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 $(/usr/local/bin/readhash /var/ipfire/optionsfw/settings)
   9 IFACE=`/bin/cat /var/ipfire/red/iface 2> /dev/null | /usr/bin/tr -d '\012'`
  10
  11 if [ -f /var/ipfire/red/device ]; then
  12         DEVICE=`/bin/cat /var/ipfire/red/device 2> /dev/null | /usr/bin/tr -d '\012'`
  13 fi
  14
  15 NAT_MASK="0x0f000000"
  16
  17 IPS_REPEAT_MARK="0x80000000"
  18 IPS_REPEAT_MASK="0x80000000"
  19 IPS_BYPASS_MARK="0x40000000"
  20 IPS_BYPASS_MASK="0x40000000"
  21
  22 function iptables() {
  23         /sbin/iptables --wait "$@"
  24 }
  25
  26 iptables_init() {
  27         # Flush all rules and delete all custom chains
  28         iptables -F
  29         iptables -t nat -F
  30         iptables -t mangle -F
  31         iptables -t raw -F
  32         iptables -X
  33         iptables -t nat -X
  34         iptables -t mangle -X
  35         iptables -t raw -X
  36
  37         # Set up policies
  38         iptables -P INPUT DROP
  39         iptables -P FORWARD DROP
  40         iptables -P OUTPUT ACCEPT
  41
  42         # Enable TRACE logging to syslog
  43         modprobe nf_log_ipv4
  44         sysctl -q -w net.netfilter.nf_log.2=nf_log_ipv4
  45
  46         # IPS Bypass Chain which stores the BYPASS bit in connection tracking
  47         iptables -N IPSBYPASS
  48         iptables -A IPSBYPASS -j CONNMARK --save-mark --mask "$(( ~IPS_REPEAT_MASK & 0xffffffff ))"
  49
  50         # Jump into bypass chain when the BYPASS bit is set
  51         for chain in INPUT FORWARD OUTPUT; do
  52                 iptables -A "${chain}" -m mark \
  53                         --mark "$(( IPS_REPEAT_MARK | IPS_BYPASS_MARK ))/$(( IPS_REPEAT_MASK | IPS_BYPASS_MASK ))" -j IPSBYPASS
  54         done
  55
  56         # Empty LOG_DROP and LOG_REJECT chains
  57         iptables -N LOG_DROP
  58         iptables -A LOG_DROP   -m limit --limit 10/second -j LOG
  59         iptables -A LOG_DROP   -j DROP
  60         iptables -N LOG_REJECT
  61         iptables -A LOG_REJECT -m limit --limit 10/second -j LOG
  62         iptables -A LOG_REJECT -j REJECT
  63
  64         # This chain will log, then DROPs packets with certain bad combinations
  65         # of flags might indicate a port-scan attempt (xmas, null, etc.)
  66         iptables -N PSCAN
  67         if [ "$DROPPORTSCAN" == "on" ]; then
  68                 iptables -A PSCAN -p tcp  -m limit --limit 10/second -j LOG --log-prefix "DROP_TCP Scan "  -m comment --comment "DROP_TCP PScan"
  69                 iptables -A PSCAN -p udp  -m limit --limit 10/second -j LOG --log-prefix "DROP_UDP Scan "  -m comment --comment "DROP_UDP PScan"
  70                 iptables -A PSCAN -p icmp -m limit --limit 10/second -j LOG --log-prefix "DROP_ICMP Scan " -m comment --comment "DROP_ICMP PScan"
  71                 iptables -A PSCAN -f      -m limit --limit 10/second -j LOG --log-prefix "DROP_FRAG Scan " -m comment --comment "DROP_FRAG PScan"
  72         fi
  73         iptables -A PSCAN -j DROP -m comment --comment "DROP_PScan"
  74
  75         # New tcp packets without SYN set - could well be an obscure type of port scan
  76         # that's not covered above, may just be a broken Windows machine
  77         iptables -N NEWNOTSYN
  78         if [ "$DROPNEWNOTSYN" == "on" ]; then
  79                 iptables -A NEWNOTSYN  -m limit --limit 10/second -j LOG  --log-prefix "DROP_NEWNOTSYN "
  80         fi
  81         iptables -A NEWNOTSYN  -j DROP -m comment --comment "DROP_NEWNOTSYN"
  82
  83         # Log and subsequently drop spoofed packets or "martians", arriving from sources
  84         # on interfaces where we don't expect them
  85         iptables -N SPOOFED_MARTIAN
  86         if [ "$DROPSPOOFEDMARTIAN" == "on" ]; then
  87                 iptables -A SPOOFED_MARTIAN  -m limit --limit 10/second -j LOG  --log-prefix "DROP_SPOOFED_MARTIAN "
  88         fi
  89         iptables -A SPOOFED_MARTIAN -j DROP -m comment --comment "DROP_SPOOFED_MARTIAN"
  90
  91         # Chain to contain all the rules relating to bad TCP flags
  92         iptables -N BADTCP
  93
  94         # Don't check loopback
  95         iptables -A BADTCP -i lo -j RETURN
  96
  97         # Disallow packets frequently used by port-scanners
  98         # NMAP FIN/URG/PSH (XMAS scan)
  99         iptables -A BADTCP -p tcp --tcp-flags ALL FIN,URG,PSH -j PSCAN
 100         # SYN/RST/ACK/FIN/URG
 101         iptables -A BADTCP -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j PSCAN
 102         # ALL/ALL
 103         iptables -A BADTCP -p tcp --tcp-flags ALL ALL -j PSCAN
 104         # FIN Stealth
 105         iptables -A BADTCP -p tcp --tcp-flags ALL FIN -j PSCAN
 106         # SYN/RST (also catches xmas variants that set SYN+RST+...)
 107         iptables -A BADTCP -p tcp --tcp-flags SYN,RST SYN,RST -j PSCAN
 108         # SYN/FIN (QueSO or nmap OS probe)
 109         iptables -A BADTCP -p tcp --tcp-flags SYN,FIN SYN,FIN -j PSCAN
 110         # Null
 111         iptables -A BADTCP -p tcp --tcp-flags ALL NONE -j PSCAN
 112         # NEW TCP without SYN
 113         iptables -A BADTCP -p tcp ! --syn -m conntrack --ctstate NEW -j NEWNOTSYN
 114
 115         iptables -A INPUT   -p tcp -j BADTCP
 116         iptables -A FORWARD -p tcp -j BADTCP
 117
 118         # Connection tracking chains
 119         iptables -N CONNTRACK
 120         iptables -A CONNTRACK -m conntrack --ctstate ESTABLISHED -j ACCEPT
 121         iptables -A CONNTRACK -m conntrack --ctstate INVALID -j LOG_DROP
 122         iptables -A CONNTRACK -p icmp -m conntrack --ctstate RELATED -j ACCEPT
 123
 124         # Restore any connection marks
 125         iptables -t mangle -A PREROUTING -j CONNMARK --restore-mark
 126
 127         # Fix for braindead ISPs
 128         iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
 129
 130         # CUSTOM chains, can be used by the users themselves
 131         iptables -N CUSTOMINPUT
 132         iptables -A INPUT -j CUSTOMINPUT
 133         iptables -N CUSTOMFORWARD
 134         iptables -A FORWARD -j CUSTOMFORWARD
 135         iptables -N CUSTOMOUTPUT
 136         iptables -A OUTPUT -j CUSTOMOUTPUT
 137         iptables -t nat -N CUSTOMPREROUTING
 138         iptables -t nat -A PREROUTING -j CUSTOMPREROUTING
 139         iptables -t nat -N CUSTOMPOSTROUTING
 140         iptables -t nat -A POSTROUTING -j CUSTOMPOSTROUTING
 141
 142         # P2PBLOCK
 143         iptables -N P2PBLOCK
 144         iptables -A INPUT -j P2PBLOCK
 145         iptables -A FORWARD -j P2PBLOCK
 146         iptables -A OUTPUT -j P2PBLOCK
 147
 148         # IPS (Guardian) chains
 149         iptables -N GUARDIAN
 150         iptables -A INPUT -j GUARDIAN
 151         iptables -A FORWARD -j GUARDIAN
 152
 153         # Block non-established IPsec networks
 154         iptables -N IPSECBLOCK
 155         iptables -A FORWARD -m policy --dir out --pol none -j IPSECBLOCK
 156         iptables -A OUTPUT  -m policy --dir out --pol none -j IPSECBLOCK
 157
 158         # Block OpenVPN transfer networks
 159         iptables -N OVPNBLOCK
 160         iptables -A INPUT   -i tun+ -j OVPNBLOCK
 161         iptables -A FORWARD -i tun+ -j OVPNBLOCK
 162         iptables -A FORWARD -o tun+ -j OVPNBLOCK
 163
 164         # IPS (Suricata) chains
 165         iptables -N IPS_INPUT
 166         iptables -N IPS_FORWARD
 167         iptables -N IPS_OUTPUT
 168
 169         for chain in INPUT FORWARD OUTPUT; do
 170                 iptables -A "${chain}" -m mark --mark "0x0/$(( IPS_REPEAT_MASK | IPS_BYPASS_MASK ))" -j "IPS_${chain}"
 171         done
 172
 173         # OpenVPN transfer network translation
 174         iptables -t nat -N OVPNNAT
 175         iptables -t nat -A POSTROUTING -j OVPNNAT
 176
 177         # IPTV chains for IGMPPROXY
 178         iptables -N IPTVINPUT
 179         iptables -A INPUT -j IPTVINPUT
 180         iptables -N IPTVFORWARD
 181         iptables -A FORWARD -j IPTVFORWARD
 182
 183         # Allow to ping the firewall.
 184         iptables -N ICMPINPUT
 185         iptables -A INPUT -j ICMPINPUT
 186         iptables -A ICMPINPUT -p icmp --icmp-type 8 -j ACCEPT
 187
 188         # Accept everything on loopback if source/destination is loopback space...
 189         iptables -N LOOPBACK
 190         iptables -A LOOPBACK -i lo -s 127.0.0.0/8 -j ACCEPT
 191         iptables -A LOOPBACK -o lo -d 127.0.0.0/8 -j ACCEPT
 192
 193         # ... and drop everything else on the loopback interface, since no other traffic should appear there
 194         iptables -A LOOPBACK -i lo -j SPOOFED_MARTIAN
 195         iptables -A LOOPBACK -o lo -j SPOOFED_MARTIAN
 196
 197         # Filter all packets with loopback addresses on non-loopback interfaces (spoofed)
 198         iptables -A LOOPBACK -s 127.0.0.0/8 -j SPOOFED_MARTIAN
 199         iptables -A LOOPBACK -d 127.0.0.0/8 -j SPOOFED_MARTIAN
 200
 201         for i in INPUT FORWARD OUTPUT; do
 202                 iptables -A ${i} -j LOOPBACK
 203         done
 204
 205         # Captive portal
 206         iptables -N CAPTIVE_PORTAL
 207         iptables -N CAPTIVE_PORTAL_CLIENTS
 208         for i in INPUT FORWARD; do
 209                 iptables -A ${i} -j CAPTIVE_PORTAL
 210         done
 211
 212         # Accept everything connected
 213         for i in INPUT FORWARD OUTPUT; do
 214                 iptables -A ${i} -j CONNTRACK
 215         done
 216
 217         # Allow DHCP
 218         iptables -N DHCPINPUT
 219         iptables -A DHCPINPUT -p udp --sport 68 --dport 67 -j ACCEPT
 220         iptables -A DHCPINPUT -p tcp --sport 68 --dport 67 -j ACCEPT
 221
 222         iptables -N DHCPOUTPUT
 223         iptables -A DHCPOUTPUT -p udp --sport 67 --dport 68 -j ACCEPT
 224         iptables -A DHCPOUTPUT -p tcp --sport 67 --dport 68 -j ACCEPT
 225
 226         # Allow DHCP on GREEN
 227         iptables -N DHCPGREENINPUT
 228         iptables -N DHCPGREENOUTPUT
 229         if [ -n "${GREEN_DEV}" ]; then
 230                 iptables -A INPUT  -i "${GREEN_DEV}" -j DHCPGREENINPUT
 231                 iptables -A OUTPUT -o "${GREEN_DEV}" -j DHCPGREENOUTPUT
 232         fi
 233
 234         # Allow DHCP on BLUE to be turned on/off
 235         iptables -N DHCPBLUEINPUT
 236         iptables -N DHCPBLUEOUTPUT
 237         if [ -n "${BLUE_DEV}" ]; then
 238                 iptables -A INPUT  -i "${BLUE_DEV}" -j DHCPBLUEINPUT
 239                 iptables -A OUTPUT -o "${BLUE_DEV}" -j DHCPBLUEOUTPUT
 240         fi
 241
 242         # Tor (inbound)
 243         iptables -N TOR_INPUT
 244         iptables -A INPUT -j TOR_INPUT
 245
 246         # Location Block
 247         iptables -N LOCATIONBLOCK
 248         iptables -A INPUT -j LOCATIONBLOCK
 249         iptables -A FORWARD -j LOCATIONBLOCK
 250
 251         # trafic from ipsecX/TUN/TAP interfaces, before "-i GREEN_DEV" accept everything
 252         iptables -N IPSECINPUT
 253         iptables -N IPSECFORWARD
 254         iptables -N IPSECOUTPUT
 255         iptables -A INPUT -j IPSECINPUT
 256         iptables -A FORWARD -j IPSECFORWARD
 257         iptables -A OUTPUT -j IPSECOUTPUT
 258         iptables -t nat -N IPSECNAT
 259         iptables -t nat -A POSTROUTING -j IPSECNAT
 260
 261         # localhost and ethernet.
 262         # Always allow accessing the web GUI from GREEN.
 263         iptables -N GUIINPUT
 264         iptables -A INPUT -j GUIINPUT
 265         if [ -n "${GREEN_DEV}" ]; then
 266                 iptables -A GUIINPUT -i "${GREEN_DEV}" -p tcp --dport 444 -j ACCEPT
 267         fi
 268
 269         # WIRELESS chains
 270         iptables -N WIRELESSINPUT
 271         iptables -A INPUT -m conntrack --ctstate NEW -j WIRELESSINPUT
 272         iptables -N WIRELESSFORWARD
 273         iptables -A FORWARD -m conntrack --ctstate NEW -j WIRELESSFORWARD
 274
 275         # OpenVPN
 276         iptables -N OVPNINPUT
 277         iptables -A INPUT -j OVPNINPUT
 278
 279         # Tor (outbound)
 280         iptables -N TOR_OUTPUT
 281         iptables -A OUTPUT -j TOR_OUTPUT
 282
 283         # Jump into the actual firewall ruleset.
 284         iptables -N INPUTFW
 285         iptables -A INPUT -j INPUTFW
 286
 287         iptables -N OUTGOINGFW
 288         iptables -A OUTPUT -j OUTGOINGFW
 289
 290         iptables -N FORWARDFW
 291         iptables -A FORWARD -j FORWARDFW
 292
 293         # SNAT rules
 294         iptables -t nat -N NAT_SOURCE
 295         iptables -t nat -A POSTROUTING -j NAT_SOURCE
 296
 297         # Captive Portal
 298         iptables -t nat -N CAPTIVE_PORTAL
 299         iptables -t nat -A PREROUTING -j CAPTIVE_PORTAL
 300
 301         # Custom prerouting chains (for transparent proxy)
 302         iptables -t nat -N SQUID
 303         iptables -t nat -A PREROUTING -j SQUID
 304
 305         # DNAT rules
 306         iptables -t nat -N NAT_DESTINATION
 307         iptables -t nat -A PREROUTING -j NAT_DESTINATION
 308         iptables -t nat -A OUTPUT -j NAT_DESTINATION
 309
 310         iptables -t mangle -N NAT_DESTINATION
 311         iptables -t mangle -A PREROUTING -j NAT_DESTINATION
 312
 313         iptables -t nat -N NAT_DESTINATION_FIX
 314         iptables -t nat -A POSTROUTING -j NAT_DESTINATION_FIX
 315
 316         if [ -n "${GREEN_ADDRESS}" ]; then
 317                 iptables -t nat -A NAT_DESTINATION_FIX \
 318                         -m mark --mark "0x01000000/${NAT_MASK}" -j SNAT --to-source "${GREEN_ADDRESS}"
 319         fi
 320
 321         if [ -n "${BLUE_ADDRESS}" ]; then
 322                 iptables -t nat -A NAT_DESTINATION_FIX \
 323                         -m mark --mark "0x02000000/${NAT_MASK}" -j SNAT --to-source "${BLUE_ADDRESS}"
 324         fi
 325
 326         if [ -n "${ORANGE_ADDRESS}" ]; then
 327                 iptables -t nat -A NAT_DESTINATION_FIX \
 328                         -m mark --mark "0x04000000/${NAT_MASK}" -j SNAT --to-source "${ORANGE_ADDRESS}"
 329         fi
 330
 331         # RED chain, used for the red interface
 332         iptables -N REDINPUT
 333         iptables -A INPUT -j REDINPUT
 334         iptables -N REDFORWARD
 335         iptables -A FORWARD -j REDFORWARD
 336         iptables -t nat -N REDNAT
 337         iptables -t nat -A POSTROUTING -j REDNAT
 338
 339         # Populate IPsec chains
 340         /usr/lib/firewall/ipsec-policy
 341
 342         # Apply OpenVPN firewall rules
 343         /usr/local/bin/openvpnctrl --firewall-rules
 344
 345         # run wirelessctrl
 346         /usr/local/bin/wirelessctrl
 347
 348         # run captivectrl
 349         /usr/local/bin/captivectrl
 350
 351         # POLICY CHAIN
 352         iptables -N POLICYIN
 353         iptables -A INPUT -j POLICYIN
 354         iptables -N POLICYFWD
 355         iptables -A FORWARD -j POLICYFWD
 356         iptables -N POLICYOUT
 357         iptables -A OUTPUT -j POLICYOUT
 358
 359         # Initialize firewall policies.
 360         /usr/sbin/firewall-policy
 361
 362         # Install firewall rules for the red interface.
 363         iptables_red_up
 364
 365         # If red has not been brought up yet, we will
 366         # add the blocking rules for MASQUERADE
 367         if [ ! -e "/var/ipfire/red/active" ]; then
 368                 iptables_red_down
 369         fi
 370 }
 371
 372 iptables_red_up() {
 373         iptables -F REDINPUT
 374         iptables -F REDFORWARD
 375         iptables -t nat -F REDNAT
 376
 377         # Prohibit spoofing our own IP address on RED
 378         if [ -f /var/ipfire/red/active ]; then
 379                 REDIP="$( cat /var/ipfire/red/local-ipaddress )";
 380
 381                 if [ "$IFACE" != "" ]; then
 382                         iptables -A REDINPUT -s $REDIP -i $IFACE -j SPOOFED_MARTIAN
 383                 elif [ "$DEVICE" != "" ]; then
 384                         iptables -A REDINPUT -s $REDIP -i $DEVICE -j SPOOFED_MARTIAN
 385                 fi
 386         fi
 387
 388         # PPPoE / PPTP Device
 389         if [ "$IFACE" != "" ]; then
 390                 # PPPoE / PPTP
 391                 if [ "$DEVICE" != "" ]; then
 392                         iptables -A REDINPUT -i $DEVICE -j ACCEPT
 393                 fi
 394                 if [ "$RED_TYPE" == "PPTP" -o "$RED_TYPE" == "PPPOE" ]; then
 395                         if [ "$RED_DEV" != "" ]; then
 396                                 iptables -A REDINPUT -i $RED_DEV -j ACCEPT
 397                         fi
 398                 fi
 399         fi
 400
 401         # PPTP over DHCP
 402         if [ "$DEVICE" != "" -a "$TYPE" == "PPTP" -a "$METHOD" == "DHCP" ]; then
 403                 iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
 404                 iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
 405         fi
 406
 407         if [ "$IFACE" != "" -a -f /var/ipfire/red/active ]; then
 408                 # DHCP
 409                 if [ "$RED_DEV" != "" -a "$RED_TYPE" == "DHCP" ]; then
 410                         iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 411                         iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 412                 fi
 413                 if [ "$METHOD" == "DHCP"  -a "$PROTOCOL" == "RFC1483" ]; then
 414                         iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 415                         iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 416                 fi
 417
 418                 # Outgoing masquerading (don't masqerade IPsec)
 419                 iptables -t nat -A REDNAT -m policy --pol ipsec --dir=out -o "${IFACE}" -j RETURN
 420
 421                 if [ "${IFACE}" = "${GREEN_DEV}" ]; then
 422                         iptables -t nat -A REDNAT -i "${GREEN_DEV}" -o "${IFACE}" -j RETURN
 423                 fi
 424
 425                 local NO_MASQ_NETWORKS
 426
 427                 if [ "${MASQUERADE_GREEN}" = "off" ]; then
 428                         NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${GREEN_NETADDRESS}/${GREEN_NETMASK}"
 429                 fi
 430
 431                 if [ "${MASQUERADE_BLUE}" = "off" ]; then
 432                         NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${BLUE_NETADDRESS}/${BLUE_NETMASK}"
 433                 fi
 434
 435                 if [ "${MASQUERADE_ORANGE}" = "off" ]; then
 436                         NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${ORANGE_NETADDRESS}/${ORANGE_NETMASK}"
 437                 fi
 438
 439                 local network
 440                 for network in ${NO_MASQ_NETWORKS}; do
 441                         iptables -t nat -A REDNAT -s "${network}" -o "${IFACE}" -j RETURN
 442                 done
 443
 444                 # Masquerade everything else
 445                 iptables -t nat -A REDNAT -o $IFACE -j MASQUERADE
 446         fi
 447
 448         # Reload all rules.
 449         /usr/local/bin/firewallctrl
 450 }
 451
 452 iptables_red_down() {
 453         # Prohibit packets to reach the masquerading rule
 454         # while the WAN interface is down - this is required to
 455         # circumvent udp related NAT issues
 456         # http://forum.ipfire.org/index.php?topic=11127.0
 457         if [ -n "${IFACE}" ]; then
 458                 iptables -F REDFORWARD
 459                 iptables -A REDFORWARD -o "${IFACE}" -j DROP
 460         fi
 461
 462         # Reload all rules.
 463         /usr/local/bin/firewallctrl
 464 }
 465
 466 # See how we were called.
 467 case "$1" in
 468   start)
 469         boot_mesg "Setting up firewall"
 470         iptables_init
 471         evaluate_retval
 472         ;;
 473   reload|up)
 474         boot_mesg "Reloading firewall"
 475         iptables_red_up
 476         evaluate_retval
 477         ;;
 478   down)
 479         boot_mesg "Disabling firewall access to RED"
 480         iptables_red_down
 481         evaluate_retval
 482         ;;
 483   restart)
 484         $0 start
 485         ;;
 486   *)
 487         echo "Usage: $0 {start|reload|restart}"
 488         exit 1
 489         ;;
 490 esac
 491
 492 exit 0