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authorGuilhem Moulin <guilhem@fripost.org>2013-10-31 03:25:01 +0100
committerGuilhem Moulin <guilhem@fripost.org>2015-06-07 02:50:32 +0200
commit662120af880623fd0ba16b83cd80320e1a3806cc (patch)
tree4326f497b4a5659ae6199b8e3457028f000e2db4 /roles/common/files/usr
parentbda835d0051950c63c0f38bbf11fb6fe47b4af36 (diff)
Add a 'check' switch to the firewall.
update-firewall.sh -c does not update the firewall, but returns a non-zero value iff. running it without the switch would modify it.
Diffstat (limited to 'roles/common/files/usr')
-rwxr-xr-xroles/common/files/usr/local/sbin/update-firewall.sh104
1 files changed, 80 insertions, 24 deletions
diff --git a/roles/common/files/usr/local/sbin/update-firewall.sh b/roles/common/files/usr/local/sbin/update-firewall.sh
index cefeea5..8840174 100755
--- a/roles/common/files/usr/local/sbin/update-firewall.sh
+++ b/roles/common/files/usr/local/sbin/update-firewall.sh
@@ -1,10 +1,14 @@
#!/bin/bash
#
-# Create iptables (v4 and v6) rules. Unless [-f] is given, a
-# confirmation is asked after loading the new rulesets; if the user
-# answers No or doesn't answer, the old ruleset is restored. If the user
-# answer Yes (or if the flag [-f] is given), the new ruleset is made
-# persistent using iptables-persistent.
+# Create iptables (v4 and v6) rules. Unless one of [-f] or [-c] is
+# given, a confirmation is asked after loading the new rulesets; if the
+# user answers No or doesn't answer, the old ruleset is restored. If the
+# user answer Yes (or if the flag [-f] is given), the new ruleset is
+# made persistent using iptables-persistent.
+#
+# The [-c] flag switch to dry-run (check) mode. The rulesets are not
+# applied, but merely checked against the existing ones. If they differ
+# the return value is one, and 0 otherwise.
#
# This firewall is only targeted towards end-servers, not gateways. In
# particular, there is no NAT'ing at the moment.
@@ -21,6 +25,19 @@ PATH=/usr/sbin:/usr/bin:/sbin:/bin
timeout=10
force=0
+check=0
+
+usage() {
+ echo "Usage: $0 [-c|-f]" >&2
+ exit 1
+}
+
+[ $# -le 1 ] || usage
+case "${1:-}" in
+ -f) force=1;;
+ -c) check=1;;
+ ?*) usage
+esac
[ "${1:-}" = -f ] && force=1
if ! /usr/bin/tty -s && [ $force -eq 0 ]; then
@@ -58,6 +75,30 @@ fatal() {
/usr/bin/logger -st firewall -p syslog.err -- "$@"
exit 1
}
+save() {
+ mkdir -p /etc/iptables
+ /sbin/iptables-save > /etc/iptables/rules.v4
+ /sbin/ip6tables-save > /etc/iptables/rules.v6
+
+ # Ignore the counters
+ sed -ri 's/^(:.*)\[[0-9]+:[0-9]+\]$/\1[0:0]/' \
+ /etc/iptables/rules.v4 /etc/iptables/rules.v6
+}
+iptdiff() {
+ local v="$1" old="$2" new="$3" rv1=0 rv2=0
+
+ diff -qI '^#' "$old" "$new" >/dev/null || rv1=$?
+ if [ -f /etc/iptables/rules.$v ]; then
+ diff -qI '^#' "$old" /etc/iptables/rules.$v >/dev/null || rv2=$?
+ else
+ rv2=1
+ fi
+
+ [ $rv1 -eq 0 ] || log "WARN: The IP$v firewall is not up to date! Please run '$0'."
+ [ $rv2 -eq 0 ] || log "WARN: The current IP$v firewall is not persistent! Please run '$0'."
+
+ return $(( $rv1 | $rv2 ))
+}
[ -n "$WAN" -o -n "$WAN6" ] || fatal "Error: couldn't find a network interface"
@@ -106,14 +147,14 @@ if [ -n "$WAN" ]; then
[ -n "$MyNetwork" ] && \
for ip in 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 169.254.0.0/16; do
[ "$ip" = "$(/usr/bin/netmask -nc $ip $MyNetwork | sed 's/ //g')" ] \
- || iptables -A INPUT -i $WAN -s "$ip" -j DROP
+ || iptables -A INPUT -i $WAN -s "$ip" -j DROP
done
# Other martian packets: "This" network, multicast, broadcast (RFCs
# 1122, 3171 and 919).
for ip in 0.0.0.0/8 224.0.0.0/4 240.0.0.0/4 255.255.255.255/32; do
- iptables -A INPUT -i $WAN -s "$ip" -j DROP
- iptables -A INPUT -i $WAN -d "$ip" -j DROP
+ iptables -A INPUT -i $WAN -s "$ip" -j DROP
+ iptables -A INPUT -i $WAN -d "$ip" -j DROP
done
fi
@@ -121,8 +162,8 @@ fi
# 3879).
for ip6 in fc00::/7 fec0::/10
do
- ip6tables -A INPUT -i $WAN6 -s "$ip6" -j DROP
- ip6tables -A INPUT -i $WAN6 -d "$ip6" -j DROP
+ ip6tables -A INPUT -i $WAN6 -s "$ip6" -j DROP
+ ip6tables -A INPUT -i $WAN6 -d "$ip6" -j DROP
done
@@ -134,7 +175,7 @@ done
# DROP bogus TCP packets.
-iptables -A INPUT -p tcp -m tcp --tcp-flags SYN,FIN SYN,FIN -j DROP
+iptables -A INPUT -p tcp -m tcp --tcp-flags FIN,SYN FIN,SYN -j DROP
iptables -A INPUT -p tcp -m tcp --tcp-flags SYN,RST SYN,RST -j DROP
ip6tables -A INPUT -p tcp -m tcp --tcp-flags SYN,FIN SYN,FIN -j DROP
@@ -142,11 +183,11 @@ ip6tables -A INPUT -p tcp -m tcp --tcp-flags SYN,RST SYN,RST -j DROP
# Allow all input/output to/from the loopback interface.
-iptables -A INPUT -i lo -s 127.0.0.1 -d 127.0.0.1 -j ACCEPT
-iptables -A OUTPUT -o lo -s 127.0.0.1 -d 127.0.0.1 -j ACCEPT
+iptables -A INPUT -i lo -s 127.0.0.1/32 -d 127.0.0.1/32 -j ACCEPT
+iptables -A OUTPUT -o lo -s 127.0.0.1/32 -d 127.0.0.1/32 -j ACCEPT
-ip6tables -A INPUT -i lo -s ::1 -d ::1 -j ACCEPT
-ip6tables -A OUTPUT -o lo -s ::1 -d ::1 -j ACCEPT
+ip6tables -A INPUT -i lo -s ::1/128 -d ::1/128 lo -j ACCEPT
+ip6tables -A OUTPUT -o lo -s ::1/128 -d ::1/128 lo -j ACCEPT
# Allow only ICMP of type 0, 3 and 8. The rate-limiting is done directly
@@ -172,7 +213,7 @@ while read dir proto dport sport; do
stEst=ESTABLISHED
# In-Out means full-duplex
- [[ "$dir" =~ inout ]] && stEst="$stNew"
+ [[ "$dir" =~ ^inout ]] && stEst="$stNew"
optsNew=
optsEst=
@@ -211,17 +252,32 @@ tgrep '^-[AI] fail2ban-\S+ '
echo COMMIT >> "$newv4table"
echo COMMIT >> "$newv6table"
-/usr/bin/uniq "$newv4table" | /sbin/iptables-restore
-/usr/bin/uniq "$newv6table" | /sbin/ip6tables-restore
+netns=
+innetns=
+if [ $check -eq 1 ]; then
+ # Create an alternative net namespace in which we apply the ruleset,
+ # so we can easily get a normalized version we can compare latter.
+ # See http://bugzilla.netfilter.org/show_bug.cgi?id=790
+ netns="ipt-firewall-test-$$"
+ /bin/ip netns add $netns
+ innetns="/bin/ip netns exec $netns"
+fi
-save() {
- mkdir -p /etc/iptables
- /sbin/iptables-save > /etc/iptables/rules.v4
- /sbin/ip6tables-save > /etc/iptables/rules.v6
-}
+/usr/bin/uniq "$newv4table" | $innetns /sbin/iptables-restore
+/usr/bin/uniq "$newv6table" | $innetns /sbin/ip6tables-restore
rv=0
-if [ $force -eq 1 ]; then
+if [ $check -eq 1 ]; then
+ $innetns /sbin/iptables-save > "$newv4table"
+ $innetns /sbin/ip6tables-save > "$newv6table"
+ /bin/ip netns del $netns
+
+ # Reset the counters, they are not relevant here
+ sed -ri 's/^(:.*)\[[0-9]+:[0-9]+\]$/\1[0:0]/' "$oldv4table" "$oldv6table"
+ iptdiff v4 "$oldv4table" "$newv4table" || rv=$(( $rv | $? ))
+ iptdiff v6 "$oldv6table" "$newv6table" || rv=$(( $rv | $? ))
+
+elif [ $force -eq 1 ]; then
# At the user's own risks...
save
else