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Code Issues Releases Wiki Activity

Restructured MAC/cookie calculation

Browse Source 
Added copy-right headers accidentally removed
This commit is contained in:
Mathias Hall-Andersen 2017-07-12 23:11:49 +02:00
parent 86707cbc88
commit 8393cbff52
7 changed files with 374 additions and 96 deletions
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4
src/helper_test.go
View File

@ -18,8 +18,8 @@ func (tun *DummyTUN) Name() string {
return tun.name
}
func (tun *DummyTUN) MTU() int {
return tun.mtu
func (tun *DummyTUN) MTU() (int, error) {
return tun.mtu, nil
}
func (tun *DummyTUN) Write(d []byte) (int, error) {

109
src/macs_device.go → src/macs.go
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@ -1,10 +1,9 @@
package main
import (
"crypto/cipher"
"crypto/hmac"
"crypto/rand"
"github.com/aead/chacha20poly1305" // Needed for XChaCha20Poly1305, TODO:
"errors"
"golang.org/x/crypto/blake2s"
"net"
"sync"
@ -17,9 +16,22 @@ type MACStateDevice struct {
secret [blake2s.Size]byte
keyMAC1 [blake2s.Size]byte
keyMAC2 [blake2s.Size]byte
xaead cipher.AEAD
}
type MACStatePeer struct {
mutex sync.RWMutex
cookieSet time.Time
cookie [blake2s.Size128]byte
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()
@ -38,7 +50,6 @@ func (state *MACStateDevice) Init(pk NoisePublicKey) {
hsh.Sum(state.keyMAC2[:0])
}()
state.xaead, _ = chacha20poly1305.NewXCipher(state.keyMAC2[:])
state.refreshed = time.Time{}
}
@ -90,7 +101,10 @@ func (state *MACStateDevice) CheckMAC2(msg []byte, addr *net.UDPAddr) bool {
return hmac.Equal(mac2[:], msg[start:])
}
func (device *Device) CreateMessageCookieReply(msg []byte, receiver uint32, addr *net.UDPAddr) (*MessageCookieReply, error) {
func (device *Device) CreateMessageCookieReply(
msg []byte, receiver uint32, addr *net.UDPAddr,
) (*MessageCookieReply, error) {
state := &device.mac
state.mutex.RLock()
@ -137,7 +151,15 @@ func (device *Device) CreateMessageCookieReply(msg []byte, receiver uint32, addr
state.mutex.RUnlock()
return nil, err
}
state.xaead.Seal(reply.Cookie[:0], reply.Nonce[:], cookie[:], mac1)
XChaCha20Poly1305Encrypt(
reply.Cookie[:0],
&reply.Nonce,
cookie[:],
mac1,
&state.keyMAC2,
)
state.mutex.RUnlock()
return reply, nil
}
@ -163,7 +185,14 @@ func (device *Device) ConsumeMessageCookieReply(msg *MessageCookieReply) bool {
state.mutex.Lock()
defer state.mutex.Unlock()
_, err := state.xaead.Open(cookie[:0], msg.Nonce[:], msg.Cookie[:], state.lastMAC1[:])
_, err := XChaCha20Poly1305Decrypt(
cookie[:0],
&msg.Nonce,
msg.Cookie[:],
state.lastMAC1[:],
&state.keyMAC2,
)
if err != nil {
return false
}
@ -171,3 +200,69 @@ func (device *Device) ConsumeMessageCookieReply(msg *MessageCookieReply) bool {
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)
if size < blake2s.Size128*2 {
panic(errors.New("bug: message too short"))
}
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)
// 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])
}()
}

83
src/macs_peer.go
View File

@ -1,83 +0,0 @@
package main
import (
"crypto/cipher"
"errors"
"github.com/aead/chacha20poly1305" // Needed for XChaCha20Poly1305, TODO:
"golang.org/x/crypto/blake2s"
"sync"
"time"
)
type MACStatePeer struct {
mutex sync.RWMutex
cookieSet time.Time
cookie [blake2s.Size128]byte
lastMAC1 [blake2s.Size128]byte
keyMAC1 [blake2s.Size]byte
keyMAC2 [blake2s.Size]byte
xaead cipher.AEAD
}
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.xaead, _ = chacha20poly1305.NewXCipher(state.keyMAC2[:])
state.cookieSet = time.Time{} // never
}
func (state *MACStatePeer) AddMacs(msg []byte) {
size := len(msg)
if size < blake2s.Size128*2 {
panic(errors.New("bug: message too short"))
}
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(state.lastMAC1[:0])
}()
copy(mac1, state.lastMAC1[:])
// 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])
}()
}

7
src/ratelimiter.go
View File

@ -1,9 +1,8 @@
package main
/* Implementation of the ratelimited form the linux kernel version
*
*
*
/* Copyright (C) 2015-2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
/* This file contains a port of the ratelimited from the linux kernel version
*/
import (

2
src/replay.go
View File

@ -1,5 +1,7 @@
package main
/* Copyright (C) 2015-2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
/* Implementation of RFC6479
* https://tools.ietf.org/html/rfc6479
*

169
src/xchacha20.go Normal file
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@ -0,0 +1,169 @@
// Copyright (c) 2016 Andreas Auernhammer. All rights reserved.
// Use of this source code is governed by a license that can be
// found in the LICENSE file.
package main
import (
"encoding/binary"
"golang.org/x/crypto/chacha20poly1305"
)
func HChaCha20(out *[32]byte, nonce []byte, key *[32]byte) {
v00 := uint32(0x61707865)
v01 := uint32(0x3320646e)
v02 := uint32(0x79622d32)
v03 := uint32(0x6b206574)
v04 := binary.LittleEndian.Uint32(key[0:])
v05 := binary.LittleEndian.Uint32(key[4:])
v06 := binary.LittleEndian.Uint32(key[8:])
v07 := binary.LittleEndian.Uint32(key[12:])
v08 := binary.LittleEndian.Uint32(key[16:])
v09 := binary.LittleEndian.Uint32(key[20:])
v10 := binary.LittleEndian.Uint32(key[24:])
v11 := binary.LittleEndian.Uint32(key[28:])
v12 := binary.LittleEndian.Uint32(nonce[0:])
v13 := binary.LittleEndian.Uint32(nonce[4:])
v14 := binary.LittleEndian.Uint32(nonce[8:])
v15 := binary.LittleEndian.Uint32(nonce[12:])
for i := 0; i < 20; i += 2 {
v00 += v04
v12 ^= v00
v12 = (v12 << 16) | (v12 >> 16)
v08 += v12
v04 ^= v08
v04 = (v04 << 12) | (v04 >> 20)
v00 += v04
v12 ^= v00
v12 = (v12 << 8) | (v12 >> 24)
v08 += v12
v04 ^= v08
v04 = (v04 << 7) | (v04 >> 25)
v01 += v05
v13 ^= v01
v13 = (v13 << 16) | (v13 >> 16)
v09 += v13
v05 ^= v09
v05 = (v05 << 12) | (v05 >> 20)
v01 += v05
v13 ^= v01
v13 = (v13 << 8) | (v13 >> 24)
v09 += v13
v05 ^= v09
v05 = (v05 << 7) | (v05 >> 25)
v02 += v06
v14 ^= v02
v14 = (v14 << 16) | (v14 >> 16)
v10 += v14
v06 ^= v10
v06 = (v06 << 12) | (v06 >> 20)
v02 += v06
v14 ^= v02
v14 = (v14 << 8) | (v14 >> 24)
v10 += v14
v06 ^= v10
v06 = (v06 << 7) | (v06 >> 25)
v03 += v07
v15 ^= v03
v15 = (v15 << 16) | (v15 >> 16)
v11 += v15
v07 ^= v11
v07 = (v07 << 12) | (v07 >> 20)
v03 += v07
v15 ^= v03
v15 = (v15 << 8) | (v15 >> 24)
v11 += v15
v07 ^= v11
v07 = (v07 << 7) | (v07 >> 25)
v00 += v05
v15 ^= v00
v15 = (v15 << 16) | (v15 >> 16)
v10 += v15
v05 ^= v10
v05 = (v05 << 12) | (v05 >> 20)
v00 += v05
v15 ^= v00
v15 = (v15 << 8) | (v15 >> 24)
v10 += v15
v05 ^= v10
v05 = (v05 << 7) | (v05 >> 25)
v01 += v06
v12 ^= v01
v12 = (v12 << 16) | (v12 >> 16)
v11 += v12
v06 ^= v11
v06 = (v06 << 12) | (v06 >> 20)
v01 += v06
v12 ^= v01
v12 = (v12 << 8) | (v12 >> 24)
v11 += v12
v06 ^= v11
v06 = (v06 << 7) | (v06 >> 25)
v02 += v07
v13 ^= v02
v13 = (v13 << 16) | (v13 >> 16)
v08 += v13
v07 ^= v08
v07 = (v07 << 12) | (v07 >> 20)
v02 += v07
v13 ^= v02
v13 = (v13 << 8) | (v13 >> 24)
v08 += v13
v07 ^= v08
v07 = (v07 << 7) | (v07 >> 25)
v03 += v04
v14 ^= v03
v14 = (v14 << 16) | (v14 >> 16)
v09 += v14
v04 ^= v09
v04 = (v04 << 12) | (v04 >> 20)
v03 += v04
v14 ^= v03
v14 = (v14 << 8) | (v14 >> 24)
v09 += v14
v04 ^= v09
v04 = (v04 << 7) | (v04 >> 25)
}
binary.LittleEndian.PutUint32(out[0:], v00)
binary.LittleEndian.PutUint32(out[4:], v01)
binary.LittleEndian.PutUint32(out[8:], v02)
binary.LittleEndian.PutUint32(out[12:], v03)
binary.LittleEndian.PutUint32(out[16:], v12)
binary.LittleEndian.PutUint32(out[20:], v13)
binary.LittleEndian.PutUint32(out[24:], v14)
binary.LittleEndian.PutUint32(out[28:], v15)
}
func XChaCha20Poly1305Encrypt(
dst []byte,
nonceFull *[24]byte,
plaintext []byte,
additionalData []byte,
key *[chacha20poly1305.KeySize]byte,
) []byte {
var nonce [chacha20poly1305.NonceSize]byte
var derivedKey [chacha20poly1305.KeySize]byte
HChaCha20(&derivedKey, nonceFull[:16], key)
aead, _ := chacha20poly1305.New(derivedKey[:])
copy(nonce[4:], nonceFull[16:])
return aead.Seal(dst, nonce[:], plaintext, additionalData)
}
func XChaCha20Poly1305Decrypt(
dst []byte,
nonceFull *[24]byte,
plaintext []byte,
additionalData []byte,
key *[chacha20poly1305.KeySize]byte,
) ([]byte, error) {
var nonce [chacha20poly1305.NonceSize]byte
var derivedKey [chacha20poly1305.KeySize]byte
HChaCha20(&derivedKey, nonceFull[:16], key)
aead, _ := chacha20poly1305.New(derivedKey[:])
copy(nonce[4:], nonceFull[16:])
return aead.Open(dst, nonce[:], plaintext, additionalData)
}

96
src/xchacha20_test.go Normal file
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@ -0,0 +1,96 @@
package main
import (
"encoding/hex"
"testing"
)
type XChaCha20Test struct {
Nonce string
Key string
PT string
CT string
}
func TestXChaCha20(t *testing.T) {
tests := []XChaCha20Test{
{
Nonce: "000000000000000000000000000000000000000000000000",
Key: "0000000000000000000000000000000000000000000000000000000000000000",
PT: "00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
CT: "789e9689e5208d7fd9e1f3c5b5341f48ef18a13e418998addadd97a3693a987f8e82ecd5c1433bfed1af49750c0f1ff29c4174a05b119aa3a9e8333812e0c0feb1299c5949d895ee01dbf50f8395dd84",
},
{
Nonce: "0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f",
Key: "0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f",
PT: "0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f",
CT: "e1a046aa7f71e2af8b80b6408b2fd8d3a350278cde79c94d9efaa475e1339b3dd490127b",
},
{
Nonce: "d9a8213e8a697508805c2c171ad54487ead9e3e02d82d5bc",
Key: "979196dbd78526f2f584f7534db3f5824d8ccfa858ca7e09bdd3656ecd36033c",
PT: "43cc6d624e451bbed952c3e071dc6c03392ce11eb14316a94b2fdc98b22fedea",
CT: "53c1e8bef2dbb8f2505ec010a7afe21d5a8e6dd8f987e4ea1a2ed5dfbc844ea400db34496fd2153526c6e87c36694200",
},
}
for _, test := range tests {
nonce, err := hex.DecodeString(test.Nonce)
if err != nil {
panic(err)
}
key, err := hex.DecodeString(test.Key)
if err != nil {
panic(err)
}
pt, err := hex.DecodeString(test.PT)
if err != nil {
panic(err)
}
func() {
var nonceArray [24]byte
var keyArray [32]byte
copy(nonceArray[:], nonce)
copy(keyArray[:], key)
// test encryption
ct := XChaCha20Poly1305Encrypt(
nil,
&nonceArray,
pt,
nil,
&keyArray,
)
ctHex := hex.EncodeToString(ct)
if ctHex != test.CT {
t.Fatal("encryption failed, expected:", test.CT, "got", ctHex)
}
// test decryption
ptp, err := XChaCha20Poly1305Decrypt(
nil,
&nonceArray,
ct,
nil,
&keyArray,
)
if err != nil {
t.Fatal(err)
}
ptHex := hex.EncodeToString(ptp)
if ptHex != test.PT {
t.Fatal("decryption failed, expected:", test.PT, "got", ptHex)
}
}()
}
}