src/rc.d/rc.firewall

   1 #!/bin/sh
   2 #
   3 # $Id: rc.firewall,v 1.7.2.20 2006/01/12 01:24:30 franck78 Exp $
   4 #
   5
   6 eval $(/usr/local/bin/readhash CONFIG_ROOT/ppp/settings)
   7 eval $(/usr/local/bin/readhash CONFIG_ROOT/ethernet/settings)
   8 IFACE=`/bin/cat CONFIG_ROOT/red/iface 2> /dev/null | /usr/bin/tr -d '\012'`
   9
  10 if [ -f CONFIG_ROOT/red/device ]; then
  11         DEVICE=`/bin/cat CONFIG_ROOT/red/device 2> /dev/null | /usr/bin/tr -d '\012'`
  12 fi
  13
  14 iptables_init() {
  15         # Flush all rules and delete all custom chains
  16         /sbin/iptables -F
  17         /sbin/iptables -t nat -F
  18         /sbin/iptables -t mangle -F
  19         /sbin/iptables -X
  20         /sbin/iptables -t nat -X
  21         /sbin/iptables -t mangle -X
  22
  23         # Set up policies
  24         /sbin/iptables -P INPUT DROP
  25         /sbin/iptables -P FORWARD DROP
  26         /sbin/iptables -P OUTPUT ACCEPT
  27
  28         # Empty LOG_DROP and LOG_REJECT chains
  29         /sbin/iptables -N LOG_DROP
  30         /sbin/iptables -A LOG_DROP   -m limit --limit 10/minute -j LOG
  31         /sbin/iptables -A LOG_DROP   -j DROP
  32         /sbin/iptables -N LOG_REJECT
  33         /sbin/iptables -A LOG_REJECT -m limit --limit 10/minute -j LOG
  34         /sbin/iptables -A LOG_REJECT -j REJECT
  35
  36         # This chain will log, then DROPs packets with certain bad combinations
  37         # of flags might indicate a port-scan attempt (xmas, null, etc)
  38         /sbin/iptables -N PSCAN
  39         /sbin/iptables -A PSCAN -p tcp  -m limit --limit 10/minute -j LOG --log-prefix "TCP Scan? "
  40         /sbin/iptables -A PSCAN -p udp  -m limit --limit 10/minute -j LOG --log-prefix "UDP Scan? "
  41         /sbin/iptables -A PSCAN -p icmp -m limit --limit 10/minute -j LOG --log-prefix "ICMP Scan? "
  42         /sbin/iptables -A PSCAN -f      -m limit --limit 10/minute -j LOG --log-prefix "FRAG Scan? "
  43         /sbin/iptables -A PSCAN -j DROP
  44
  45         # New tcp packets without SYN set - could well be an obscure type of port scan
  46         # that's not covered above, may just be a broken windows machine
  47         /sbin/iptables -N NEWNOTSYN
  48         /sbin/iptables -A NEWNOTSYN  -m limit --limit 10/minute -j LOG  --log-prefix "NEW not SYN? "
  49         /sbin/iptables -A NEWNOTSYN  -j DROP
  50
  51         # Chain to contain all the rules relating to bad TCP flags
  52         /sbin/iptables -N BADTCP
  53
  54         # Disallow packets frequently used by port-scanners
  55         # nmap xmas
  56         /sbin/iptables -A BADTCP -p tcp --tcp-flags ALL FIN,URG,PSH  -j PSCAN
  57         # Null
  58         /sbin/iptables -A BADTCP -p tcp --tcp-flags ALL NONE -j PSCAN
  59         # FIN
  60         /sbin/iptables -A BADTCP -p tcp --tcp-flags ALL FIN -j PSCAN
  61         # SYN/RST (also catches xmas variants that set SYN+RST+...)
  62         /sbin/iptables -A BADTCP -p tcp --tcp-flags SYN,RST SYN,RST -j PSCAN
  63         # SYN/FIN (QueSO or nmap OS probe)
  64         /sbin/iptables -A BADTCP -p tcp --tcp-flags SYN,FIN SYN,FIN -j PSCAN
  65         # NEW TCP without SYN
  66         /sbin/iptables -A BADTCP -p tcp ! --syn -m state --state NEW -j NEWNOTSYN
  67
  68         /sbin/iptables -A INPUT   -j BADTCP
  69         /sbin/iptables -A FORWARD -j BADTCP
  70
  71 }
  72
  73 iptables_red() {
  74         /sbin/iptables -F REDINPUT
  75         /sbin/iptables -F REDFORWARD
  76         /sbin/iptables -t nat -F REDNAT
  77
  78         # PPPoE / PPTP Device
  79         if [ "$IFACE" != "" ]; then
  80                 # PPPoE / PPTP
  81                 if [ "$DEVICE" != "" ]; then
  82                         /sbin/iptables -A REDINPUT -i $DEVICE -j ACCEPT
  83                 fi
  84                 if [ "$RED_TYPE" == "PPTP" -o "$RED_TYPE" == "PPPOE" ]; then
  85                         if [ "$RED_DEV" != "" ]; then
  86                                 /sbin/iptables -A REDINPUT -i $RED_DEV -j ACCEPT
  87                         fi
  88                 fi
  89         fi
  90
  91         # PPTP over DHCP
  92         if [ "$DEVICE" != "" -a "$TYPE" == "PPTP" -a "$METHOD" == "DHCP" ]; then
  93                 /sbin/iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
  94                 /sbin/iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
  95         fi
  96
  97         # Orange pinholes
  98         if [ "$ORANGE_DEV" != "" ]; then
  99                 # This rule enables a host on ORANGE network to connect to the outside
 100                 # (only if we have a red connection)
 101                 if [ "$IFACE" != "" ]; then
 102                         /sbin/iptables -A REDFORWARD -i $ORANGE_DEV -p tcp -o $IFACE -j ACCEPT
 103                         /sbin/iptables -A REDFORWARD -i $ORANGE_DEV -p udp -o $IFACE -j ACCEPT
 104                 fi
 105         fi
 106
 107         if [ "$IFACE" != "" -a -f CONFIG_ROOT/red/active ]; then
 108                 # DHCP
 109                 if [ "$RED_DEV" != "" -a "$RED_TYPE" == "DHCP" ]; then
 110                         /sbin/iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 111                         /sbin/iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 112                 fi
 113                 if [ "$METHOD" == "DHCP"  -a "$PROTOCOL" == "RFC1483" ]; then
 114                         /sbin/iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 115                         /sbin/iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 116                 fi
 117
 118                 # Outgoing masquerading
 119                 /sbin/iptables -t nat -A REDNAT -o $IFACE -j MASQUERADE
 120
 121         fi
 122 }
 123
 124 # See how we were called.
 125 case "$1" in
 126   start)
 127         iptables_init
 128
 129         # Limit Packets- helps reduce dos/syn attacks
 130         # original do nothing line
 131         #/sbin/iptables -A INPUT -p tcp -m tcp --tcp-flags SYN,RST,ACK SYN -m limit --limit 10/sec
 132         # the correct one, but the negative '!' do nothing...
 133         #/sbin/iptables -A INPUT -p tcp -m tcp --tcp-flags SYN,RST,ACK SYN -m limit ! --limit 10/sec -j DROP
 134
 135         # Fix for braindead ISP's
 136         /sbin/iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
 137
 138         # CUSTOM chains, can be used by the users themselves
 139         /sbin/iptables -N CUSTOMINPUT
 140         /sbin/iptables -A INPUT -j CUSTOMINPUT
 141         /sbin/iptables -N CUSTOMFORWARD
 142         /sbin/iptables -A FORWARD -j CUSTOMFORWARD
 143         /sbin/iptables -N CUSTOMOUTPUT
 144         /sbin/iptables -A OUTPUT -j CUSTOMOUTPUT
 145         /sbin/iptables -t nat -N CUSTOMPREROUTING
 146         /sbin/iptables -t nat -A PREROUTING -j CUSTOMPREROUTING
 147         /sbin/iptables -t nat -N CUSTOMPOSTROUTING
 148         /sbin/iptables -t nat -A POSTROUTING -j CUSTOMPOSTROUTING
 149
 150         # filtering from GUI
 151         /sbin/iptables -N GUIINPUT
 152         /sbin/iptables -A INPUT -j GUIINPUT
 153
 154         # Accept everything connected
 155         /sbin/iptables -A INPUT   -m state --state ESTABLISHED,RELATED -j ACCEPT
 156         /sbin/iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
 157
 158         # localhost and ethernet.
 159         /sbin/iptables -A INPUT   -i lo          -m state --state NEW -j ACCEPT
 160         /sbin/iptables -A INPUT   -s 127.0.0.0/8 -m state --state NEW -j DROP   # Loopback not on lo
 161         /sbin/iptables -A INPUT   -d 127.0.0.0/8 -m state --state NEW -j DROP
 162         /sbin/iptables -A FORWARD -i lo          -m state --state NEW -j ACCEPT
 163         /sbin/iptables -A FORWARD -s 127.0.0.0/8 -m state --state NEW -j DROP
 164         /sbin/iptables -A FORWARD -d 127.0.0.0/8 -m state --state NEW -j DROP
 165         /sbin/iptables -A INPUT   -i $GREEN_DEV  -m state --state NEW -j ACCEPT -p ! icmp
 166         /sbin/iptables -A FORWARD -i $GREEN_DEV  -m state --state NEW -j ACCEPT
 167
 168         # If a host on orange tries to initiate a connection to IPFire's red IP and
 169         # the connection gets DNATed back through a port forward to a server on orange
 170         # we end up with orange -> orange traffic passing through IPFire
 171         [ "$ORANGE_DEV" != "" ] && /sbin/iptables -A FORWARD -i $ORANGE_DEV -o $ORANGE_DEV -m state --state NEW -j ACCEPT
 172
 173         # accept all traffic from ipsec interfaces
 174         /sbin/iptables -A INPUT   -i ipsec+ -j ACCEPT
 175         /sbin/iptables -A FORWARD -i ipsec+ -j ACCEPT
 176
 177         # allow DHCP on BLUE to be turned on/off
 178         /sbin/iptables -N DHCPBLUEINPUT
 179         /sbin/iptables -A INPUT -j DHCPBLUEINPUT
 180
 181         # IPSec chains
 182         /sbin/iptables -N IPSECRED
 183         /sbin/iptables -A INPUT -j IPSECRED
 184         /sbin/iptables -N IPSECBLUE
 185         /sbin/iptables -A INPUT -j IPSECBLUE
 186
 187         # WIRELESS chains
 188         /sbin/iptables -N WIRELESSINPUT
 189         /sbin/iptables -A INPUT -m state --state NEW -j WIRELESSINPUT
 190         /sbin/iptables -N WIRELESSFORWARD
 191         /sbin/iptables -A FORWARD -m state --state NEW -j WIRELESSFORWARD
 192
 193         # RED chain, used for the red interface
 194         /sbin/iptables -N REDINPUT
 195         /sbin/iptables -A INPUT -j REDINPUT
 196         /sbin/iptables -N REDFORWARD
 197         /sbin/iptables -A FORWARD -j REDFORWARD
 198         /sbin/iptables -t nat -N REDNAT
 199         /sbin/iptables -t nat -A POSTROUTING -j REDNAT
 200
 201         iptables_red
 202
 203         # DMZ pinhole chain.  setdmzholes setuid prog adds rules here to allow
 204         # ORANGE to talk to GREEN / BLUE.
 205         /sbin/iptables -N DMZHOLES
 206         if [ "$ORANGE_DEV" != "" ]; then
 207                 /sbin/iptables -A FORWARD -i $ORANGE_DEV -m state --state NEW -j DMZHOLES
 208         fi
 209
 210         # XTACCESS chain, used for external access
 211         /sbin/iptables -N XTACCESS
 212         /sbin/iptables -A INPUT -m state --state NEW -j XTACCESS
 213
 214         # PORTFWACCESS chain, used for portforwarding
 215         /sbin/iptables -N PORTFWACCESS
 216         /sbin/iptables -A FORWARD -m state --state NEW -j PORTFWACCESS
 217
 218         # Custom prerouting chains (for transparent proxy and port forwarding)
 219         /sbin/iptables -t nat -N SQUID
 220         /sbin/iptables -t nat -A PREROUTING -j SQUID
 221         /sbin/iptables -t nat -N PORTFW
 222         /sbin/iptables -t nat -A PREROUTING -j PORTFW
 223
 224
 225         # Custom mangle chain (for port fowarding)
 226         /sbin/iptables -t mangle -N PORTFWMANGLE
 227         /sbin/iptables -t mangle -A PREROUTING -j PORTFWMANGLE
 228
 229         # Postrouting rules (for port forwarding)
 230         /sbin/iptables -t nat -A POSTROUTING -m mark --mark 1 -j SNAT \
 231          --to-source $GREEN_ADDRESS
 232         if [ "$BLUE_DEV" != "" ]; then
 233                 /sbin/iptables -t nat -A POSTROUTING -m mark --mark 2 -j SNAT --to-source $BLUE_ADDRESS
 234         fi
 235         if [ "$ORANGE_DEV" != "" ]; then
 236                 /sbin/iptables -t nat -A POSTROUTING -m mark --mark 3 -j SNAT --to-source $ORANGE_ADDRESS
 237         fi
 238
 239
 240         # run local firewall configuration, if present
 241         if [ -x /etc/rc.d/rc.firewall.local ]; then
 242                 /etc/rc.d/rc.firewall.local start
 243         fi
 244
 245         # last rule in input and forward chain is for logging.
 246         /sbin/iptables -A INPUT   -m limit --limit 10/minute -j LOG --log-prefix "INPUT "
 247         /sbin/iptables -A FORWARD -m limit --limit 10/minute -j LOG --log-prefix "OUTPUT "
 248         ;;
 249   stop)
 250         iptables_init
 251         # Accept everyting connected
 252         /sbin/iptables -A INPUT   -m state --state ESTABLISHED,RELATED -j ACCEPT
 253
 254         # localhost and ethernet.
 255         /sbin/iptables -A INPUT -i lo -j ACCEPT
 256         /sbin/iptables -A INPUT -i $GREEN_DEV -m state --state NEW -j ACCEPT
 257
 258         if [ "$RED_DEV" != "" -a "$RED_TYPE" == "DHCP" ]; then
 259                 /sbin/iptables -A INPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 260                 /sbin/iptables -A INPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 261         fi
 262         if [ "$PROTOCOL" == "RFC1483" -a "$METHOD" == "DHCP" ]; then
 263                 /sbin/iptables -A INPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 264                 /sbin/iptables -A INPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
 265         fi
 266
 267         # run local firewall configuration, if present
 268         if [ -x /etc/rc.d/rc.firewall.local ]; then
 269                 /etc/rc.d/rc.firewall.local stop
 270         fi
 271
 272         /sbin/iptables -A INPUT   -m limit --limit 10/minute -j LOG --log-prefix "INPUT "
 273         /sbin/iptables -A FORWARD -m limit --limit 10/minute -j LOG --log-prefix "OUTPUT "
 274         ;;
 275   reload)
 276         iptables_red
 277
 278         # run local firewall configuration, if present
 279         if [ -x /etc/rc.d/rc.firewall.local ]; then
 280                 /etc/rc.d/rc.firewall.local reload
 281         fi
 282         ;;
 283   restart)
 284         $0 stop
 285         $0 start
 286         ;;
 287   *)
 288         echo "Usage: $0 {start|stop|reload|restart}"
 289         exit 1
 290         ;;
 291 esac
 292
 293 exit 0