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 helpers (https://home.regit.org/netfilter-en/secure-use-of-helpers/)
 102
 103         # GRE (always enabled)
 104         modprobe nf_conntrack_proto_gre
 105
 106         # SIP
 107         if [ "${CONNTRACK_SIP}" = "on" ]; then
 108                 modprobe nf_nat_sip
 109                 iptables -A CONNTRACK -m conntrack --ctstate RELATED \
 110                         -m helper --helper sip -j ACCEPT
 111                 for proto in udp tcp; do
 112                         iptables -t raw -A CONNTRACK -p "${proto}" --dport 5060 -j CT --helper sip
 113                 done
 114         fi
 115
 116         # H.323
 117         if [ "${CONNTRACK_H323}" = "on" ]; then
 118                 modprobe nf_nat_h323
 119                 iptables -A CONNTRACK -m conntrack --ctstate RELATED \
 120                         -m helper --helper h323 -j ACCEPT
 121
 122                 # Gatekeeper RAS
 123                 iptables -t raw -A CONNTRACK -p udp --dport 1719 -j CT --helper RAS
 124
 125                 # Q.931
 126                 iptables -t raw -A CONNTRACK -p tcp --dport 1720 -j CT --helper Q.931
 127         fi
 128
 129         # FTP
 130         if [ "${CONNTRACK_FTP}" = "on" ]; then
 131                 modprobe nf_nat_ftp
 132                 iptables -A CONNTRACK -m conntrack --ctstate RELATED \
 133                         -m helper --helper ftp -p tcp --dport 1024: -j ACCEPT
 134                 iptables -t raw -A CONNTRACK -p tcp --dport 21 -j CT --helper ftp
 135         fi
 136
 137         # PPTP
 138         if [ "${CONNTRACK_PPTP}" = "on" ]; then
 139                 modprobe nf_nat_pptp
 140                 iptables -A CONNTRACK -m conntrack --ctstate RELATED \
 141                         -m helper --helper pptp -j ACCEPT
 142                 iptables -t raw -A CONNTRACK -p tcp --dport 1723 -j CT --helper pptp
 143         fi
 144
 145         # TFTP
 146         if [ "${CONNTRACK_TFTP}" = "on" ]; then
 147                 modprobe nf_nat_tftp
 148                 iptables -A CONNTRACK -m conntrack --ctstate RELATED \
 149                         -m helper --helper tftp -j ACCEPT
 150                 iptables -t raw -A CONNTRACK -p udp --dport 69 -j CT --helper tftp
 151         fi
 152
 153         # IRC
 154         if [ "${CONNTRACK_IRC}" = "on" ]; then
 155                 modprobe nf_nat_irc
 156                 iptables -A CONNTRACK -m conntrack --ctstate RELATED \
 157                         -m helper --helper irc -j ACCEPT
 158                 iptables -t raw -A CONNTRACK -p tcp --dport 6667 -j CT --helper irc
 159         fi
 160
 161         # Amanda
 162         if [ "${CONNTRACK_AMANDA}" = "on" ]; then
 163                 modprobe nf_nat_amanda
 164                 iptables -A CONNTRACK -m conntrack --ctstate RELATED \
 165                         -m helper --helper amanda -j ACCEPT
 166                 iptables -t raw -A CONNTRACK -p tcp -j CT --helper amanda
 167         fi
 168
 169         # Fix for braindead ISPs
 170         iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
 171
 172         # CUSTOM chains, can be used by the users themselves
 173         iptables -N CUSTOMINPUT
 174         iptables -A INPUT -j CUSTOMINPUT
 175         iptables -N CUSTOMFORWARD
 176         iptables -A FORWARD -j CUSTOMFORWARD
 177         iptables -N CUSTOMOUTPUT
 178         iptables -A OUTPUT -j CUSTOMOUTPUT
 179         iptables -t nat -N CUSTOMPREROUTING
 180         iptables -t nat -A PREROUTING -j CUSTOMPREROUTING
 181         iptables -t nat -N CUSTOMPOSTROUTING
 182         iptables -t nat -A POSTROUTING -j CUSTOMPOSTROUTING
 183
 184         # P2PBLOCK
 185         iptables -N P2PBLOCK
 186         iptables -A INPUT -j P2PBLOCK
 187         iptables -A FORWARD -j P2PBLOCK
 188         iptables -A OUTPUT -j P2PBLOCK
 189
 190         # IPS (Guardian) chains
 191         iptables -N GUARDIAN
 192         iptables -A INPUT -j GUARDIAN
 193         iptables -A FORWARD -j GUARDIAN
 194
 195         # Block non-established IPsec networks
 196         iptables -N IPSECBLOCK
 197         iptables -A FORWARD -m policy --dir out --pol none -j IPSECBLOCK
 198         iptables -A OUTPUT  -m policy --dir out --pol none -j IPSECBLOCK
 199
 200         # Block OpenVPN transfer networks
 201         iptables -N OVPNBLOCK
 202         iptables -A INPUT   -i tun+ -j OVPNBLOCK
 203         iptables -A FORWARD -i tun+ -j OVPNBLOCK
 204         iptables -A FORWARD -o tun+ -j OVPNBLOCK
 205
 206         # IPS (Suricata) chains
 207         iptables -N IPS_INPUT
 208         iptables -N IPS_FORWARD
 209         iptables -N IPS_OUTPUT
 210         iptables -A INPUT -j IPS_INPUT
 211         iptables -A FORWARD -j IPS_FORWARD
 212         iptables -A OUTPUT -j IPS_OUTPUT
 213
 214         # OpenVPN transfer network translation
 215         iptables -t nat -N OVPNNAT
 216         iptables -t nat -A POSTROUTING -j OVPNNAT
 217
 218         # IPTV chains for IGMPPROXY
 219         iptables -N IPTVINPUT
 220         iptables -A INPUT -j IPTVINPUT
 221         iptables -N IPTVFORWARD
 222         iptables -A FORWARD -j IPTVFORWARD
 223
 224         # Allow to ping the firewall.
 225         iptables -N ICMPINPUT
 226         iptables -A INPUT -j ICMPINPUT
 227         iptables -A ICMPINPUT -p icmp --icmp-type 8 -j ACCEPT
 228
 229         # Accept everything on loopback
 230         iptables -N LOOPBACK
 231         iptables -A LOOPBACK -i lo -j ACCEPT
 232         iptables -A LOOPBACK -o lo -j ACCEPT
 233
 234         # Filter all packets with loopback addresses on non-loopback interfaces.
 235         iptables -A LOOPBACK -s 127.0.0.0/8 -j DROP
 236         iptables -A LOOPBACK -d 127.0.0.0/8 -j DROP
 237
 238         for i in INPUT FORWARD OUTPUT; do
 239                 iptables -A ${i} -j LOOPBACK
 240         done
 241
 242         # Captive portal
 243         iptables -N CAPTIVE_PORTAL
 244         iptables -N CAPTIVE_PORTAL_CLIENTS
 245         for i in INPUT FORWARD; do
 246                 iptables -A ${i} -j CAPTIVE_PORTAL
 247         done
 248
 249         # Accept everything connected
 250         for i in INPUT FORWARD OUTPUT; do
 251                 iptables -A ${i} -j CONNTRACK
 252         done
 253
 254         # Allow DHCP
 255         iptables -N DHCPINPUT
 256         iptables -A DHCPINPUT -p udp --sport 68 --dport 67 -j ACCEPT
 257         iptables -A DHCPINPUT -p tcp --sport 68 --dport 67 -j ACCEPT
 258
 259         iptables -N DHCPOUTPUT
 260         iptables -A DHCPOUTPUT -p udp --sport 67 --dport 68 -j ACCEPT
 261         iptables -A DHCPOUTPUT -p tcp --sport 67 --dport 68 -j ACCEPT
 262
 263         # Allow DHCP on GREEN
 264         iptables -N DHCPGREENINPUT
 265         iptables -N DHCPGREENOUTPUT
 266         if [ -n "${GREEN_DEV}" ]; then
 267                 iptables -A INPUT  -i "${GREEN_DEV}" -j DHCPGREENINPUT
 268                 iptables -A OUTPUT -o "${GREEN_DEV}" -j DHCPGREENOUTPUT
 269         fi
 270
 271         # Allow DHCP on BLUE to be turned on/off
 272         iptables -N DHCPBLUEINPUT
 273         iptables -N DHCPBLUEOUTPUT
 274         if [ -n "${BLUE_DEV}" ]; then
 275                 iptables -A INPUT  -i "${BLUE_DEV}" -j DHCPBLUEINPUT
 276                 iptables -A OUTPUT -o "${BLUE_DEV}" -j DHCPBLUEOUTPUT
 277         fi
 278
 279         # Location Block
 280         iptables -N LOCATIONBLOCK
 281         iptables -A INPUT -j LOCATIONBLOCK
 282         iptables -A FORWARD -j LOCATIONBLOCK
 283
 284         # trafic from ipsecX/TUN/TAP interfaces, before "-i GREEN_DEV" accept everything
 285         iptables -N IPSECINPUT
 286         iptables -N IPSECFORWARD
 287         iptables -N IPSECOUTPUT
 288         iptables -A INPUT -j IPSECINPUT
 289         iptables -A FORWARD -j IPSECFORWARD
 290         iptables -A OUTPUT -j IPSECOUTPUT
 291         iptables -t nat -N IPSECNAT
 292         iptables -t nat -A POSTROUTING -j IPSECNAT
 293
 294         # localhost and ethernet.
 295         # Always allow accessing the web GUI from GREEN.
 296         iptables -N GUIINPUT
 297         iptables -A INPUT -j GUIINPUT
 298         if [ -n "${GREEN_DEV}" ]; then
 299                 iptables -A GUIINPUT -i "${GREEN_DEV}" -p tcp --dport 444 -j ACCEPT
 300         fi
 301
 302         # WIRELESS chains
 303         iptables -N WIRELESSINPUT
 304         iptables -A INPUT -m conntrack --ctstate NEW -j WIRELESSINPUT
 305         iptables -N WIRELESSFORWARD
 306         iptables -A FORWARD -m conntrack --ctstate NEW -j WIRELESSFORWARD
 307
 308         # OpenVPN
 309         iptables -N OVPNINPUT
 310         iptables -A INPUT -j OVPNINPUT
 311
 312         # Tor (inbound and outbound)
 313         iptables -N TOR_INPUT
 314         iptables -A INPUT -j TOR_INPUT
 315         iptables -N TOR_OUTPUT
 316         iptables -A OUTPUT -j TOR_OUTPUT
 317
 318         # Jump into the actual firewall ruleset.
 319         iptables -N INPUTFW
 320         iptables -A INPUT -j INPUTFW
 321
 322         iptables -N OUTGOINGFW
 323         iptables -A OUTPUT -j OUTGOINGFW
 324
 325         iptables -N FORWARDFW
 326         iptables -A FORWARD -j FORWARDFW
 327
 328         # SNAT rules
 329         iptables -t nat -N NAT_SOURCE
 330         iptables -t nat -A POSTROUTING -j NAT_SOURCE
 331
 332         # Captive Portal
 333         iptables -t nat -N CAPTIVE_PORTAL
 334         iptables -t nat -A PREROUTING -j CAPTIVE_PORTAL
 335
 336         # Custom prerouting chains (for transparent proxy)
 337         iptables -t nat -N SQUID
 338         iptables -t nat -A PREROUTING -j SQUID
 339
 340         # DNAT rules
 341         iptables -t nat -N NAT_DESTINATION
 342         iptables -t nat -A PREROUTING -j NAT_DESTINATION
 343         iptables -t nat -A OUTPUT -j NAT_DESTINATION
 344
 345         iptables -t mangle -N NAT_DESTINATION
 346         iptables -t mangle -A PREROUTING -j NAT_DESTINATION
 347
 348         iptables -t nat -N NAT_DESTINATION_FIX
 349         iptables -t nat -A POSTROUTING -j NAT_DESTINATION_FIX
 350
 351         if [ -n "${GREEN_ADDRESS}" ]; then
 352                 iptables -t nat -A NAT_DESTINATION_FIX \
 353                         -m mark --mark 1 -j SNAT --to-source "${GREEN_ADDRESS}"
 354         fi
 355
 356         if [ -n "${BLUE_ADDRESS}" ]; then
 357                 iptables -t nat -A NAT_DESTINATION_FIX \
 358                         -m mark --mark 2 -j SNAT --to-source "${BLUE_ADDRESS}"
 359         fi
 360
 361         if [ -n "${ORANGE_ADDRESS}" ]; then
 362                 iptables -t nat -A NAT_DESTINATION_FIX \
 363                         -m mark --mark 3 -j SNAT --to-source "${ORANGE_ADDRESS}"
 364         fi
 365
 366         # RED chain, used for the red interface
 367         iptables -N REDINPUT
 368         iptables -A INPUT -j REDINPUT
 369         iptables -N REDFORWARD
 370         iptables -A FORWARD -j REDFORWARD
 371         iptables -t nat -N REDNAT
 372         iptables -t nat -A POSTROUTING -j REDNAT
 373
 374         # Populate IPsec chains
 375         /usr/lib/firewall/ipsec-policy
 376
 377         # Apply OpenVPN firewall rules
 378         /usr/local/bin/openvpnctrl --firewall-rules
 379
 380         # run wirelessctrl
 381         /usr/local/bin/wirelessctrl
 382
 383         # run captivectrl
 384         /usr/local/bin/captivectrl
 385
 386         # POLICY CHAIN
 387         iptables -N POLICYIN
 388         iptables -A INPUT -j POLICYIN
 389         iptables -N POLICYFWD
 390         iptables -A FORWARD -j POLICYFWD
 391         iptables -N POLICYOUT
 392         iptables -A OUTPUT -j POLICYOUT
 393
 394         # Initialize firewall policies.
 395         /usr/sbin/firewall-policy
 396
 397         # Install firewall rules for the red interface.
 398         iptables_red_up
 399
 400         # If red has not been brought up yet, we will
 401         # add the blocking rules for MASQUERADE
 402         if [ ! -e "/var/ipfire/red/active" ]; then
 403                 iptables_red_down
 404         fi
 405 }
 406
 407 iptables_red_up() {
 408         iptables -F REDINPUT
 409         iptables -F REDFORWARD
 410         iptables -t nat -F REDNAT
 411
 412         # PPPoE / PPTP Device
 413         if [ "$IFACE" != "" ]; then
 414                 # PPPoE / PPTP
 415                 if [ "$DEVICE" != "" ]; then
 416                         iptables -A REDINPUT -i $DEVICE -j ACCEPT
 417                 fi
 418                 if [ "$RED_TYPE" == "PPTP" -o "$RED_TYPE" == "PPPOE" ]; then
 419                         if [ "$RED_DEV" != "" ]; then
 420                                 iptables -A REDINPUT -i $RED_DEV -j ACCEPT
 421                         fi
 422                 fi
 423         fi
 424
 425         # PPTP over DHCP
 426         if [ "$DEVICE" != "" -a "$TYPE" == "PPTP" -a "$METHOD" == "DHCP" ]; then
 427                 iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
 428                 iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
 429         fi
 430
 431         if [ "$IFACE" != "" -a -f /var/ipfire/red/active ]; then
 432                 # DHCP
 433                 if [ "$RED_DEV" != "" -a "$RED_TYPE" == "DHCP" ]; then
 434                         iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 435                         iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 436                 fi
 437                 if [ "$METHOD" == "DHCP"  -a "$PROTOCOL" == "RFC1483" ]; then
 438                         iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 439                         iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 440                 fi
 441
 442                 # Outgoing masquerading (don't masqerade IPsec (mark 50))
 443                 iptables -t nat -A REDNAT -m mark --mark 50 -o $IFACE -j RETURN
 444
 445                 if [ "${IFACE}" = "${GREEN_DEV}" ]; then
 446                         iptables -t nat -A REDNAT -i "${GREEN_DEV}" -o "${IFACE}" -j RETURN
 447                 fi
 448
 449                 local NO_MASQ_NETWORKS
 450
 451                 if [ "${MASQUERADE_GREEN}" = "off" ]; then
 452                         NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${GREEN_NETADDRESS}/${GREEN_NETMASK}"
 453                 fi
 454
 455                 if [ "${MASQUERADE_BLUE}" = "off" ]; then
 456                         NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${BLUE_NETADDRESS}/${BLUE_NETMASK}"
 457                 fi
 458
 459                 if [ "${MASQUERADE_ORANGE}" = "off" ]; then
 460                         NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${ORANGE_NETADDRESS}/${ORANGE_NETMASK}"
 461                 fi
 462
 463                 local network
 464                 for network in ${NO_MASQ_NETWORKS}; do
 465                         iptables -t nat -A REDNAT -s "${network}" -o "${IFACE}" -j RETURN
 466                 done
 467
 468                 # Masquerade everything else
 469                 iptables -t nat -A REDNAT -o $IFACE -j MASQUERADE
 470         fi
 471
 472         # Reload all rules.
 473         /usr/local/bin/firewallctrl
 474 }
 475
 476 iptables_red_down() {
 477         # Prohibit packets to reach the masquerading rule
 478         # while the WAN interface is down - this is required to
 479         # circumvent udp related NAT issues
 480         # http://forum.ipfire.org/index.php?topic=11127.0
 481         if [ -n "${IFACE}" ]; then
 482                 iptables -F REDFORWARD
 483                 iptables -A REDFORWARD -o "${IFACE}" -j DROP
 484         fi
 485
 486         # Reload all rules.
 487         /usr/local/bin/firewallctrl
 488 }
 489
 490 # See how we were called.
 491 case "$1" in
 492   start)
 493         boot_mesg "Setting up firewall"
 494         iptables_init
 495         evaluate_retval
 496         ;;
 497   reload|up)
 498         boot_mesg "Reloading firewall"
 499         iptables_red_up
 500         evaluate_retval
 501         ;;
 502   down)
 503         boot_mesg "Disabling firewall access to RED"
 504         iptables_red_down
 505         evaluate_retval
 506         ;;
 507   restart)
 508         $0 start
 509         ;;
 510   *)
 511         echo "Usage: $0 {start|reload|restart}"
 512         exit 1
 513         ;;
 514 esac
 515
 516 exit 0