84 lines
1.6 KiB
Go
84 lines
1.6 KiB
Go
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])
|
|
}()
|
|
}
|