// Copyright (C) 2018-2021 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 . package vpn import ( "errors" "fmt" "io/ioutil" "log" "os" "path" "path/filepath" "strconv" "strings" "0xacab.org/leap/bitmask-vpn/pkg/config" "0xacab.org/leap/shapeshifter" ) const ( openvpnManagementAddr = "127.0.0.1" openvpnManagementPort = "6061" ) // StartVPN for provider func (b *Bitmask) StartVPN(provider string) error { if !b.CanStartVPN() { return errors.New("BUG: cannot start vpn") } var err error b.certPemPath, err = b.getCert() if err != nil { return err } b.openvpnArgs, err = b.bonafide.GetOpenvpnArgs() if err != nil { return err } return b.startOpenVPN() } func (b *Bitmask) CanStartVPN() bool { /* FIXME this is not enough. We should check, if provider needs * credentials, if we have a valid token, otherwise remove it and make sure that we're asking for the credentials input */ return !b.bonafide.NeedsCredentials() } func (b *Bitmask) startTransport(host string) (proxy string, err error) { // TODO configure port if not available proxy = "127.0.0.1:4430" if b.shapes != nil { return proxy, nil } gateways, err := b.bonafide.GetGateways(b.transport) if err != nil { return "", err } if len(gateways) == 0 { log.Printf("No gateway for transport %s in provider", b.transport) return "", nil } for _, gw := range gateways { if gw.Host != host { continue } if _, ok := gw.Options["cert"]; !ok { continue } log.Println("Selected Gateway:", gw.Host, gw.IPAddress) b.shapes = &shapeshifter.ShapeShifter{ Cert: gw.Options["cert"], Target: gw.IPAddress + ":" + gw.Ports[0], SocksAddr: proxy, } go b.listenShapeErr() if iatMode, ok := gw.Options["iat-mode"]; ok { b.shapes.IatMode, err = strconv.Atoi(iatMode) if err != nil { b.shapes.IatMode = 0 } } err = b.shapes.Open() if err != nil { log.Printf("Can't connect to transport %s: %v", b.transport, err) continue } log.Println("Connected via obfs4 to", gw.IPAddress, "(", gw.Host, ")") return proxy, nil } return "", fmt.Errorf("No working gateway for transport %s: %v", b.transport, err) } func (b *Bitmask) listenShapeErr() { ch := b.shapes.GetErrorChannel() for { err, more := <-ch if !more { return } log.Printf("Error from shappeshifter: %v", err) } } func (b *Bitmask) startOpenVPN() error { arg := []string{} b.statusCh <- Starting if b.GetTransport() == "obfs4" { gateways, err := b.bonafide.GetGateways("obfs4") if err != nil { return err } if len(gateways) == 0 { log.Printf("ERROR No gateway for transport %s in provider", b.transport) return errors.New("ERROR: cannot find any gateway for selected transport") } gw := gateways[0] proxy, err := b.startTransport(gw.Host) if err != nil { return err } b.ptGateway = gw err = b.launch.firewallStart(gateways) if err != nil { return err } proxyArgs := strings.Split(proxy, ":") arg = append(arg, "--remote", proxyArgs[0], proxyArgs[1], "tcp4") arg = append(arg, "--route", gw.IPAddress, "255.255.255.255", "net_gateway") } else { arg = b.openvpnArgs gateways, err := b.bonafide.GetGateways("openvpn") if err != nil { return err } err = b.launch.firewallStart(gateways) if err != nil { return err } for _, gw := range gateways { for _, port := range gw.Ports { arg = append(arg, "--remote", gw.IPAddress, port, "tcp4") } } } arg = append(arg, "--verb", "3", "--management-client", "--management", openvpnManagementAddr, openvpnManagementPort, "--ca", b.getTempCaCertPath(), "--cert", b.certPemPath, "--key", b.certPemPath, "--persist-tun") /* persist-tun is needed for reconnects */ return b.launch.openvpnStart(arg...) } func (b *Bitmask) getCert() (certPath string, err error) { failed := false persistentCertFile := filepath.Join(config.Path, strings.ToLower(config.Provider)+".pem") if _, err := os.Stat(persistentCertFile); !os.IsNotExist(err) && isValidCert(persistentCertFile) { // reuse cert. for the moment we're not writing one there, this is // only to allow users to get certs off-band and place them there // as a last-resort fallback for circumvention. certPath = persistentCertFile err = nil } else { // download one fresh certPath = b.getTempCertPemPath() if _, err := os.Stat(certPath); os.IsNotExist(err) { log.Println("Fetching certificate to", certPath) cert, err := b.bonafide.GetPemCertificate() if err != nil { log.Println(err) failed = true } err = ioutil.WriteFile(certPath, cert, 0600) if err != nil { failed = true } } } if failed || !isValidCert(certPath) { d := config.APIURL[8 : len(config.APIURL)-1] logDnsLookup(d) cert, err := b.bonafide.GetPemCertificateNoDNS() if cert != nil { log.Println("Successfully did certificate bypass") err = nil } else { err = errors.New("Cannot get vpn certificate") } err = ioutil.WriteFile(certPath, cert, 0600) if err != nil { failed = true } } return certPath, err } // Explicit call to GetGateways, to be able to fetch them all before starting the vpn func (b *Bitmask) fetchGateways() { log.Println("Fetching gateways...") _, err := b.bonafide.GetAllGateways(b.transport) if err != nil { log.Println("ERROR Cannot fetch gateways") } } // StopVPN or cancel func (b *Bitmask) StopVPN() error { err := b.launch.firewallStop() if err != nil { return err } if b.shapes != nil { b.shapes.Close() b.shapes = nil } return b.launch.openvpnStop() } // Reconnect to the VPN func (b *Bitmask) Reconnect() error { if !b.CanStartVPN() { return errors.New("BUG: cannot start vpn") } status, err := b.GetStatus() if err != nil { return err } log.Println("DEBUG Reconnecting") if status != Off { b.statusCh <- Stopping if b.shapes != nil { b.shapes.Close() b.shapes = nil } err = b.launch.openvpnStop() if err != nil { return err } } err = b.launch.firewallStop() // FIXME - there's a window in which we might leak traffic here! if err != nil { return err } return b.startOpenVPN() } // ReloadFirewall restarts the firewall func (b *Bitmask) ReloadFirewall() error { err := b.launch.firewallStop() if err != nil { return err } status, err := b.GetStatus() if err != nil { return err } if status != Off { gateways, err := b.bonafide.GetAllGateways("any") if err != nil { return err } return b.launch.firewallStart(gateways) } return nil } // GetStatus returns the VPN status func (b *Bitmask) GetStatus() (string, error) { status, err := b.getOpenvpnState() if err != nil { status = Off } if status == Off && b.launch.firewallIsUp() { return Failed, nil } return status, nil } func (b *Bitmask) InstallHelpers() error { // TODO use pickle module from here return nil } // VPNCheck returns if the helpers are installed and up to date and if polkit is running func (b *Bitmask) VPNCheck() (helpers bool, privilege bool, err error) { return b.launch.check() } func (b *Bitmask) ListLocationFullness(transport string) map[string]float64 { return b.bonafide.ListLocationFullness(transport) } // UseGateway selects a gateway, by label, as the default gateway func (b *Bitmask) UseGateway(label string) { b.bonafide.SetManualGateway(label) } // UseAutomaticGateway sets the gateway to be selected automatically // best gateway will be used func (b *Bitmask) UseAutomaticGateway() { b.bonafide.SetAutomaticGateway() } // SetTransport selects an obfuscation transport to use func (b *Bitmask) SetTransport(t string) error { if t != "openvpn" && t != "obfs4" { return fmt.Errorf("Transport %s not implemented", t) } log.Println("Setting transport to", t) // compare and set string looks strange, but if assigning directly // we're getting some kind of corruption with the transport string. // I suspect something's // not quite right with the c<->go char pointers handling. if t == "obfs4" { b.transport = "obfs4" } else if t == "openvpn" { b.transport = "openvpn" } return nil } // GetTransport gets the obfuscation transport to use. Only obfs4 available for now. func (b *Bitmask) GetTransport() string { if b.transport == "obfs4" { return "obfs4" } else { return "openvpn" } } func (b *Bitmask) getTempCertPemPath() string { return path.Join(b.tempdir, "openvpn.pem") } func (b *Bitmask) getTempCaCertPath() string { return path.Join(b.tempdir, "cacert.pem") }