firewall: add more pscan matches and filter INVALID conntrack packages.

[ipfire-2.x.git] / src / initscripts / init.d / firewall

diff --git a/src/initscripts/init.d/firewall b/src/initscripts/init.d/firewall
index a67af7056486ad4e93db4786100d0a83ea80d100..23d0c23ff7a3a03642727c85b102ce3589d3d118 100644 (file)
--- a/src/initscripts/init.d/firewall
+++ b/src/initscripts/init.d/firewall
@@ -64,16 +64,20 @@ iptables_init() {
        iptables -A BADTCP -i lo -j RETURN
 
        # Disallow packets frequently used by port-scanners
-       # nmap xmas
-       iptables -A BADTCP -p tcp --tcp-flags ALL FIN,URG,PSH  -j PSCAN
-       # Null
-       iptables -A BADTCP -p tcp --tcp-flags ALL NONE -j PSCAN
-       # FIN
+       # NMAP FIN/URG/PSH (XMAS scan)
+       iptables -A BADTCP -p tcp --tcp-flags ALL FIN,URG,PSH -j PSCAN
+       # SYN/RST/ACK/FIN/URG
+       iptables -A BADTCP -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j PSCAN
+       # ALL/ALL
+       iptables -A BADTCP -p tcp --tcp-flags ALL ALL -j PSCAN
+       # FIN Stealth
        iptables -A BADTCP -p tcp --tcp-flags ALL FIN -j PSCAN
        # SYN/RST (also catches xmas variants that set SYN+RST+...)
        iptables -A BADTCP -p tcp --tcp-flags SYN,RST SYN,RST -j PSCAN
        # SYN/FIN (QueSO or nmap OS probe)
        iptables -A BADTCP -p tcp --tcp-flags SYN,FIN SYN,FIN -j PSCAN
+       # Null
+       iptables -A BADTCP -p tcp --tcp-flags ALL NONE -j PSCAN
        # NEW TCP without SYN
        iptables -A BADTCP -p tcp ! --syn -m conntrack --ctstate NEW -j NEWNOTSYN
 
@@ -83,6 +87,7 @@ iptables_init() {
        # Connection tracking chain
        iptables -N CONNTRACK
        iptables -A CONNTRACK -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
+       iptables -A CONNTRACK -m conntrack --ctstate INVALID -j DROP
 
        # Fix for braindead ISP's
        iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
@@ -107,7 +112,6 @@ iptables_init() {
        # Block OpenVPN transfer networks
        iptables -N OVPNBLOCK
        iptables -A INPUT   -i tun+ -j OVPNBLOCK
-       iptables -A OUTPUT  -o tun+ -j OVPNBLOCK
        iptables -A FORWARD -i tun+ -j OVPNBLOCK
        iptables -A FORWARD -o tun+ -j OVPNBLOCK
 
@@ -121,10 +125,10 @@ iptables_init() {
        iptables -N IPTVFORWARD
        iptables -A FORWARD -j IPTVFORWARD
 
-       # filtering from GUI
-       iptables -N GUIINPUT
-       iptables -A INPUT -j GUIINPUT
-       iptables -A GUIINPUT -p icmp --icmp-type 8 -j ACCEPT
+       # Allow to ping the firewall.
+       iptables -N ICMPINPUT
+       iptables -A INPUT -j ICMPINPUT
+       iptables -A ICMPINPUT -p icmp --icmp-type 8 -j ACCEPT
 
        # Accept everything on loopback
        iptables -N LOOPBACK
@@ -144,6 +148,31 @@ iptables_init() {
                iptables -A ${i} -j CONNTRACK
        done
 
+       # Allow DHCP
+       iptables -N DHCPINPUT
+       iptables -A DHCPINPUT -p udp --sport 68 --dport 67 -j ACCEPT
+       iptables -A DHCPINPUT -p tcp --sport 68 --dport 67 -j ACCEPT
+
+       iptables -N DHCPOUTPUT
+       iptables -A DHCPOUTPUT -p udp --sport 67 --dport 68 -j ACCEPT
+       iptables -A DHCPOUTPUT -p tcp --sport 67 --dport 68 -j ACCEPT
+
+       # Allow DHCP on GREEN
+       iptables -N DHCPGREENINPUT
+       iptables -N DHCPGREENOUTPUT
+       if [ -n "${GREEN_DEV}" ]; then
+               iptables -A INPUT  -i "${GREEN_DEV}" -j DHCPGREENINPUT
+               iptables -A OUTPUT -o "${GREEN_DEV}" -j DHCPGREENOUTPUT
+       fi
+
+       # allow DHCP on BLUE to be turned on/off
+       iptables -N DHCPBLUEINPUT
+       iptables -N DHCPBLUEOUTPUT
+       if [ -n "${BLUE_DEV}" ]; then
+               iptables -A INPUT  -i "${BLUE_DEV}" -j DHCPBLUEINPUT
+               iptables -A OUTPUT -o "${BLUE_DEV}" -j DHCPBLUEOUTPUT
+       fi
+
        # trafic from ipsecX/TUN/TAP interfaces, before "-i GREEN_DEV" accept everything
        iptables -N IPSECINPUT
        iptables -N IPSECFORWARD
@@ -155,12 +184,11 @@ iptables_init() {
        iptables -t nat -A POSTROUTING -j IPSECNAT
 
        # localhost and ethernet.
-       iptables -A INPUT   -i $GREEN_DEV  -m conntrack --ctstate NEW -j ACCEPT ! -p icmp
-       
-       # allow DHCP on BLUE to be turned on/off
-       iptables -N DHCPBLUEINPUT 
-       iptables -A INPUT -j DHCPBLUEINPUT
-       
+       # Always allow accessing the web GUI from GREEN.
+       iptables -N GUIINPUT
+       iptables -A INPUT -j GUIINPUT
+       iptables -A GUIINPUT -i "${GREEN_DEV}" -p tcp --dport 444 -j ACCEPT
+
        # WIRELESS chains
        iptables -N WIRELESSINPUT
        iptables -A INPUT -m conntrack --ctstate NEW -j WIRELESSINPUT
@@ -196,6 +224,7 @@ iptables_init() {
        # DNAT rules
        iptables -t nat -N NAT_DESTINATION
        iptables -t nat -A PREROUTING -j NAT_DESTINATION
+       iptables -t nat -A OUTPUT -j NAT_DESTINATION
 
        iptables -t mangle -N NAT_DESTINATION
        iptables -t mangle -A PREROUTING -j NAT_DESTINATION
@@ -230,20 +259,6 @@ iptables_init() {
        iptables -t nat -N REDNAT
        iptables -t nat -A POSTROUTING -j REDNAT
 
-       # Filter logging of incoming broadcasts.
-       iptables -N BROADCAST_FILTER
-       iptables -A INPUT -j BROADCAST_FILTER
-
-       iptables -A BROADCAST_FILTER -i "${GREEN_DEV}" -d "${GREEN_BROADCAST}" -j DROP
-
-       if [ -n "${BLUE_DEV}" -a -n "${BLUE_BROADCAST}" ]; then
-               iptables -A BROADCAST_FILTER -i "${BLUE_DEV}" -d "${BLUE_BROADCAST}" -j DROP
-       fi
-
-       if [ -n "${ORANGE_DEV}" -a -n "${ORANGE_BROADCAST}" ]; then
-               iptables -A BROADCAST_FILTER -i "${ORANGE_DEV}" -d "${ORANGE_BROADCAST}" -j DROP
-       fi
-
        # Apply OpenVPN firewall rules
        /usr/local/bin/openvpnctrl --firewall-rules
 
@@ -311,7 +326,10 @@ iptables_red() {
 
                # Outgoing masquerading (don't masqerade IPSEC (mark 50))
                iptables -t nat -A REDNAT -m mark --mark 50 -o $IFACE -j RETURN
-               iptables -t nat -A REDNAT -o $IFACE -j MASQUERADE
+
+               if [ "$IFACE" != "$GREEN_DEV" ]; then
+                       iptables -t nat -A REDNAT -o $IFACE -j MASQUERADE
+               fi
 
        fi