mirror of
https://github.com/KusakabeShi/EtherGuard-VPN.git
synced 2024-11-29 02:33:17 +01:00
a86492a567
Now that we block when enqueueing to the decryption queue, there is only one case in which we "drop" a inbound element, when decryption fails. We can use a simple, obvious, sync-free sentinel for that, elem.packet == nil. Also, we can return the message buffer to the pool slightly later, which further simplifies the code. Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
607 lines
13 KiB
Go
607 lines
13 KiB
Go
/* SPDX-License-Identifier: MIT
|
|
*
|
|
* Copyright (C) 2017-2020 WireGuard LLC. All Rights Reserved.
|
|
*/
|
|
|
|
package device
|
|
|
|
import (
|
|
"bytes"
|
|
"encoding/binary"
|
|
"errors"
|
|
"net"
|
|
"strconv"
|
|
"sync"
|
|
"sync/atomic"
|
|
"time"
|
|
|
|
"golang.org/x/crypto/chacha20poly1305"
|
|
"golang.org/x/net/ipv4"
|
|
"golang.org/x/net/ipv6"
|
|
|
|
"golang.zx2c4.com/wireguard/conn"
|
|
)
|
|
|
|
type QueueHandshakeElement struct {
|
|
msgType uint32
|
|
packet []byte
|
|
endpoint conn.Endpoint
|
|
buffer *[MaxMessageSize]byte
|
|
}
|
|
|
|
type QueueInboundElement struct {
|
|
sync.Mutex
|
|
buffer *[MaxMessageSize]byte
|
|
packet []byte
|
|
counter uint64
|
|
keypair *Keypair
|
|
endpoint conn.Endpoint
|
|
}
|
|
|
|
// clearPointers clears elem fields that contain pointers.
|
|
// This makes the garbage collector's life easier and
|
|
// avoids accidentally keeping other objects around unnecessarily.
|
|
// It also reduces the possible collateral damage from use-after-free bugs.
|
|
func (elem *QueueInboundElement) clearPointers() {
|
|
elem.buffer = nil
|
|
elem.packet = nil
|
|
elem.keypair = nil
|
|
elem.endpoint = nil
|
|
}
|
|
|
|
func (device *Device) addToHandshakeQueue(queue chan QueueHandshakeElement, elem QueueHandshakeElement) bool {
|
|
select {
|
|
case queue <- elem:
|
|
return true
|
|
default:
|
|
return false
|
|
}
|
|
}
|
|
|
|
/* Called when a new authenticated message has been received
|
|
*
|
|
* NOTE: Not thread safe, but called by sequential receiver!
|
|
*/
|
|
func (peer *Peer) keepKeyFreshReceiving() {
|
|
if peer.timers.sentLastMinuteHandshake.Get() {
|
|
return
|
|
}
|
|
keypair := peer.keypairs.Current()
|
|
if keypair != nil && keypair.isInitiator && time.Since(keypair.created) > (RejectAfterTime-KeepaliveTimeout-RekeyTimeout) {
|
|
peer.timers.sentLastMinuteHandshake.Set(true)
|
|
peer.SendHandshakeInitiation(false)
|
|
}
|
|
}
|
|
|
|
/* Receives incoming datagrams for the device
|
|
*
|
|
* Every time the bind is updated a new routine is started for
|
|
* IPv4 and IPv6 (separately)
|
|
*/
|
|
func (device *Device) RoutineReceiveIncoming(IP int, bind conn.Bind) {
|
|
|
|
logDebug := device.log.Debug
|
|
defer func() {
|
|
logDebug.Println("Routine: receive incoming IPv" + strconv.Itoa(IP) + " - stopped")
|
|
device.queue.decryption.wg.Done()
|
|
device.net.stopping.Done()
|
|
}()
|
|
|
|
logDebug.Println("Routine: receive incoming IPv" + strconv.Itoa(IP) + " - started")
|
|
|
|
// receive datagrams until conn is closed
|
|
|
|
buffer := device.GetMessageBuffer()
|
|
|
|
var (
|
|
err error
|
|
size int
|
|
endpoint conn.Endpoint
|
|
deathSpiral int
|
|
)
|
|
|
|
for {
|
|
switch IP {
|
|
case ipv4.Version:
|
|
size, endpoint, err = bind.ReceiveIPv4(buffer[:])
|
|
case ipv6.Version:
|
|
size, endpoint, err = bind.ReceiveIPv6(buffer[:])
|
|
default:
|
|
panic("invalid IP version")
|
|
}
|
|
|
|
if err != nil {
|
|
device.PutMessageBuffer(buffer)
|
|
if errors.Is(err, net.ErrClosed) {
|
|
return
|
|
}
|
|
device.log.Error.Printf("Failed to receive packet: %v", err)
|
|
if deathSpiral < 10 {
|
|
deathSpiral++
|
|
time.Sleep(time.Second / 3)
|
|
continue
|
|
}
|
|
return
|
|
}
|
|
deathSpiral = 0
|
|
|
|
if size < MinMessageSize {
|
|
continue
|
|
}
|
|
|
|
// check size of packet
|
|
|
|
packet := buffer[:size]
|
|
msgType := binary.LittleEndian.Uint32(packet[:4])
|
|
|
|
var okay bool
|
|
|
|
switch msgType {
|
|
|
|
// check if transport
|
|
|
|
case MessageTransportType:
|
|
|
|
// check size
|
|
|
|
if len(packet) < MessageTransportSize {
|
|
continue
|
|
}
|
|
|
|
// lookup key pair
|
|
|
|
receiver := binary.LittleEndian.Uint32(
|
|
packet[MessageTransportOffsetReceiver:MessageTransportOffsetCounter],
|
|
)
|
|
value := device.indexTable.Lookup(receiver)
|
|
keypair := value.keypair
|
|
if keypair == nil {
|
|
continue
|
|
}
|
|
|
|
// check keypair expiry
|
|
|
|
if keypair.created.Add(RejectAfterTime).Before(time.Now()) {
|
|
continue
|
|
}
|
|
|
|
// create work element
|
|
peer := value.peer
|
|
elem := device.GetInboundElement()
|
|
elem.packet = packet
|
|
elem.buffer = buffer
|
|
elem.keypair = keypair
|
|
elem.endpoint = endpoint
|
|
elem.counter = 0
|
|
elem.Mutex = sync.Mutex{}
|
|
elem.Lock()
|
|
|
|
// add to decryption queues
|
|
|
|
peer.queue.RLock()
|
|
if peer.isRunning.Get() {
|
|
peer.queue.inbound <- elem
|
|
device.queue.decryption.c <- elem
|
|
buffer = device.GetMessageBuffer()
|
|
} else {
|
|
device.PutInboundElement(elem)
|
|
}
|
|
peer.queue.RUnlock()
|
|
|
|
continue
|
|
|
|
// otherwise it is a fixed size & handshake related packet
|
|
|
|
case MessageInitiationType:
|
|
okay = len(packet) == MessageInitiationSize
|
|
|
|
case MessageResponseType:
|
|
okay = len(packet) == MessageResponseSize
|
|
|
|
case MessageCookieReplyType:
|
|
okay = len(packet) == MessageCookieReplySize
|
|
|
|
default:
|
|
logDebug.Println("Received message with unknown type")
|
|
}
|
|
|
|
if okay {
|
|
if (device.addToHandshakeQueue(
|
|
device.queue.handshake,
|
|
QueueHandshakeElement{
|
|
msgType: msgType,
|
|
buffer: buffer,
|
|
packet: packet,
|
|
endpoint: endpoint,
|
|
},
|
|
)) {
|
|
buffer = device.GetMessageBuffer()
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func (device *Device) RoutineDecryption() {
|
|
|
|
var nonce [chacha20poly1305.NonceSize]byte
|
|
|
|
logDebug := device.log.Debug
|
|
defer func() {
|
|
logDebug.Println("Routine: decryption worker - stopped")
|
|
device.state.stopping.Done()
|
|
}()
|
|
logDebug.Println("Routine: decryption worker - started")
|
|
|
|
for elem := range device.queue.decryption.c {
|
|
// split message into fields
|
|
counter := elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent]
|
|
content := elem.packet[MessageTransportOffsetContent:]
|
|
|
|
// decrypt and release to consumer
|
|
var err error
|
|
elem.counter = binary.LittleEndian.Uint64(counter)
|
|
// copy counter to nonce
|
|
binary.LittleEndian.PutUint64(nonce[0x4:0xc], elem.counter)
|
|
elem.packet, err = elem.keypair.receive.Open(
|
|
content[:0],
|
|
nonce[:],
|
|
content,
|
|
nil,
|
|
)
|
|
if err != nil {
|
|
elem.packet = nil
|
|
}
|
|
elem.Unlock()
|
|
}
|
|
}
|
|
|
|
/* Handles incoming packets related to handshake
|
|
*/
|
|
func (device *Device) RoutineHandshake() {
|
|
|
|
logInfo := device.log.Info
|
|
logError := device.log.Error
|
|
logDebug := device.log.Debug
|
|
|
|
var elem QueueHandshakeElement
|
|
var ok bool
|
|
|
|
defer func() {
|
|
logDebug.Println("Routine: handshake worker - stopped")
|
|
device.state.stopping.Done()
|
|
if elem.buffer != nil {
|
|
device.PutMessageBuffer(elem.buffer)
|
|
}
|
|
}()
|
|
|
|
logDebug.Println("Routine: handshake worker - started")
|
|
|
|
for {
|
|
if elem.buffer != nil {
|
|
device.PutMessageBuffer(elem.buffer)
|
|
elem.buffer = nil
|
|
}
|
|
|
|
select {
|
|
case elem, ok = <-device.queue.handshake:
|
|
case <-device.signals.stop:
|
|
return
|
|
}
|
|
|
|
if !ok {
|
|
return
|
|
}
|
|
|
|
// handle cookie fields and ratelimiting
|
|
|
|
switch elem.msgType {
|
|
|
|
case MessageCookieReplyType:
|
|
|
|
// unmarshal packet
|
|
|
|
var reply MessageCookieReply
|
|
reader := bytes.NewReader(elem.packet)
|
|
err := binary.Read(reader, binary.LittleEndian, &reply)
|
|
if err != nil {
|
|
logDebug.Println("Failed to decode cookie reply")
|
|
return
|
|
}
|
|
|
|
// lookup peer from index
|
|
|
|
entry := device.indexTable.Lookup(reply.Receiver)
|
|
|
|
if entry.peer == nil {
|
|
continue
|
|
}
|
|
|
|
// consume reply
|
|
|
|
if peer := entry.peer; peer.isRunning.Get() {
|
|
logDebug.Println("Receiving cookie response from ", elem.endpoint.DstToString())
|
|
if !peer.cookieGenerator.ConsumeReply(&reply) {
|
|
logDebug.Println("Could not decrypt invalid cookie response")
|
|
}
|
|
}
|
|
|
|
continue
|
|
|
|
case MessageInitiationType, MessageResponseType:
|
|
|
|
// check mac fields and maybe ratelimit
|
|
|
|
if !device.cookieChecker.CheckMAC1(elem.packet) {
|
|
logDebug.Println("Received packet with invalid mac1")
|
|
continue
|
|
}
|
|
|
|
// endpoints destination address is the source of the datagram
|
|
|
|
if device.IsUnderLoad() {
|
|
|
|
// verify MAC2 field
|
|
|
|
if !device.cookieChecker.CheckMAC2(elem.packet, elem.endpoint.DstToBytes()) {
|
|
device.SendHandshakeCookie(&elem)
|
|
continue
|
|
}
|
|
|
|
// check ratelimiter
|
|
|
|
if !device.rate.limiter.Allow(elem.endpoint.DstIP()) {
|
|
continue
|
|
}
|
|
}
|
|
|
|
default:
|
|
logError.Println("Invalid packet ended up in the handshake queue")
|
|
continue
|
|
}
|
|
|
|
// handle handshake initiation/response content
|
|
|
|
switch elem.msgType {
|
|
case MessageInitiationType:
|
|
|
|
// unmarshal
|
|
|
|
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")
|
|
continue
|
|
}
|
|
|
|
// consume initiation
|
|
|
|
peer := device.ConsumeMessageInitiation(&msg)
|
|
if peer == nil {
|
|
logInfo.Println(
|
|
"Received invalid initiation message from",
|
|
elem.endpoint.DstToString(),
|
|
)
|
|
continue
|
|
}
|
|
|
|
// update timers
|
|
|
|
peer.timersAnyAuthenticatedPacketTraversal()
|
|
peer.timersAnyAuthenticatedPacketReceived()
|
|
|
|
// update endpoint
|
|
peer.SetEndpointFromPacket(elem.endpoint)
|
|
|
|
logDebug.Println(peer, "- Received handshake initiation")
|
|
atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)))
|
|
|
|
peer.SendHandshakeResponse()
|
|
|
|
case MessageResponseType:
|
|
|
|
// unmarshal
|
|
|
|
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")
|
|
continue
|
|
}
|
|
|
|
// consume response
|
|
|
|
peer := device.ConsumeMessageResponse(&msg)
|
|
if peer == nil {
|
|
logInfo.Println(
|
|
"Received invalid response message from",
|
|
elem.endpoint.DstToString(),
|
|
)
|
|
continue
|
|
}
|
|
|
|
// update endpoint
|
|
peer.SetEndpointFromPacket(elem.endpoint)
|
|
|
|
logDebug.Println(peer, "- Received handshake response")
|
|
atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)))
|
|
|
|
// update timers
|
|
|
|
peer.timersAnyAuthenticatedPacketTraversal()
|
|
peer.timersAnyAuthenticatedPacketReceived()
|
|
|
|
// derive keypair
|
|
|
|
err = peer.BeginSymmetricSession()
|
|
|
|
if err != nil {
|
|
logError.Println(peer, "- Failed to derive keypair:", err)
|
|
continue
|
|
}
|
|
|
|
peer.timersSessionDerived()
|
|
peer.timersHandshakeComplete()
|
|
peer.SendKeepalive()
|
|
select {
|
|
case peer.signals.newKeypairArrived <- struct{}{}:
|
|
default:
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func (peer *Peer) RoutineSequentialReceiver() {
|
|
|
|
device := peer.device
|
|
logInfo := device.log.Info
|
|
logError := device.log.Error
|
|
logDebug := device.log.Debug
|
|
|
|
var elem *QueueInboundElement
|
|
|
|
defer func() {
|
|
logDebug.Println(peer, "- Routine: sequential receiver - stopped")
|
|
peer.routines.stopping.Done()
|
|
if elem != nil {
|
|
device.PutMessageBuffer(elem.buffer)
|
|
device.PutInboundElement(elem)
|
|
}
|
|
}()
|
|
|
|
logDebug.Println(peer, "- Routine: sequential receiver - started")
|
|
|
|
for {
|
|
if elem != nil {
|
|
device.PutMessageBuffer(elem.buffer)
|
|
device.PutInboundElement(elem)
|
|
elem = nil
|
|
}
|
|
|
|
var elemOk bool
|
|
select {
|
|
case <-peer.routines.stop:
|
|
return
|
|
case elem, elemOk = <-peer.queue.inbound:
|
|
if !elemOk {
|
|
return
|
|
}
|
|
}
|
|
|
|
// wait for decryption
|
|
elem.Lock()
|
|
if elem.packet == nil {
|
|
// decryption failed
|
|
continue
|
|
}
|
|
|
|
// check for replay
|
|
if !elem.keypair.replayFilter.ValidateCounter(elem.counter, RejectAfterMessages) {
|
|
continue
|
|
}
|
|
|
|
// update endpoint
|
|
peer.SetEndpointFromPacket(elem.endpoint)
|
|
|
|
// check if using new keypair
|
|
if peer.ReceivedWithKeypair(elem.keypair) {
|
|
peer.timersHandshakeComplete()
|
|
select {
|
|
case peer.signals.newKeypairArrived <- struct{}{}:
|
|
default:
|
|
}
|
|
}
|
|
|
|
peer.keepKeyFreshReceiving()
|
|
peer.timersAnyAuthenticatedPacketTraversal()
|
|
peer.timersAnyAuthenticatedPacketReceived()
|
|
atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)+MinMessageSize))
|
|
|
|
// check for keepalive
|
|
|
|
if len(elem.packet) == 0 {
|
|
logDebug.Println(peer, "- Receiving keepalive packet")
|
|
continue
|
|
}
|
|
peer.timersDataReceived()
|
|
|
|
// verify source and strip padding
|
|
|
|
switch elem.packet[0] >> 4 {
|
|
case ipv4.Version:
|
|
|
|
// strip padding
|
|
|
|
if len(elem.packet) < ipv4.HeaderLen {
|
|
continue
|
|
}
|
|
|
|
field := elem.packet[IPv4offsetTotalLength : IPv4offsetTotalLength+2]
|
|
length := binary.BigEndian.Uint16(field)
|
|
if int(length) > len(elem.packet) || int(length) < ipv4.HeaderLen {
|
|
continue
|
|
}
|
|
|
|
elem.packet = elem.packet[:length]
|
|
|
|
// verify IPv4 source
|
|
|
|
src := elem.packet[IPv4offsetSrc : IPv4offsetSrc+net.IPv4len]
|
|
if device.allowedips.LookupIPv4(src) != peer {
|
|
logInfo.Println(
|
|
"IPv4 packet with disallowed source address from",
|
|
peer,
|
|
)
|
|
continue
|
|
}
|
|
|
|
case ipv6.Version:
|
|
|
|
// strip padding
|
|
|
|
if len(elem.packet) < ipv6.HeaderLen {
|
|
continue
|
|
}
|
|
|
|
field := elem.packet[IPv6offsetPayloadLength : IPv6offsetPayloadLength+2]
|
|
length := binary.BigEndian.Uint16(field)
|
|
length += ipv6.HeaderLen
|
|
if int(length) > len(elem.packet) {
|
|
continue
|
|
}
|
|
|
|
elem.packet = elem.packet[:length]
|
|
|
|
// verify IPv6 source
|
|
|
|
src := elem.packet[IPv6offsetSrc : IPv6offsetSrc+net.IPv6len]
|
|
if device.allowedips.LookupIPv6(src) != peer {
|
|
logInfo.Println(
|
|
"IPv6 packet with disallowed source address from",
|
|
peer,
|
|
)
|
|
continue
|
|
}
|
|
|
|
default:
|
|
logInfo.Println("Packet with invalid IP version from", peer)
|
|
continue
|
|
}
|
|
|
|
// write to tun device
|
|
|
|
offset := MessageTransportOffsetContent
|
|
_, err := device.tun.device.Write(elem.buffer[:offset+len(elem.packet)], offset)
|
|
if err != nil && !device.isClosed.Get() {
|
|
logError.Println("Failed to write packet to TUN device:", err)
|
|
}
|
|
if len(peer.queue.inbound) == 0 {
|
|
err := device.tun.device.Flush()
|
|
if err != nil {
|
|
peer.device.log.Error.Printf("Unable to flush packets: %v", err)
|
|
}
|
|
}
|
|
}
|
|
}
|