#!/bin/sh
#
# check-requirements: verify all the required iptables functionality is
# available
#
# Copyright 2008-2020 Canonical Ltd.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 3,
# 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, see <http://www.gnu.org/licenses/>.
#
set -e
chain="ufw-check-requirements"
error=""
error_runtime=""
runcmd() {
runtime="no"
if [ "$1" = "runtime" ]; then
runtime="yes"
shift 1
fi
local output ret=0
# make sure to always return success below because of set -e
output=$( "$@" 2>&1 ) || ret=$?
if [ $ret -eq 0 ]; then
echo pass
else
if [ "$runtime" = "yes" ]; then
echo "FAIL (no runtime support)"
echo "error was: $output"
error_runtime="yes"
else
echo FAIL
echo "error was: $output"
error="yes"
fi
fi
}
# check python
found_python="no"
echo -n "Has python: "
for exe in python3 python2 python ; do
if ! which $exe >/dev/null 2>&1; then
continue
fi
v=`$exe --version 2>&1 | cut -f 2 -d ' '`
if echo "$v" | grep -q "^2.[5-7]"; then
echo "pass (binary: $exe, version: $v, py2)"
found_python="yes"
break
elif echo "$v" | grep -q "^3.[1-9][0-9]*"; then
echo "pass (binary: $exe, version: $v, py3)"
found_python="yes"
break
fi
done
if [ "$found_python" != "yes" ]; then
echo "ERROR: could not find valid python" >&2
error="yes"
fi
# check binaries
for i in "" 6; do
exe="iptables"
if [ "$i" = "6" ]; then
exe="ip6tables"
fi
echo -n "Has $exe: "
if ! PATH=/sbin:/usr/sbin:/bin:/usr/bin which $exe >/dev/null 2>&1; then
echo "ERROR: could not find '$exe'" >&2
error="yes"
else
echo "pass"
fi
done
if [ -n "$error" ]; then
exit 1
fi
echo ""
# check /proc
for i in /proc/net/dev /proc/net/if_inet6; do
echo -n "Has $i: "
if [ ! -e "$i" ]; then
echo "no"
error="yes"
else
echo "pass"
fi
done
if [ -n "$error" ]; then
exit 1
fi
echo ""
echo "This script will now attempt to create various rules using the iptables"
echo "and ip6tables commands. This may result in module autoloading (eg, for"
echo "IPv6)."
if [ "$1" != "-f" ]; then
echo -n "Proceed with checks (Y/n)? "
read ans
if [ "$ans" = "n" ] || [ "$ans" = "N" ] || [ "$ans" = "no" ]; then
echo "Aborting"
exit 1
fi
fi
# check modules
for i in "" 6; do
exe="iptables"
c="${chain}"
ipv="4"
if [ "$i" = "6" ]; then
exe="ip6tables"
c="${chain}6"
ipv="6"
fi
if [ "$i" = "6" ]; then
echo "== IPv6 =="
else
echo "== IPv4 =="
fi
echo -n "Creating '$c'... "
$exe -N "$c" || {
echo "ERROR: could not create '$c'. Aborting" >&2
error="yes"
break
}
echo "done"
# set up a RETURN rule right at the top, so we don't open anything up when
# running the script. Isn't attached to INPUT, but better safe than sorry.
echo -n "Inserting RETURN at top of '$c'... "
$exe -I "$c" -j RETURN || {
echo "ERROR: could insert RETURN rule into '$c'. Aborting" >&2
error="yes"
break
}
echo "done"
echo -n "TCP: "
runcmd $exe -A $c -p tcp -j ACCEPT
echo -n "UDP: "
runcmd $exe -A $c -p udp -j ACCEPT
echo -n "destination port: "
runcmd $exe -A $c -p tcp --dport 22 -j ACCEPT
echo -n "source port: "
runcmd $exe -A $c -p tcp --sport 22 -j ACCEPT
for j in ACCEPT DROP REJECT LOG; do
echo -n "$j: "
runcmd $exe -A $c -p tcp --sport 23 -j $j
done
echo -n "hashlimit: "
runcmd $exe -A $c -m hashlimit -m tcp -p tcp --dport 22 --hashlimit 1/min --hashlimit-mode srcip --hashlimit-name ssh -m conntrack --ctstate NEW -j ACCEPT
echo -n "limit: "
runcmd $exe -A $c -m limit --limit 3/min --limit-burst 10 -j ACCEPT
for j in NEW RELATED ESTABLISHED INVALID; do
echo -n "ctstate ($j): "
runcmd $exe -A $c -m conntrack --ctstate $j
done
echo -n "ctstate (new, recent set): "
runcmd runtime $exe -A $c -m conntrack --ctstate NEW -m recent --set
echo -n "ctstate (new, recent update): "
runcmd runtime $exe -A $c -m conntrack --ctstate NEW -m recent --update --seconds 30 --hitcount 6 -j ACCEPT
echo -n "ctstate (new, limit): "
runcmd $exe -A $c -m conntrack --ctstate NEW -m limit --limit 3/min --limit-burst 10 -j ACCEPT
echo -n "interface (input): "
runcmd $exe -A $c -i eth0 -j ACCEPT
echo -n "interface (output): "
runcmd $exe -A $c -o eth0 -j ACCEPT
echo -n "multiport: "
runcmd $exe -A $c -p tcp -m multiport --dports 80,443,8080:8090 -j ACCEPT
echo -n "comment: "
runcmd $exe -A $c -m comment --comment 'dapp_Samba'
if [ -z "$i" ]; then
for j in LOCAL MULTICAST BROADCAST; do
echo -n "addrtype ($j): "
runcmd $exe -A $c -m addrtype --dst-type $j -j RETURN
done
for j in destination-unreachable source-quench time-exceeded parameter-problem echo-request; do
echo -n "icmp ($j): "
runcmd $exe -A $c -p icmp --icmp-type $j -j ACCEPT
done
else
for j in destination-unreachable packet-too-big time-exceeded parameter-problem echo-request; do
echo -n "icmpv6 ($j): "
runcmd $exe -A $c -p icmpv6 --icmpv6-type $j -j ACCEPT
done
for j in neighbor-solicitation neighbor-advertisement router-solicitation router-advertisement; do
echo -n "icmpv6 with hl ($j): "
runcmd $exe -A $c -p icmpv6 --icmpv6-type $j -m hl --hl-eq 255 -j ACCEPT
done
echo -n "ipv6 rt: "
runcmd $exe -A $c -m rt --rt-type 0 -j ACCEPT
fi
echo ""
done
# cleanup
for i in "" 6; do
exe="iptables"
c="${chain}"
if [ "$i" = "6" ]; then
exe="ip6tables"
c="${chain}6"
fi
$exe -F $c >/dev/null 2>&1 || {
if [ -z "$error" ]; then
echo "ERROR: could not flush '$c'" >&2
error="yes"
fi
}
$exe -X $c >/dev/null 2>&1 || {
if [ -z "$error" ]; then
error="yes"
echo "ERROR: could not remove '$c'" >&2
fi
}
done
# check and warn if various firewall applications are installed
found=
for exe in apf arno-iptables-firewall ferm firehol firewalld ipkungfu iptables-persistent netfilter-persistent pyroman uruk ; do
if PATH=/sbin:/usr/sbin:/bin:/usr/bin which "$exe" >/dev/null 2>&1; then
found="$found $exe"
fi
done
if [ ! -z "$found" ]; then
echo "WARN: detected other firewall applications:"
echo "$found"
echo "(if enabled, these applications may interfere with ufw)"
echo ""
fi
if [ -n "$error" ] || [ -n "$error_runtime" ]; then
if [ -n "$error" ]; then
echo "FAIL: check your kernel and that you have iptables >= 1.4.0"
fi
if [ -n "$error_runtime" ]; then
echo "FAIL: check your kernel and iptables for additional runtime support"
fi
exit 1
fi
echo "All tests passed"
exit 0
Mini Shell