Fail2ban integration on SME Server
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#!/usr/bin/perl -w
use strict;
use warnings;
use esmith::ConfigDB;
use Getopt::Long;
our $f2bdb = esmith::ConfigDB->open('fail2ban') || esmith::ConfigDB->create('fail2ban');
our $c = esmith::ConfigDB->open_ro;
our %opts;
sub usage(){
print<<"EOF";
Usage: $0 --host=<ip> [--unban] [--protocol=tcp|udp|icmp|all] [--port=<port number>] [--bantime]
* --host must specify a valid IPv4 adress in the form 10.11.12.13
* --protocol can be used to specify the protocol to block. Only tcp, udp, icmp and all are valid (default is all)
* --port can be used to specify the port(s) to block. Only valid for tcp and udp. You can also specify a range
of port like 10000:20000. You can also specify several ports or range of port separated by a comma
* if --unban is specified, the given host will be removed from the blacklist
default is to add to the blacklist instead
* --bantime can be used to specify how long the ban should be (in seconds)
EOF
}
# Check if port is valid
sub is_valid_port($){
my $ports = shift;
my $ret = 0;
foreach my $port (split /,/, $ports){
if ($port =~ m/^(\d+):(\d+)$/){
$ret = 1 if ($1 >= 0 &&
$1 < 65636 &&
$2 >= 0 &&
$2 < 65636);
}
else{
$ret = 1 if ($port > 0 &&
$port < 65636);
}
}
return $ret;
}
# Generate a random uniq ID
sub generate_uniq_id(){
my @chars = ('a'..'z','0'..'9');
my $id = '';
my $round = 0;
foreach (1..10){
foreach (1..15){
$id .= $chars[rand @chars];
}
my $eid = $f2bdb->get($id);
last unless ($eid);
}
die "Couldn't generate a valid uniq ID\n"
if ($id eq '');
return $id;
}
my $f2b = $c->get('fail2ban') ||
die "fail2ban service not found in the configuration database\n";
# default is to ban a host
$opts{unban} = '0';
$opts{bantime} = $f2b->prop('BanTime') || '1800';
GetOptions(
"host=s" => \$opts{host},
"unban" => \$opts{unban},
"protocol=s" => \$opts{proto},
"port=s" => \$opts{port},
"bantime=s" => \$opts{bantime}
);
# special "undef" value for port and proto
undef $opts{proto} if ($opts{proto} eq 'undef');
undef $opts{port} if ($opts{port} eq 'undef');
$opts{bantime} = ($f2b->prop('BanTime') || '1800')
if ($opts{bantime} eq 'undef');
# Check options are valid
# host is required
my @req = qw(host);
foreach (@req){
usage() && die unless (defined $opts{$_});
}
# host must look like an IP address
usage() && die
unless ($opts{host} =~ m/^(?:(?:[01]?\d?\d?|2[0-4]\d|25[0-5])(?:\.|$)){4}$/);
# protocol must can only be undefined, tcp, udp or icmp
usage() && die
if ($opts{proto} && $opts{proto} !~ m/^tcp|udp|icmp|all$/);
# port must be a valid port number, and is only valid for tcp and udp
usage && die
if ($opts{port} && (($opts{proto} && $opts{proto} !~ m/^tcp|udp$/) || !is_valid_port($opts{port})));
if ($opts{unban}){
foreach ($f2bdb->get_all_by_prop(Host => $opts{host})){
my $proto = $_->prop('Protocol') || '';
my $port = $_->prop('Port') || '';
next if ($opts{proto} && $proto ne $opts{proto});
next if ($opts{port} && $port ne $opts{port} && $proto =~ m/^tcp|udp$/);
$_->delete();
}
}
else{
my $id = generate_uniq_id();
my %props;
$props{'type'} = 'ban';
$props{'Host'} = $opts{host};
$props{'Protocol'} = $opts{proto}
if ($opts{proto});
$props{'Port'} = $opts{port}
if ($opts{port});
$props{'BanTimestamp'} = time();
$props{'UnbanTimestamp'} = time()+$opts{bantime};
$f2bdb->new_record($id, \%props);
}
die "An error occured while updating the firewall rules"
unless (system("/sbin/e-smith/signal-event fail2ban-update") == 0);
exit(0);