libricochet-go/connectivity/torProvider.go

package connectivity

import (
	"errors"
	"git.openprivacy.ca/openprivacy/libricochet-go/utils"
	"github.com/cretz/bine/control"
	"github.com/cretz/bine/tor"
	"log"
	"net"
	"net/textproto"
	"os"
	"os/exec"
	"path"
	"regexp"
	"strconv"
	"strings"
	"sync"
)

const (
	// CannotResolveLocalTCPAddressError is thrown when a local ricochet connection has the wrong format.
	CannotResolveLocalTCPAddressError = utils.Error("CannotResolveLocalTCPAddressError")
	// CannotDialLocalTCPAddressError is thrown when a connection to a local ricochet address fails.
	CannotDialLocalTCPAddressError = utils.Error("CannotDialLocalTCPAddressError")
	// CannotDialRicochetAddressError is thrown when a connection to a ricochet address fails.
	CannotDialRicochetAddressError = utils.Error("CannotDialRicochetAddressError")
)

type onionListenService struct {
	os *tor.OnionService
}

type torProvider struct {
	t    *tor.Tor
	lock sync.Mutex
}

func (ols *onionListenService) AddressFull() string {
	return ols.os.Addr().String()
}

func (ols *onionListenService) AddressIdentity() string {
	return ols.os.Addr().String()[:56]
}

func (ols *onionListenService) Accept() (net.Conn, error) {
	return ols.os.Accept()
}

func (ols *onionListenService) Close() {
	ols.os.Close()
}

func (tp *torProvider) Listen(identity PrivateKey, port int) (ListenService, error) {
	tp.lock.Lock()
	defer tp.lock.Unlock()
	conf := &tor.ListenConf{NoWait: true, Version3: true, Key: identity, RemotePorts: []int{port}, Detach: true, DiscardKey: true}
	os, err := tp.t.Listen(nil, conf)
	return &onionListenService{os}, err
}

func (tp *torProvider) Open(hostname string) (net.Conn, string, error) {
	tp.lock.Lock()
	defer tp.lock.Unlock()
	torDailer, err := tp.t.Dialer(nil, &tor.DialConf{})
	if err != nil {
		return nil, "", err
	}
	resolvedHostname := hostname
	if strings.HasPrefix(hostname, "ricochet:") {
		addrParts := strings.Split(hostname, ":")
		resolvedHostname = addrParts[1]
	}

	conn, err := torDailer.Dial("tcp", resolvedHostname+".onion:9878")
	// if there was an error, we may have been cycling too fast
	// clear the tor cache and try one more time
	if err != nil {
		tp.t.Control.Signal("NEWNYM")
		conn, err = torDailer.Dial("tcp", resolvedHostname+".onion:9878")
	}
	return conn, resolvedHostname, err
}

func (tp *torProvider) Close() {
	tp.lock.Lock()
	defer tp.lock.Unlock()
	tp.t.Close()
}

// StartTor creates/starts a Tor mixnet and returns a usable Mixnet object
func StartTor(appDirectory string, bundledTorPath string) (Mixnet, error) {
	dataDir := path.Join(appDirectory, "tor")
	os.MkdirAll(dataDir, 0700)

	// attempt connect to system tor
	log.Printf("dialing system tor control port\n")
	controlport, err := dialControlPort(9051)

	if err == nil {
		// TODO: configurable auth
		err := controlport.Authenticate("")
		if err == nil {
			log.Printf("connected to control port")
			pinfo, err := controlport.ProtocolInfo()
			if err == nil && minTorVersionReqs(pinfo.TorVersion) {
				log.Println("OK version " + pinfo.TorVersion)
				return createFromExisting(controlport, dataDir), nil
			}
			controlport.Close()
		}
	}

	// if not, try running system tor
	if checkCmdlineTorVersion("tor") {
		t, err := tor.Start(nil, &tor.StartConf{DataDir: dataDir, DebugWriter: nil})
		if err == nil {
			return &torProvider{t: t}, err
		}
		log.Printf("Error connecting to self-run system tor: %v\n", err)
	}

	// try running bundledTor
	if bundledTorPath != "" && checkCmdlineTorVersion(bundledTorPath) {
		log.Println("using bundled tor '" + bundledTorPath + "'")
		t, err := tor.Start(nil, &tor.StartConf{DataDir: dataDir, ExePath: bundledTorPath, DebugWriter: nil})
		if err != nil {
			log.Printf("Error running bundled tor: %v\n", err)
		}
		return &torProvider{t: t}, err
	}
	return nil, errors.New("Could not connect to or start Tor that met requirments")
}

func createFromExisting(controlport *control.Conn, datadir string) Mixnet {
	t := &tor.Tor{
		Process:              nil,
		Control:              controlport,
		ProcessCancelFunc:    nil,
		DataDir:              datadir,
		DeleteDataDirOnClose: false,
		DebugWriter:          nil,
		StopProcessOnClose:   false,
		GeoIPCreatedFile:     "",
		GeoIPv6CreatedFile:   "",
	}
	t.Control.DebugWriter = t.DebugWriter

	t.EnableNetwork(nil, true)

	return &torProvider{t: t}
}

func checkCmdlineTorVersion(torCmd string) bool {
	cmd := exec.Command(torCmd, "--version")
	out, err := cmd.CombinedOutput()
	log.Println("cmdline tor version: " + string(out))
	re := regexp.MustCompile("[0-1]\\.[0-9]\\.[0-9]\\.[0-9]")
	sysTorVersion := re.Find(out)
	log.Println("cmdline tor version: " + string(sysTorVersion))
	return err == nil && minTorVersionReqs(string(sysTorVersion))
}

// returns true if supplied version meets our min requirments
// min requirment 0.3.5.x
func minTorVersionReqs(torversion string) bool {
	torversions := strings.Split(torversion, ".") //eg: 0.3.4.8 or 0.3.5.1-alpha
	log.Printf("torversions: %v", torversions)
	tva, _ := strconv.Atoi(torversions[0])
	tvb, _ := strconv.Atoi(torversions[1])
	tvc, _ := strconv.Atoi(torversions[2])
	return tva > 0 || (tva == 0 && (tvb > 3 || (tvb == 3 && tvc >= 5)))
}

func dialControlPort(port int) (*control.Conn, error) {
	textConn, err := textproto.Dial("tcp", "127.0.0.1:"+strconv.Itoa(port))
	if err != nil {
		return nil, err
	}
	return control.NewConn(textConn), nil
}