match_def
'account', qw(aaddr=s aname=s ashort*0);
225 add_match_def
'addrtype', qw(src-type dst-type);
226 add_match_def
'ah', qw(ahspi! ahlen! ahres*0);
227 add_match_def
'comment', qw(comment=s);
228 add_match_def
'condition', qw(condition!);
229 add_match_def
'connbytes', qw(!connbytes connbytes-dir connbytes-mode);
230 add_match_def
'connlimit', qw(!connlimit-above connlimit-mask);
231 add_match_def
'connmark', qw(mark);
232 add_match_def
'conntrack', qw(ctstate=c ctproto ctorigsrc! ctorigdst!),
233 qw(ctreplsrc! ctrepldst! ctstatus ctexpire=s);
234 add_match_def
'dscp', qw(dscp dscp-class);
235 add_match_def
'dst', qw(dst-len!=s dst-opts=c);
236 add_match_def
'ecn', qw(ecn-tcp-cwr*0 ecn-tcp-ece*0 ecn-ip-ect);
237 add_match_def
'esp', qw(espspi!);
238 add_match_def
'eui64';
239 add_match_def
'frag', qw(fragid! fraglen! fragres*0 fragmore*0 fragfirst*0 fraglast*0);
240 add_match_def
'fuzzy', qw(lower-limit=s upper-limit=s);
241 add_match_def
'hbh', qw(hbh-len! hbh-opts=c);
242 add_match_def
'helper', qw(helper);
243 add_match_def
'hl', qw(hl-eq! hl-lt=s hl-gt=s);
244 add_match_def
'length', qw(length!);
245 add_match_def
'hashlimit', qw(hashlimit=s hashlimit-burst=s hashlimit-mode=s hashlimit-name=s),
246 qw(hashlimit-htable-size=s hashlimit-htable-max=s),
247 qw(hashlimit-htable-expire=s hashlimit-htable-gcinterval=s);
248 add_match_def
'iprange', qw(!src-range !dst-range);
249 add_match_def
'iplimit', qw(!iplimit-above=s iplimit-mask=s);
250 add_match_def
'ipv6header', qw(header!=c soft*0);
251 add_match_def
'limit', qw(limit=s limit-burst=s);
252 add_match_def
'mac', qw(mac-source!);
253 add_match_def
'mark', qw(mark);
254 add_match_def
'multiport', qw(source-ports!&multiport_params),
255 qw(destination-ports!&multiport_params ports!&multiport_params);
256 add_match_def
'nth', qw(every counter start packet);
257 add_match_def
'owner', qw(uid-owner gid-owner pid-owner sid-owner cmd-owner);
258 add_match_def
'physdev', qw(physdev-in! physdev-out!),
259 qw(!physdev-is-in*0 !physdev-is-out*0 !physdev-is-bridged*0);
260 add_match_def
'pkttype', qw(pkt-type),
261 add_match_def
'policy',
262 qw(dir pol strict*0 reqid spi proto mode tunnel-src tunnel-dst next*0);
263 add_match_def
'psd', qw(psd-weight-threshold psd-delay-threshold),
264 qw(psd-lo-ports-weight psd-hi-ports-weight);
265 add_match_def
'quota', qw(quota=s);
266 add_match_def
'random', qw(average);
267 add_match_def
'realm', qw(realm!);
268 add_match_def
'recent', qw(name=s !set*0 !rcheck*0 !update*0 !seconds !hitcount rttl*0);
269 add_match_def
'rt', qw(rt-type! rt-segsleft! rt-len! rt-0-res*0 rt-0-addrs=c rt-0-not-strict*0);
270 add_match_def
'set', qw(set=sc);
271 add_match_def
'state', qw(state=c);
272 add_match_def
'statistic', qw(mode=s probability=s every=s packet=s);
273 add_match_def
'tcpmss', qw(!mss);
274 add_match_def
'time', qw(timestart=s timestop=s days=c datestart=s datestop=s);
275 add_match_def
'tos', qw(!tos);
276 add_match_def
'ttl', qw(ttl-eq ttl-lt=s ttl-gt=s);
278 add_target_def
'BALANCE', qw(to-destination to:=to-destination);
279 add_target_def
'CLASSIFY', qw(set-class);
280 add_target_def
'CONNMARK', qw(set-mark save-mark*0 restore-mark*0 mask);
281 add_target_def
'CONNSECMARK', qw(save*0 restore*0);
282 add_target_def
'DNAT', qw(to-destination to:=to-destination);
283 add_target_def
'DSCP', qw(set-dscp set-dscp-class);
284 add_target_def
'ECN', qw(ecn-tcp-remove*0);
285 add_target_def
'HL', qw(hl-set hl-dec hl-inc);
286 add_target_def
'LOG', qw(log-level log-prefix),
287 qw(log-tcp-sequence*0 log-tcp-options*0 log-ip-options*0 log-uid*0);
288 add_target_def
'MARK', qw(set-mark);
289 add_target_def
'MASQUERADE', qw(to-ports);
290 add_target_def
'MIRROR';
291 add_target_def
'NETMAP', qw(to);
292 add_target_def
'NFLOG', qw(nflog-group nflog-prefix nflog-range nflog-threshold);
293 add_target_def
'NFQUEUE', qw(queue-num);
294 add_target_def
'NOTRACK';
295 add_target_def
'REDIRECT', qw(to-ports);
296 add_target_def
'REJECT', qw(reject-with);
297 add_target_def
'ROUTE', qw(oif iif gw continue*0 tee*0);
298 add_target_def
'SAME', qw(to nodst*0);
299 add_target_def
'SECMARK', qw(selctx);
300 add_target_def
'SET', qw(add-set=sc del-set=sc);
301 add_target_def
'SNAT', qw(to-source=a to:=to-source);
302 add_target_def
'TARPIT';
303 add_target_def
'TCPMSS', qw(set-mss clamp-mss-to-pmtu*0);
304 add_target_def
'TOS', qw(set-tos);
305 add_target_def
'TRACE';
306 add_target_def
'TTL', qw(ttl-set ttl-dec ttl-inc);
307 add_target_def
'ULOG', qw(ulog-nlgroup ulog-prefix ulog-cprange ulog-qthreshold);
309 add_match_def_x
'arp', '',
311 qw(source-ip! destination-ip! saddr:=source-ip daddr:=destination-ip),
313 qw(source-mac! destination-mac!),
315 qw(in-interface! interface:=in-interface if:=in-interface),
317 qw(out-interface! outerface:=out-interface of:=out-interface),
319 qw(h-length=s opcode=s h-type=s proto-type=s),
320 qw(mangle-ip-s=s mangle-ip-d=s mangle-mac-s=s mangle-mac-d=s mangle-target=s);
322 add_match_def_x
'eb', '',
324 qw(protocol! proto:=protocol),
326 qw(in-interface! interface:=in-interface if:=in-interface),
328 qw(out-interface! outerface:=out-interface of:=out-interface),
330 qw(logical-in! logical-out!),
331 # --source, --destination
332 qw(source! saddr:=source destination! daddr:=destination),
334 qw(802_3-sap! 802_3-type!),
336 qw(arp-opcode! arp-htype!=ss arp-ptype!=ss),
337 qw(arp-ip-src! arp-ip-dst! arp-mac-src! arp-mac-dst!),
339 qw(ip-source! ip-destination! ip-tos! ip-protocol! ip-sport! ip-dport!),
345 qw(stp-type! stp-flags! stp-root-prio! stp-root-addr! stp-root-cost!),
346 qw(stp-sender-prio! stp-sender-addr! stp-port! stp-msg-age! stp-max-age!),
347 qw(stp-hello-time! stp-forward-delay!),
349 qw(vlan-id! vlan-prio! vlan-encap!),
351 qw(log*0 log-level=s log-prefix=s log-ip*0 log-arp*0);
353 add_target_def_x
'eb', 'arpreply', qw(arpreply-mac arpreply-target);
354 add_target_def_x
'eb', 'dnat', qw(to-destination dnat-target);
355 add_target_def_x
'eb', 'mark', qw(set-mark mark-target);
356 add_target_def_x
'eb', 'redirect', qw(redirect-target);
357 add_target_def_x
'eb', 'snat', qw(to-source snat-target);
359 # parameter parser for ipt_multiport
360 sub multiport_params
{
363 # multiport only allows 15 ports at a time. For this
364 # reason, we do a little magic here: split the ports
365 # into portions of 15, and handle these portions as
368 my $proto = find_option
($fw, 'builtin____protocol');
369 error
('To use multiport, you have to specify "proto tcp" or "proto udp" first')
370 unless defined $proto and grep { /^(?:tcp|udp|udplite)$/ } to_array
($proto);
372 my $value = getvalues
(undef, undef,
374 allow_array_negation
=> 1);
375 if (ref $value and ref $value eq 'ARRAY') {
380 push @params, join(',', splice(@value, 0, 15));
387 return join_value
(',', $value);
391 # initialize stack: command line definitions
394 # Get command line stuff
396 my ($opt_noexec, $opt_flush, $opt_lines, $opt_interactive,
397 $opt_verbose, $opt_debug,
399 $opt_version, $opt_test, $opt_fast, $opt_shell,
402 Getopt
::Long
::Configure
('bundling', 'auto_help', 'no_ignore_case',
406 my ($opt, $value) = @_;
407 die 'Invalid --def specification'
408 unless $value =~ /^\$?(\w+)=(.*)$/s;
409 my ($name, $unparsed_value) = ($1, $2);
410 my @tokens = tokenize_string
($unparsed_value);
411 my $value = getvalues
(\
&next_array_token
, \
@tokens);
412 die 'Extra tokens after --def'
414 $stack[0]{vars
}{$name} = $value;
417 local $SIG{__WARN__
} = sub { die $_[0]; };
418 GetOptions
('noexec|n' => \
$opt_noexec,
419 'flush|F' => \
$opt_flush,
420 'lines|l' => \
$opt_lines,
421 'interactive|i' => \
$opt_interactive,
422 'verbose|v' => \
$opt_verbose,
423 'debug|d' => \
$opt_debug,
424 'help|h' => \
$opt_help,
425 'version|V' => \
$opt_version,
427 remote
=> \
$opt_test,
429 shell
=> \
$opt_shell,
430 'domain=s' => \
$opt_domain,
431 'def=s' => \
&opt_def
,
434 if (defined $opt_help) {
436 Pod
::Usage
::pod2usage
(-exitstatus
=> 0);
439 if (defined $opt_version) {
444 $option{'noexec'} = (defined $opt_noexec);
445 $option{flush
} = defined $opt_flush;
446 $option{'lines'} = (defined $opt_lines);
447 $option{interactive
} = (defined $opt_interactive);
448 $option{test
} = (defined $opt_test);
455 delete $option{interactive
} if $option{noexec
};
457 mydie
('ferm interactive mode not possible: /dev/stdin is not a tty')
458 if $option{interactive
} and not -t STDIN
;
459 mydie
('ferm interactive mode not possible: /dev/stderr is not a tty')
460 if $option{interactive
} and not -t STDERR
;
462 $option{fast
} = 1 if defined $opt_fast;
464 if (defined $opt_shell) {
465 $option{$_} = 1 foreach qw(shell fast lines);
468 $option{domain
} = $opt_domain if defined $opt_domain;
470 print STDERR
"Warning: ignoring the obsolete --debug option\n"
471 if defined $opt_debug;
472 print STDERR
"Warning: ignoring the obsolete --verbose option\n"
473 if defined $opt_verbose;
475 # tiny getopt emulation for microperl
478 if ($_ eq '--noexec' or $_ eq '-n') {
480 } elsif ($_ eq '--lines' or $_ eq '-l') {
482 } elsif ($_ eq '--fast') {
484 } elsif ($_ eq '--test') {
487 } elsif ($_ eq '--shell') {
488 $option{$_} = 1 foreach qw(shell fast lines);
490 printf STDERR
"Usage: ferm [--noexec] [--lines] [--fast] [--shell] FILENAME\n";
497 push @ARGV, $filename;
500 unless (@ARGV == 1) {
502 Pod
::Usage
::pod2usage
(-exitstatus
=> 1);
506 open LINES
, ">&STDOUT" if $option{lines
};
507 open STDOUT
, ">&STDERR" if $option{shell
};
509 # microperl can't redirect file handles
512 if ($option{fast
} and not $option{noexec
}) {
513 print STDERR
"Sorry, ferm on microperl does not allow --fast without --noexec\n";
519 open_script
($ARGV[0]);
521 # parse all input recursively
523 die unless @stack == 2;
528 # execute all generated rules
531 foreach my $cmd (@pre_hooks) {
532 print LINES
"$cmd\n" if $option{lines
};
533 system($cmd) unless $option{noexec
};
536 while (my ($domain, $rules) = each %rules) {
537 my $s = $option{fast
} &&
538 defined $domains{$domain}{tools
}{'tables-restore'}
539 ? execute_fast
($domain, rules_to_save
($domain, $rules))
540 : execute_slow
($domain, $rules);
541 $status = $s if defined $s;
544 foreach my $cmd (@post_hooks) {
545 print "$cmd\n" if $option{lines
};
546 system($cmd) unless $option{noexec
};
549 if (defined $status) {
554 # ask user, and rollback if there is no confirmation
556 confirm_rules
() or rollback
() if $option{interactive
};
560 # end of program execution!
566 print "ferm $VERSION\n";
567 print "Copyright (C) 2001-2007 Auke Kok, Max Kellermann\n";
568 print "This program is free software released under GPLv2.\n";
569 print "See the included COPYING file for license details.\n";
581 # returns a nice formatted error message, showing the
582 # location of the error.
586 my @words = @
{$script->{past_tokens
}};
588 for my $w ( 0 .. $#words ) {
589 if ($words[$w] eq "\x29")
590 { $l++ ; $lines[$l] = " " x
($tabs-- -1) ;};
591 if ($words[$w] eq "\x28")
592 { $l++ ; $lines[$l] = " " x
$tabs++ ;};
593 if ($words[$w] eq "\x7d")
594 { $l++ ; $lines[$l] = " " x
($tabs-- -1) ;};
595 if ($words[$w] eq "\x7b")
596 { $l++ ; $lines[$l] = " " x
$tabs++ ;};
597 if ( $l > $#lines ) { $lines[$l] = "" };
598 $lines[$l] .= $words[$w] . " ";
599 if ($words[$w] eq "\x28")
600 { $l++ ; $lines[$l] = " " x
$tabs ;};
601 if (($words[$w] eq "\x29") && ($words[$w+1] ne "\x7b"))
602 { $l++ ; $lines[$l] = " " x
$tabs ;};
603 if ($words[$w] eq "\x7b")
604 { $l++ ; $lines[$l] = " " x
$tabs ;};
605 if (($words[$w] eq "\x7d") && ($words[$w+1] ne "\x7d"))
606 { $l++ ; $lines[$l] = " " x
$tabs ;};
607 if (($words[$w] eq "\x3b") && ($words[$w+1] ne "\x7d"))
608 { $l++ ; $lines[$l] = " " x
$tabs ;}
609 if ($words[$w-1] eq "option")
610 { $l++ ; $lines[$l] = " " x
$tabs ;}
612 my $start = $#lines - 4;
613 if ($start < 0) { $start = 0 } ;
614 print STDERR
"Error in $script->{filename} line $script->{line}:\n";
615 for $l ( $start .. $#lines)
616 { print STDERR
$lines[$l]; if ($l != $#lines ) {print STDERR
"\n"} ; };
617 print STDERR
"<--\n";
621 # print a warning message about code from an input file
623 print STDERR
"Warning in $script->{filename} line $script->{line}: "
629 return $name if $option{test
};
630 for my $path ('/sbin', split ':', $ENV{PATH
}) {
631 my $ret = "$path/$name";
632 return $ret if -x
$ret;
634 die "$name not found in PATH\n";
637 sub initialize_domain
{
640 return if exists $domains{$domain}{initialized
};
642 die "Invalid domain '$domain'\n" unless $domain =~ /^(?:ip6?|arp|eb)$/;
644 my @tools = qw(tables);
645 push @tools, qw(tables-save tables-restore)
646 if $domain =~ /^ip6?$/;
648 # determine the location of this domain's tools
649 foreach my $tool (@tools) {
650 $domains{$domain}{tools
}{$tool} = find_tool
("${domain}${tool}");
653 # make tables-save tell us about the state of this domain
654 # (which tables and chains do exist?), also remember the old
655 # save data which may be used later by the rollback function
657 if (!$option{test
} &&
658 exists $domains{$domain}{tools
}{'tables-save'} &&
659 open(SAVE
, "$domains{$domain}{tools}{'tables-save'}|")) {
668 $table_info = $domains{$domain}{tables
}{$table} ||= {};
669 } elsif (defined $table_info and /^:(\w+)\s+(\S+)/
671 $table_info->{chains
}{$1}{builtin
} = 1;
672 $table_info->{has_builtin
} = 1;
677 $domains{$domain}{previous
} = $save;
680 $domains{$domain}{initialized
} = 1;
683 # split the an input string into words and delete comments
684 sub tokenize_string
($) {
689 foreach my $word ($string =~ m/(".*?"|'.*?'|`.*?`|[!,=&\$\%\(\){};]|[-+\w\/\
.:]+|@\w
+|#)/g) {
690 last if $word eq '#';
697 # shift an array; helper function to be passed to &getvar / &getvalues
698 sub next_array_token
{
703 # read some more tokens from the input file into a buffer
704 sub prepare_tokens
() {
706 unless defined $script;
708 my $tokens = $script->{tokens
};
709 die unless ref $tokens eq 'ARRAY';
711 while (@
$tokens == 0) {
712 my $handle = $script->{handle
};
713 my $line = <$handle>;
714 return unless defined $line;
718 my @line = tokenize_string
($line);
720 # the next parser stage eats this
721 push @
$tokens, @line;
727 # open a ferm sub script
729 my $filename = shift;
731 for (my $s = $script; defined $s; $s = $s->{parent
}) {
732 mydie
("Circular reference in $script->{filename} line $script->{line}: $filename")
733 if $s->{filename
} eq $filename;
737 open FILE
, "<$filename"
738 or mydie
("Failed to open $filename: $!");
741 $script = { filename
=> $filename,
752 # collect script filenames which are being included
753 sub collect_filenames
(@
) {
756 # determine the current script's parent directory for relative
758 die unless defined $script;
759 my $parent_dir = $script->{filename
} =~ m
,^(.*/),
762 foreach my $pathname (@_) {
763 # non-absolute file names are relative to the parent script's
765 $pathname = $parent_dir . $pathname
766 unless $pathname =~ m
,^/,;
768 if ($pathname =~ m
,/$,) {
769 # include all regular files in a directory
771 error
("'$pathname' is not a directory")
775 opendir DIR
, $pathname
776 or error
("Failed to open directory '$pathname': $!");
777 my @names = readdir DIR
;
780 # sort those names for a well-defined order
781 foreach my $name (sort { $a cmp $b } @names) {
782 # don't include hidden and backup files
785 my $filename = $pathname . $name;
789 } elsif ($pathname =~ m
,\
|$,) {
790 # run a program and use its output
791 push @ret, $pathname;
792 } elsif ($pathname =~ m
,^\
|,) {
793 error
('This kind of pipe is not allowed');
795 # include a regular file
797 error
("'$pathname' is a directory; maybe use trailing '/' to include a directory?")
799 error
("'$pathname' is not a file")
802 push @ret, $pathname;
809 # peek a token from the queue, but don't remove it
815 unless defined $script;
817 my $tokens = $script->{tokens
};
818 die unless ref $tokens eq 'ARRAY';
826 # get a token from the queue
831 unless defined $script;
833 my $tokens = $script->{tokens
};
834 die unless ref $tokens eq 'ARRAY';
839 my $token = shift @
$tokens;
841 # update $script->{past_tokens}
842 my $past_tokens = $script->{past_tokens
};
843 die unless ref $past_tokens eq 'ARRAY';
845 if (@
$past_tokens and
846 ($past_tokens->[@
$past_tokens - 1] eq '}' or
847 $past_tokens->[@
$past_tokens - 1] eq ';')) {
848 # now this is tricky: $script->{past_tokens} is used in error
849 # messages. in the following lines, we filter out everything
850 # which has become irrelevant for error messages,
851 # i.e. previous (completed) commands
853 my $t = pop @
$past_tokens;
855 # track the current level - a '}' means one level up (we are
857 my $level = $t eq '}' ?
1 : 0;
859 while (@
$past_tokens and $level >= 0) {
860 $t = pop @
$past_tokens;
862 if ($level == 0 and ($t eq '}' or $t eq ';')) {
863 # don't delete another command
864 push @
$past_tokens, $t;
866 } elsif ($t eq '}') {
869 } elsif ($t eq '{') {
870 # one level down. stop here if we're already at level
873 push @
$past_tokens, $t;
882 push @
$past_tokens, $token;
888 # require that another token exists, and that it's not a "special"
889 # token, e.g. ";" and "{"
890 sub require_next_token
{
891 my $code = shift || \
&next_token
;
893 my $token = &$code(@_);
895 error
('unexpected end of file')
896 unless defined $token;
898 error
("'$token' not allowed here")
899 if $token =~ /^[;{}]$/;
904 # return the value of a variable
905 sub variable_value
($) {
909 return $_->{vars
}{$name}
910 if exists $_->{vars
}{$name};
913 return $stack[0]{auto
}{$name}
914 if exists $stack[0]{auto
}{$name};
919 # determine the value of a variable, die if the value is an array
920 sub string_variable_value
($) {
922 my $value = variable_value
($name);
924 error
("variable '$name' must be a string, is an array")
930 # similar to the built-in "join" function, but also handle negated
931 # values in a special way
933 my ($expr, $value) = @_;
935 unless (ref $value) {
937 } elsif (ref $value eq 'ARRAY') {
938 return join($expr, @
$value);
939 } elsif (ref $value eq 'negated') {
940 # bless'negated' is a special marker for negated values
941 $value = join_value
($expr, $value->[0]);
942 return bless [ $value ], 'negated';
948 # returns the next parameter, which may either be a scalar or an array
950 my ($code, $param) = (shift, shift);
953 my $token = require_next_token
($code, $param);
956 # read an array until ")"
960 $token = getvalues
($code, $param,
961 parenthesis_allowed
=> 1,
964 unless (ref $token) {
965 last if $token eq ')';
968 error
('Comma is not allowed within arrays, please use only a space');
972 push @wordlist, $token;
973 } elsif (ref $token eq 'ARRAY') {
974 push @wordlist, @
$token;
976 error
('unknown toke type');
980 error
('empty array not allowed here')
981 unless @wordlist or not $options{non_empty
};
983 return @wordlist == 1
986 } elsif ($token =~ /^\`(.*)\`$/s) {
987 # execute a shell command, insert output
989 my $output = `$command`;
992 error
("failed to execute: $!");
993 } elsif ($?
& 0x7f) {
994 error
("child died with signal " . ($?
& 0x7f));
996 error
("child exited with status " . ($?
>> 8));
1001 $output =~ s/#.*//mg;
1004 my @tokens = grep { length } split /\s+/s, $output;
1008 my $value = getvalues
(\
&next_array_token
, \
@tokens);
1009 push @values, to_array
($value);
1016 } elsif ($token =~ /^\'(.*)\'$/s) {
1017 # single quotes: a string
1019 } elsif ($token =~ /^\"(.*)\"$/s) {
1020 # double quotes: a string with escapes
1022 $token =~ s
,\
$(\w
+),string_variable_value
($1),eg
;
1024 } elsif ($token eq '!') {
1025 error
('negation is not allowed here')
1026 unless $options{allow_negation
};
1028 $token = getvalues
($code, $param);
1030 error
('it is not possible to negate an array')
1031 if ref $token and not $options{allow_array_negation
};
1033 return bless [ $token ], 'negated';
1034 } elsif ($token eq ',') {
1036 if $options{comma_allowed
};
1038 error
('comma is not allowed here');
1039 } elsif ($token eq '=') {
1040 error
('equals operator ("=") is not allowed here');
1041 } elsif ($token eq '$') {
1042 my $name = require_next_token
($code, $param);
1043 error
('variable name expected - if you want to concatenate strings, try using double quotes')
1044 unless $name =~ /^\w+$/;
1046 my $value = variable_value
($name);
1048 error
("no such variable: \$$name")
1049 unless defined $value;
1052 } elsif ($token eq '&') {
1053 error
("function calls are not allowed as keyword parameter");
1054 } elsif ($token eq ')' and not $options{parenthesis_allowed
}) {
1055 error
('Syntax error');
1056 } elsif ($token =~ /^@/) {
1057 if ($token eq '@resolve') {
1058 my @params = get_function_params
();
1059 error
('Usage: @resolve((hostname ...))')
1060 unless @params == 1;
1061 eval { require Net
::DNS
; };
1062 error
('For the @resolve() function, you need the Perl library Net::DNS')
1065 my $resolver = new Net
::DNS
::Resolver
;
1067 foreach my $hostname (to_array
($params[0])) {
1068 my $query = $resolver->search($hostname, $type);
1069 error
("DNS query for '$hostname' failed: " . $resolver->errorstring)
1071 foreach my $rr ($query->answer) {
1072 next unless $rr->type eq $type;
1073 push @result, $rr->address;
1078 error
("unknown ferm built-in function");
1085 # returns the next parameter, but only allow a scalar
1087 my $token = getvalues
(@_);
1089 error
('array not allowed here')
1090 if ref $token and ref $token eq 'ARRAY';
1095 sub get_function_params
(%) {
1096 my $token = next_token
();
1097 error
('function name must be followed by "()"')
1098 unless defined $token and $token eq '(';
1100 $token = peek_token
();
1101 if ($token eq ')') {
1110 $token = require_next_token
();
1114 error
('"," expected')
1115 unless $token eq ',';
1118 push @params, getvalues
(undef, undef, @_);
1124 # collect all tokens in a flat array reference until the end of the
1125 # command is reached
1126 sub collect_tokens
() {
1131 my $keyword = next_token
();
1132 error
('unexpected end of file within function/variable declaration')
1133 unless defined $keyword;
1135 if ($keyword =~ /^[\{\(]$/) {
1136 push @level, $keyword;
1137 } elsif ($keyword =~ /^[\}\)]$/) {
1138 my $expected = $keyword;
1139 $expected =~ tr/\}\)/\{\(/;
1140 my $opener = pop @level;
1141 error
("unmatched '$keyword'")
1142 unless defined $opener and $opener eq $expected;
1143 } elsif ($keyword eq ';' and @level == 0) {
1147 push @tokens, $keyword;
1150 if $keyword eq '}' and @level == 0;
1157 # returns the specified value as an array. dereference arrayrefs
1160 die unless wantarray;
1162 unless (ref $value) {
1164 } elsif (ref $value eq 'ARRAY') {
1171 # evaluate the specified value as bool
1176 unless (ref $value) {
1178 } elsif (ref $value eq 'ARRAY') {
1185 sub is_netfilter_core_target
($) {
1187 die unless defined $target and length $target;
1189 return $target =~ /^(?:ACCEPT|DROP|RETURN|QUEUE)$/;
1192 sub is_netfilter_module_target
($$) {
1193 my ($domain_family, $target) = @_;
1194 die unless defined $target and length $target;
1196 return defined $domain_family &&
1197 exists $target_defs{$domain_family} &&
1198 exists $target_defs{$domain_family}{$target};
1201 sub is_netfilter_builtin_chain
($$) {
1202 my ($table, $chain) = @_;
1204 return grep { $_ eq $chain }
1205 qw(PREROUTING INPUT FORWARD OUTPUT POSTROUTING);
1208 # escape the string in a way safe for the shell
1209 sub shell_escape
($) {
1212 if ($option{fast
}) {
1213 # iptables-save/iptables-restore are quite buggy concerning
1214 # escaping and special characters... we're trying our best
1218 $token = '"' . $token . '"'
1219 if $token =~ /[\s\'\\;]/s;
1222 if $token =~ /^\`.*\`$/;
1223 $token =~ s/'/\\'/g;
1224 $token = '\'' . $token . '\''
1225 if $token =~ /[\s\"\\;<>|]/s;
1231 # append parameters to a shell command line, with the correct escape
1233 sub shell_append($@) {
1237 $$ref .= ' ' . shell_escape($_);
1241 # append an option to the shell command line, using information from
1242 # the module definition (see %match_defs etc.)
1243 sub shell_append_option($$$$) {
1244 my ($ref, $def, $keyword, $value) = @_;
1247 if (ref $value and ref $value eq 'negated') {
1248 $value = $value->[0];
1250 if (exists $def->{pre_negation}) {
1251 shell_append($ref, '!');
1257 unless (defined $value) {
1258 shell_append($ref, "--$keyword");
1259 } elsif (ref $value and ref $value eq 'params') {
1260 shell_append($ref, "--$keyword", @negated, @$value);
1261 } elsif (ref $value and ref $value eq 'ARRAY') {
1263 shell_append($ref, "--$keyword", $_);
1266 shell_append($ref, "--$keyword", @negated, $value);
1270 # dereference a bless'negated'
1271 sub extract_negation($) {
1273 ref && ref eq 'negated'
1278 # reset a netfilter domain: set all policies to ACCEPT, clear all
1279 # rules, delete custom chains
1280 sub reset_domain($) {
1282 my $domain_info = $domains{$domain};
1284 my $path = $domain_info->{tools}{tables};
1287 while (my ($table, $table_info) = each %{$domain_info->{tables}}) {
1288 while (my ($chain, $chain_info) = each %{$table_info->{chains}}) {
1289 next unless $chain_info->{builtin} or
1290 (not $table_info->{has_builtin} and
1291 is_netfilter_builtin_chain($table, $chain));
1292 push @rules, "$path -t
$table -P
$chain ACCEPT
\n";
1296 "$path -t
$table -F
\n", "$path -t
$table -X
\n";
1302 # convert an internal rule structure into an iptables call
1307 my $domain = $rule{domain};
1308 my $domain_info = $domains{$domain};
1309 my $domain_family = $rule{domain_family};
1311 my $table = $rule{table};
1312 my $table_info = $domain_info->{tables}{$table} ||= {};
1314 my $rules = $rules{$domain} ||= [];
1316 my $chain = $rule{chain};
1317 my $chain_info = $table_info->{chains}{$chain} ||= {};
1319 return if $option{flush};
1321 my $action = $rule{action};
1323 my $rr = shell_escape($domain_info->{tools}{tables});
1324 shell_append(\$rr, '-t', $table);
1326 # should we set a policy?
1327 if (exists $chain_info->{set_policy}) {
1328 my $policy = $chain_info->{policy};
1330 push @$rules, "$rr -P
$chain $policy\n";
1332 delete $chain_info->{set_policy};
1335 # mark this chain as "non
-empty
" because we will add stuff to
1336 # it now; this flag is later used to check if a custom chain
1337 # referenced by "jump
" was actually defined
1338 $chain_info->{non_empty} = 1;
1340 # check if the chain is already defined
1341 unless (exists $chain_info->{was_created} or
1342 is_netfilter_builtin_chain($table, $chain)) {
1343 push @$rules, "$rr -N
$chain\n";
1344 $chain_info->{was_created} = 1;
1347 # check for unknown jump target
1348 if (defined $action and
1349 ($action->{type} eq 'jump' or
1350 $action->{type} eq 'goto') and
1351 not exists $table_info->{chains}{$action->{chain}}{was_created}) {
1352 my $chain = $action->{chain};
1353 push @$rules, "$rr -N
$chain\n";
1354 $table_info->{chains}{$chain}{was_created} = 1;
1357 # return if this is a policy-only rule
1359 unless $rule{has_rule};
1361 shell_append(\$rr, '-A', $chain);
1363 # modules; copy the hash because we might add automatic protocol
1366 if (exists $rule{modules}) {
1367 %modules = %{$rule{modules}};
1368 shell_append(\$rr, '-m', $_)
1369 foreach keys %modules;
1372 # general iptables options
1374 if (exists $match_defs{$domain_family} and
1375 exists $match_defs{$domain_family}{''}) {
1376 while (my ($keyword, $k) = each %{$match_defs{$domain_family}{''}{keywords}}) {
1377 my $key = "builtin____
${keyword
}";
1378 next unless exists $rule{$key};
1379 my $value = $rule->{$key};
1381 shell_append_option(\$rr, $k, $keyword, $value);
1386 # match module options
1389 if (defined $rule{builtin____protocol}) {
1390 my $proto = $rule{builtin____protocol};
1392 if $domain eq 'ip6' and $proto eq 'ipv6-icmp';
1394 if $domain eq 'ip6' and $proto eq 'ipv6-mh';
1396 if (exists $proto_defs{$domain_family}{$proto}) {
1397 my $def = $proto_defs{$domain_family}{$proto};
1398 while (my ($keyword, $k) = each %{$def->{keywords}}) {
1399 my $key = "protocol__
${proto
}__
$keyword";
1400 next unless exists $rule{$key};
1401 my $value = $rule->{$key};
1403 my $module = $proto eq 'icmpv6' ? 'icmp6' : $proto;
1404 unless (exists $modules{$module}) {
1405 shell_append(\$rr, '-m', $module);
1406 $modules{$module} = 1;
1409 shell_append_option(\$rr, $k, $keyword, $value);
1413 # special case: --dport and --sport for TCP/UDP
1414 if ($domain_family eq 'ip' and
1415 (exists $rule{dport} or exists $rule{sport}) and
1416 $proto =~ /^(?:tcp|udp|udplite|dccp|sctp)$/) {
1417 unless (exists $modules{$proto}) {
1418 shell_append(\$rr, '-m', $proto);
1419 $modules{$proto} = 1;
1422 shell_append_option(\$rr, { params => 1,
1424 }, 'dport', $rule{dport})
1425 if exists $rule{dport};
1426 shell_append_option(\$rr, { params => 1,
1428 }, 'sport', $rule{sport})
1429 if exists $rule{sport};
1433 # modules stored in %match_defs
1434 while (my ($key, $value) = each %rule) {
1435 next unless $key =~ /^module__(\w+)__([-\w]+)$/;
1436 my ($module_name, $keyword) = ($1, $2);
1438 my $def = $match_defs{$rule{domain_family}}{$module_name}{keywords}{$keyword};
1439 die unless defined $def;
1441 shell_append_option(\$rr, $def, $keyword, $value);
1448 if ($action->{type} eq 'jump') {
1449 shell_append(\$rr, '-j', $action->{chain});
1450 } elsif ($action->{type} eq 'goto') {
1451 shell_append(\$rr, '-g', $action->{chain});
1452 } elsif ($action->{type} eq 'target') {
1453 shell_append(\$rr, '-j', $action->{target});
1455 # targets stored in %target_defs
1457 while (my ($keyword, $value) = each %{$rule{target_options}}) {
1458 my $def = $target_defs{$domain_family}{$action->{target}}{keywords}{$keyword};
1459 die unless defined $def;
1461 shell_append_option(\$rr, $def, $keyword, $value);
1463 } elsif ($action->{type} ne 'nop') {
1469 push @$rules, { rule => $rr,
1470 script => $rule{script},
1474 sub transform_rule($) {
1477 $rule->{builtin____protocol} = 'icmpv6'
1478 if $rule->{domain} eq 'ip6' and $rule->{builtin____protocol} eq 'icmp';
1484 transform_rule($rule);
1486 # prints all rules in a hash
1491 # convert a bunch of internal rule structures in iptables calls,
1492 # unfold arrays during that
1494 # compile the list hashes into rules
1497 # pack the data in a handy format (list-of-hashes with one kw
1498 # per level, so we can recurse...
1501 foreach my $current (@$fw) {
1502 while (my ($key, $value) = each %$current) {
1503 push @fr, [ $key, $value ];
1509 my $current = shift;
1511 my ($key, $value_string) = @$current;
1513 unless (ref $value_string and
1514 $key ne 'target_options' and
1515 ref $value_string ne 'params' and
1516 ref $value_string ne 'negated') {
1517 # set this one and recurse
1518 $rule->{$key} = $value_string;
1526 delete $rule->{$key};
1527 } elsif (ref $value_string eq 'ARRAY') {
1528 # recurse for every value
1529 foreach my $value (@$value_string) {
1530 # set this one and recurse
1531 $rule->{$key} = $value;
1540 delete $rule->{$key};
1541 } elsif (ref $value_string eq 'HASH') {
1543 my $old = $rule->{$key};
1545 $rule->{$key} = { ( defined $old
1561 $rule->{$key} = $old;
1563 delete $rule->{$key};
1566 die ref $value_string;
1573 # find an option in the rule stack
1574 sub find_option($$) {
1575 my ($fw, $key) = @_;
1577 my $item = (grep { exists $_->{$key} } reverse @$fw)[0];
1578 return unless defined $item;
1580 return $item->{$key};
1583 sub filter_domains($) {
1584 my $domains = shift;
1587 foreach my $domain (to_array $domains) {
1588 next if exists $option{domain}
1589 and $domain ne $option{domain};
1592 initialize_domain($domain);
1596 push @$result, $domain;
1599 return @$result == 1 ? $result->[0] : $result;
1602 # parse tokens from builtin match modules
1603 sub parse_builtin_matches($$$$$) {
1604 my ($fw, $current, $domain_family, $keyword, $negated_ref) = @_;
1606 if (exists $match_defs{$domain_family}) {
1607 parse_option('builtin', $match_defs{$domain_family}, '',
1609 $keyword, $negated_ref)
1616 # parse a keyword from a module definition
1617 sub parse_keyword($$$$) {
1618 my ($fw, $def, $keyword, $negated_ref) = @_;
1620 my $params = $def->{params};
1625 if ($$negated_ref && exists $def->{pre_negation}) {
1627 undef $$negated_ref;
1630 unless (defined $params) {
1632 } elsif (ref $params && ref $params eq 'CODE') {
1633 $value = &$params($fw);
1634 } elsif ($params =~ /^[a-z]/) {
1635 if (exists $def->{negation} and not $negated) {
1636 my $token = peek_token();
1637 if ($token eq '!') {
1644 foreach my $p (split(//, $params)) {
1646 push @params, getvar();
1647 } elsif ($p eq 'a') {
1648 push @params, getvalues();
1649 } elsif ($p eq 'c') {
1650 my @v = to_array getvalues(undef, undef,
1652 push @params, join(',', @v);
1658 $value = @params == 1
1660 : bless \@params, 'params';
1661 } elsif ($params == 1) {
1662 if (exists $def->{negation} and not $negated) {
1663 my $token = peek_token();
1664 if ($token eq '!') {
1670 $value = getvalues();
1672 warning("log-prefix is too long
; truncating to
29 characters
: '$1'")
1673 if $keyword eq 'log-prefix' && $value =~ s,^(.{29}).+$,$1,;
1675 if (exists $def->{negation} and not $negated) {
1676 my $token = peek_token();
1677 if ($token eq '!') {
1683 $value = bless [ map {
1685 } (1..$params) ], 'params';
1688 $value = bless [ $value ], 'negated'
1694 # parse options of a module
1695 sub parse_option($$$$$$$) {
1696 my ($type, $defs, $name, $fw, $current, $keyword, $negated_ref) = @_;
1698 my $def = $defs->{$name};
1699 return unless defined $def;
1701 my $k = $def->{keywords}{$keyword};
1702 return unless defined $k;
1704 while (exists $k->{alias}) {
1705 die if $k->{alias} eq $keyword;
1706 $keyword = $k->{alias};
1707 $k = $defs->{$name}{keywords}{$keyword};
1708 die unless defined $k;
1711 $current->{"${type
}__
${name
}__
${keyword
}"}
1712 = parse_keyword($fw, $k,
1713 $keyword, $negated_ref);
1717 # parse options for a protocol module definition
1718 sub parse_protocol_options($$$$$) {
1719 my ($fw, $current, $proto, $keyword, $negated_ref) = @_;
1721 my $domain_family = find_option($fw, 'domain_family');
1722 my $proto_defs = $proto_defs{$domain_family};
1723 return unless defined $proto_defs;
1725 return parse_option('protocol', $proto_defs, $proto, $fw, $current,
1726 $keyword, $negated_ref);
1729 # parse options of a match module
1730 sub parse_match_option($$$$$$) {
1731 my ($match_defs, $name, $fw, $current, $keyword, $negated_ref) = @_;
1733 return parse_option('module', $match_defs, $name, $fw, $current,
1734 $keyword, $negated_ref);
1737 # parse options for a match module definition
1738 sub parse_module_options($$$$$$) {
1739 my ($fw, $current, $modules, $keyword, $negated_ref, $proto) = @_;
1741 my $domain_family = find_option($fw, 'domain_family');
1742 my $match_defs = $match_defs{$domain_family};
1743 return unless defined $match_defs;
1745 # modules stored in %match_defs
1746 foreach my $name (keys %$modules) {
1747 parse_match_option($match_defs, $name, $fw, $current,
1748 $keyword, $negated_ref)
1759 # parse options for a target module definition
1760 sub parse_target_options($$$$) {
1761 my ($fw, $current, $target, $keyword) = @_;
1763 my $domain_family = find_option($fw, 'domain_family');
1764 my $target_defs = $target_defs{$domain_family};
1765 return unless defined $target_defs &&
1766 exists $target_defs->{$target}{keywords}{$keyword};
1768 my $k = $target_defs->{$target}{keywords}{$keyword};
1770 while (exists $k->{alias}) {
1771 die if $k->{alias} eq $keyword;
1772 $keyword = $k->{alias};
1773 $k = $target_defs->{$target}{keywords}{$keyword};
1774 die unless defined $k;
1778 $current->{target_options}{$keyword}
1779 = parse_keyword($fw, $k,
1780 $keyword, \$negated_dummy);
1785 # the main parser loop: read tokens, convert them into internal rule
1788 my $lev = shift; # current recursion depth
1789 my @fw = @_; # fwset in list of hashes
1791 die unless @fw == $lev;
1793 # enter is the core of the firewall setup, it is a
1794 # simple parser program that recognizes keywords and
1795 # retreives parameters to set up the kernel routing
1798 my $base_level = $script->{base_level} || 0;
1799 die if $base_level > $lev;
1804 my $domain_family = find_option(\@fw, 'domain_family');
1806 my %modules = map { $_->{modules} ? %{$_->{modules}} : () } @fw;
1808 # read keywords 1 by 1 and dump into parser
1809 while (defined (my $keyword = next_token())) {
1810 # check if the current rule should be negated
1811 my $negated = $keyword eq '!';
1813 # negation. get the next word which contains the 'real'
1815 $keyword = getvar();
1817 error('unexpected end of file after negation')
1818 unless defined $keyword;
1821 # the core: parse all data
1822 SWITCH: for ($keyword)
1824 # deprecated keyword?
1825 if (exists $deprecated_keywords{$keyword}) {
1826 my $new_keyword = $deprecated_keywords{$keyword};
1827 warning("'$keyword' is deprecated
, please
use '$new_keyword' instead
");
1828 $keyword = $new_keyword;
1831 # effectuation operator
1832 if ($keyword eq ';') {
1833 my $has_rule = find_option(\@fw, 'has_rule');
1834 my $action = find_option(\@fw, 'action');
1835 my $policy = find_option(\@fw, 'policy');
1836 my $chain = find_option(\@fw, 'chain');
1838 if ($has_rule and not defined $action) {
1839 # something is wrong when a rule was specifiedd,
1841 error('No action defined; did you mean "NOP
"?');
1844 error('No chain defined') unless defined $chain;
1846 $current->{script} = { filename => $script->{filename},
1847 line => $script->{line},
1851 if $has_rule or defined $policy;
1853 # and clean up variables set in this level
1859 # conditional expression
1860 if ($keyword eq '@if') {
1861 unless (eval_bool(getvalues)) {
1863 my $token = peek_token();
1864 require_next_token() if $token and $token eq '@else';
1870 if ($keyword eq '@else') {
1871 # hack: if this "else" has not been eaten by the "if"
1872 # handler above, we believe it came from an if clause
1873 # which evaluated "true
" - remove the "else" part now.
1878 # hooks for custom shell commands
1879 if ($keyword eq 'hook') {
1880 error('"hook
" must be the first token in a command')
1883 my $position = getvar();
1885 if ($position eq 'pre') {
1886 $hooks = \@pre_hooks;
1887 } elsif ($position eq 'post') {
1888 $hooks = \@post_hooks;
1890 error("Invalid hook position
: '$position'");
1893 push @$hooks, getvar();
1895 $keyword = next_token();
1896 error('";" expected after hook declaration')
1897 unless defined $keyword and $keyword eq ';';
1902 # recursing operators
1903 if ($keyword eq '{') {
1905 my $old_stack_depth = @stack;
1907 unshift @stack, { auto => { %{$stack[0]{auto} || {}} } };
1910 enter($lev + 1, @fw);
1914 die unless @stack == $old_stack_depth;
1916 # after a block, the command is finished, clear this
1923 if ($keyword eq '}') {
1924 error('Unmatched "}"')
1925 if $lev <= $base_level;
1927 # consistency check: check if they havn't forgotten
1928 # the ';' before the last statement
1929 error('Missing semicolon before "}"')
1936 # include another file
1937 if ($keyword eq '@include' or $keyword eq 'include') {
1938 my @files = collect_filenames to_array getvalues;
1939 $keyword = next_token;
1940 error('Missing ";" - "include FILENAME
" must be the last command in a rule')
1941 unless defined $keyword and $keyword eq ';';
1943 foreach my $filename (@files) {
1944 # save old script, open new script
1945 my $old_script = $script;
1946 open_script($filename);
1947 $script->{base_level} = $lev + 1;
1950 my $old_stack_depth = @stack;
1955 # include files may set variables for their parent
1956 $stack->{vars} = ($stack[0]{vars} ||= {});
1957 $stack->{functions} = ($stack[0]{functions} ||= {});
1958 $stack->{auto} = { %{ $stack[0]{auto} || {} } };
1961 unshift @stack, $stack;
1964 enter($lev + 1, @fw);
1968 die unless @stack == $old_stack_depth;
1970 # restore old script
1971 $script = $old_script;
1977 # definition of a variable or function
1978 if ($keyword eq '@def' or $keyword eq 'def') {
1979 error('"def
" must be the first token in a command')
1982 my $type = require_next_token();
1984 my $name = require_next_token();
1985 error('invalid variable name')
1986 unless $name =~ /^\w+$/;
1988 $keyword = require_next_token();
1989 error('"=" expected after variable name')
1990 unless $keyword eq '=';
1992 my $value = getvalues(undef, undef, allow_negation => 1);
1994 $keyword = next_token();
1995 error('";" expected after variable declaration')
1996 unless defined $keyword and $keyword eq ';';
1998 $stack[0]{vars}{$name} = $value
1999 unless exists $stack[-1]{vars}{$name};
2000 } elsif ($type eq '&') {
2001 my $name = require_next_token();
2002 error('invalid function name')
2003 unless $name =~ /^\w+$/;
2006 my $token = next_token();
2007 error('function parameter list or "()" expected')
2008 unless defined $token and $token eq '(';
2010 $token = require_next_token();
2011 last if $token eq ')';
2014 error('"," expected')
2015 unless $token eq ',';
2017 $token = require_next_token();
2020 error('"$" and parameter name expected')
2021 unless $token eq '$';
2023 $token = require_next_token();
2024 error('invalid function parameter name')
2025 unless $token =~ /^\w+$/;
2027 push @params, $token;
2032 $function{params} = \@params;
2034 $keyword = require_next_token;
2035 error('"=" expected')
2036 unless $keyword eq '=';
2038 my $tokens = collect_tokens();
2039 $function{block} = 1 if grep { $_ eq '{' } @$tokens;
2040 $function{tokens} = $tokens;
2042 $stack[0]{functions}{$name} = \%function
2043 unless exists $stack[-1]{functions}{$name};
2045 error('"$" (variable) or "&" (function) expected');
2052 if ($keyword eq '$') {
2053 error('variable references are only allowed as keyword parameter');
2056 if ($keyword eq '&') {
2057 my $name = require_next_token;
2058 error('function name expected')
2059 unless $name =~ /^\w+$/;
2063 $function = $_->{functions}{$name};
2064 last if defined $function;
2066 error("no such function
: \
&$name")
2067 unless defined $function;
2069 my $paramdef = $function->{params};
2070 die unless defined $paramdef;
2072 my @params = get_function_params(allow_negation => 1);
2074 error("Wrong number of parameters
for function
'\&$name': "
2075 . @$paramdef . " expected
, " . @params . " given")
2076 unless @params == @$paramdef;
2079 for (my $i = 0; $i < @params; $i++) {
2080 $vars{$paramdef->[$i]} = $params[$i];
2083 if ($function->{block}) {
2084 # block {} always ends the current rule, so if the
2085 # function contains a block, we have to require
2086 # the calling rule also ends here
2087 my $token = next_token();
2088 error("';' expected after block function call
'\&$name'")
2089 unless defined $token and $token eq ';';
2092 my @tokens = @{$function->{tokens}};
2093 for (my $i = 0; $i < @tokens; $i++) {
2094 if ($tokens[$i] eq '$' and $i + 1 < @tokens and
2095 exists $vars{$tokens[$i + 1]}) {
2096 my @value = to_array($vars{$tokens[$i + 1]});
2097 @value = ('(', @value, ')')
2098 unless @tokens == 1;
2099 splice(@tokens, $i, 2, @value);
2101 } elsif ($tokens[$i] =~ m,^"(.*)"$,) {
2102 $tokens[$i] =~ s,\$(\w+),exists $vars{$1} ? $vars{$1} : "\
$$1",eg;
2106 unshift @{$script->{tokens}}, @tokens;
2111 # where to put the rule?
2112 if ($keyword eq 'domain') {
2113 error('Domain is already specified')
2114 if exists $current->{domain};
2116 my $domain = getvalues();
2117 my $filtered_domain = filter_domains($domain);
2118 unless (ref $domain) {
2119 $domain_family = $domain eq 'ip6' ? 'ip' : $domain;
2120 } elsif (@$domain == 0) {
2121 $domain_family = 'none';
2122 } elsif (grep { not /^ip6?$/s } @$domain) {
2123 error('Cannot combine non-IP domains');
2125 $domain_family = 'ip';
2127 $current->{domain_family} = $domain_family;
2129 $current->{domain} = $stack[0]{auto}{DOMAIN} = $filtered_domain;
2134 if ($keyword eq 'table') {
2135 error('Table is already specified')
2136 if exists $current->{table};
2137 $current->{table} = $stack[0]{auto}{TABLE} = getvalues();
2139 unless (defined find_option(\@fw, 'domain')) {
2140 $current->{domain} = filter_domains('ip');
2141 $current->{domain_family} = $domain_family = 'ip';
2147 if ($keyword eq 'chain') {
2148 error('Chain is already specified')
2149 if exists $current->{chain};
2150 $current->{chain} = $stack[0]{auto}{CHAIN} = getvalues();
2152 # ferm 1.1 allowed lower case built-in chain names
2153 foreach (ref $current->{chain} ? @{$current->{chain}} : $current->{chain}) {
2154 error('Please write built-in chain names in upper case')
2155 if /^(?:input|forward|output|prerouting|postrouting)$/;
2158 my $domain = find_option(\@fw, 'domain');
2159 unless (defined find_option(\@fw, 'domain')) {
2160 $current->{domain} = filter_domains('ip');
2161 $current->{domain_family} = $domain_family = 'ip';
2164 $current->{table} = 'filter'
2165 unless defined find_option(\@fw, 'table');
2170 # policy for built-in chain
2171 if ($keyword eq 'policy') {
2172 my $domains = find_option(\@fw, 'domain');
2173 my $tables = find_option(\@fw, 'table');
2174 my $chains = find_option(\@fw, 'chain');
2176 error('Chain must be specified')
2177 unless defined $chains;
2179 my $policy = uc getvar();
2180 error("Invalid policy target
: $policy")
2181 unless $policy =~ /^(?:ACCEPT|DROP)$/;
2183 foreach my $domain (to_array $domains) {
2184 foreach my $table (to_array $tables) {
2185 my $chains_info = $domains{$domain}{tables}{$table}{chains} ||= {};
2187 foreach my $chain (to_array $chains) {
2188 error("cannot set the policy
for non
-builtin chain
'$chain'")
2189 unless is_netfilter_builtin_chain($table, $chain);
2191 if (exists $chains_info->{$chain}{policy}) {
2192 warning('policy for this chain is specified for the second time');
2194 $chains_info->{$chain}{policy} = $policy;
2195 $chains_info->{$chain}{set_policy} = 1;
2201 $current->{policy} = $policy;
2206 if ($keyword eq '@subchain' or $keyword eq 'subchain') {
2207 error('No rule specified before "@subchain"')
2208 unless find_option(\@fw, 'has_rule');
2211 $keyword = next_token();
2213 if ($keyword =~ /^(["'])(.*)\1$/s) {
2215 $keyword = next_token();
2217 $subchain = 'ferm_auto_
' . ++$auto_chain;
2220 error('"{" or chain name expected after
"sub"')
2221 unless $keyword eq '{';
2223 # create a deep copy of @fw, only containing values
2224 # which must be in the subchain
2226 foreach my $fw (@fw) {
2228 foreach my $key (qw(domain domain_family table builtin____protocol)) {
2229 my $value = $fw->{$key};
2230 next unless defined $value;
2232 ?
( ref $value eq 'HASH'
2237 $fw2->{$key} = $value;
2242 $fw2[-1]->{chain
} = $fw2[-1]->{auto
}{CHAIN
} = $subchain;
2245 enter
($lev + 1, @fw2);
2247 # now handle the parent - it's a jump to the sub chain
2248 $current->{action
} = { type
=> 'jump',
2252 $current->{script
} = { filename
=> $script->{filename
},
2253 line
=> $script->{line
},
2258 # and clean up variables set in this level
2264 # everything else must be part of a "real" rule, not just
2266 $current->{has_rule
}++;
2268 # extended parameters:
2269 if ($keyword =~ /^mod(?:ule)?$/) {
2270 my $domains = find_option
(\
@fw, 'domain');
2272 foreach my $module (to_array getvalues
) {
2273 $current->{modules
}{$module} = 1;
2274 $modules{$module} = 1;
2280 parse_builtin_matches
(\
@fw, $current, $domain_family,
2281 $keyword, \
$negated)
2289 if ($keyword eq 'jump') {
2290 error
('There can only one action per rule')
2291 if exists $current->{action
};
2292 warning
('Please declare the policy in a separate statement')
2293 if find_option
(\
@fw, 'policy');
2294 my $chain = getvar
();
2295 if (is_netfilter_core_target
($chain) or
2296 is_netfilter_module_target
($domain_family, $chain)) {
2297 $current->{action
} = { type
=> 'target',
2301 $current->{action
} = { type
=> 'jump',
2309 if ($keyword eq 'realgoto') {
2310 error
('There can only one action per rule')
2311 if exists $current->{action
};
2312 warning
('Please declare the policy in a separate statement')
2313 if find_option
(\
@fw, 'policy');
2314 $current->{action
} = { type
=> 'goto',
2321 if (is_netfilter_core_target
($keyword)) {
2322 error
('There can only one action per rule')
2323 if exists $current->{action
};
2324 warning
('Please declare the policy in a separate statement')
2325 if find_option
(\
@fw, 'policy');
2326 $current->{action
} = { type
=> 'target',
2332 if ($keyword eq 'NOP') {
2333 error
('There can only one action per rule')
2334 if exists $current->{action
};
2335 warning
('Please declare the policy in a separate statement')
2336 if find_option
(\
@fw, 'policy');
2337 $current->{action
} = { type
=> 'nop',
2342 if (is_netfilter_module_target
($domain_family, $keyword)) {
2343 error
('There can only one action per rule')
2344 if exists $current->{action
};
2345 warning
('Please declare the policy in a separate statement')
2346 if find_option
(\
@fw, 'policy');
2348 if ($keyword eq 'TCPMSS') {
2349 my $protos = find_option
(\
@fw, 'builtin____protocol');
2350 error
('No protocol specified before TCPMSS')
2351 unless defined $protos;
2352 foreach my $proto (to_array
$protos) {
2353 error
('TCPMSS not available for protocol "$proto"')
2354 unless $proto eq 'tcp';
2358 $current->{action
} = { type
=> 'target',
2365 # protocol specific options
2368 my $proto = find_option
(\
@fw, 'builtin____protocol');
2369 if (defined $proto and not ref $proto) {
2370 $proto = 'icmpv6' if $proto eq 'ipv6-icmp';
2371 $proto = 'mh' if $proto eq 'ipv6-mh';
2373 if ($proto eq 'icmp') {
2374 my $domains = find_option
(\
@fw, 'domain');
2375 $proto = 'icmpv6' if not ref $domains and $domains eq 'ip6';
2378 parse_protocol_options
(\
@fw, $current, $proto, $keyword, \
$negated)
2383 if ($keyword =~ /^[sd]port$/) {
2384 error
('To use sport or dport, you have to specify "proto tcp" or "proto udp" first')
2385 unless defined $proto and grep { /^(?:tcp|udp|udplite|dccp|sctp)$/ } to_array
$proto;
2387 $current->{$keyword} = getvalues
(undef, undef,
2388 allow_negation
=> 1);
2393 # module specific options
2396 if (keys %modules) {
2397 parse_module_options
(\
@fw, $current, \
%modules, $keyword, \
$negated, $proto)
2402 # target specific options
2405 my $action = find_option
(\
@fw, 'action');
2406 if (defined $action and $action->{type
} eq 'target') {
2407 parse_target_options
(\
@fw, $current,
2408 $action->{target
}, $keyword);
2413 error
("Unrecognized keyword: $keyword");
2416 # if the rule didn't reset the negated flag, it's not
2418 error
("Doesn't support negation: $keyword")
2422 error
('Missing "}" at end of file')
2423 if $lev > $base_level;
2425 # consistency check: check if they havn't forgotten
2426 # the ';' before the last statement
2427 error
("Missing semicolon before end of file")
2432 while (my ($domain_name, $domain) = each %domains) {
2433 while (my ($table_name, $table_info) = each %{$domain->{tables
}}) {
2434 while (my ($chain_name, $chain) = each %{$table_info->{chains
}}) {
2435 warning
("chain $chain_name (domain $domain_name, table $table_name) was referenced, but not declared")
2436 if $chain->{was_created
} and not $chain->{non_empty
};
2442 sub execute_slow
($$) {
2443 my ($domain, $rules) = @_;
2446 foreach (reset_domain
($domain), @
$rules) {
2450 $script = $_->{script
};
2457 next if $option{noexec
};
2460 my $ret = system($_);
2461 unless ($ret == 0) {
2463 print STDERR
"failed to execute: $!\n";
2465 } elsif ($?
& 0x7f) {
2466 printf STDERR
"child died with signal %d\n", $?
& 0x7f;
2469 print STDERR
"(rule declared in $script->{filename}:$script->{line})\n"
2479 sub rules_to_save
($$) {
2480 my ($domain, $rules) = @_;
2482 # parse the current ruleset, ignore -X and -F, handle policies and
2486 foreach my $rule (reset_domain
($domain), @
$rules) {
2487 $rule = $rule->{rule
}
2490 $rule =~ s/^\S+\s+//;
2491 my $table = $rule =~ s/-t\s+(\w+)\s*//
2493 if ($rule =~ /-P\s+(\S+)\s+(\w+)\s*/) {
2494 $policies{$table}{$1} = $2;
2495 } elsif ($rule =~ /-A\s+(\w+)/) {
2496 push @
{$rules{$table}{$1}}, $rule;
2497 } elsif ($rule =~ /-N\s+(\S+)\s*/) {
2498 $policies{$table}{$1} = '-';
2502 # convert this into an iptables-save text
2503 my $result = "# Generated by ferm $VERSION on " . localtime() . "\n";
2505 foreach my $table (qw(nat filter mangle raw)) {
2506 my $policies = $policies{$table};
2507 my $r = $rules{$table};
2510 unless defined $policies or defined $r;
2513 $result .= '*' . $table . "\n";
2515 # create chains / set policy
2516 if (defined $policies) {
2517 foreach my $chain (sort keys %$policies) {
2518 my $policy = $policies->{$chain};
2519 $result .= ":$chain $policy\ [0:0]\n";
2525 foreach my $chain (sort keys %$r) {
2526 my $rs = $r->{$chain};
2534 $result .= "COMMIT\n";
2540 sub restore_domain
($$) {
2541 my ($domain, $save) = @_;
2543 my $path = $domains{$domain}{tools
}{'tables-restore'};
2546 open RESTORE
, "|$path"
2547 or die "Failed to run $path: $!\n";
2549 print RESTORE
$save;
2552 or die "Failed to run $path\n";
2555 sub execute_fast
($$) {
2556 my ($domain, $save) = @_;
2558 if ($option{lines
}) {
2559 print LINES
"$domains{$domain}{tools}{'tables-restore'} <<EOT\n"
2566 return if $option{noexec};
2569 restore_domain($domain, $save);
2581 foreach my $domain (keys %rules) {
2582 unless (defined $domains{$domain}{tools}{'tables-restore'}) {
2583 print STDERR "Cannot rollback domain
'$domain' because there is
no ${domain
}tables
-restore
\n";
2588 while (my ($table, $table_info) = each %{$domains{$domain}{tables}}) {
2589 my $reset_chain = '';
2590 foreach my $chain (keys %{$table_info->{chains}{$table}}) {
2591 next unless is_netfilter_builtin_chain($table, $chain);
2592 $reset_chain .= ":${chain
} ACCEPT
[0:0]\n";
2594 $reset .= "*${table
}\n${reset_chain
}COMMIT
\n"
2595 if length $reset_chain;
2598 $reset .= $domains{$domain}{previous}
2599 if defined $domains{$domain}{previous};
2601 restore_domain($domain, $reset);
2604 print STDERR "\nFirewall rules rolled back
.\n" unless $error;
2609 # do nothing, just interrupt a system call
2612 sub confirm_rules() {
2613 $SIG{ALRM} = \&alrm_handler;
2618 . "ferm has applied the new firewall rules
.\n"
2619 . "Please type
'yes' to confirm
:\n";
2625 STDIN->sysread($line, 3);
2629 POSIX::tcflush(*STDIN, 2);
2631 print STDERR "$@
" if $@;
2633 $SIG{ALRM} = 'DEFAULT';
2635 return $line eq 'yes';
2644 ferm - a firewall rule parser for linux
2648 B<ferm> I<options> I<inputfiles>
2652 -n, --noexec Do not execute the rules, just simulate
2653 -F, --flush Flush all netfilter tables managed by ferm
2654 -l, --lines Show all rules that were created
2655 -i, --interactive Interactive mode: revert if user does not confirm
2656 --remote Remote mode; ignore host specific configuration.
2657 This implies --noexec and --lines.
2658 -V, --version Show current version number
2659 -h, --help Look at this text
2660 --fast Generate an iptables-save file, used by iptables-restore
2661 --shell Generate a shell script which calls iptables-restore
2662 --domain {ip|ip6} Handle only the specified domain
2663 --def '$name=v' Override a variable