safing-portmaster/firewall/interception/nfqueue_linux.go
2020-08-06 21:36:43 +02:00

317 lines
8.2 KiB
Go

package interception
import (
"flag"
"fmt"
"sort"
"strings"
"github.com/coreos/go-iptables/iptables"
"github.com/hashicorp/go-multierror"
"github.com/safing/portbase/log"
"github.com/safing/portmaster/firewall/interception/nfqexp"
"github.com/safing/portmaster/firewall/interception/nfqueue"
"github.com/safing/portmaster/network/packet"
)
// iptables -A OUTPUT -p icmp -j", "NFQUEUE", "--queue-num", "1", "--queue-bypass
var (
v4chains []string
v4rules []string
v4once []string
v6chains []string
v6rules []string
v6once []string
out4Queue nfQueue
in4Queue nfQueue
out6Queue nfQueue
in6Queue nfQueue
shutdownSignal = make(chan struct{})
experimentalNfqueueBackend bool
)
func init() {
flag.BoolVar(&experimentalNfqueueBackend, "experimental-nfqueue", false, "use experimental nfqueue packet")
}
// nfQueueFactoryFunc creates a new nfQueue with qid as the queue number.
type nfQueueFactoryFunc func(qid uint16, v6 bool) (nfQueue, error)
// nfQueue encapsulates nfQueue providers
type nfQueue interface {
PacketChannel() <-chan packet.Packet
Destroy()
}
func init() {
v4chains = []string{
"mangle C170",
"mangle C171",
"filter C17",
}
v4rules = []string{
"mangle C170 -j CONNMARK --restore-mark",
"mangle C170 -m mark --mark 0 -j NFQUEUE --queue-num 17040 --queue-bypass",
"mangle C171 -j CONNMARK --restore-mark",
"mangle C171 -m mark --mark 0 -j NFQUEUE --queue-num 17140 --queue-bypass",
"filter C17 -m mark --mark 0 -j DROP",
"filter C17 -m mark --mark 1700 -j RETURN",
"filter C17 -m mark --mark 1701 -j REJECT --reject-with icmp-host-prohibited",
"filter C17 -m mark --mark 1702 -j DROP",
"filter C17 -j CONNMARK --save-mark",
"filter C17 -m mark --mark 1710 -j RETURN",
"filter C17 -m mark --mark 1711 -j REJECT --reject-with icmp-host-prohibited",
"filter C17 -m mark --mark 1712 -j DROP",
"filter C17 -m mark --mark 1717 -j RETURN",
}
v4once = []string{
"mangle OUTPUT -j C170",
"mangle INPUT -j C171",
"filter OUTPUT -j C17",
"filter INPUT -j C17",
"nat OUTPUT -m mark --mark 1799 -p udp -j DNAT --to 127.0.0.1:53",
"nat OUTPUT -m mark --mark 1717 -p tcp -j DNAT --to 127.0.0.17:717",
"nat OUTPUT -m mark --mark 1717 -p udp -j DNAT --to 127.0.0.17:717",
// "nat OUTPUT -m mark --mark 1717 ! -p tcp ! -p udp -j DNAT --to 127.0.0.17",
}
v6chains = []string{
"mangle C170",
"mangle C171",
"filter C17",
}
v6rules = []string{
"mangle C170 -j CONNMARK --restore-mark",
"mangle C170 -m mark --mark 0 -j NFQUEUE --queue-num 17060 --queue-bypass",
"mangle C171 -j CONNMARK --restore-mark",
"mangle C171 -m mark --mark 0 -j NFQUEUE --queue-num 17160 --queue-bypass",
"filter C17 -m mark --mark 0 -j DROP",
"filter C17 -m mark --mark 1700 -j RETURN",
"filter C17 -m mark --mark 1701 -j REJECT --reject-with icmp6-adm-prohibited",
"filter C17 -m mark --mark 1702 -j DROP",
"filter C17 -j CONNMARK --save-mark",
"filter C17 -m mark --mark 1710 -j RETURN",
"filter C17 -m mark --mark 1711 -j REJECT --reject-with icmp6-adm-prohibited",
"filter C17 -m mark --mark 1712 -j DROP",
"filter C17 -m mark --mark 1717 -j RETURN",
}
v6once = []string{
"mangle OUTPUT -j C170",
"mangle INPUT -j C171",
"filter OUTPUT -j C17",
"filter INPUT -j C17",
"nat OUTPUT -m mark --mark 1799 -p udp -j DNAT --to [::1]:53",
"nat OUTPUT -m mark --mark 1717 -p tcp -j DNAT --to [fd17::17]:717",
"nat OUTPUT -m mark --mark 1717 -p udp -j DNAT --to [fd17::17]:717",
// "nat OUTPUT -m mark --mark 1717 ! -p tcp ! -p udp -j DNAT --to [fd17::17]",
}
// Reverse because we'd like to insert in a loop
_ = sort.Reverse(sort.StringSlice(v4once)) // silence vet (sort is used just like in the docs)
_ = sort.Reverse(sort.StringSlice(v6once)) // silence vet (sort is used just like in the docs)
}
func activateNfqueueFirewall() error {
if err := activateIPTables(iptables.ProtocolIPv4, v4rules, v4once, v4chains); err != nil {
return err
}
if err := activateIPTables(iptables.ProtocolIPv6, v6rules, v6once, v6chains); err != nil {
return err
}
return nil
}
// DeactivateNfqueueFirewall drops portmaster related IP tables rules.
// Any errors encountered accumulated into a *multierror.Error.
func DeactivateNfqueueFirewall() error {
// IPv4
var result *multierror.Error
if err := deactivateIPTables(iptables.ProtocolIPv4, v4once, v4chains); err != nil {
result = multierror.Append(result, err)
}
// IPv6
if err := deactivateIPTables(iptables.ProtocolIPv6, v6once, v6chains); err != nil {
result = multierror.Append(result, err)
}
return result
}
func activateIPTables(protocol iptables.Protocol, rules, once, chains []string) error {
tbls, err := iptables.NewWithProtocol(protocol)
if err != nil {
return err
}
for _, chain := range chains {
splittedRule := strings.Split(chain, " ")
if err = tbls.ClearChain(splittedRule[0], splittedRule[1]); err != nil {
return err
}
}
for _, rule := range rules {
splittedRule := strings.Split(rule, " ")
if err = tbls.Append(splittedRule[0], splittedRule[1], splittedRule[2:]...); err != nil {
return err
}
}
for _, rule := range once {
splittedRule := strings.Split(rule, " ")
ok, err := tbls.Exists(splittedRule[0], splittedRule[1], splittedRule[2:]...)
if err != nil {
return err
}
if !ok {
if err = tbls.Insert(splittedRule[0], splittedRule[1], 1, splittedRule[2:]...); err != nil {
return err
}
}
}
return nil
}
func deactivateIPTables(protocol iptables.Protocol, rules, chains []string) error {
tbls, err := iptables.NewWithProtocol(protocol)
if err != nil {
return err
}
var multierr *multierror.Error
for _, rule := range rules {
splittedRule := strings.Split(rule, " ")
ok, err := tbls.Exists(splittedRule[0], splittedRule[1], splittedRule[2:]...)
if err != nil {
multierr = multierror.Append(multierr, err)
}
if ok {
if err = tbls.Delete(splittedRule[0], splittedRule[1], splittedRule[2:]...); err != nil {
multierr = multierror.Append(multierr, err)
}
}
}
for _, chain := range chains {
splittedRule := strings.Split(chain, " ")
if err = tbls.ClearChain(splittedRule[0], splittedRule[1]); err != nil {
multierr = multierror.Append(multierr, err)
}
if err = tbls.DeleteChain(splittedRule[0], splittedRule[1]); err != nil {
multierr = multierror.Append(multierr, err)
}
}
return multierr
}
// StartNfqueueInterception starts the nfqueue interception.
func StartNfqueueInterception() (err error) {
var nfQueueFactory nfQueueFactoryFunc = func(qid uint16, v6 bool) (nfQueue, error) {
return nfqueue.NewNFQueue(qid)
}
if experimentalNfqueueBackend {
log.Infof("nfqueue: using experimental nfqueue backend")
nfQueueFactory = func(qid uint16, v6 bool) (nfQueue, error) {
return nfqexp.New(qid, v6)
}
}
err = activateNfqueueFirewall()
if err != nil {
_ = Stop()
return fmt.Errorf("could not initialize nfqueue: %s", err)
}
out4Queue, err = nfQueueFactory(17040, false)
if err != nil {
_ = Stop()
return fmt.Errorf("nfqueue(IPv4, out): %w", err)
}
in4Queue, err = nfQueueFactory(17140, false)
if err != nil {
_ = Stop()
return fmt.Errorf("nfqueue(IPv4, in): %w", err)
}
out6Queue, err = nfQueueFactory(17060, true)
if err != nil {
_ = Stop()
return fmt.Errorf("nfqueue(IPv6, out): %w", err)
}
in6Queue, err = nfQueueFactory(17160, true)
if err != nil {
_ = Stop()
return fmt.Errorf("nfqueue(IPv6, in): %w", err)
}
go handleInterception()
return nil
}
// StopNfqueueInterception stops the nfqueue interception.
func StopNfqueueInterception() error {
defer close(shutdownSignal)
if out4Queue != nil {
out4Queue.Destroy()
}
if in4Queue != nil {
in4Queue.Destroy()
}
if out6Queue != nil {
out6Queue.Destroy()
}
if in6Queue != nil {
in6Queue.Destroy()
}
err := DeactivateNfqueueFirewall()
if err != nil {
return fmt.Errorf("interception: error while deactivating nfqueue: %s", err)
}
return nil
}
func handleInterception() {
for {
select {
case <-shutdownSignal:
return
case pkt := <-out4Queue.PacketChannel():
pkt.SetOutbound()
Packets <- pkt
case pkt := <-in4Queue.PacketChannel():
pkt.SetInbound()
Packets <- pkt
case pkt := <-out6Queue.PacketChannel():
pkt.SetOutbound()
Packets <- pkt
case pkt := <-in6Queue.PacketChannel():
pkt.SetInbound()
Packets <- pkt
}
}
}