/*
GoVPN -- simple secure free software virtual private network daemon
-Copyright (C) 2014-2016 Sergey Matveev <stargrave@stargrave.org>
+Copyright (C) 2014-2017 Sergey Matveev <stargrave@stargrave.org>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
"crypto/subtle"
"encoding/base64"
"encoding/binary"
+ "hash"
"log"
"sync"
"time"
- "golang.org/x/crypto/xtea"
+ "golang.org/x/crypto/blake2b"
)
const (
IDSize = 128 / 8
)
-type PeerId [IDSize]byte
+type PeerID [IDSize]byte
-func (id PeerId) String() string {
+func (id PeerID) String() string {
return base64.RawStdEncoding.EncodeToString(id[:])
}
-func (id PeerId) MarshalJSON() ([]byte, error) {
+func (id PeerID) MarshalJSON() ([]byte, error) {
return []byte(`"` + id.String() + `"`), nil
}
-type CipherAndTimeSync struct {
- c *xtea.Cipher
- t int
+type MACAndTimeSync struct {
+ mac hash.Hash
+ ts int
+ l sync.Mutex
}
-type CipherCache struct {
- c map[PeerId]*CipherAndTimeSync
- l sync.RWMutex
+type MACCache struct {
+ cache map[PeerID]*MACAndTimeSync
+ l sync.RWMutex
}
-func NewCipherCache() *CipherCache {
- return &CipherCache{c: make(map[PeerId]*CipherAndTimeSync)}
+func NewMACCache() *MACCache {
+ return &MACCache{cache: make(map[PeerID]*MACAndTimeSync)}
}
-// Remove disappeared keys, add missing ones with initialized ciphers.
-func (cc *CipherCache) Update(peers *map[PeerId]*PeerConf) {
- cc.l.Lock()
- for pid, _ := range cc.c {
+// Remove disappeared keys, add missing ones with initialized MACs.
+func (mc *MACCache) Update(peers *map[PeerID]*PeerConf) {
+ mc.l.Lock()
+ for pid := range mc.cache {
if _, exists := (*peers)[pid]; !exists {
log.Println("Cleaning key:", pid)
- delete(cc.c, pid)
+ delete(mc.cache, pid)
}
}
for pid, pc := range *peers {
- if _, exists := cc.c[pid]; exists {
- cc.c[pid].t = pc.TimeSync
+ if _, exists := mc.cache[pid]; exists {
+ mc.cache[pid].ts = pc.TimeSync
} else {
log.Println("Adding key", pid)
- cipher, err := xtea.NewCipher(pid[:])
+ mac, err := blake2b.New256(pid[:])
if err != nil {
panic(err)
}
- cc.c[pid] = &CipherAndTimeSync{cipher, pc.TimeSync}
+ mc.cache[pid] = &MACAndTimeSync{
+ mac: mac,
+ ts: pc.TimeSync,
+ }
}
}
- cc.l.Unlock()
+ mc.l.Unlock()
}
// If timeSync > 0, then XOR timestamp with the data.
}
}
-// Try to find peer's identity (that equals to an encryption key)
+// Try to find peer's identity (that equals to MAC)
// by taking first blocksize sized bytes from data at the beginning
// as plaintext and last bytes as cyphertext.
-func (cc *CipherCache) Find(data []byte) *PeerId {
- if len(data) < xtea.BlockSize*2 {
+func (mc *MACCache) Find(data []byte) *PeerID {
+ if len(data) < 8*2 {
return nil
}
- buf := make([]byte, xtea.BlockSize)
- cc.l.RLock()
- for pid, ct := range cc.c {
- ct.c.Decrypt(buf, data[len(data)-xtea.BlockSize:])
- AddTimeSync(ct.t, buf)
- if subtle.ConstantTimeCompare(buf, data[:xtea.BlockSize]) == 1 {
- ppid := PeerId(pid)
- cc.l.RUnlock()
+ buf := make([]byte, 8)
+ sum := make([]byte, 32)
+ mc.l.RLock()
+ for pid, mt := range mc.cache {
+ copy(buf, data)
+ AddTimeSync(mt.ts, buf)
+ mt.l.Lock()
+ mt.mac.Reset()
+ mt.mac.Write(buf)
+ mt.mac.Sum(sum[:0])
+ mt.l.Unlock()
+ if subtle.ConstantTimeCompare(sum[len(sum)-8:], data[len(data)-8:]) == 1 {
+ ppid := PeerID(pid)
+ mc.l.RUnlock()
return &ppid
}
}
- cc.l.RUnlock()
+ mc.l.RUnlock()
return nil
}