Add token to Unix Socket API message

internal/api/message.go

@@ -1,14 +1,21 @@
 package api
 
 import (
+	"crypto/rand"
+	"encoding/base64"
 	"encoding/binary"
 	"errors"
 	"io"
 )
 
 const (
-	// MaxPayloadLength is the maximum allowed length of a message payload.
-	MaxPayloadLength = 2097152
+	// TokenLength is the length of the message token in bytes.
+	TokenLength = 16
+)
+
+var (
+	// token is the message token.
+	token [TokenLength]byte
 )
 
 // Message types.
@@ -24,6 +31,7 @@ const (
 type Header struct {
 	Type   uint16
 	Length uint32
+	Token  [TokenLength]byte
 }
 
 // Message is an API message.
@@ -34,13 +42,11 @@ type Message struct {
 
 // NewMessage returns a new message with type t and payload p.
 func NewMessage(t uint16, p []byte) *Message {
-	if len(p) > MaxPayloadLength {
-		return nil
-	}
 	return &Message{
 		Header: Header{
 			Type:   t,
 			Length: uint32(len(p)),
+			Token:  token,
 		},
 		Value: p,
 	}
@@ -69,8 +75,8 @@ func ReadMessage(r io.Reader) (*Message, error) {
 	if h.Type == TypeNone || h.Type >= TypeUndefined {
 		return nil, errors.New("invalid message type")
 	}
-	if h.Length > MaxPayloadLength {
-		return nil, errors.New("invalid message length")
+	if h.Token != token {
+		return nil, errors.New("invalid message token")
 	}
 
 	// read payload
@@ -107,3 +113,26 @@ func WriteMessage(w io.Writer, m *Message) error {
 
 	return nil
 }
+
+// GetToken generates and returns the message token as string. This should be
+// used once on the server side before the server is started. Token must be
+// passed to the client side.
+func GetToken() (string, error) {
+	_, err := rand.Read(token[:])
+	if err != nil {
+		return "", err
+	}
+	return base64.RawURLEncoding.EncodeToString(token[:]), nil
+}
+
+// SetToken sets the message token from string. This should be used on the
+// client side before sending requests to the server. Token must match token on
+// the server side.
+func SetToken(s string) error {
+	b, err := base64.RawURLEncoding.DecodeString(s)
+	if err != nil {
+		return err
+	}
+	copy(token[:], b)
+	return nil
+}

internal/api/message_test.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"bytes"
+	"encoding/base64"
 	"errors"
 	"log"
 	"reflect"
@@ -24,12 +25,6 @@ func TestNewMessage(t *testing.T) {
 			t.Errorf("got %d, want %d", msg.Type, typ)
 		}
 	}
-
-	// invalid payload length
-	p := [MaxPayloadLength + 1]byte{}
-	if NewMessage(TypeOK, p[:]) != nil {
-		t.Error("should not create message with invalid payload length")
-	}
 }
 
 // TestNewOK tests NewOK.
@@ -62,11 +57,11 @@ func TestReadMessageErrors(t *testing.T) {
 		// invalid type
 		{Header: Header{Type: TypeUndefined}},
 
-		// invalid length
-		{Header: Header{Type: TypeOK, Length: MaxPayloadLength + 1}},
-
 		// short message
-		{Header: Header{Type: TypeOK, Length: MaxPayloadLength}},
+		{Header: Header{Type: TypeOK, Length: 4096}},
+
+		// invalid token
+		{Header: Header{Type: TypeOK, Token: [16]byte{1}}},
 	} {
 		if err := WriteMessage(buf, msg); err != nil {
 			t.Fatal(err)
@@ -132,3 +127,35 @@ func TestReadWriteMessage(t *testing.T) {
 		t.Errorf("got %v, want %v", got, want)
 	}
 }
+
+// TestGetSetToken tests GetToken and SetToken.
+func TestGetSetToken(t *testing.T) {
+	// reset token after tests
+	defer func() { token = [TokenLength]byte{} }()
+
+	// get new test token
+	testToken, err := GetToken()
+	if err != nil {
+		t.Fatal(err)
+	}
+	s := base64.RawURLEncoding.EncodeToString(token[:])
+	if testToken != s {
+		t.Fatal("encoded token should match internal token")
+	}
+
+	// set token
+	if err := SetToken(testToken); err != nil {
+		t.Fatal(err)
+	}
+
+	// check token
+	s = base64.RawURLEncoding.EncodeToString(token[:])
+	if s != testToken {
+		t.Fatal("internal token should match encoded token")
+	}
+
+	// setting invalid token
+	if err := SetToken("not a valid encoded token!"); err == nil {
+		t.Fatal("invalid token should return error")
+	}
+}

internal/daemon/daemon.go

@@ -3,8 +3,6 @@ package daemon
 
 import (
 	"context"
-	"crypto/rand"
-	"encoding/base64"
 	"fmt"
 	"net"
 	"reflect"
@@ -344,13 +342,6 @@ func (d *Daemon) updateVPNConfig(request *api.Request) {
 		return
 	}
 
-	// check token
-	if configUpdate.Token != d.token {
-		log.Error("Daemon got invalid token in vpn config update")
-		request.Error("invalid token in config update message")
-		return
-	}
-
 	// handle config update for vpn (dis)connect
 	if configUpdate.Reason == "disconnect" {
 		d.updateVPNConfigDown()
@@ -508,13 +499,11 @@ func (d *Daemon) cleanup(ctx context.Context) {
 
 // initToken creates the daemon token for client authentication.
 func (d *Daemon) initToken() error {
-	// TODO: is this good enough for us?
-	b := make([]byte, 16)
-	_, err := rand.Read(b)
+	token, err := api.GetToken()
 	if err != nil {
 		return err
 	}
-	d.token = base64.RawURLEncoding.EncodeToString(b)
+	d.token = token
 	return nil
 }
 

internal/daemon/vpnconfigupdate.go

@@ -9,24 +9,20 @@ import (
 // VPNConfigUpdate is a VPN configuration update.
 type VPNConfigUpdate struct {
 	Reason string
-	Token  string
 	Config *vpnconfig.Config
 }
 
 // Valid returns whether the config update is valid.
 func (c *VPNConfigUpdate) Valid() bool {
 	switch c.Reason {
 	case "disconnect":
-		// token must be valid and config nil
-		if c.Token == "" || c.Config != nil {
+		// config must be nil
+		if c.Config != nil {
 			return false
 		}
 	case "connect":
-		// token and config must be valid
-		if c.Token == "" || c.Config == nil {
-			return false
-		}
-		if !c.Config.Valid() {
+		// config must be valid
+		if c.Config == nil || !c.Config.Valid() {
 			return false
 		}
 	default:

internal/daemon/vpnconfigupdate_test.go

@@ -22,14 +22,15 @@ func TestVPNConfigUpdateValid(t *testing.T) {
 	// test invalid disconnect
 	u = NewVPNConfigUpdate()
 	u.Reason = "disconnect"
+	u.Config = vpnconfig.New()
 
 	got = u.Valid()
 	want = false
 	if got != want {
 		t.Errorf("got %t, want %t", got, want)
 	}
 
-	// test invalid connect, no token and no config
+	// test invalid connect, no config
 	u = NewVPNConfigUpdate()
 	u.Reason = "connect"
 
@@ -42,7 +43,6 @@ func TestVPNConfigUpdateValid(t *testing.T) {
 	// test invalid connect, invalid config
 	u = NewVPNConfigUpdate()
 	u.Reason = "connect"
-	u.Token = "some test token"
 	u.Config = vpnconfig.New()
 	u.Config.Device.Name = "name is too long for a network device"
 
@@ -55,7 +55,6 @@ func TestVPNConfigUpdateValid(t *testing.T) {
 	// test valid disconnect
 	u = NewVPNConfigUpdate()
 	u.Reason = "disconnect"
-	u.Token = "some test token"
 
 	got = u.Valid()
 	want = true
@@ -66,7 +65,6 @@ func TestVPNConfigUpdateValid(t *testing.T) {
 	// test valid connect
 	u = NewVPNConfigUpdate()
 	u.Reason = "connect"
-	u.Token = "some test token"
 	u.Config = vpnconfig.New()
 
 	got = u.Valid()
@@ -87,13 +85,11 @@ func TestVPNConfigUpdateJSON(t *testing.T) {
 	// valid disconnect
 	u = NewVPNConfigUpdate()
 	u.Reason = "disconnect"
-	u.Token = "some test token"
 	updates = append(updates, u)
 
 	// valid connect
 	u = NewVPNConfigUpdate()
 	u.Reason = "connect"
-	u.Token = "some test token"
 	u.Config = vpnconfig.New()
 	updates = append(updates, u)
 

internal/vpncscript/client_test.go

@@ -69,7 +69,7 @@ func TestRunClient(t *testing.T) {
 		return confUpdate
 	}
 
-	// test with maximum payload length
+	// test with varying payload lengths
 	server = api.NewServer(config)
 	go func() {
 		for r := range server.Requests() {
@@ -79,23 +79,12 @@ func TestRunClient(t *testing.T) {
 	if err := server.Start(); err != nil {
 		t.Fatal(err)
 	}
-	if err := runClient(sockfile, getConfUpdate(api.MaxPayloadLength)); err != nil {
-		t.Fatal(err)
-	}
-	server.Stop()
-
-	// test with more than maximum payload length
-	server = api.NewServer(config)
-	go func() {
-		for r := range server.Requests() {
-			r.Close()
+	for _, length := range []int{
+		2048, 4096, 8192, 65536, 2097152,
+	} {
+		if err := runClient(sockfile, getConfUpdate(length)); err != nil {
+			t.Errorf("length %d returned error: %v", length, err)
 		}
-	}()
-	if err := server.Start(); err != nil {
-		t.Fatal(err)
-	}
-	if err := runClient(sockfile, getConfUpdate(api.MaxPayloadLength+1)); err == nil {
-		t.Fatal("too long message should return error")
 	}
 	server.Stop()
 }

internal/vpncscript/cmd.go

@@ -8,6 +8,7 @@ import (
 	"os"
 
 	log "github.com/sirupsen/logrus"
+	"github.com/telekom-mms/oc-daemon/internal/api"
 	"github.com/telekom-mms/oc-daemon/internal/daemon"
 )
 
@@ -47,6 +48,11 @@ func run(args []string) error {
 		socketFile = e.socketFile
 	}
 
+	// set token from environemt
+	if err := api.SetToken(e.token); err != nil {
+		return fmt.Errorf("VPNCScript could not set token: %w", err)
+	}
+
 	printDebugEnvironment()
 	log.WithField("env", e).Debug("VPNCScript parsed environment")
 

internal/vpncscript/cmd_test.go

@@ -24,6 +24,12 @@ func TestRun(t *testing.T) {
 		t.Errorf("help should return ErrHelp, got: %v", err)
 	}
 
+	// test with invalid token
+	t.Setenv("oc_daemon_token", "this is not a valid encoded token!")
+	if err := run([]string{"test"}); err == nil {
+		t.Errorf("invalid token should return error")
+	}
+
 	// prepare environment with not existing sockfile
 	os.Clearenv()
 	sockfile := filepath.Join(t.TempDir(), "sockfile")

internal/vpncscript/config.go

@@ -221,7 +221,6 @@ func createConfig(env *env) (*vpnconfig.Config, error) {
 func createConfigUpdate(env *env) (*daemon.VPNConfigUpdate, error) {
 	update := daemon.NewVPNConfigUpdate()
 	update.Reason = env.reason
-	update.Token = env.token
 	if env.reason == "connect" {
 		c, err := createConfig(env)
 		if err != nil {

internal/vpncscript/config_test.go

@@ -87,7 +87,6 @@ func TestCreateConfigUpdate(t *testing.T) {
 
 	// create expected values based on test environment
 	reason := "connect"
-	token := "some token"
 	config := &vpnconfig.Config{
 		Gateway: net.IPv4(10, 1, 1, 1),
 		PID:     12345,
@@ -129,9 +128,6 @@ func TestCreateConfigUpdate(t *testing.T) {
 	if got.Reason != reason {
 		t.Errorf("got %s, want %s", got.Reason, reason)
 	}
-	if got.Token != token {
-		t.Errorf("got %s, want %s", got.Token, token)
-	}
 	if !reflect.DeepEqual(got.Config, config) {
 		t.Errorf("got:\n%#v\nwant:\n%#v", got.Config, config)
 	}