src/initscripts/system/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 -t raw -F
  25         iptables -X
  26         iptables -t nat -X
  27         iptables -t mangle -X
  28         iptables -t raw -X
  29
  30         # Set up policies
  31         iptables -P INPUT DROP
  32         iptables -P FORWARD DROP
  33         iptables -P OUTPUT ACCEPT
  34
  35         # Enable TRACE logging to syslog
  36         modprobe nf_log_ipv4
  37         sysctl -q -w net.netfilter.nf_log.2=nf_log_ipv4
  38
  39         # Empty LOG_DROP and LOG_REJECT chains
  40         iptables -N LOG_DROP
  41         iptables -A LOG_DROP   -m limit --limit 10/second -j LOG
  42         iptables -A LOG_DROP   -j DROP
  43         iptables -N LOG_REJECT
  44         iptables -A LOG_REJECT -m limit --limit 10/second -j LOG
  45         iptables -A LOG_REJECT -j REJECT
  46
  47         # This chain will log, then DROPs packets with certain bad combinations
  48         # of flags might indicate a port-scan attempt (xmas, null, etc.)
  49         iptables -N PSCAN
  50         if [ "$DROPPORTSCAN" == "on" ]; then
  51                 iptables -A PSCAN -p tcp  -m limit --limit 10/second -j LOG --log-prefix "DROP_TCP Scan "  -m comment --comment "DROP_TCP PScan"
  52                 iptables -A PSCAN -p udp  -m limit --limit 10/second -j LOG --log-prefix "DROP_UDP Scan "  -m comment --comment "DROP_UDP PScan"
  53                 iptables -A PSCAN -p icmp -m limit --limit 10/second -j LOG --log-prefix "DROP_ICMP Scan " -m comment --comment "DROP_ICMP PScan"
  54                 iptables -A PSCAN -f      -m limit --limit 10/second -j LOG --log-prefix "DROP_FRAG Scan " -m comment --comment "DROP_FRAG PScan"
  55         fi
  56         iptables -A PSCAN -j DROP -m comment --comment "DROP_PScan"
  57
  58         # New tcp packets without SYN set - could well be an obscure type of port scan
  59         # that's not covered above, may just be a broken Windows machine
  60         iptables -N NEWNOTSYN
  61         if [ "$DROPNEWNOTSYN" == "on" ]; then
  62                 iptables -A NEWNOTSYN  -m limit --limit 10/second -j LOG  --log-prefix "DROP_NEWNOTSYN "
  63         fi
  64         iptables -A NEWNOTSYN  -j DROP -m comment --comment "DROP_NEWNOTSYN"
  65
  66         # Chain to contain all the rules relating to bad TCP flags
  67         iptables -N BADTCP
  68
  69         # Don't check loopback
  70         iptables -A BADTCP -i lo -j RETURN
  71
  72         # Disallow packets frequently used by port-scanners
  73         # NMAP FIN/URG/PSH (XMAS scan)
  74         iptables -A BADTCP -p tcp --tcp-flags ALL FIN,URG,PSH -j PSCAN
  75         # SYN/RST/ACK/FIN/URG
  76         iptables -A BADTCP -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j PSCAN
  77         # ALL/ALL
  78         iptables -A BADTCP -p tcp --tcp-flags ALL ALL -j PSCAN
  79         # FIN Stealth
  80         iptables -A BADTCP -p tcp --tcp-flags ALL FIN -j PSCAN
  81         # SYN/RST (also catches xmas variants that set SYN+RST+...)
  82         iptables -A BADTCP -p tcp --tcp-flags SYN,RST SYN,RST -j PSCAN
  83         # SYN/FIN (QueSO or nmap OS probe)
  84         iptables -A BADTCP -p tcp --tcp-flags SYN,FIN SYN,FIN -j PSCAN
  85         # Null
  86         iptables -A BADTCP -p tcp --tcp-flags ALL NONE -j PSCAN
  87         # NEW TCP without SYN
  88         iptables -A BADTCP -p tcp ! --syn -m conntrack --ctstate NEW -j NEWNOTSYN
  89
  90         iptables -A INPUT   -p tcp -j BADTCP
  91         iptables -A FORWARD -p tcp -j BADTCP
  92
  93         # Connection tracking chains
  94         iptables -N CONNTRACK
  95         iptables -A CONNTRACK -m conntrack --ctstate ESTABLISHED -j ACCEPT
  96         iptables -A CONNTRACK -m conntrack --ctstate INVALID -j DROP
  97         iptables -A CONNTRACK -p icmp -m conntrack --ctstate RELATED -j ACCEPT
  98         iptables -t raw -N CONNTRACK
  99         iptables -t raw -A PREROUTING -j CONNTRACK
 100
 101         # Conntrack helper (https://home.regit.org/netfilter-en/secure-use-of-helpers/)
 102
 103         # GRE (always enabled)
 104         modprobe nf_conntrack_proto_gre
 105
 106         # Fix for braindead ISPs
 107         iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
 108
 109         # CUSTOM chains, can be used by the users themselves
 110         iptables -N CUSTOMINPUT
 111         iptables -A INPUT -j CUSTOMINPUT
 112         iptables -N CUSTOMFORWARD
 113         iptables -A FORWARD -j CUSTOMFORWARD
 114         iptables -N CUSTOMOUTPUT
 115         iptables -A OUTPUT -j CUSTOMOUTPUT
 116         iptables -t nat -N CUSTOMPREROUTING
 117         iptables -t nat -A PREROUTING -j CUSTOMPREROUTING
 118         iptables -t nat -N CUSTOMPOSTROUTING
 119         iptables -t nat -A POSTROUTING -j CUSTOMPOSTROUTING
 120
 121         # P2PBLOCK
 122         iptables -N P2PBLOCK
 123         iptables -A INPUT -j P2PBLOCK
 124         iptables -A FORWARD -j P2PBLOCK
 125         iptables -A OUTPUT -j P2PBLOCK
 126
 127         # IPS (Guardian) chains
 128         iptables -N GUARDIAN
 129         iptables -A INPUT -j GUARDIAN
 130         iptables -A FORWARD -j GUARDIAN
 131
 132         # Block non-established IPsec networks
 133         iptables -N IPSECBLOCK
 134         iptables -A FORWARD -m policy --dir out --pol none -j IPSECBLOCK
 135         iptables -A OUTPUT  -m policy --dir out --pol none -j IPSECBLOCK
 136
 137         # Block OpenVPN transfer networks
 138         iptables -N OVPNBLOCK
 139         iptables -A INPUT   -i tun+ -j OVPNBLOCK
 140         iptables -A FORWARD -i tun+ -j OVPNBLOCK
 141         iptables -A FORWARD -o tun+ -j OVPNBLOCK
 142
 143         # IPS (Suricata) chains
 144         iptables -N IPS_INPUT
 145         iptables -N IPS_FORWARD
 146         iptables -N IPS_OUTPUT
 147         iptables -A INPUT -j IPS_INPUT
 148         iptables -A FORWARD -j IPS_FORWARD
 149         iptables -A OUTPUT -j IPS_OUTPUT
 150
 151         # OpenVPN transfer network translation
 152         iptables -t nat -N OVPNNAT
 153         iptables -t nat -A POSTROUTING -j OVPNNAT
 154
 155         # IPTV chains for IGMPPROXY
 156         iptables -N IPTVINPUT
 157         iptables -A INPUT -j IPTVINPUT
 158         iptables -N IPTVFORWARD
 159         iptables -A FORWARD -j IPTVFORWARD
 160
 161         # Allow to ping the firewall.
 162         iptables -N ICMPINPUT
 163         iptables -A INPUT -j ICMPINPUT
 164         iptables -A ICMPINPUT -p icmp --icmp-type 8 -j ACCEPT
 165
 166         # Accept everything on loopback
 167         iptables -N LOOPBACK
 168         iptables -A LOOPBACK -i lo -j ACCEPT
 169         iptables -A LOOPBACK -o lo -j ACCEPT
 170
 171         # Filter all packets with loopback addresses on non-loopback interfaces.
 172         iptables -A LOOPBACK -s 127.0.0.0/8 -j DROP
 173         iptables -A LOOPBACK -d 127.0.0.0/8 -j DROP
 174
 175         for i in INPUT FORWARD OUTPUT; do
 176                 iptables -A ${i} -j LOOPBACK
 177         done
 178
 179         # Captive portal
 180         iptables -N CAPTIVE_PORTAL
 181         iptables -N CAPTIVE_PORTAL_CLIENTS
 182         for i in INPUT FORWARD; do
 183                 iptables -A ${i} -j CAPTIVE_PORTAL
 184         done
 185
 186         # Accept everything connected
 187         for i in INPUT FORWARD OUTPUT; do
 188                 iptables -A ${i} -j CONNTRACK
 189         done
 190
 191         # Allow DHCP
 192         iptables -N DHCPINPUT
 193         iptables -A DHCPINPUT -p udp --sport 68 --dport 67 -j ACCEPT
 194         iptables -A DHCPINPUT -p tcp --sport 68 --dport 67 -j ACCEPT
 195
 196         iptables -N DHCPOUTPUT
 197         iptables -A DHCPOUTPUT -p udp --sport 67 --dport 68 -j ACCEPT
 198         iptables -A DHCPOUTPUT -p tcp --sport 67 --dport 68 -j ACCEPT
 199
 200         # Allow DHCP on GREEN
 201         iptables -N DHCPGREENINPUT
 202         iptables -N DHCPGREENOUTPUT
 203         if [ -n "${GREEN_DEV}" ]; then
 204                 iptables -A INPUT  -i "${GREEN_DEV}" -j DHCPGREENINPUT
 205                 iptables -A OUTPUT -o "${GREEN_DEV}" -j DHCPGREENOUTPUT
 206         fi
 207
 208         # Allow DHCP on BLUE to be turned on/off
 209         iptables -N DHCPBLUEINPUT
 210         iptables -N DHCPBLUEOUTPUT
 211         if [ -n "${BLUE_DEV}" ]; then
 212                 iptables -A INPUT  -i "${BLUE_DEV}" -j DHCPBLUEINPUT
 213                 iptables -A OUTPUT -o "${BLUE_DEV}" -j DHCPBLUEOUTPUT
 214         fi
 215
 216         # Location Block
 217         iptables -N LOCATIONBLOCK
 218         iptables -A INPUT -j LOCATIONBLOCK
 219         iptables -A FORWARD -j LOCATIONBLOCK
 220
 221         # trafic from ipsecX/TUN/TAP interfaces, before "-i GREEN_DEV" accept everything
 222         iptables -N IPSECINPUT
 223         iptables -N IPSECFORWARD
 224         iptables -N IPSECOUTPUT
 225         iptables -A INPUT -j IPSECINPUT
 226         iptables -A FORWARD -j IPSECFORWARD
 227         iptables -A OUTPUT -j IPSECOUTPUT
 228         iptables -t nat -N IPSECNAT
 229         iptables -t nat -A POSTROUTING -j IPSECNAT
 230
 231         # localhost and ethernet.
 232         # Always allow accessing the web GUI from GREEN.
 233         iptables -N GUIINPUT
 234         iptables -A INPUT -j GUIINPUT
 235         if [ -n "${GREEN_DEV}" ]; then
 236                 iptables -A GUIINPUT -i "${GREEN_DEV}" -p tcp --dport 444 -j ACCEPT
 237         fi
 238
 239         # WIRELESS chains
 240         iptables -N WIRELESSINPUT
 241         iptables -A INPUT -m conntrack --ctstate NEW -j WIRELESSINPUT
 242         iptables -N WIRELESSFORWARD
 243         iptables -A FORWARD -m conntrack --ctstate NEW -j WIRELESSFORWARD
 244
 245         # OpenVPN
 246         iptables -N OVPNINPUT
 247         iptables -A INPUT -j OVPNINPUT
 248
 249         # Tor (inbound and outbound)
 250         iptables -N TOR_INPUT
 251         iptables -A INPUT -j TOR_INPUT
 252         iptables -N TOR_OUTPUT
 253         iptables -A OUTPUT -j TOR_OUTPUT
 254
 255         # Jump into the actual firewall ruleset.
 256         iptables -N INPUTFW
 257         iptables -A INPUT -j INPUTFW
 258
 259         iptables -N OUTGOINGFW
 260         iptables -A OUTPUT -j OUTGOINGFW
 261
 262         iptables -N FORWARDFW
 263         iptables -A FORWARD -j FORWARDFW
 264
 265         # SNAT rules
 266         iptables -t nat -N NAT_SOURCE
 267         iptables -t nat -A POSTROUTING -j NAT_SOURCE
 268
 269         # Captive Portal
 270         iptables -t nat -N CAPTIVE_PORTAL
 271         iptables -t nat -A PREROUTING -j CAPTIVE_PORTAL
 272
 273         # Custom prerouting chains (for transparent proxy)
 274         iptables -t nat -N SQUID
 275         iptables -t nat -A PREROUTING -j SQUID
 276
 277         # DNAT rules
 278         iptables -t nat -N NAT_DESTINATION
 279         iptables -t nat -A PREROUTING -j NAT_DESTINATION
 280         iptables -t nat -A OUTPUT -j NAT_DESTINATION
 281
 282         iptables -t mangle -N NAT_DESTINATION
 283         iptables -t mangle -A PREROUTING -j NAT_DESTINATION
 284
 285         iptables -t nat -N NAT_DESTINATION_FIX
 286         iptables -t nat -A POSTROUTING -j NAT_DESTINATION_FIX
 287
 288         if [ -n "${GREEN_ADDRESS}" ]; then
 289                 iptables -t nat -A NAT_DESTINATION_FIX \
 290                         -m mark --mark 1 -j SNAT --to-source "${GREEN_ADDRESS}"
 291         fi
 292
 293         if [ -n "${BLUE_ADDRESS}" ]; then
 294                 iptables -t nat -A NAT_DESTINATION_FIX \
 295                         -m mark --mark 2 -j SNAT --to-source "${BLUE_ADDRESS}"
 296         fi
 297
 298         if [ -n "${ORANGE_ADDRESS}" ]; then
 299                 iptables -t nat -A NAT_DESTINATION_FIX \
 300                         -m mark --mark 3 -j SNAT --to-source "${ORANGE_ADDRESS}"
 301         fi
 302
 303         # RED chain, used for the red interface
 304         iptables -N REDINPUT
 305         iptables -A INPUT -j REDINPUT
 306         iptables -N REDFORWARD
 307         iptables -A FORWARD -j REDFORWARD
 308         iptables -t nat -N REDNAT
 309         iptables -t nat -A POSTROUTING -j REDNAT
 310
 311         # Populate IPsec chains
 312         /usr/lib/firewall/ipsec-policy
 313
 314         # Apply OpenVPN firewall rules
 315         /usr/local/bin/openvpnctrl --firewall-rules
 316
 317         # run wirelessctrl
 318         /usr/local/bin/wirelessctrl
 319
 320         # run captivectrl
 321         /usr/local/bin/captivectrl
 322
 323         # POLICY CHAIN
 324         iptables -N POLICYIN
 325         iptables -A INPUT -j POLICYIN
 326         iptables -N POLICYFWD
 327         iptables -A FORWARD -j POLICYFWD
 328         iptables -N POLICYOUT
 329         iptables -A OUTPUT -j POLICYOUT
 330
 331         # Initialize firewall policies.
 332         /usr/sbin/firewall-policy
 333
 334         # Install firewall rules for the red interface.
 335         iptables_red_up
 336
 337         # If red has not been brought up yet, we will
 338         # add the blocking rules for MASQUERADE
 339         if [ ! -e "/var/ipfire/red/active" ]; then
 340                 iptables_red_down
 341         fi
 342 }
 343
 344 iptables_red_up() {
 345         iptables -F REDINPUT
 346         iptables -F REDFORWARD
 347         iptables -t nat -F REDNAT
 348
 349         # PPPoE / PPTP Device
 350         if [ "$IFACE" != "" ]; then
 351                 # PPPoE / PPTP
 352                 if [ "$DEVICE" != "" ]; then
 353                         iptables -A REDINPUT -i $DEVICE -j ACCEPT
 354                 fi
 355                 if [ "$RED_TYPE" == "PPTP" -o "$RED_TYPE" == "PPPOE" ]; then
 356                         if [ "$RED_DEV" != "" ]; then
 357                                 iptables -A REDINPUT -i $RED_DEV -j ACCEPT
 358                         fi
 359                 fi
 360         fi
 361
 362         # PPTP over DHCP
 363         if [ "$DEVICE" != "" -a "$TYPE" == "PPTP" -a "$METHOD" == "DHCP" ]; then
 364                 iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
 365                 iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
 366         fi
 367
 368         if [ "$IFACE" != "" -a -f /var/ipfire/red/active ]; then
 369                 # DHCP
 370                 if [ "$RED_DEV" != "" -a "$RED_TYPE" == "DHCP" ]; then
 371                         iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 372                         iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 373                 fi
 374                 if [ "$METHOD" == "DHCP"  -a "$PROTOCOL" == "RFC1483" ]; then
 375                         iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 376                         iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 377                 fi
 378
 379                 # Outgoing masquerading (don't masqerade IPsec (mark 50))
 380                 iptables -t nat -A REDNAT -m mark --mark 50 -o $IFACE -j RETURN
 381
 382                 if [ "${IFACE}" = "${GREEN_DEV}" ]; then
 383                         iptables -t nat -A REDNAT -i "${GREEN_DEV}" -o "${IFACE}" -j RETURN
 384                 fi
 385
 386                 local NO_MASQ_NETWORKS
 387
 388                 if [ "${MASQUERADE_GREEN}" = "off" ]; then
 389                         NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${GREEN_NETADDRESS}/${GREEN_NETMASK}"
 390                 fi
 391
 392                 if [ "${MASQUERADE_BLUE}" = "off" ]; then
 393                         NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${BLUE_NETADDRESS}/${BLUE_NETMASK}"
 394                 fi
 395
 396                 if [ "${MASQUERADE_ORANGE}" = "off" ]; then
 397                         NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${ORANGE_NETADDRESS}/${ORANGE_NETMASK}"
 398                 fi
 399
 400                 local network
 401                 for network in ${NO_MASQ_NETWORKS}; do
 402                         iptables -t nat -A REDNAT -s "${network}" -o "${IFACE}" -j RETURN
 403                 done
 404
 405                 # Masquerade everything else
 406                 iptables -t nat -A REDNAT -o $IFACE -j MASQUERADE
 407         fi
 408
 409         # Reload all rules.
 410         /usr/local/bin/firewallctrl
 411 }
 412
 413 iptables_red_down() {
 414         # Prohibit packets to reach the masquerading rule
 415         # while the WAN interface is down - this is required to
 416         # circumvent udp related NAT issues
 417         # http://forum.ipfire.org/index.php?topic=11127.0
 418         if [ -n "${IFACE}" ]; then
 419                 iptables -F REDFORWARD
 420                 iptables -A REDFORWARD -o "${IFACE}" -j DROP
 421         fi
 422
 423         # Reload all rules.
 424         /usr/local/bin/firewallctrl
 425 }
 426
 427 # See how we were called.
 428 case "$1" in
 429   start)
 430         boot_mesg "Setting up firewall"
 431         iptables_init
 432         evaluate_retval
 433         ;;
 434   reload|up)
 435         boot_mesg "Reloading firewall"
 436         iptables_red_up
 437         evaluate_retval
 438         ;;
 439   down)
 440         boot_mesg "Disabling firewall access to RED"
 441         iptables_red_down
 442         evaluate_retval
 443         ;;
 444   restart)
 445         $0 start
 446         ;;
 447   *)
 448         echo "Usage: $0 {start|reload|restart}"
 449         exit 1
 450         ;;
 451 esac
 452
 453 exit 0