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// +build darwin
// Copyright (C) 2018 LEAP
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
/*
This module holds some specific constants for osx, and it also contains the implementation of the pf firewall.
To inspect the rules in the firewall manually, use the bitmask anchor:
sudo pfctl -s rules -a com.apple/250.BitmaskFirewall
*/
package helper
import (
"errors"
"fmt"
"log"
"os"
"os/exec"
"path"
"strconv"
"strings"
"0xacab.org/leap/bitmask-vpn/pkg/config"
"github.com/sevlyar/go-daemon"
)
const (
appPath = "/Applications/" + config.ApplicationName + ".app/"
helperPath = appPath + "Contents/helper/"
LogFolder = helperPath
openvpnPath = appPath + "Contents/Resources/openvpn.leap"
rulefilePath = helperPath + "bitmask.pf.conf"
bitmask_anchor = "com.apple/250.BitmaskFirewall"
gateways_table = "bitmask_gateways"
pfctl = "/sbin/pfctl"
)
var (
platformOpenvpnFlags = []string{
"--script-security", "2",
"--up", helperPath + "client.up.sh",
"--down", helperPath + "client.down.sh",
}
)
func parseCliArgs() {
// OSX helper does not respond to arguments
}
func daemonize() {
cntxt := &daemon.Context{
PidFileName: "pid",
PidFilePerm: 0644,
LogFileName: "bitmask-helper.log",
LogFilePerm: 0640,
WorkDir: "./",
Umask: 027,
Args: []string{"[bitmask-helper]"},
}
d, err := cntxt.Reborn()
if err != nil {
log.Fatal("Unable to run: ", err)
}
if d != nil {
return
}
defer cntxt.Release()
log.Print("bitmask-helper daemon started")
}
func doHandleCommands(preferredPort int) {
port := getFirstAvailablePortFrom(preferredPort)
writePortToFile(port)
bindAddr := "localhost:" + strconv.Itoa(port)
runCommandServer(bindAddr)
}
func getOpenvpnPath() string {
return openvpnPath
}
func kill(cmd *exec.Cmd) error {
log.Printf("Sending kill signal to pid: %v", cmd.Process.Pid)
err := cmd.Process.Signal(os.Interrupt)
if err != nil {
return err
}
return nil
}
func firewallStart(gateways []string) error {
enablePf()
err := resetGatewaysTable(gateways)
if err != nil {
return err
}
return loadBitmaskAnchor()
}
func firewallStop() error {
out, err := exec.Command(pfctl, "-a", bitmask_anchor, "-F", "all").Output()
if err != nil {
log.Printf("An error ocurred stopping the firewall: %v", out)
/* TODO return error if different from anchor not exists */
/*return errors.New("Error while stopping firewall")*/
return nil
}
return nil
}
func firewallIsUp() bool {
out, err := exec.Command(pfctl, "-a", bitmask_anchor, "-sr").Output()
if err != nil {
log.Printf("An error ocurred getting the status of the firewall: %v", err)
log.Printf(string(out))
return false
}
return strings.Contains(string(out), "block drop out proto udp from any to any port = 53")
}
func enablePf() {
cmd := exec.Command(pfctl, "-e")
cmd.Run()
}
func resetGatewaysTable(gateways []string) error {
log.Println("Resetting gateways")
cmd := exec.Command(pfctl, "-a", bitmask_anchor, "-t", gateways_table, "-T", "delete")
err := cmd.Run()
if err != nil {
log.Printf("Can't delete table: %v", err)
}
for _, gateway := range gateways {
log.Println("Adding Gateway:", gateway)
cmd = exec.Command(pfctl, "-a", bitmask_anchor, "-t", gateways_table, "-T", "add", gateway)
err = cmd.Run()
if err != nil {
log.Printf("Error adding gateway to table: %v", err)
}
}
cmd = exec.Command(pfctl, "-a", bitmask_anchor, "-t", gateways_table, "-T", "add", nameserver)
return cmd.Run()
}
func getDefaultDevice() string {
out, err := exec.Command("/bin/sh", "-c", "/sbin/route -n get -net default | /usr/bin/grep interface | /usr/bin/awk '{print $2}'").Output()
if err != nil {
log.Printf("Error getting default device")
}
return strings.TrimSpace(bytesToString(out))
}
func loadBitmaskAnchor() error {
dev := getDefaultDevice()
rulePath, err := getRulefilePath()
if err != nil {
return err
}
cmdline := fmt.Sprintf("%s -D default_device=%s -a %s -f %s", pfctl, dev, bitmask_anchor, rulePath)
log.Println("Loading Bitmask Anchor:", cmdline)
_, err = exec.Command("/bin/sh", "-c", cmdline).Output()
return err
}
func getRulefilePath() (string, error) {
if _, err := os.Stat(rulefilePath); !os.IsNotExist(err) {
return rulefilePath, nil
}
gopath := os.Getenv("GOPATH")
if gopath == "" {
gopath = path.Join(os.Getenv("HOME"), "go")
}
rulefile := path.Join(gopath, "0xacab.org", "leap", "riseup_vpn", "osx", "bitmask.pf.conf")
if _, err := os.Stat(rulefile); !os.IsNotExist(err) {
return rulefile, nil
}
return "", errors.New("Can't find rule file for the firewall")
}
func bytesToString(data []byte) string {
return string(data[:])
}
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