firewall: add more pscan matches and filter INVALID conntrack packages.
[ipfire-2.x.git] / src / initscripts / init.d / firewall
1 #!/bin/sh
2
3 . /etc/sysconfig/rc
4 . ${rc_functions}
5
6 eval $(/usr/local/bin/readhash /var/ipfire/ppp/settings)
7 eval $(/usr/local/bin/readhash /var/ipfire/ethernet/settings)
8 eval $(/usr/local/bin/readhash /var/ipfire/optionsfw/settings)
9 IFACE=`/bin/cat /var/ipfire/red/iface 2> /dev/null | /usr/bin/tr -d '\012'`
10
11 if [ -f /var/ipfire/red/device ]; then
12 DEVICE=`/bin/cat /var/ipfire/red/device 2> /dev/null | /usr/bin/tr -d '\012'`
13 fi
14
15 function iptables() {
16 /sbin/iptables --wait "$@"
17 }
18
19 iptables_init() {
20 # Flush all rules and delete all custom chains
21 iptables -F
22 iptables -t nat -F
23 iptables -t mangle -F
24 iptables -X
25 iptables -t nat -X
26 iptables -t mangle -X
27
28 # Set up policies
29 iptables -P INPUT DROP
30 iptables -P FORWARD DROP
31 iptables -P OUTPUT ACCEPT
32
33 # Empty LOG_DROP and LOG_REJECT chains
34 iptables -N LOG_DROP
35 iptables -A LOG_DROP -m limit --limit 10/minute -j LOG
36 iptables -A LOG_DROP -j DROP
37 iptables -N LOG_REJECT
38 iptables -A LOG_REJECT -m limit --limit 10/minute -j LOG
39 iptables -A LOG_REJECT -j REJECT
40
41 # This chain will log, then DROPs packets with certain bad combinations
42 # of flags might indicate a port-scan attempt (xmas, null, etc)
43 iptables -N PSCAN
44 if [ "$DROPPORTSCAN" == "on" ]; then
45 iptables -A PSCAN -p tcp -m limit --limit 10/minute -j LOG --log-prefix "DROP_TCP Scan " -m comment --comment "DROP_TCP PScan"
46 iptables -A PSCAN -p udp -m limit --limit 10/minute -j LOG --log-prefix "DROP_UDP Scan " -m comment --comment "DROP_UDP PScan"
47 iptables -A PSCAN -p icmp -m limit --limit 10/minute -j LOG --log-prefix "DROP_ICMP Scan " -m comment --comment "DROP_ICMP PScan"
48 iptables -A PSCAN -f -m limit --limit 10/minute -j LOG --log-prefix "DROP_FRAG Scan " -m comment --comment "DROP_FRAG PScan"
49 fi
50 iptables -A PSCAN -j DROP -m comment --comment "DROP_PScan"
51
52 # New tcp packets without SYN set - could well be an obscure type of port scan
53 # that's not covered above, may just be a broken windows machine
54 iptables -N NEWNOTSYN
55 if [ "$DROPNEWNOTSYN" == "on" ]; then
56 iptables -A NEWNOTSYN -m limit --limit 10/minute -j LOG --log-prefix "DROP_NEWNOTSYN "
57 fi
58 iptables -A NEWNOTSYN -j DROP -m comment --comment "DROP_NEWNOTSYN"
59
60 # Chain to contain all the rules relating to bad TCP flags
61 iptables -N BADTCP
62
63 # Don't check loopback
64 iptables -A BADTCP -i lo -j RETURN
65
66 # Disallow packets frequently used by port-scanners
67 # NMAP FIN/URG/PSH (XMAS scan)
68 iptables -A BADTCP -p tcp --tcp-flags ALL FIN,URG,PSH -j PSCAN
69 # SYN/RST/ACK/FIN/URG
70 iptables -A BADTCP -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j PSCAN
71 # ALL/ALL
72 iptables -A BADTCP -p tcp --tcp-flags ALL ALL -j PSCAN
73 # FIN Stealth
74 iptables -A BADTCP -p tcp --tcp-flags ALL FIN -j PSCAN
75 # SYN/RST (also catches xmas variants that set SYN+RST+...)
76 iptables -A BADTCP -p tcp --tcp-flags SYN,RST SYN,RST -j PSCAN
77 # SYN/FIN (QueSO or nmap OS probe)
78 iptables -A BADTCP -p tcp --tcp-flags SYN,FIN SYN,FIN -j PSCAN
79 # Null
80 iptables -A BADTCP -p tcp --tcp-flags ALL NONE -j PSCAN
81 # NEW TCP without SYN
82 iptables -A BADTCP -p tcp ! --syn -m conntrack --ctstate NEW -j NEWNOTSYN
83
84 iptables -A INPUT -p tcp -j BADTCP
85 iptables -A FORWARD -p tcp -j BADTCP
86
87 # Connection tracking chain
88 iptables -N CONNTRACK
89 iptables -A CONNTRACK -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
90 iptables -A CONNTRACK -m conntrack --ctstate INVALID -j DROP
91
92 # Fix for braindead ISP's
93 iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
94
95 # CUSTOM chains, can be used by the users themselves
96 iptables -N CUSTOMINPUT
97 iptables -A INPUT -j CUSTOMINPUT
98 iptables -N CUSTOMFORWARD
99 iptables -A FORWARD -j CUSTOMFORWARD
100 iptables -N CUSTOMOUTPUT
101 iptables -A OUTPUT -j CUSTOMOUTPUT
102 iptables -t nat -N CUSTOMPREROUTING
103 iptables -t nat -A PREROUTING -j CUSTOMPREROUTING
104 iptables -t nat -N CUSTOMPOSTROUTING
105 iptables -t nat -A POSTROUTING -j CUSTOMPOSTROUTING
106
107 # Guardian (IPS) chains
108 iptables -N GUARDIAN
109 iptables -A INPUT -j GUARDIAN
110 iptables -A FORWARD -j GUARDIAN
111
112 # Block OpenVPN transfer networks
113 iptables -N OVPNBLOCK
114 iptables -A INPUT -i tun+ -j OVPNBLOCK
115 iptables -A FORWARD -i tun+ -j OVPNBLOCK
116 iptables -A FORWARD -o tun+ -j OVPNBLOCK
117
118 # OpenVPN transfer network translation
119 iptables -t nat -N OVPNNAT
120 iptables -t nat -A POSTROUTING -j OVPNNAT
121
122 # IPTV chains for IGMPPROXY
123 iptables -N IPTVINPUT
124 iptables -A INPUT -j IPTVINPUT
125 iptables -N IPTVFORWARD
126 iptables -A FORWARD -j IPTVFORWARD
127
128 # Allow to ping the firewall.
129 iptables -N ICMPINPUT
130 iptables -A INPUT -j ICMPINPUT
131 iptables -A ICMPINPUT -p icmp --icmp-type 8 -j ACCEPT
132
133 # Accept everything on loopback
134 iptables -N LOOPBACK
135 iptables -A LOOPBACK -i lo -j ACCEPT
136 iptables -A LOOPBACK -o lo -j ACCEPT
137
138 # Filter all packets with loopback addresses on non-loopback interfaces.
139 iptables -A LOOPBACK -s 127.0.0.0/8 -j DROP
140 iptables -A LOOPBACK -d 127.0.0.0/8 -j DROP
141
142 for i in INPUT FORWARD OUTPUT; do
143 iptables -A ${i} -j LOOPBACK
144 done
145
146 # Accept everything connected
147 for i in INPUT FORWARD OUTPUT; do
148 iptables -A ${i} -j CONNTRACK
149 done
150
151 # Allow DHCP
152 iptables -N DHCPINPUT
153 iptables -A DHCPINPUT -p udp --sport 68 --dport 67 -j ACCEPT
154 iptables -A DHCPINPUT -p tcp --sport 68 --dport 67 -j ACCEPT
155
156 iptables -N DHCPOUTPUT
157 iptables -A DHCPOUTPUT -p udp --sport 67 --dport 68 -j ACCEPT
158 iptables -A DHCPOUTPUT -p tcp --sport 67 --dport 68 -j ACCEPT
159
160 # Allow DHCP on GREEN
161 iptables -N DHCPGREENINPUT
162 iptables -N DHCPGREENOUTPUT
163 if [ -n "${GREEN_DEV}" ]; then
164 iptables -A INPUT -i "${GREEN_DEV}" -j DHCPGREENINPUT
165 iptables -A OUTPUT -o "${GREEN_DEV}" -j DHCPGREENOUTPUT
166 fi
167
168 # allow DHCP on BLUE to be turned on/off
169 iptables -N DHCPBLUEINPUT
170 iptables -N DHCPBLUEOUTPUT
171 if [ -n "${BLUE_DEV}" ]; then
172 iptables -A INPUT -i "${BLUE_DEV}" -j DHCPBLUEINPUT
173 iptables -A OUTPUT -o "${BLUE_DEV}" -j DHCPBLUEOUTPUT
174 fi
175
176 # trafic from ipsecX/TUN/TAP interfaces, before "-i GREEN_DEV" accept everything
177 iptables -N IPSECINPUT
178 iptables -N IPSECFORWARD
179 iptables -N IPSECOUTPUT
180 iptables -A INPUT -j IPSECINPUT
181 iptables -A FORWARD -j IPSECFORWARD
182 iptables -A OUTPUT -j IPSECOUTPUT
183 iptables -t nat -N IPSECNAT
184 iptables -t nat -A POSTROUTING -j IPSECNAT
185
186 # localhost and ethernet.
187 # Always allow accessing the web GUI from GREEN.
188 iptables -N GUIINPUT
189 iptables -A INPUT -j GUIINPUT
190 iptables -A GUIINPUT -i "${GREEN_DEV}" -p tcp --dport 444 -j ACCEPT
191
192 # WIRELESS chains
193 iptables -N WIRELESSINPUT
194 iptables -A INPUT -m conntrack --ctstate NEW -j WIRELESSINPUT
195 iptables -N WIRELESSFORWARD
196 iptables -A FORWARD -m conntrack --ctstate NEW -j WIRELESSFORWARD
197
198 # OpenVPN
199 iptables -N OVPNINPUT
200 iptables -A INPUT -j OVPNINPUT
201
202 # TOR
203 iptables -N TOR_INPUT
204 iptables -A INPUT -j TOR_INPUT
205
206 # Jump into the actual firewall ruleset.
207 iptables -N INPUTFW
208 iptables -A INPUT -j INPUTFW
209
210 iptables -N OUTGOINGFW
211 iptables -A OUTPUT -j OUTGOINGFW
212
213 iptables -N FORWARDFW
214 iptables -A FORWARD -j FORWARDFW
215
216 # SNAT rules
217 iptables -t nat -N NAT_SOURCE
218 iptables -t nat -A POSTROUTING -j NAT_SOURCE
219
220 # Custom prerouting chains (for transparent proxy)
221 iptables -t nat -N SQUID
222 iptables -t nat -A PREROUTING -j SQUID
223
224 # DNAT rules
225 iptables -t nat -N NAT_DESTINATION
226 iptables -t nat -A PREROUTING -j NAT_DESTINATION
227 iptables -t nat -A OUTPUT -j NAT_DESTINATION
228
229 iptables -t mangle -N NAT_DESTINATION
230 iptables -t mangle -A PREROUTING -j NAT_DESTINATION
231
232 iptables -t nat -N NAT_DESTINATION_FIX
233 iptables -t nat -A POSTROUTING -j NAT_DESTINATION_FIX
234
235 iptables -t nat -A NAT_DESTINATION_FIX \
236 -m mark --mark 1 -j SNAT --to-source "${GREEN_ADDRESS}"
237
238 if [ -n "${BLUE_ADDRESS}" ]; then
239 iptables -t nat -A NAT_DESTINATION_FIX \
240 -m mark --mark 2 -j SNAT --to-source "${BLUE_ADDRESS}"
241 fi
242
243 if [ -n "${ORANGE_ADDRESS}" ]; then
244 iptables -t nat -A NAT_DESTINATION_FIX \
245 -m mark --mark 3 -j SNAT --to-source "${ORANGE_ADDRESS}"
246 fi
247
248 # upnp chain for our upnp daemon
249 iptables -t nat -N UPNPFW
250 iptables -t nat -A PREROUTING -j UPNPFW
251 iptables -N UPNPFW
252 iptables -A FORWARD -m conntrack --ctstate NEW -j UPNPFW
253
254 # RED chain, used for the red interface
255 iptables -N REDINPUT
256 iptables -A INPUT -j REDINPUT
257 iptables -N REDFORWARD
258 iptables -A FORWARD -j REDFORWARD
259 iptables -t nat -N REDNAT
260 iptables -t nat -A POSTROUTING -j REDNAT
261
262 # Apply OpenVPN firewall rules
263 /usr/local/bin/openvpnctrl --firewall-rules
264
265 # run wirelessctrl
266 /usr/local/bin/wirelessctrl
267
268 # POLICY CHAIN
269 iptables -N POLICYIN
270 iptables -A INPUT -j POLICYIN
271 iptables -N POLICYFWD
272 iptables -A FORWARD -j POLICYFWD
273 iptables -N POLICYOUT
274 iptables -A OUTPUT -j POLICYOUT
275
276 # Initialize firewall policies.
277 /usr/sbin/firewall-policy
278
279 # Install firewall rules for the red interface.
280 iptables_red
281 }
282
283 iptables_red() {
284 iptables -F REDINPUT
285 iptables -F REDFORWARD
286 iptables -t nat -F REDNAT
287
288 # PPPoE / PPTP Device
289 if [ "$IFACE" != "" ]; then
290 # PPPoE / PPTP
291 if [ "$DEVICE" != "" ]; then
292 iptables -A REDINPUT -i $DEVICE -j ACCEPT
293 fi
294 if [ "$RED_TYPE" == "PPTP" -o "$RED_TYPE" == "PPPOE" ]; then
295 if [ "$RED_DEV" != "" ]; then
296 iptables -A REDINPUT -i $RED_DEV -j ACCEPT
297 fi
298 fi
299 fi
300
301 # PPTP over DHCP
302 if [ "$DEVICE" != "" -a "$TYPE" == "PPTP" -a "$METHOD" == "DHCP" ]; then
303 iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
304 iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
305 fi
306
307 # Orange pinholes
308 if [ "$ORANGE_DEV" != "" ]; then
309 # This rule enables a host on ORANGE network to connect to the outside
310 # (only if we have a red connection)
311 if [ "$IFACE" != "" ]; then
312 iptables -A REDFORWARD -i $ORANGE_DEV -o $IFACE -j ACCEPT
313 fi
314 fi
315
316 if [ "$IFACE" != "" -a -f /var/ipfire/red/active ]; then
317 # DHCP
318 if [ "$RED_DEV" != "" -a "$RED_TYPE" == "DHCP" ]; then
319 iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
320 iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
321 fi
322 if [ "$METHOD" == "DHCP" -a "$PROTOCOL" == "RFC1483" ]; then
323 iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
324 iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
325 fi
326
327 # Outgoing masquerading (don't masqerade IPSEC (mark 50))
328 iptables -t nat -A REDNAT -m mark --mark 50 -o $IFACE -j RETURN
329
330 if [ "$IFACE" != "$GREEN_DEV" ]; then
331 iptables -t nat -A REDNAT -o $IFACE -j MASQUERADE
332 fi
333
334 fi
335
336 # Reload all rules.
337 /usr/local/bin/firewallctrl
338 }
339
340 # See how we were called.
341 case "$1" in
342 start)
343 boot_mesg "Loading firewall modules into the kernel"
344 modprobe iptable_nat || failed=1
345 for i in $(find /lib/modules/$(uname -r) -name nf_conntrack*); do
346 modprobe $(basename $i | cut -d. -f1) || failed=1
347 done
348 for i in $(find /lib/modules/$(uname -r) -name nf_nat*); do
349 modprobe $(basename $i | cut -d. -f1) || failed=1
350 done
351 (exit ${failed})
352 evaluate_retval
353
354 if [ -e /var/ipfire/main/disable_nf_sip ]; then
355 rmmod nf_nat_sip
356 rmmod nf_conntrack_sip
357 rmmod nf_nat_h323
358 rmmod nf_conntrack_h323
359 fi
360
361 boot_mesg "Setting up firewall"
362 iptables_init
363 evaluate_retval
364
365 # run local firewall configuration, if present
366 if [ -x /etc/sysconfig/firewall.local ]; then
367 /etc/sysconfig/firewall.local start
368 fi
369 ;;
370 reload)
371 boot_mesg "Reloading firewall"
372 iptables_red
373 evaluate_retval
374
375 # run local firewall configuration, if present
376 if [ -x /etc/sysconfig/firewall.local ]; then
377 /etc/sysconfig/firewall.local reload
378 fi
379 ;;
380 restart)
381 # run local firewall configuration, if present
382 if [ -x /etc/sysconfig/firewall.local ]; then
383 /etc/sysconfig/firewall.local stop
384 fi
385 $0 start
386 ;;
387 *)
388 echo "Usage: $0 {start|reload|restart}"
389 exit 1
390 ;;
391 esac
392
393 exit 0