// Handle processes a container to pair with a new client without going through the pairing process.
func (c *PairingController) Handle(cont util.Container) (util.Container, error) {
method := pairMethodType(cont.GetByte(TagPairingMethod))
username := cont.GetString(TagUsername)
publicKey := cont.GetBytes(TagPublicKey)
log.Println("[VERB] -> Method:", method)
log.Println("[VERB] -> Username:"******"[VERB] -> LTPK:", publicKey)
entity := db.NewEntity(username, publicKey, nil)
switch method {
case PairingMethodDelete:
log.Printf("[INFO] Remove LTPK for client '%s'\n", username)
c.database.DeleteEntity(entity)
case PairingMethodAdd:
err := c.database.SaveEntity(entity)
if err != nil {
log.Println("[ERRO]", err)
return nil, err
}
default:
return nil, fmt.Errorf("Invalid pairing method type %v", method)
}
out := util.NewTLV8Container()
out.SetByte(TagSequence, 0x2)
return out, nil
}
// Client -> Server
// - encrypted tlv8: client LTPK, client name and signature (of H, client name, LTPK)
// - auth tag (mac)
//
// Server
// - Validate signature of encrpyted tlv8
// - Read and store client LTPK and name
//
// Server -> Client
// - encrpyted tlv8: bridge LTPK, bridge name, signature (of hash `H2`, bridge name, LTPK)
func (setup *SetupClientController) handleKeyExchange(in util.Container) (util.Container, error) {
data := in.GetBytes(TagEncryptedData)
message := data[:(len(data) - 16)]
var mac [16]byte
copy(mac[:], data[len(message):]) // 16 byte (MAC)
fmt.Println("-> Message:", hex.EncodeToString(message))
fmt.Println("-> MAC:", hex.EncodeToString(mac[:]))
decrypted, err := chacha20poly1305.DecryptAndVerify(setup.session.EncryptionKey[:], []byte("PS-Msg06"), message, mac, nil)
if err != nil {
fmt.Println(err)
} else {
decryptedBuf := bytes.NewBuffer(decrypted)
in, err := util.NewTLV8ContainerFromReader(decryptedBuf)
if err != nil {
fmt.Println(err)
}
username := in.GetString(TagUsername)
ltpk := in.GetBytes(TagPublicKey)
signature := in.GetBytes(TagSignature)
fmt.Println("-> Username:"******"-> LTPK:", hex.EncodeToString(ltpk))
fmt.Println("-> Signature:", hex.EncodeToString(signature))
entity := db.NewEntity(username, ltpk, nil)
err = setup.database.SaveEntity(entity)
if err != nil {
fmt.Println("[ERRO]", err)
}
}
return nil, err
}
// Server -> Client
// - only sequence number
// - error code (optional)
func (verify *VerifyServerController) handlePairVerifyFinish(in util.Container) (util.Container, error) {
verify.step = VerifyStepFinishResponse
data := in.GetBytes(TagEncryptedData)
message := data[:(len(data) - 16)]
var mac [16]byte
copy(mac[:], data[len(message):]) // 16 byte (MAC)
log.Debug.Println("-> Message:", hex.EncodeToString(message))
log.Debug.Println("-> MAC:", hex.EncodeToString(mac[:]))
decryptedBytes, err := chacha20poly1305.DecryptAndVerify(verify.session.EncryptionKey[:], []byte("PV-Msg03"), message, mac, nil)
out := util.NewTLV8Container()
out.SetByte(TagSequence, verify.step.Byte())
if err != nil {
verify.reset()
log.Info.Panic(err)
out.SetByte(TagErrCode, ErrCodeAuthenticationFailed.Byte()) // return error 2
} else {
in, err := util.NewTLV8ContainerFromReader(bytes.NewBuffer(decryptedBytes))
if err != nil {
return nil, err
}
username := in.GetString(TagUsername)
signature := in.GetBytes(TagSignature)
log.Debug.Println(" client:", username)
log.Debug.Println(" signature:", hex.EncodeToString(signature))
entity, err := verify.database.EntityWithName(username)
if err != nil {
return nil, fmt.Errorf("Client %s is unknown", username)
}
if len(entity.PublicKey) == 0 {
return nil, fmt.Errorf("No LTPK available for client %s", username)
}
var material []byte
material = append(material, verify.session.OtherPublicKey[:]...)
material = append(material, []byte(username)...)
material = append(material, verify.session.PublicKey[:]...)
if crypto.ValidateED25519Signature(entity.PublicKey, material, signature) == false {
log.Debug.Println("signature is invalid")
verify.reset()
out.SetByte(TagErrCode, ErrCodeUnknownPeer.Byte()) // return error 4
} else {
log.Debug.Println("signature is valid")
}
}
return out, nil
}
// Client -> Server
// - encrypted tlv8: entity ltpk, entity name and signature (of H, entity name, ltpk)
// - auth tag (mac)
//
// Server
// - Validate signature of encrpyted tlv8
// - Read and store entity ltpk and name
//
// Server -> Client
// - encrpyted tlv8: bridge ltpk, bridge name, signature (of hash, bridge name, ltpk)
func (setup *SetupServerController) handleKeyExchange(in util.Container) (util.Container, error) {
out := util.NewTLV8Container()
setup.step = PairStepKeyExchangeResponse
out.SetByte(TagSequence, setup.step.Byte())
data := in.GetBytes(TagEncryptedData)
message := data[:(len(data) - 16)]
var mac [16]byte
copy(mac[:], data[len(message):]) // 16 byte (MAC)
log.Debug.Println("-> Message:", hex.EncodeToString(message))
log.Debug.Println("-> MAC:", hex.EncodeToString(mac[:]))
decrypted, err := chacha20poly1305.DecryptAndVerify(setup.session.EncryptionKey[:], []byte("PS-Msg05"), message, mac, nil)
if err != nil {
setup.reset()
log.Info.Panic(err)
out.SetByte(TagErrCode, ErrCodeUnknown.Byte()) // return error 1
} else {
decryptedBuf := bytes.NewBuffer(decrypted)
in, err := util.NewTLV8ContainerFromReader(decryptedBuf)
if err != nil {
return nil, err
}
username := in.GetString(TagUsername)
clientltpk := in.GetBytes(TagPublicKey)
signature := in.GetBytes(TagSignature)
log.Debug.Println("-> Username:"******"-> ltpk:", hex.EncodeToString(clientltpk))
log.Debug.Println("-> Signature:", hex.EncodeToString(signature))
// Calculate hash `H`
hash, _ := hkdf.Sha512(setup.session.PrivateKey, []byte("Pair-Setup-Controller-Sign-Salt"), []byte("Pair-Setup-Controller-Sign-Info"))
var material []byte
material = append(material, hash[:]...)
material = append(material, []byte(username)...)
material = append(material, clientltpk...)
if crypto.ValidateED25519Signature(clientltpk, material, signature) == false {
log.Debug.Println("ed25519 signature is invalid")
setup.reset()
out.SetByte(TagErrCode, ErrCodeAuthenticationFailed.Byte()) // return error 2
} else {
log.Debug.Println("ed25519 signature is valid")
// Store entity ltpk and name
entity := db.NewEntity(username, clientltpk, nil)
setup.database.SaveEntity(entity)
log.Debug.Printf("Stored ltpk '%s' for entity '%s'\n", hex.EncodeToString(clientltpk), username)
ltpk := setup.device.PublicKey()
ltsk := setup.device.PrivateKey()
// Send username, ltpk, signature as encrypted message
hash, err := hkdf.Sha512(setup.session.PrivateKey, []byte("Pair-Setup-Accessory-Sign-Salt"), []byte("Pair-Setup-Accessory-Sign-Info"))
material = make([]byte, 0)
material = append(material, hash[:]...)
material = append(material, []byte(setup.session.Username)...)
material = append(material, ltpk...)
signature, err := crypto.ED25519Signature(ltsk, material)
if err != nil {
log.Info.Panic(err)
return nil, err
}
tlvPairKeyExchange := util.NewTLV8Container()
tlvPairKeyExchange.SetBytes(TagUsername, setup.session.Username)
tlvPairKeyExchange.SetBytes(TagPublicKey, ltpk)
tlvPairKeyExchange.SetBytes(TagSignature, []byte(signature))
log.Debug.Println("<- Username:"******"<- ltpk:", hex.EncodeToString(tlvPairKeyExchange.GetBytes(TagPublicKey)))
log.Debug.Println("<- Signature:", hex.EncodeToString(tlvPairKeyExchange.GetBytes(TagSignature)))
encrypted, mac, _ := chacha20poly1305.EncryptAndSeal(setup.session.EncryptionKey[:], []byte("PS-Msg06"), tlvPairKeyExchange.BytesBuffer().Bytes(), nil)
out.SetByte(TagSequence, PairStepKeyExchangeRequest.Byte())
out.SetBytes(TagEncryptedData, append(encrypted, mac[:]...))
}
}
return out, nil
}
