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#!/bin/bash
#
# iptables-apply -- a safer way to update iptables remotely
#
# Copyright © Martin F. Krafft <madduck@madduck.net>
# Released under the terms of the Artistic Licence 2.0
#
set -eu
PROGNAME="${0##*/}";
VERSION=1.0
TIMEOUT=10
DEFAULT_FILE=/etc/network/iptables
function blurb()
{
cat <<-_eof
$PROGNAME $VERSION -- a safer way to update iptables remotely
_eof
}
function copyright()
{
cat <<-_eof
$PROGNAME is C Martin F. Krafft <madduck@madduck.net>.
The program has been published under the terms of the Artistic Licence 2.0
_eof
}
function about()
{
blurb
echo
copyright
}
function usage()
{
cat <<-_eof
Usage: $PROGNAME [options] ruleset
The script will try to apply a new ruleset (as output by iptables-save/read
by iptables-restore) to iptables, then prompt the user whether the changes
are okay. If the new ruleset cut the existing connection, the user will not
be able to answer affirmatively. In this case, the script rolls back to the
previous ruleset.
The following options may be specified, using standard conventions:
-t | --timeout Specify the timeout in seconds (default: $TIMEOUT)
-V | --version Display version information
-h | --help Display this help text
_eof
}
SHORTOPTS="t:Vh";
LONGOPTS="timeout:,version,help";
OPTS=$(getopt -s bash -o "$SHORTOPTS" -l "$LONGOPTS" -n "$PROGNAME" -- "$@") || exit $?
for opt in $OPTS; do
case "$opt" in
(-*) unset OPT_STATE;;
(*)
case "${OPT_STATE:-}" in
(SET_TIMEOUT)
eval TIMEOUT=$opt
case "$TIMEOUT" in
([0-9]*) :;;
(*)
echo "E: non-numeric timeout value." >&2
exit 1
;;
esac
;;
esac
;;
esac
case "$opt" in
(-h|--help) usage >&2; exit 0;;
(-V|--version) about >&2; exit 0;;
(-t|--timeout) OPT_STATE=SET_TIMEOUT;;
(--) break;;
esac
shift
done
FILE="${1:-$DEFAULT_FILE}";
if [[ -z "$FILE" ]]; then
echo "E: missing file argument." >&2
exit 1
fi
if [[ ! -r "$FILE" ]]; then
echo "E: cannot read $FILE" >&2
exit 2
fi
case "${0##*/}" in
(*6*)
SAVE=ip6tables-save
RESTORE=ip6tables-restore
;;
(*)
SAVE=iptables-save
RESTORE=iptables-restore
;;
esac
COMMANDS=(tempfile "$SAVE" "$RESTORE")
for cmd in "${COMMANDS[@]}"; do
if ! command -v $cmd >/dev/null; then
echo "E: command not found: $cmd" >&2
exit 127
fi
done
umask 0700
TMPFILE=$(tempfile -p iptap)
trap "rm -f $TMPFILE" EXIT 1 2 3 4 5 6 7 8 10 11 12 13 14 15
if ! "$SAVE" >"$TMPFILE"; then
if ! grep -q ipt /proc/modules 2>/dev/null; then
echo "E: iptables support lacking from the kernel." >&2
exit 3
else
echo "E: unknown error saving current iptables ruleset." >&2
exit 4
fi
fi
[ -x /etc/init.d/fail2ban ] && /etc/init.d/fail2ban stop
echo -n "Applying new ruleset... "
if ! "$RESTORE" <"$FILE"; then
echo "failed."
echo "E: unknown error applying new iptables ruleset." >&2
exit 5
else
echo done.
fi
echo -n "Can you establish NEW connections to the machine? (y/N) "
read -n1 -t "${TIMEOUT:-15}" ret 2>&1 || :
case "${ret:-}" in
(y*|Y*)
echo
echo ... then my job is done. See you next time.
;;
(*)
if [[ -z "${ret:-}" ]]; then
echo "apparently not..."
else
echo
fi
echo "Timeout. Something happened (or did not). Better play it safe..."
echo -n "Reverting to old ruleset... "
"$RESTORE" <"$TMPFILE";
echo done.
exit 255
;;
esac
[ -x /etc/init.d/fail2ban ] && /etc/init.d/fail2ban start
exit 0
# vim:noet:sw=8
|
