# The LearningOnline Network with CAPA
# Firewall configuration to allow internal LON-CAPA communication between servers
#
# $Id: Firewall.pm,v 1.13 2013/09/22 15:50:35 raeburn Exp $
#
# The LearningOnline Network with CAPA
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA 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 LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
# Startup script for the LON-CAPA network processes
#
package LONCAPA::Firewall;
use strict;
use lib '/home/httpd/perl/lib';
use LONCAPA::Configuration;
use LONCAPA;
sub firewall_open_port {
my ($iptables,$fw_chains,$lond_port,$iphost,$ports) = @_;
return 'inactive firewall' if (!&firewall_is_active());
return 'port number unknown' if !$lond_port;
return 'invalid firewall chain' unless (ref($fw_chains) eq 'ARRAY');
my (@opened,@chains,@badchains,@okchains);
foreach my $chain (@{$fw_chains}) {
if ($chain =~ /^([\w\-]+)$/) {
push(@okchains,$1);
} else {
push(@badchains,$chain);
}
}
if (!@okchains) {
return 'None of the chain names has the expected format'."\n";
}
if (ref($ports) ne 'ARRAY') {
return 'List of ports to open needed.';
}
foreach my $portnum (@{$ports}) {
my $port = '';
if ($portnum =~ /^(\d+)$/) {
$port = $1;
} else {
print "Skipped non-numeric port: $portnum\n";
next;
}
print "Opening firewall access on port $port.\n";
my $result;
if ($port eq $lond_port) {
# For lond port, restrict the servers allowed to attempt to communicate
# to include only source IPs in the LON-CAPA cluster.
my (@port_error,%command_error,@lond_port_open,
@lond_port_curropen);
if (ref($iphost) eq 'HASH') {
if (keys(%{$iphost}) > 0) {
my %curropen;
foreach my $fw_chain (@okchains) {
&firewall_close_anywhere($iptables,$fw_chain,$port);
my $current = &firewall_is_port_open($iptables,$fw_chain,$port,$lond_port,$iphost,\%curropen);
}
foreach my $key (keys(%{$iphost})) {
my $ip = '';
if ($key =~ /^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/) {
if (($1<=255) && ($2<=255) && ($3<=255) && ($4<=255)) {
$ip = "$1.$2.$3.$4";
} else {
print "IP address: $key does not have expected format\n";
next;
}
} else {
print "IP address: $key does not have expected format\n";
next;
}
if ($curropen{$ip}) {
push(@lond_port_curropen,$ip);
} else {
foreach my $fw_chain (@okchains) {
my $firewall_command =
"$iptables -I $fw_chain -p tcp -s $ip -d 0/0 --dport $port -j ACCEPT";
system($firewall_command);
my $return_status = $?>>8;
if ($return_status == 1) {
unless(grep(/^\Q$ip\E$/,@port_error)) {
push (@port_error,$ip);
}
} elsif ($return_status == 2) {
push(@{$command_error{$fw_chain}},$ip);
} elsif ($return_status == 0) {
push(@lond_port_open,$ip);
last;
}
}
}
}
} else {
print "no key found in $iphost hash ref\n";
}
} else {
print "$iphost is not a reference to a hash\n";
}
if (@lond_port_curropen) {
unless (grep(/^\Q$port\E$/,@opened)) {
push(@opened,$port);
}
print "Port already open for ".scalar(@lond_port_curropen)." IP addresses\n";
}
if (@lond_port_open) {
unless (grep(/^\Q$port\E$/,@opened)) {
push(@opened,$port);
}
print "Port opened for ".scalar(@lond_port_open)." IP addresses\n";
}
if (@port_error) {
print "Error opening port for following IP addresses: ".join(', ',@port_error)."\n";
}
if (keys(%command_error) > 0) {
foreach my $chain (sort(keys(%command_error))) {
if (ref($command_error{$chain}) eq 'ARRAY') {
if (@{$command_error{$chain}}) {
print "Bad command error opening port for following IP addresses: ".
join(', ',@{$command_error{$chain}})."\n".
'Command was: "'."$iptables -I $chain -p tcp -s ".'$ip'." -d 0/0 --dport $port -j ACCEPT".'", where $ip is IP address'."\n";
}
}
}
}
} else {
my (@port_errors,%command_errors);
foreach my $fw_chain (@okchains) {
my $firewall_command =
"$iptables -I $fw_chain -p tcp -d 0/0 --dport $port -j ACCEPT";
system($firewall_command);
my $return_status = $?>>8;
if ($return_status == 1) {
push(@port_errors,$fw_chain);
} elsif ($return_status == 2) {
$command_errors{$fw_chain} = $firewall_command;
} elsif ($return_status == 0) {
push(@opened,$port);
last;
}
}
unless (grep(/^\Q$port\E$/,@opened)) {
if (@port_errors) {
print "Error opening port for chains: ".
join(', ',@port_errors).".\n";
}
if (keys(%command_errors)) {
foreach my $fw_chain (sort(keys(%command_errors))) {
print "Bad command error opening port for chain: $fw_chain. Command was\n".
" ".$command_errors{$fw_chain}."\n";
}
}
}
}
}
foreach my $port (@{$ports}) {
if (!grep(/^\Q$port\E$/,@opened)) {
return 'Required port not open: '.$port."\n";
}
}
return 'ok';
}
sub firewall_is_port_open {
my ($iptables,$fw_chain,$port,$lond_port,$iphost,$curropen) = @_;
# for lond port returns number of source IPs for which firewall port is open
# for other ports returns 1 if the firewall port is open, 0 if not.
#
# check if firewall is active or installed
return if (! &firewall_is_active());
my $count = 0;
if (open(PIPE,"$iptables -L $fw_chain -n |")) {
while(<PIPE>) {
if ($port eq $lond_port) {
if (ref($iphost) eq 'HASH') {
if (/^ACCEPT\s+tcp\s+\-{2}\s+(\S+)\s+\S+\s+tcp\s+dpt\:\Q$port\E/) {
my $ip = $1;
if ($iphost->{$ip}) {
$count ++;
if (ref($curropen) eq 'HASH') {
$curropen->{$ip} ++;
}
}
}
}
} else {
if (/tcp dpt\:\Q$port\E/) {
$count ++;
last;
}
}
}
close(PIPE);
}
return $count;
}
sub firewall_is_active {
if (-e '/proc/net/ip_tables_names') {
return 1;
} else {
return 0;
}
}
sub firewall_close_port {
my ($iptables,$fw_chains,$lond_port,$iphost,$ports) = @_;
return 'inactive firewall' if (!&firewall_is_active());
return 'port number unknown' if !$lond_port;
return 'invalid firewall chain' unless (ref($fw_chains) eq 'ARRAY');
my (@opened,@chains,@badchains,@okchains);
foreach my $chain (@{$fw_chains}) {
if ($chain =~ /^([\w\-]+)$/) {
push(@okchains,$1);
} else {
push(@badchains,$chain);
}
}
if (!@okchains) {
return 'None of the chain names has the expected format'."\n";
}
if (ref($ports) ne 'ARRAY') {
return 'List of ports to close needed.';
}
foreach my $portnum (@{$ports}) {
my $port = '';
if ($portnum =~ /^(\d+)$/) {
$port = $1;
} else {
print "Skipped non-numeric port: $portnum\n";
next;
}
print "Closing firewall access on port $port.\n";
if (($port ne '') && ($port eq $lond_port)) {
my $output;
foreach my $fw_chain (@okchains) {
my (@port_error,@command_error,@lond_port_close);
my %to_close;
if (open(PIPE, "$iptables -n -L $fw_chain |")) {
while (<PIPE>) {
chomp();
next unless (/dpt:\Q$port\E\s*$/);
if (/^ACCEPT\s+tcp\s+\-{2}\s+(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\s+/) {
my $ip = $1;
my $keepopen = 0;
if (ref($iphost) eq 'HASH') {
if (exists($iphost->{$ip})) {
$keepopen = 1;
}
}
unless ($keepopen) {
$to_close{$ip} = $port;
}
}
}
close(PIPE);
}
if (keys(%to_close) > 0) {
foreach my $ip (keys(%to_close)) {
my $firewall_command =
"$iptables -D $fw_chain -p tcp -s $ip -d 0/0 --dport $port -j ACCEPT";
system($firewall_command);
my $return_status = $?>>8;
if ($return_status == 1) {
push (@port_error,$ip);
} elsif ($return_status == 2) {
push(@command_error,$ip);
} elsif ($return_status == 0) {
push(@lond_port_close,$ip);
}
}
}
if (@lond_port_close) {
$output .= "Port closed for ".scalar(@lond_port_close)." IP addresses\n";
}
if (@port_error) {
$output .= "Error closing port for following IP addresses: ".join(', ',@port_error)."\n";
}
if (@command_error) {
$output .= "Bad command error opening port for following IP addresses: ".
join(', ',@command_error)."\n".
'Command was: "'."$iptables -D $fw_chain -p tcp -s ".'$ip'." -d 0/0 --dport $port -j ACCEPT".'", where $ip is IP address'."\n";
}
}
if ($output) {
print $output;
} else {
print "No IP addresses required discontinuation of access.\n";
}
} else {
foreach my $fw_chain (@okchains) {
my (@port_error,@command_error,@lond_port_close);
my $to_close;
if (open(PIPE, "$iptables -n -L $fw_chain |")) {
while (<PIPE>) {
chomp();
next unless (/dpt:\Q$port\E\s*$/);
$to_close = 1;
}
close(PIPE);
}
if ($to_close) {
my $firewall_command =
"$iptables -D $fw_chain -p tcp -d 0/0 --dport $port -j ACCEPT";
system($firewall_command);
my $return_status = $?>>8;
if ($return_status == 1) {
# Error
print "Error closing port for chain: $fw_chain.\n";
} elsif ($return_status == 2) {
# Bad command
print "Bad command error closing port. Command was\n".
" ".$firewall_command."\n";
} else {
print "Port closed for chain $fw_chain.\n";
}
}
}
}
}
return;
}
sub firewall_close_anywhere {
my ($iptables,$fw_chain,$port) = @_;
if (open(PIPE, "$iptables --line-numbers -n -L $fw_chain |")) {
while (<PIPE>) {
next unless (/dpt:\Q$port\E/);
chomp();
if (/^(\d+)\s+ACCEPT\s+tcp\s+\-{2}\s+0\.0\.0\.0\/0\s+0\.0\.0\.0\/0/) {
my $firewall_command = "$iptables -D $fw_chain $1";
system($firewall_command);
my $return_status = $?>>8;
if ($return_status == 1) {
print 'Error closing port '.$port.' for source "anywhere"'."\n";
} elsif ($return_status == 2) {
print 'Bad command error closing port '.$port.' for source "anywhere". Command was'."\n".
' '.$firewall_command."\n";
} else {
print 'Port '.$port.' closed for source "anywhere"'."\n";
}
}
}
close(PIPE);
}
}
sub get_lond_port {
my $perlvarref=&LONCAPA::Configuration::read_conf();
my $lond_port;
if (ref($perlvarref) eq 'HASH') {
if (defined($perlvarref->{'londPort'})) {
$lond_port = $perlvarref->{'londPort'};
}
}
if (!$lond_port) {
print("Unable to determine lond port number from LON-CAPA configuration.\n");
}
return $lond_port;
}
sub get_fw_chains {
my ($iptables) = @_;
my $distro = &LONCAPA::distro();
my @fw_chains;
my $suse_config = "/etc/sysconfig/SuSEfirewall2";
my $ubuntu_config = "/etc/ufw/ufw.conf";
if (-e $suse_config) {
push(@fw_chains,'input_ext');
} else {
my @posschains;
if (-e $ubuntu_config) {
@posschains = ('ufw-user-input','INPUT');
} else {
if ($distro =~ /^(debian|ubuntu|suse|sles)/) {
@posschains = ('INPUT');
} else {
@posschains = ('RH-Firewall-1-INPUT','INPUT');
}
if (!-e '/etc/sysconfig/iptables') {
if (!-e '/var/lib/iptables') {
unless ($distro =~ /^(debian|ubuntu)/) {
print("Unable to find iptables file containing static definitions\n");
}
}
if ($distro =~ /^(fedora|rhes|centos|scientific)/) {
push(@fw_chains,'RH-Firewall-1-INPUT');
}
}
}
if ($iptables eq '') {
$iptables = &get_pathto_iptables();
}
my %counts;
if (open(PIPE,"$iptables -L -n |")) {
while(<PIPE>) {
foreach my $chain (@posschains) {
if (/(\Q$chain\E)/) {
$counts{$1} ++;
}
}
}
close(PIPE);
}
foreach my $fw_chain (@posschains) {
if ($counts{$fw_chain}) {
unless(grep(/^\Q$fw_chain\E$/,@fw_chains)) {
push(@fw_chains,$fw_chain);
}
}
}
}
return @fw_chains;
}
sub get_pathto_iptables {
my $iptables;
if (-e '/sbin/iptables') {
$iptables = '/sbin/iptables';
} elsif (-e '/usr/sbin/iptables') {
$iptables = '/usr/sbin/iptables';
} else {
print("Unable to find iptables command\n");
}
return $iptables;
}
1;
__END__
=pod
=head1 NAME
B<LONCAPA::Firewall> - dynamic opening/closing of firewall ports
=head1 SYNOPSIS
use lib '/home/httpd/lib/perl/';
use LONCAPA::Firewall;
LONCAPA::Firewall::firewall_open_port();
LONCAPA::Firewall::firewall_close_port();
LONCAPA::Firewall::firewall_is_port_open();
LONCAPA::Firewall::firewall_is_active();
LONCAPA::Firewall::firewall_close_anywhere();
=head1 DESCRIPTION
The scripts: /etc/init.d/loncontrol, used to stop or start LON-CAPA services,
as well as the setuid script /home/httpd/perl/lciptables, called by loncron
for housekeeping tasks, make use of the methods provided by this module to
open and close firewall ports (currently the default port: 5663), used
for socket-based communication between LON-CAPA servers in the cluster
of networked servers to which the server belongs.
The following methods are available:
=over 4
=item LONCAPA::Firewall::firewall_open_port( $iptables,$fw_chains,$lond_port,$iphost,$port );
=back
=over 4
=item LONCAPA::Firewall::firewall_close_port( $iptables,$fw_chains,$lond_port,$iphost,$ports );
=back
=over 4
=item LONCAPA::Firewall::firewall_is_port_open( $iptables,$fw_chain,$port,$lond_port,$iphost,$curropen );
=back
=over 4
=item LONCAPA::Firewall::firewall_is_active();
=back
=over 4
=item LONCAPA::Firewall::firewall_close_anywhere( $iptables,$fw_chain,$port );
=back
=over 4
=item LONCAPA::Firewall::get_lond_port();
=back
=over 4
=item LONCAPA::Firewall::get_fw_chains();
=back
=over 4
=item LONCAPA::Firewall::get_pathto_iptables();
=head1 AUTHORS
This library is free software; you can redistribute it and/or
modify it under the same terms as LON-CAPA itself.
=cut
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