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Handshake negotiation functioning

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This commit is contained in:
Mathias Hall-Andersen 2017-07-01 23:29:22 +02:00
parent a4cc0a30fa
commit 1e620427bd
10 changed files with 512 additions and 82 deletions
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6
src/constants.go
View file

@ -17,5 +17,9 @@ const (
)
const (
QueueOutboundSize = 1024
QueueOutboundSize = 1024
QueueInboundSize = 1024
QueueHandshakeSize = 1024
QueueHandshakeBusySize = QueueHandshakeSize / 8
MinMessageSize = MessageTransportSize
)

19
src/device.go
View file

@ -23,7 +23,13 @@ type Device struct {
routingTable RoutingTable
indices IndexTable
queue struct {
encryption chan *QueueOutboundElement // parallel work queue
encryption chan *QueueOutboundElement
decryption chan *QueueInboundElement
handshake chan QueueHandshakeElement
inbound chan []byte // inbound queue for TUN
}
signal struct {
stop chan struct{}
}
peers map[NoisePublicKey]*Peer
mac MacStateDevice
@ -56,6 +62,7 @@ func NewDevice(tun TUNDevice, logLevel int) *Device {
defer device.mutex.Unlock()
device.log = NewLogger(logLevel)
device.mtu = tun.MTU()
device.peers = make(map[NoisePublicKey]*Peer)
device.indices.Init()
device.routingTable.Reset()
@ -71,13 +78,22 @@ func NewDevice(tun TUNDevice, logLevel int) *Device {
// create queues
device.queue.encryption = make(chan *QueueOutboundElement, QueueOutboundSize)
device.queue.handshake = make(chan QueueHandshakeElement, QueueHandshakeSize)
device.queue.decryption = make(chan *QueueInboundElement, QueueInboundSize)
// prepare signals
device.signal.stop = make(chan struct{})
// start workers
for i := 0; i < runtime.NumCPU(); i += 1 {
go device.RoutineEncryption()
go device.RoutineDecryption()
go device.RoutineHandshake()
}
go device.RoutineReadFromTUN(tun)
go device.RoutineReceiveIncomming()
return device
}
@ -115,5 +131,6 @@ func (device *Device) RemoveAllPeers() {
func (device *Device) Close() {
device.RemoveAllPeers()
close(device.signal.stop)
close(device.queue.encryption)
}

60
src/handshake.go
View file

@ -3,7 +3,6 @@ package main
import (
"bytes"
"encoding/binary"
"net"
"sync/atomic"
"time"
)
@ -24,14 +23,6 @@ func (peer *Peer) SendKeepAlive() bool {
return true
}
func StoppedTimer() *time.Timer {
timer := time.NewTimer(time.Hour)
if !timer.Stop() {
<-timer.C
}
return timer
}
/* Called when a new authenticated message has been send
*
* TODO: This might be done in a faster way
@ -71,7 +62,7 @@ func (peer *Peer) RoutineHandshakeInitiator() {
device := peer.device
buffer := make([]byte, 1024)
logger := device.log.Debug
timeout := time.NewTimer(time.Hour)
timeout := stoppedTimer()
var work *QueueOutboundElement
@ -129,13 +120,8 @@ func (peer *Peer) RoutineHandshakeInitiator() {
// set timeout
if !timeout.Stop() {
select {
case <-timeout.C:
default:
}
}
attempts += 1
stopTimer(timeout)
timeout.Reset(RekeyTimeout)
device.log.Debug.Println("Handshake initiation attempt", attempts, "queued for peer", peer.id)
@ -163,45 +149,3 @@ func (peer *Peer) RoutineHandshakeInitiator() {
logger.Println("Routine, handshake initator, stopped for peer", peer.id)
}
/* Handles incomming packets related to handshake
*
*
*/
func (device *Device) HandshakeWorker(queue chan struct {
msg []byte
msgType uint32
addr *net.UDPAddr
}) {
for {
elem := <-queue
switch elem.msgType {
case MessageInitiationType:
if len(elem.msg) != MessageInitiationSize {
continue
}
// check for cookie
var msg MessageInitiation
binary.Read(nil, binary.LittleEndian, &msg)
case MessageResponseType:
if len(elem.msg) != MessageResponseSize {
continue
}
// check for cookie
case MessageCookieReplyType:
if len(elem.msg) != MessageCookieReplySize {
continue
}
default:
device.log.Error.Println("Invalid message type in handshake queue")
}
}
}

19
src/misc.go
View file

@ -1,5 +1,9 @@
package main
import (
"time"
)
func min(a uint, b uint) uint {
if a > b {
return b
@ -13,3 +17,18 @@ func sendSignal(c chan struct{}) {
default:
}
}
func stopTimer(timer *time.Timer) {
if !timer.Stop() {
select {
case <-timer.C:
default:
}
}
}
func stoppedTimer() *time.Timer {
timer := time.NewTimer(time.Hour)
stopTimer(timer)
return timer
}

21
src/noise_protocol.go
View file

@ -6,6 +6,7 @@ import (
"golang.org/x/crypto/chacha20poly1305"
"golang.org/x/crypto/poly1305"
"sync"
"time"
)
const (
@ -34,6 +35,13 @@ const (
MessageInitiationSize = 148
MessageResponseSize = 92
MessageCookieReplySize = 64
MessageTransportSize = 16 + poly1305.TagSize // size of empty transport
)
const (
MessageTransportOffsetReceiver = 4
MessageTransportOffsetCounter = 8
MessageTransportOffsetContent = 16
)
/* Type is an 8-bit field, followed by 3 nul bytes,
@ -55,7 +63,7 @@ type MessageInitiation struct {
type MessageResponse struct {
Type uint32
Sender uint32
Reciever uint32
Receiver uint32
Ephemeral NoisePublicKey
Empty [poly1305.TagSize]byte
Mac1 [blake2s.Size128]byte
@ -64,7 +72,7 @@ type MessageResponse struct {
type MessageTransport struct {
Type uint32
Reciever uint32
Receiver uint32
Counter uint64
Content []byte
}
@ -292,7 +300,7 @@ func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error
var msg MessageResponse
msg.Type = MessageResponseType
msg.Sender = handshake.localIndex
msg.Reciever = handshake.remoteIndex
msg.Receiver = handshake.remoteIndex
// create ephemeral key
@ -302,6 +310,7 @@ func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error
}
msg.Ephemeral = handshake.localEphemeral.publicKey()
handshake.mixHash(msg.Ephemeral[:])
handshake.mixKey(msg.Ephemeral[:])
func() {
ss := handshake.localEphemeral.sharedSecret(handshake.remoteEphemeral)
@ -334,7 +343,7 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
// lookup handshake by reciever
lookup := device.indices.Lookup(msg.Reciever)
lookup := device.indices.Lookup(msg.Receiver)
handshake := lookup.handshake
if handshake == nil {
return nil
@ -359,7 +368,7 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
// finish 3-way DH
hash = mixHash(handshake.hash, msg.Ephemeral[:])
chainKey = handshake.chainKey
chainKey = mixKey(handshake.chainKey, msg.Ephemeral[:])
func() {
ss := handshake.localEphemeral.sharedSecret(msg.Ephemeral)
@ -380,6 +389,7 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
aead, _ := chacha20poly1305.New(key[:])
_, err := aead.Open(nil, ZeroNonce[:], msg.Empty[:], hash[:])
if err != nil {
device.log.Debug.Println("failed to open")
return false
}
hash = mixHash(hash, msg.Empty[:])
@ -438,6 +448,7 @@ func (peer *Peer) NewKeyPair() *KeyPair {
keyPair.recv, _ = chacha20poly1305.New(recvKey[:])
keyPair.sendNonce = 0
keyPair.recvNonce = 0
keyPair.created = time.Now()
// remap index

15
src/peer.go
View file

@ -37,6 +37,7 @@ type Peer struct {
queue struct {
nonce chan []byte // nonce / pre-handshake queue
outbound chan *QueueOutboundElement // sequential ordering of work
inbound chan *QueueInboundElement // sequential ordering of work
}
mac MacStatePeer
}
@ -47,11 +48,10 @@ func (device *Device) NewPeer(pk NoisePublicKey) *Peer {
peer := new(Peer)
peer.mutex.Lock()
defer peer.mutex.Unlock()
peer.device = device
peer.mac.Init(pk)
peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
peer.queue.nonce = make(chan []byte, QueueOutboundSize)
peer.timer.sendKeepalive = StoppedTimer()
peer.device = device
peer.timer.sendKeepalive = stoppedTimer()
// assign id for debugging
@ -76,6 +76,12 @@ func (device *Device) NewPeer(pk NoisePublicKey) *Peer {
handshake.precomputedStaticStatic = device.privateKey.sharedSecret(handshake.remoteStatic)
handshake.mutex.Unlock()
// prepare queuing
peer.queue.nonce = make(chan []byte, QueueOutboundSize)
peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)
peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
// prepare signaling
peer.signal.stop = make(chan struct{})
@ -89,6 +95,7 @@ func (device *Device) NewPeer(pk NoisePublicKey) *Peer {
go peer.RoutineNonce()
go peer.RoutineHandshakeInitiator()
go peer.RoutineSequentialSender()
go peer.RoutineSequentialReceiver()
return peer
}

404
src/receive.go Normal file
View file

@ -0,0 +1,404 @@
package main
import (
"bytes"
"encoding/binary"
"golang.org/x/crypto/chacha20poly1305"
"net"
"sync"
"sync/atomic"
"time"
)
const (
ElementStateOkay = iota
ElementStateDropped
)
type QueueHandshakeElement struct {
msgType uint32
packet []byte
source *net.UDPAddr
}
type QueueInboundElement struct {
state uint32
mutex sync.Mutex
packet []byte
counter uint64
keyPair *KeyPair
}
func (elem *QueueInboundElement) Drop() {
atomic.StoreUint32(&elem.state, ElementStateDropped)
elem.mutex.Unlock()
}
func (device *Device) RoutineReceiveIncomming() {
var packet []byte
debugLog := device.log.Debug
debugLog.Println("Routine, receive incomming, started")
errorLog := device.log.Error
for {
// check if stopped
select {
case <-device.signal.stop:
return
default:
}
// read next datagram
if packet == nil {
packet = make([]byte, 1<<16)
}
device.net.mutex.RLock()
conn := device.net.conn
device.net.mutex.RUnlock()
conn.SetReadDeadline(time.Now().Add(time.Second))
size, raddr, err := conn.ReadFromUDP(packet)
if err != nil {
continue
}
if size < MinMessageSize {
continue
}
// handle packet
packet = packet[:size]
msgType := binary.LittleEndian.Uint32(packet[:4])
func() {
switch msgType {
case MessageInitiationType, MessageResponseType:
// verify mac1
if !device.mac.CheckMAC1(packet) {
debugLog.Println("Received packet with invalid mac1")
return
}
// check if busy, TODO: refine definition of "busy"
busy := len(device.queue.handshake) > QueueHandshakeBusySize
if busy && !device.mac.CheckMAC2(packet, raddr) {
sender := binary.LittleEndian.Uint32(packet[4:8]) // "sender" follows "type"
reply, err := device.CreateMessageCookieReply(packet, sender, raddr)
if err != nil {
errorLog.Println("Failed to create cookie reply:", err)
return
}
writer := bytes.NewBuffer(packet[:0])
binary.Write(writer, binary.LittleEndian, reply)
packet = writer.Bytes()
_, err = device.net.conn.WriteToUDP(packet, raddr)
if err != nil {
debugLog.Println("Failed to send cookie reply:", err)
}
return
}
// add to handshake queue
device.queue.handshake <- QueueHandshakeElement{
msgType: msgType,
packet: packet,
source: raddr,
}
case MessageCookieReplyType:
// verify and update peer cookie state
if len(packet) != MessageCookieReplySize {
return
}
var reply MessageCookieReply
reader := bytes.NewReader(packet)
err := binary.Read(reader, binary.LittleEndian, &reply)
if err != nil {
debugLog.Println("Failed to decode cookie reply")
return
}
device.ConsumeMessageCookieReply(&reply)
case MessageTransportType:
debugLog.Println("DEBUG: Got transport")
// lookup key pair
if len(packet) < MessageTransportSize {
return
}
receiver := binary.LittleEndian.Uint32(
packet[MessageTransportOffsetReceiver:MessageTransportOffsetCounter],
)
value := device.indices.Lookup(receiver)
keyPair := value.keyPair
if keyPair == nil {
return
}
// check key-pair expiry
if keyPair.created.Add(RejectAfterTime).Before(time.Now()) {
return
}
// add to peer queue
peer := value.peer
work := new(QueueInboundElement)
work.packet = packet
work.keyPair = keyPair
work.state = ElementStateOkay
work.mutex.Lock()
// add to parallel decryption queue
func() {
for {
select {
case device.queue.decryption <- work:
return
default:
select {
case elem := <-device.queue.decryption:
elem.Drop()
default:
}
}
}
}()
// add to sequential inbound queue
func() {
for {
select {
case peer.queue.inbound <- work:
break
default:
select {
case elem := <-peer.queue.inbound:
elem.Drop()
default:
}
}
}
}()
default:
// unknown message type
}
}()
}
}
func (device *Device) RoutineDecryption() {
var elem *QueueInboundElement
var nonce [chacha20poly1305.NonceSize]byte
for {
select {
case elem = <-device.queue.decryption:
case <-device.signal.stop:
return
}
// check if dropped
state := atomic.LoadUint32(&elem.state)
if state != ElementStateOkay {
continue
}
// split message into fields
counter := binary.LittleEndian.Uint64(
elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent],
)
content := elem.packet[MessageTransportOffsetContent:]
// decrypt with key-pair
var err error
binary.LittleEndian.PutUint64(nonce[4:], counter)
elem.packet, err = elem.keyPair.recv.Open(elem.packet[:0], nonce[:], content, nil)
if err != nil {
elem.Drop()
continue
}
// release to consumer
elem.counter = counter
elem.mutex.Unlock()
}
}
/* Handles incomming packets related to handshake
*
*
*/
func (device *Device) RoutineHandshake() {
logInfo := device.log.Info
logError := device.log.Error
logDebug := device.log.Debug
var elem QueueHandshakeElement
for {
select {
case elem = <-device.queue.handshake:
case <-device.signal.stop:
return
}
func() {
switch elem.msgType {
case MessageInitiationType:
// unmarshal
if len(elem.packet) != MessageInitiationSize {
return
}
var msg MessageInitiation
reader := bytes.NewReader(elem.packet)
err := binary.Read(reader, binary.LittleEndian, &msg)
if err != nil {
logError.Println("Failed to decode initiation message")
return
}
// consume initiation
peer := device.ConsumeMessageInitiation(&msg)
if peer == nil {
logInfo.Println(
"Recieved invalid initiation message from",
elem.source.IP.String(),
elem.source.Port,
)
return
}
logDebug.Println("Recieved valid initiation message for peer", peer.id)
case MessageResponseType:
// unmarshal
if len(elem.packet) != MessageResponseSize {
return
}
var msg MessageResponse
reader := bytes.NewReader(elem.packet)
err := binary.Read(reader, binary.LittleEndian, &msg)
if err != nil {
logError.Println("Failed to decode response message")
return
}
// consume response
peer := device.ConsumeMessageResponse(&msg)
if peer == nil {
logInfo.Println(
"Recieved invalid response message from",
elem.source.IP.String(),
elem.source.Port,
)
return
}
sendSignal(peer.signal.handshakeCompleted)
logDebug.Println("Recieved valid response message for peer", peer.id)
peer.NewKeyPair()
peer.SendKeepAlive()
default:
device.log.Error.Println("Invalid message type in handshake queue")
}
}()
}
}
func (peer *Peer) RoutineSequentialReceiver() {
var elem *QueueInboundElement
device := peer.device
logDebug := device.log.Debug
logDebug.Println("Routine, sequential receiver, started for peer", peer.id)
for {
// wait for decryption
select {
case <-peer.signal.stop:
return
case elem = <-peer.queue.inbound:
}
elem.mutex.Lock()
// check if dropped
logDebug.Println("MESSSAGE:", elem)
state := atomic.LoadUint32(&elem.state)
if state != ElementStateOkay {
continue
}
// check for replay
// check for keep-alive
if len(elem.packet) == 0 {
continue
}
// insert into inbound TUN queue
device.queue.inbound <- elem.packet
}
}
func (device *Device) RoutineWriteToTUN(tun TUNDevice) {
for {
var packet []byte
select {
case <-device.signal.stop:
case packet = <-device.queue.inbound:
}
device.log.Debug.Println("GOT:", packet)
size, err := tun.Write(packet)
device.log.Debug.Println("DEBUG:", size, err)
if err != nil {
}
}
}

44
src/send.go
View file

@ -27,6 +27,7 @@ import (
* workers release lock when they have completed work on the packet.
*/
type QueueOutboundElement struct {
state uint32
mutex sync.Mutex
packet []byte
nonce uint64
@ -59,6 +60,14 @@ func (peer *Peer) InsertOutbound(elem *QueueOutboundElement) {
}
}
func (elem *QueueOutboundElement) Drop() {
atomic.StoreUint32(&elem.state, ElementStateDropped)
}
func (elem *QueueOutboundElement) IsDropped() bool {
return atomic.LoadUint32(&elem.state) == ElementStateDropped
}
/* Reads packets from the TUN and inserts
* into nonce queue for peer
*
@ -162,6 +171,8 @@ func (peer *Peer) RoutineNonce() {
}
}
logger.Println("PACKET:", packet)
// wait for key pair
for {
@ -176,6 +187,7 @@ func (peer *Peer) RoutineNonce() {
break
}
}
logger.Println("Key pair:", keyPair)
sendSignal(peer.signal.handshakeBegin)
logger.Println("Waiting for key-pair, peer", peer.id)
@ -205,10 +217,12 @@ func (peer *Peer) RoutineNonce() {
work := new(QueueOutboundElement) // TODO: profile, maybe use pool
work.keyPair = keyPair
work.packet = packet
work.nonce = atomic.AddUint64(&keyPair.sendNonce, 1)
work.nonce = atomic.AddUint64(&keyPair.sendNonce, 1) - 1
work.peer = peer
work.mutex.Lock()
logger.Println("WORK:", work)
packet = nil
// drop packets until there is space
@ -219,9 +233,11 @@ func (peer *Peer) RoutineNonce() {
case peer.device.queue.encryption <- work:
return
default:
drop := <-peer.device.queue.encryption
drop.packet = nil
drop.mutex.Unlock()
select {
case elem := <-peer.device.queue.encryption:
elem.Drop()
default:
}
}
}
}()
@ -241,18 +257,22 @@ func (peer *Peer) RoutineNonce() {
func (device *Device) RoutineEncryption() {
var nonce [chacha20poly1305.NonceSize]byte
for work := range device.queue.encryption {
if work.IsDropped() {
continue
}
// pad packet
padding := device.mtu - len(work.packet)
if padding < 0 {
// drop
work.packet = nil
work.mutex.Unlock()
work.Drop()
continue
}
for n := 0; n < padding; n += 1 {
work.packet = append(work.packet, 0)
}
device.log.Debug.Println(work.packet)
// encrypt
@ -288,6 +308,9 @@ func (peer *Peer) RoutineSequentialSender() {
logger.Println("Routine, sequential sender, stopped for peer", peer.id)
return
case work := <-peer.queue.outbound:
if work.IsDropped() {
continue
}
work.mutex.Lock()
func() {
if work.packet == nil {
@ -310,10 +333,12 @@ func (peer *Peer) RoutineSequentialSender() {
return
}
logger.Println("Sending packet for peer", peer.id, work.packet)
logger.Println(work.packet)
_, err := device.net.conn.WriteToUDP(work.packet, peer.endpoint)
logger.Println("SEND:", peer.endpoint, err)
if err != nil {
return
}
atomic.AddUint64(&peer.tx_bytes, uint64(len(work.packet)))
// shift keep-alive timer
@ -323,7 +348,6 @@ func (peer *Peer) RoutineSequentialSender() {
peer.timer.sendKeepalive.Reset(interval)
}
}()
work.mutex.Unlock()
}
}
}

2
src/tun.go
View file

@ -4,5 +4,5 @@ type TUNDevice interface {
Read([]byte) (int, error)
Write([]byte) (int, error)
Name() string
MTU() uint
MTU() int
}

4
src/tun_linux.go
View file

@ -24,14 +24,14 @@ const (
type NativeTun struct {
fd *os.File
name string
mtu uint
mtu int
}
func (tun *NativeTun) Name() string {
return tun.name
}
func (tun *NativeTun) MTU() uint {
func (tun *NativeTun) MTU() int {
return tun.mtu
}