You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
fw-daemon/main.go

259 lines
5.1 KiB

package main
import (
// _ "net/http/pprof"
"bufio"
"encoding/json"
"os"
"os/signal"
"regexp"
"strings"
"sync"
"syscall"
"time"
"unsafe"
"github.com/subgraph/fw-daemon/nfqueue"
"github.com/subgraph/go-procsnitch"
"github.com/op/go-logging"
)
var log = logging.MustGetLogger("sgfw")
var logFormat = logging.MustStringFormatter(
"%{level:.4s} %{id:03x} %{message}",
)
var ttyFormat = logging.MustStringFormatter(
"%{color}%{time:15:04:05} ▶ %{level:.4s} %{id:03x}%{color:reset} %{message}",
)
const ioctlReadTermios = 0x5401
func isTerminal(fd int) bool {
var termios syscall.Termios
_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&termios)), 0, 0, 0)
return err == 0
}
func setupLoggerBackend() logging.LeveledBackend {
format := logFormat
if isTerminal(int(os.Stderr.Fd())) {
format = ttyFormat
}
backend := logging.NewLogBackend(os.Stderr, "", 0)
formatter := logging.NewBackendFormatter(backend, format)
leveler := logging.AddModuleLevel(formatter)
leveler.SetLevel(logging.NOTICE, "sgfw")
return leveler
}
var logRedact bool
type Firewall struct {
dbus *dbusServer
dns *dnsCache
enabled bool
logBackend logging.LeveledBackend
lock sync.Mutex
policyMap map[string]*Policy
policies []*Policy
ruleLock sync.Mutex
rulesById map[uint]*Rule
nextRuleId uint
reloadRulesChan chan bool
stopChan chan bool
}
func (fw *Firewall) setEnabled(flag bool) {
fw.lock.Lock()
defer fw.lock.Unlock()
fw.enabled = flag
}
func (fw *Firewall) isEnabled() bool {
fw.lock.Lock()
defer fw.lock.Unlock()
return fw.enabled
}
func (fw *Firewall) clearRules() {
fw.ruleLock.Lock()
defer fw.ruleLock.Unlock()
fw.rulesById = nil
fw.nextRuleId = 0
}
func (fw *Firewall) addRule(r *Rule) {
fw.ruleLock.Lock()
defer fw.ruleLock.Unlock()
r.id = fw.nextRuleId
fw.nextRuleId += 1
if fw.rulesById == nil {
fw.rulesById = make(map[uint]*Rule)
}
fw.rulesById[r.id] = r
}
func (fw *Firewall) getRuleById(id uint) *Rule {
fw.ruleLock.Lock()
defer fw.ruleLock.Unlock()
if fw.rulesById == nil {
return nil
}
return fw.rulesById[id]
}
func (fw *Firewall) stop() {
fw.stopChan <- true
}
func (fw *Firewall) reloadRules() {
fw.reloadRulesChan <- true
}
func (fw *Firewall) runFilter() {
q := nfqueue.NewNFQueue(0)
defer q.Destroy()
q.DefaultVerdict = nfqueue.DROP
q.Timeout = 5 * time.Minute
packets := q.Process()
for {
select {
case pkt := <-packets:
if fw.isEnabled() {
fw.filterPacket(pkt)
} else {
pkt.Accept()
}
case <-fw.reloadRulesChan:
fw.loadRules()
case <-fw.stopChan:
return
}
}
}
type SocksJsonConfig struct {
SocksListener string
TorSocks string
}
var commentRegexp = regexp.MustCompile("^[ \t]*#")
func loadConfiguration(configFilePath string) (*SocksJsonConfig, error) {
config := SocksJsonConfig{}
file, err := os.Open(configFilePath)
if err != nil {
return nil, err
}
scanner := bufio.NewScanner(file)
bs := ""
for scanner.Scan() {
line := scanner.Text()
if !commentRegexp.MatchString(line) {
bs += line + "\n"
}
}
if err := json.Unmarshal([]byte(bs), &config); err != nil {
return nil, err
}
return &config, nil
}
func getSocksChainConfig(config *SocksJsonConfig) *socksChainConfig {
// XXX
fields := strings.Split(config.TorSocks, "|")
torSocksNet := fields[0]
torSocksAddr := fields[1]
fields = strings.Split(config.SocksListener, "|")
socksListenNet := fields[0]
socksListenAddr := fields[1]
socksConfig := socksChainConfig{
TargetSocksNet: torSocksNet,
TargetSocksAddr: torSocksAddr,
ListenSocksNet: socksListenNet,
ListenSocksAddr: socksListenAddr,
}
return &socksConfig
}
func main() {
// XXX should this really be hardcoded?
// or should i add a CLI to specify config file location?
config, err := loadConfiguration("/etc/fw-daemon-socks.json")
if err != nil {
panic(err)
}
socksConfig := getSocksChainConfig(config)
logBackend := setupLoggerBackend()
log.SetBackend(logBackend)
procsnitch.SetLogger(log)
if os.Geteuid() != 0 {
log.Error("Must be run as root")
os.Exit(1)
}
setupIPTables()
ds, err := newDbusServer()
if err != nil {
log.Error(err.Error())
os.Exit(1)
}
fw := &Firewall{
dbus: ds,
dns: NewDnsCache(),
enabled: true,
logBackend: logBackend,
policyMap: make(map[string]*Policy),
reloadRulesChan: make(chan bool, 0),
stopChan: make(chan bool, 0),
}
ds.fw = fw
fw.loadRules()
/*
go func() {
http.ListenAndServe("localhost:6060", nil)
}()
*/
wg := sync.WaitGroup{}
chain := NewSocksChain(socksConfig, &wg, fw)
chain.start()
fw.runFilter()
// observe process signals and either
// reload rules or shutdown firewall service
sigKillChan := make(chan os.Signal, 1)
signal.Notify(sigKillChan, os.Interrupt, os.Kill)
sigHupChan := make(chan os.Signal, 1)
signal.Notify(sigHupChan, syscall.SIGHUP)
for {
select {
case <-sigHupChan:
fw.reloadRules()
// XXX perhaps restart SOCKS proxy chain service with new proxy config specification?
case <-sigKillChan:
fw.stop()
return
}
}
}