Improved cookie/mac computation code

This commit is contained in:
Mathias Hall-Andersen 2017-08-14 17:09:25 +02:00
parent a4eff12d7f
commit 12e8db2066
10 changed files with 523 additions and 442 deletions

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@ -15,6 +15,7 @@ const (
RejectAfterTime = time.Second * 180 RejectAfterTime = time.Second * 180
KeepaliveTimeout = time.Second * 10 KeepaliveTimeout = time.Second * 10
CookieRefreshTime = time.Second * 120 CookieRefreshTime = time.Second * 120
HandshakeInitationRate = time.Second / 20
PaddingMultiple = 16 PaddingMultiple = 16
) )

256
src/cookie.go Normal file
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@ -0,0 +1,256 @@
package main
import (
"crypto/hmac"
"crypto/rand"
"golang.org/x/crypto/blake2s"
"golang.org/x/crypto/chacha20poly1305"
"net"
"sync"
"time"
"unsafe"
)
type CookieChecker struct {
mutex sync.RWMutex
mac1 struct {
key [blake2s.Size]byte
}
mac2 struct {
secret [blake2s.Size]byte
secretSet time.Time
encryptionKey [chacha20poly1305.KeySize]byte
}
}
type CookieGenerator struct {
mutex sync.RWMutex
mac1 struct {
key [blake2s.Size]byte
}
mac2 struct {
cookie [blake2s.Size128]byte
cookieSet time.Time
hasLastMAC1 bool
lastMAC1 [blake2s.Size128]byte
encryptionKey [chacha20poly1305.KeySize]byte
}
}
func (st *CookieChecker) Init(pk NoisePublicKey) {
st.mutex.Lock()
defer st.mutex.Unlock()
// mac1 state
func() {
hsh, _ := blake2s.New256(nil)
hsh.Write([]byte(WGLabelMAC1))
hsh.Write(pk[:])
hsh.Sum(st.mac1.key[:0])
}()
// mac2 state
func() {
hsh, _ := blake2s.New256(nil)
hsh.Write([]byte(WGLabelCookie))
hsh.Write(pk[:])
hsh.Sum(st.mac2.encryptionKey[:0])
}()
st.mac2.secretSet = time.Time{}
}
func (st *CookieChecker) CheckMAC1(msg []byte) bool {
size := len(msg)
smac2 := size - blake2s.Size128
smac1 := smac2 - blake2s.Size128
var mac1 [blake2s.Size128]byte
mac, _ := blake2s.New128(st.mac1.key[:])
mac.Write(msg[:smac1])
mac.Sum(mac1[:0])
return hmac.Equal(mac1[:], msg[smac1:smac2])
}
func (st *CookieChecker) CheckMAC2(msg []byte, src *net.UDPAddr) bool {
st.mutex.RLock()
defer st.mutex.RUnlock()
if time.Now().Sub(st.mac2.secretSet) > CookieRefreshTime {
return false
}
// derive cookie key
var cookie [blake2s.Size128]byte
func() {
mac, _ := blake2s.New128(st.mac2.secret[:])
mac.Write(src.IP)
mac.Write((*[unsafe.Sizeof(src.Port)]byte)(unsafe.Pointer(&src.Port))[:])
mac.Sum(cookie[:0])
}()
// calculate mac of packet (including mac1)
smac2 := len(msg) - blake2s.Size128
var mac2 [blake2s.Size128]byte
func() {
mac, _ := blake2s.New128(cookie[:])
mac.Write(msg[:smac2])
mac.Sum(mac2[:0])
}()
return hmac.Equal(mac2[:], msg[smac2:])
}
func (st *CookieChecker) CreateReply(
msg []byte,
recv uint32,
src *net.UDPAddr,
) (*MessageCookieReply, error) {
st.mutex.RLock()
// refresh cookie secret
if time.Now().Sub(st.mac2.secretSet) > CookieRefreshTime {
st.mutex.RUnlock()
st.mutex.Lock()
_, err := rand.Read(st.mac2.secret[:])
if err != nil {
st.mutex.Unlock()
return nil, err
}
st.mac2.secretSet = time.Now()
st.mutex.Unlock()
st.mutex.RLock()
}
// derive cookie
var cookie [blake2s.Size128]byte
func() {
mac, _ := blake2s.New128(st.mac2.secret[:])
mac.Write(src.IP)
mac.Write((*[unsafe.Sizeof(src.Port)]byte)(unsafe.Pointer(&src.Port))[:])
mac.Sum(cookie[:0])
}()
// encrypt cookie
size := len(msg)
smac2 := size - blake2s.Size128
smac1 := smac2 - blake2s.Size128
reply := new(MessageCookieReply)
reply.Type = MessageCookieReplyType
reply.Receiver = recv
_, err := rand.Read(reply.Nonce[:])
if err != nil {
st.mutex.RUnlock()
return nil, err
}
XChaCha20Poly1305Encrypt(
reply.Cookie[:0],
&reply.Nonce,
cookie[:],
msg[smac1:smac2],
&st.mac2.encryptionKey,
)
st.mutex.RUnlock()
return reply, nil
}
func (st *CookieGenerator) Init(pk NoisePublicKey) {
st.mutex.Lock()
defer st.mutex.Unlock()
func() {
hsh, _ := blake2s.New256(nil)
hsh.Write([]byte(WGLabelMAC1))
hsh.Write(pk[:])
hsh.Sum(st.mac1.key[:0])
}()
func() {
hsh, _ := blake2s.New256(nil)
hsh.Write([]byte(WGLabelCookie))
hsh.Write(pk[:])
hsh.Sum(st.mac2.encryptionKey[:0])
}()
st.mac2.cookieSet = time.Time{}
}
func (st *CookieGenerator) ConsumeReply(msg *MessageCookieReply) bool {
st.mutex.Lock()
defer st.mutex.Unlock()
if !st.mac2.hasLastMAC1 {
return false
}
var cookie [blake2s.Size128]byte
_, err := XChaCha20Poly1305Decrypt(
cookie[:0],
&msg.Nonce,
msg.Cookie[:],
st.mac2.lastMAC1[:],
&st.mac2.encryptionKey,
)
if err != nil {
return false
}
st.mac2.cookieSet = time.Now()
st.mac2.cookie = cookie
return true
}
func (st *CookieGenerator) AddMacs(msg []byte) {
size := len(msg)
smac2 := size - blake2s.Size128
smac1 := smac2 - blake2s.Size128
mac1 := msg[smac1:smac2]
mac2 := msg[smac2:]
st.mutex.Lock()
defer st.mutex.Unlock()
// set mac1
func() {
mac, _ := blake2s.New128(st.mac1.key[:])
mac.Write(msg[:smac1])
mac.Sum(mac1[:0])
}()
copy(st.mac2.lastMAC1[:], mac1)
st.mac2.hasLastMAC1 = true
// set mac2
if time.Now().Sub(st.mac2.cookieSet) > CookieRefreshTime {
return
}
func() {
mac, _ := blake2s.New128(st.mac2.cookie[:])
mac.Write(msg[:smac2])
mac.Sum(mac2[:0])
}()
}

187
src/cookie_test.go Normal file
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@ -0,0 +1,187 @@
package main
import (
"net"
"testing"
)
func TestCookieMAC1(t *testing.T) {
// setup generator / checker
var (
generator CookieGenerator
checker CookieChecker
)
sk, err := newPrivateKey()
if err != nil {
t.Fatal(err)
}
pk := sk.publicKey()
generator.Init(pk)
checker.Init(pk)
// check mac1
src, _ := net.ResolveUDPAddr("udp", "192.168.13.37:4000")
checkMAC1 := func(msg []byte) {
generator.AddMacs(msg)
if !checker.CheckMAC1(msg) {
t.Fatal("MAC1 generation/verification failed")
}
if checker.CheckMAC2(msg, src) {
t.Fatal("MAC2 generation/verification failed")
}
}
checkMAC1([]byte{
0x99, 0xbb, 0xa5, 0xfc, 0x99, 0xaa, 0x83, 0xbd,
0x7b, 0x00, 0xc5, 0x9a, 0x4c, 0xb9, 0xcf, 0x62,
0x40, 0x23, 0xf3, 0x8e, 0xd8, 0xd0, 0x62, 0x64,
0x5d, 0xb2, 0x80, 0x13, 0xda, 0xce, 0xc6, 0x91,
0x61, 0xd6, 0x30, 0xf1, 0x32, 0xb3, 0xa2, 0xf4,
0x7b, 0x43, 0xb5, 0xa7, 0xe2, 0xb1, 0xf5, 0x6c,
0x74, 0x6b, 0xb0, 0xcd, 0x1f, 0x94, 0x86, 0x7b,
0xc8, 0xfb, 0x92, 0xed, 0x54, 0x9b, 0x44, 0xf5,
0xc8, 0x7d, 0xb7, 0x8e, 0xff, 0x49, 0xc4, 0xe8,
0x39, 0x7c, 0x19, 0xe0, 0x60, 0x19, 0x51, 0xf8,
0xe4, 0x8e, 0x02, 0xf1, 0x7f, 0x1d, 0xcc, 0x8e,
0xb0, 0x07, 0xff, 0xf8, 0xaf, 0x7f, 0x66, 0x82,
0x83, 0xcc, 0x7c, 0xfa, 0x80, 0xdb, 0x81, 0x53,
0xad, 0xf7, 0xd8, 0x0c, 0x10, 0xe0, 0x20, 0xfd,
0xe8, 0x0b, 0x3f, 0x90, 0x15, 0xcd, 0x93, 0xad,
0x0b, 0xd5, 0x0c, 0xcc, 0x88, 0x56, 0xe4, 0x3f,
})
checkMAC1([]byte{
0x33, 0xe7, 0x2a, 0x84, 0x9f, 0xff, 0x57, 0x6c,
0x2d, 0xc3, 0x2d, 0xe1, 0xf5, 0x5c, 0x97, 0x56,
0xb8, 0x93, 0xc2, 0x7d, 0xd4, 0x41, 0xdd, 0x7a,
0x4a, 0x59, 0x3b, 0x50, 0xdd, 0x7a, 0x7a, 0x8c,
0x9b, 0x96, 0xaf, 0x55, 0x3c, 0xeb, 0x6d, 0x0b,
0x13, 0x0b, 0x97, 0x98, 0xb3, 0x40, 0xc3, 0xcc,
0xb8, 0x57, 0x33, 0x45, 0x6e, 0x8b, 0x09, 0x2b,
0x81, 0x2e, 0xd2, 0xb9, 0x66, 0x0b, 0x93, 0x05,
})
checkMAC1([]byte{
0x9b, 0x96, 0xaf, 0x55, 0x3c, 0xeb, 0x6d, 0x0b,
0x13, 0x0b, 0x97, 0x98, 0xb3, 0x40, 0xc3, 0xcc,
0xb8, 0x57, 0x33, 0x45, 0x6e, 0x8b, 0x09, 0x2b,
0x81, 0x2e, 0xd2, 0xb9, 0x66, 0x0b, 0x93, 0x05,
})
// exchange cookie reply
func() {
msg := []byte{
0x6d, 0xd7, 0xc3, 0x2e, 0xb0, 0x76, 0xd8, 0xdf,
0x30, 0x65, 0x7d, 0x62, 0x3e, 0xf8, 0x9a, 0xe8,
0xe7, 0x3c, 0x64, 0xa3, 0x78, 0x48, 0xda, 0xf5,
0x25, 0x61, 0x28, 0x53, 0x79, 0x32, 0x86, 0x9f,
0xa0, 0x27, 0x95, 0x69, 0xb6, 0xba, 0xd0, 0xa2,
0xf8, 0x68, 0xea, 0xa8, 0x62, 0xf2, 0xfd, 0x1b,
0xe0, 0xb4, 0x80, 0xe5, 0x6b, 0x3a, 0x16, 0x9e,
0x35, 0xf6, 0xa8, 0xf2, 0x4f, 0x9a, 0x7b, 0xe9,
0x77, 0x0b, 0xc2, 0xb4, 0xed, 0xba, 0xf9, 0x22,
0xc3, 0x03, 0x97, 0x42, 0x9f, 0x79, 0x74, 0x27,
0xfe, 0xf9, 0x06, 0x6e, 0x97, 0x3a, 0xa6, 0x8f,
0xc9, 0x57, 0x0a, 0x54, 0x4c, 0x64, 0x4a, 0xe2,
0x4f, 0xa1, 0xce, 0x95, 0x9b, 0x23, 0xa9, 0x2b,
0x85, 0x93, 0x42, 0xb0, 0xa5, 0x53, 0xed, 0xeb,
0x63, 0x2a, 0xf1, 0x6d, 0x46, 0xcb, 0x2f, 0x61,
0x8c, 0xe1, 0xe8, 0xfa, 0x67, 0x20, 0x80, 0x6d,
}
generator.AddMacs(msg)
reply, err := checker.CreateReply(msg, 1377, src)
if err != nil {
t.Fatal("Failed to create cookie reply:", err)
}
if !generator.ConsumeReply(reply) {
t.Fatal("Failed to consume cookie reply")
}
}()
// check mac2
checkMAC2 := func(msg []byte) {
generator.AddMacs(msg)
if !checker.CheckMAC1(msg) {
t.Fatal("MAC1 generation/verification failed")
}
if !checker.CheckMAC2(msg, src) {
t.Fatal("MAC2 generation/verification failed")
}
msg[5] ^= 0x20
if checker.CheckMAC1(msg) {
t.Fatal("MAC1 generation/verification failed")
}
if checker.CheckMAC2(msg, src) {
t.Fatal("MAC2 generation/verification failed")
}
msg[5] ^= 0x20
srcBad1, _ := net.ResolveUDPAddr("udp", "192.168.13.37:4001")
if checker.CheckMAC2(msg, srcBad1) {
t.Fatal("MAC2 generation/verification failed")
}
srcBad2, _ := net.ResolveUDPAddr("udp", "192.168.13.38:4000")
if checker.CheckMAC2(msg, srcBad2) {
t.Fatal("MAC2 generation/verification failed")
}
}
checkMAC2([]byte{
0x03, 0x31, 0xb9, 0x9e, 0xb0, 0x2a, 0x54, 0xa3,
0xc1, 0x3f, 0xb4, 0x96, 0x16, 0xb9, 0x25, 0x15,
0x3d, 0x3a, 0x82, 0xf9, 0x58, 0x36, 0x86, 0x3f,
0x13, 0x2f, 0xfe, 0xb2, 0x53, 0x20, 0x8c, 0x3f,
0xba, 0xeb, 0xfb, 0x4b, 0x1b, 0x22, 0x02, 0x69,
0x2c, 0x90, 0xbc, 0xdc, 0xcf, 0xcf, 0x85, 0xeb,
0x62, 0x66, 0x6f, 0xe8, 0xe1, 0xa6, 0xa8, 0x4c,
0xa0, 0x04, 0x23, 0x15, 0x42, 0xac, 0xfa, 0x38,
})
checkMAC2([]byte{
0x0e, 0x2f, 0x0e, 0xa9, 0x29, 0x03, 0xe1, 0xf3,
0x24, 0x01, 0x75, 0xad, 0x16, 0xa5, 0x66, 0x85,
0xca, 0x66, 0xe0, 0xbd, 0xc6, 0x34, 0xd8, 0x84,
0x09, 0x9a, 0x58, 0x14, 0xfb, 0x05, 0xda, 0xf5,
0x90, 0xf5, 0x0c, 0x4e, 0x22, 0x10, 0xc9, 0x85,
0x0f, 0xe3, 0x77, 0x35, 0xe9, 0x6b, 0xc2, 0x55,
0x32, 0x46, 0xae, 0x25, 0xe0, 0xe3, 0x37, 0x7a,
0x4b, 0x71, 0xcc, 0xfc, 0x91, 0xdf, 0xd6, 0xca,
0xfe, 0xee, 0xce, 0x3f, 0x77, 0xa2, 0xfd, 0x59,
0x8e, 0x73, 0x0a, 0x8d, 0x5c, 0x24, 0x14, 0xca,
0x38, 0x91, 0xb8, 0x2c, 0x8c, 0xa2, 0x65, 0x7b,
0xbc, 0x49, 0xbc, 0xb5, 0x58, 0xfc, 0xe3, 0xd7,
0x02, 0xcf, 0xf7, 0x4c, 0x60, 0x91, 0xed, 0x55,
0xe9, 0xf9, 0xfe, 0xd1, 0x44, 0x2c, 0x75, 0xf2,
0xb3, 0x5d, 0x7b, 0x27, 0x56, 0xc0, 0x48, 0x4f,
0xb0, 0xba, 0xe4, 0x7d, 0xd0, 0xaa, 0xcd, 0x3d,
0xe3, 0x50, 0xd2, 0xcf, 0xb9, 0xfa, 0x4b, 0x2d,
0xc6, 0xdf, 0x3b, 0x32, 0x98, 0x45, 0xe6, 0x8f,
0x1c, 0x5c, 0xa2, 0x20, 0x7d, 0x1c, 0x28, 0xc2,
0xd4, 0xa1, 0xe0, 0x21, 0x52, 0x8f, 0x1c, 0xd0,
0x62, 0x97, 0x48, 0xbb, 0xf4, 0xa9, 0xcb, 0x35,
0xf2, 0x07, 0xd3, 0x50, 0xd8, 0xa9, 0xc5, 0x9a,
0x0f, 0xbd, 0x37, 0xaf, 0xe1, 0x45, 0x19, 0xee,
0x41, 0xf3, 0xf7, 0xe5, 0xe0, 0x30, 0x3f, 0xbe,
0x3d, 0x39, 0x64, 0x00, 0x7a, 0x1a, 0x51, 0x5e,
0xe1, 0x70, 0x0b, 0xb9, 0x77, 0x5a, 0xf0, 0xc4,
0x8a, 0xa1, 0x3a, 0x77, 0x1a, 0xe0, 0xc2, 0x06,
0x91, 0xd5, 0xe9, 0x1c, 0xd3, 0xfe, 0xab, 0x93,
0x1a, 0x0a, 0x4c, 0xbb, 0xf0, 0xff, 0xdc, 0xaa,
0x61, 0x73, 0xcb, 0x03, 0x4b, 0x71, 0x68, 0x64,
0x3d, 0x82, 0x31, 0x41, 0xd7, 0x8b, 0x22, 0x7b,
0x7d, 0xa1, 0xd5, 0x85, 0x6d, 0xf0, 0x1b, 0xaa,
})
}

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@ -42,7 +42,7 @@ type Device struct {
underLoadUntil atomic.Value underLoadUntil atomic.Value
ratelimiter Ratelimiter ratelimiter Ratelimiter
peers map[NoisePublicKey]*Peer peers map[NoisePublicKey]*Peer
mac MACStateDevice mac CookieChecker
} }
/* Warning: /* Warning:

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@ -29,3 +29,9 @@ func (kp *KeyPairs) Current() *KeyPair {
defer kp.mutex.RUnlock() defer kp.mutex.RUnlock()
return kp.current return kp.current
} }
func (device *Device) DeleteKeyPair(key *KeyPair) {
key.send = nil
key.receive = nil
device.indices.Delete(key.localIndex)
}

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@ -1,270 +0,0 @@
package main
import (
"crypto/hmac"
"crypto/rand"
"golang.org/x/crypto/blake2s"
"net"
"sync"
"time"
)
type MACStateDevice struct {
mutex sync.RWMutex
refreshed time.Time
secret [blake2s.Size]byte
keyMAC1 [blake2s.Size]byte
keyMAC2 [blake2s.Size]byte // TODO: Change to more descriptive size constant, rename to something.
}
type MACStatePeer struct {
mutex sync.RWMutex
cookieSet time.Time
cookie [blake2s.Size128]byte
lastMAC1Set bool
lastMAC1 [blake2s.Size128]byte
keyMAC1 [blake2s.Size]byte
keyMAC2 [blake2s.Size]byte
}
/* Methods for verifing MAC fields
* and creating/consuming cookies replies
* (per device)
*/
func (state *MACStateDevice) Init(pk NoisePublicKey) {
state.mutex.Lock()
defer state.mutex.Unlock()
func() {
hsh, _ := blake2s.New256(nil)
hsh.Write([]byte(WGLabelMAC1))
hsh.Write(pk[:])
hsh.Sum(state.keyMAC1[:0])
}()
func() {
hsh, _ := blake2s.New256(nil)
hsh.Write([]byte(WGLabelCookie))
hsh.Write(pk[:])
hsh.Sum(state.keyMAC2[:0])
}()
state.refreshed = time.Time{}
}
func (state *MACStateDevice) CheckMAC1(msg []byte) bool {
size := len(msg)
startMac1 := size - (blake2s.Size128 * 2)
startMac2 := size - blake2s.Size128
var mac1 [blake2s.Size128]byte
func() {
mac, _ := blake2s.New128(state.keyMAC1[:])
mac.Write(msg[:startMac1])
mac.Sum(mac1[:0])
}()
return hmac.Equal(mac1[:], msg[startMac1:startMac2])
}
func (state *MACStateDevice) CheckMAC2(msg []byte, addr *net.UDPAddr) bool {
state.mutex.RLock()
defer state.mutex.RUnlock()
if time.Now().Sub(state.refreshed) > CookieRefreshTime {
return false
}
// derive cookie key
var cookie [blake2s.Size128]byte
func() {
port := [2]byte{byte(addr.Port >> 8), byte(addr.Port)}
mac, _ := blake2s.New128(state.secret[:])
mac.Write(addr.IP)
mac.Write(port[:]) // TODO: Be faster and more platform dependent?
mac.Sum(cookie[:0])
}()
// calculate mac of packet
start := len(msg) - blake2s.Size128
var mac2 [blake2s.Size128]byte
func() {
mac, _ := blake2s.New128(cookie[:])
mac.Write(msg[:start])
mac.Sum(mac2[:0])
}()
return hmac.Equal(mac2[:], msg[start:])
}
func (device *Device) CreateMessageCookieReply(
msg []byte, receiver uint32, addr *net.UDPAddr,
) (*MessageCookieReply, error) {
state := &device.mac
state.mutex.RLock()
// refresh cookie secret
if time.Now().Sub(state.refreshed) > CookieRefreshTime {
state.mutex.RUnlock()
state.mutex.Lock()
_, err := rand.Read(state.secret[:])
if err != nil {
state.mutex.Unlock()
return nil, err
}
state.refreshed = time.Now()
state.mutex.Unlock()
state.mutex.RLock()
}
// derive cookie key
var cookie [blake2s.Size128]byte
func() {
port := [2]byte{byte(addr.Port >> 8), byte(addr.Port)}
mac, _ := blake2s.New128(state.secret[:])
mac.Write(addr.IP)
mac.Write(port[:]) // TODO: Do whatever we did above
mac.Sum(cookie[:0])
}()
// encrypt cookie
size := len(msg)
startMac1 := size - (blake2s.Size128 * 2)
startMac2 := size - blake2s.Size128
mac1 := msg[startMac1:startMac2]
reply := new(MessageCookieReply)
reply.Type = MessageCookieReplyType
reply.Receiver = receiver
_, err := rand.Read(reply.Nonce[:])
if err != nil {
state.mutex.RUnlock()
return nil, err
}
XChaCha20Poly1305Encrypt(
reply.Cookie[:0],
&reply.Nonce,
cookie[:],
mac1,
&state.keyMAC2,
)
state.mutex.RUnlock()
return reply, nil
}
func (device *Device) ConsumeMessageCookieReply(msg *MessageCookieReply) bool {
if msg.Type != MessageCookieReplyType {
return false
}
// lookup peer
lookup := device.indices.Lookup(msg.Receiver)
if lookup.handshake == nil {
return false
}
// decrypt and store cookie
var cookie [blake2s.Size128]byte
state := &lookup.peer.mac
state.mutex.Lock()
defer state.mutex.Unlock()
if !state.lastMAC1Set {
return false
}
_, err := XChaCha20Poly1305Decrypt(
cookie[:0],
&msg.Nonce,
msg.Cookie[:],
state.lastMAC1[:],
&state.keyMAC2,
)
if err != nil {
return false
}
state.cookieSet = time.Now()
state.cookie = cookie
return true
}
/* Methods for generating the MAC fields
* (per peer)
*/
func (state *MACStatePeer) Init(pk NoisePublicKey) {
state.mutex.Lock()
defer state.mutex.Unlock()
func() {
hsh, _ := blake2s.New256(nil)
hsh.Write([]byte(WGLabelMAC1))
hsh.Write(pk[:])
hsh.Sum(state.keyMAC1[:0])
}()
func() {
hsh, _ := blake2s.New256(nil)
hsh.Write([]byte(WGLabelCookie))
hsh.Write(pk[:])
hsh.Sum(state.keyMAC2[:0])
}()
state.cookieSet = time.Time{} // never
}
func (state *MACStatePeer) AddMacs(msg []byte) {
size := len(msg)
startMac1 := size - (blake2s.Size128 * 2)
startMac2 := size - blake2s.Size128
mac1 := msg[startMac1 : startMac1+blake2s.Size128]
mac2 := msg[startMac2 : startMac2+blake2s.Size128]
state.mutex.Lock()
defer state.mutex.Unlock()
// set mac1
func() {
mac, _ := blake2s.New128(state.keyMAC1[:])
mac.Write(msg[:startMac1])
mac.Sum(mac1[:0])
}()
copy(state.lastMAC1[:], mac1)
state.lastMAC1Set = true
// set mac2
if state.cookieSet.IsZero() {
return
}
if time.Now().Sub(state.cookieSet) > CookieRefreshTime {
state.cookieSet = time.Time{}
return
}
func() {
mac, _ := blake2s.New128(state.cookie[:])
mac.Write(msg[:startMac2])
mac.Sum(mac2[:0])
}()
}

View File

@ -1,116 +0,0 @@
package main
import (
"net"
"testing"
"testing/quick"
)
func TestMAC1(t *testing.T) {
dev1 := randDevice(t)
dev2 := randDevice(t)
defer dev1.Close()
defer dev2.Close()
peer1, _ := dev2.NewPeer(dev1.privateKey.publicKey())
peer2, _ := dev1.NewPeer(dev2.privateKey.publicKey())
assertEqual(t, peer1.mac.keyMAC1[:], dev1.mac.keyMAC1[:])
assertEqual(t, peer2.mac.keyMAC1[:], dev2.mac.keyMAC1[:])
msg1 := make([]byte, 256)
copy(msg1, []byte("some content"))
peer1.mac.AddMacs(msg1)
if dev1.mac.CheckMAC1(msg1) == false {
t.Fatal("failed to verify mac1")
}
}
func TestMACs(t *testing.T) {
assertion := func(
addr net.UDPAddr,
addrInvalid net.UDPAddr,
sk1 NoisePrivateKey,
sk2 NoisePrivateKey,
msg []byte,
receiver uint32,
) bool {
device1 := randDevice(t)
device1.SetPrivateKey(sk1)
device2 := randDevice(t)
device2.SetPrivateKey(sk2)
defer device1.Close()
defer device2.Close()
peer1, _ := device2.NewPeer(device1.privateKey.publicKey())
peer2, _ := device1.NewPeer(device2.privateKey.publicKey())
if addr.Port < 0 {
return true
}
addr.Port &= 0xffff
if len(msg) < 32 {
return true
}
assertEqual(t, peer1.mac.keyMAC1[:], device1.mac.keyMAC1[:])
assertEqual(t, peer2.mac.keyMAC1[:], device2.mac.keyMAC1[:])
device2.indices.Insert(receiver, IndexTableEntry{
peer: peer1,
handshake: &peer1.handshake,
})
// test just MAC1
peer1.mac.AddMacs(msg)
if device1.mac.CheckMAC1(msg) == false {
return false
}
// exchange cookie reply
cr, err := device1.CreateMessageCookieReply(msg, receiver, &addr)
if err != nil {
return false
}
if !device2.ConsumeMessageCookieReply(cr) {
return false
}
// test MAC1 + MAC2
peer1.mac.AddMacs(msg)
if !device1.mac.CheckMAC1(msg) {
return false
}
if !device1.mac.CheckMAC2(msg, &addr) {
return false
}
// test invalid
if device1.mac.CheckMAC2(msg, &addrInvalid) {
return false
}
msg[5] ^= 1
if device1.mac.CheckMAC1(msg) {
return false
}
t.Log("Passed")
return true
}
err := quick.Check(assertion, nil)
if err != nil {
t.Error(err)
}
}

View File

@ -99,6 +99,7 @@ type Handshake struct {
remoteEphemeral NoisePublicKey // ephemeral public key remoteEphemeral NoisePublicKey // ephemeral public key
precomputedStaticStatic [NoisePublicKeySize]byte // precomputed shared secret precomputedStaticStatic [NoisePublicKeySize]byte // precomputed shared secret
lastTimestamp TAI64N lastTimestamp TAI64N
lastInitiationConsumption time.Time
} }
var ( var (
@ -239,34 +240,27 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
// verify identity // verify identity
var timestamp TAI64N var timestamp TAI64N
ok := func() bool { var key [chacha20poly1305.KeySize]byte
// read lock handshake
handshake.mutex.RLock() handshake.mutex.RLock()
defer handshake.mutex.RUnlock()
// decrypt timestamp
func() {
var key [chacha20poly1305.KeySize]byte
chainKey, key = KDF2( chainKey, key = KDF2(
chainKey[:], chainKey[:],
handshake.precomputedStaticStatic[:], handshake.precomputedStaticStatic[:],
) )
aead, _ := chacha20poly1305.New(key[:]) aead, _ := chacha20poly1305.New(key[:])
_, err = aead.Open(timestamp[:0], ZeroNonce[:], msg.Timestamp[:], hash[:]) _, err = aead.Open(timestamp[:0], ZeroNonce[:], msg.Timestamp[:], hash[:])
}()
if err != nil { if err != nil {
return false handshake.mutex.RUnlock()
return nil
} }
hash = mixHash(hash, msg.Timestamp[:]) hash = mixHash(hash, msg.Timestamp[:])
// check for replay attack // protect against replay & flood
return timestamp.After(handshake.lastTimestamp)
}()
var ok bool
ok = timestamp.After(handshake.lastTimestamp)
ok = ok && time.Now().Sub(handshake.lastInitiationConsumption) > HandshakeInitationRate
handshake.mutex.RUnlock()
if !ok { if !ok {
return nil return nil
} }
@ -280,6 +274,7 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
handshake.remoteIndex = msg.Sender handshake.remoteIndex = msg.Sender
handshake.remoteEphemeral = msg.Ephemeral handshake.remoteEphemeral = msg.Ephemeral
handshake.lastTimestamp = timestamp handshake.lastTimestamp = timestamp
handshake.lastInitiationConsumption = time.Now()
handshake.state = HandshakeInitiationConsumed handshake.state = HandshakeInitiationConsumed
handshake.mutex.Unlock() handshake.mutex.Unlock()
@ -483,15 +478,21 @@ func (peer *Peer) NewKeyPair() *KeyPair {
// TODO: Adapt kernel behavior noise.c:161 // TODO: Adapt kernel behavior noise.c:161
if isInitiator { if isInitiator {
if kp.previous != nil { if kp.previous != nil {
kp.previous.send = nil
kp.previous.receive = nil
indices.Delete(kp.previous.localIndex) indices.Delete(kp.previous.localIndex)
} }
if kp.next != nil {
kp.previous = kp.next
kp.next = keyPair
} else {
kp.previous = kp.current kp.previous = kp.current
kp.current = keyPair kp.current = keyPair
signalSend(peer.signal.newKeyPair) signalSend(peer.signal.newKeyPair) // TODO: This more places (after confirming the key)
}
} else { } else {
kp.next = keyPair kp.next = keyPair
kp.previous = nil // TODO: Discuss why
} }
}() }()

View File

@ -56,7 +56,7 @@ type Peer struct {
outbound chan *QueueOutboundElement // sequential ordering of work outbound chan *QueueOutboundElement // sequential ordering of work
inbound chan *QueueInboundElement // sequential ordering of work inbound chan *QueueInboundElement // sequential ordering of work
} }
mac MACStatePeer mac CookieGenerator
} }
func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) { func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {

View File

@ -272,7 +272,9 @@ func (device *Device) RoutineHandshake() {
case MessageCookieReplyType: case MessageCookieReplyType:
// verify and update peer cookie state // unmarshal packet
logDebug.Println("Process cookie reply from:", elem.source.String())
var reply MessageCookieReply var reply MessageCookieReply
reader := bytes.NewReader(elem.packet) reader := bytes.NewReader(elem.packet)
@ -281,7 +283,14 @@ func (device *Device) RoutineHandshake() {
logDebug.Println("Failed to decode cookie reply") logDebug.Println("Failed to decode cookie reply")
return return
} }
device.ConsumeMessageCookieReply(&reply)
// lookup peer and consume response
entry := device.indices.Lookup(reply.Receiver)
if entry.peer == nil {
return
}
entry.peer.mac.ConsumeReply(&reply)
continue continue
case MessageInitiationType, MessageResponseType: case MessageInitiationType, MessageResponseType:
@ -298,12 +307,17 @@ func (device *Device) RoutineHandshake() {
// construct cookie reply // construct cookie reply
logDebug.Println("Sending cookie reply to:", elem.source.String())
sender := binary.LittleEndian.Uint32(elem.packet[4:8]) // "sender" always follows "type" sender := binary.LittleEndian.Uint32(elem.packet[4:8]) // "sender" always follows "type"
reply, err := device.CreateMessageCookieReply(elem.packet, sender, elem.source) reply, err := device.mac.CreateReply(elem.packet, sender, elem.source)
if err != nil { if err != nil {
logError.Println("Failed to create cookie reply:", err) logError.Println("Failed to create cookie reply:", err)
return return
} }
// marshal and send reply
writer := bytes.NewBuffer(temp[:0]) writer := bytes.NewBuffer(temp[:0])
binary.Write(writer, binary.LittleEndian, reply) binary.Write(writer, binary.LittleEndian, reply)
_, err = device.net.conn.WriteToUDP( _, err = device.net.conn.WriteToUDP(
@ -392,6 +406,8 @@ func (device *Device) RoutineHandshake() {
case MessageResponseType: case MessageResponseType:
logDebug.Println("Process response")
// unmarshal // unmarshal
var msg MessageResponse var msg MessageResponse