// Tests the pairing key verification
func TestInvalidPublicKey(t *testing.T) {
storage, err := util.NewTempFileStorage()
if err != nil {
t.Fatal(err)
}
database := db.NewDatabaseWithStorage(storage)
bridge, err := hap.NewSecuredDevice("Macbook Bridge", "001-02-003", database)
if err != nil {
t.Fatal(err)
}
context := hap.NewContextForSecuredDevice(bridge)
controller := NewVerifyServerController(database, context)
client, _ := hap.NewDevice("HomeKit Client", database)
clientController := NewVerifyClientController(client, database)
req := clientController.InitialKeyVerifyRequest()
reqContainer, err := util.NewTLV8ContainerFromReader(req)
if err != nil {
t.Fatal(err)
}
reqContainer.SetByte(TagPublicKey, byte(0x01))
// 1) C -> S
if _, err = HandleReaderForHandler(reqContainer.BytesBuffer(), controller); err != errInvalidClientKeyLength {
t.Fatal("expected invalid client key length error")
}
}
func (endpoint *Pairing) ServeHTTP(response http.ResponseWriter, request *http.Request) {
log.Printf("[VERB] %v POST /pairings", request.RemoteAddr)
response.Header().Set("Content-Type", netio.HTTPContentTypePairingTLV8)
var err error
var in util.Container
var out util.Container
if in, err = util.NewTLV8ContainerFromReader(request.Body); err == nil {
out, err = endpoint.controller.Handle(in)
}
if err != nil {
log.Println(err)
response.WriteHeader(http.StatusInternalServerError)
} else {
io.Copy(response, out.BytesBuffer())
// Send events based on pairing method type
b := in.GetByte(pair.TagPairingMethod)
switch pair.PairMethodType(b) {
case pair.PairingMethodDelete: // pairing removed
endpoint.emitter.Emit(event.DeviceUnpaired{})
case pair.PairingMethodAdd: // pairing added
endpoint.emitter.Emit(event.DevicePaired{})
}
}
}
// 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
}
func bytesFromTLV8(b []byte) ([]byte, error) {
buf := bytes.NewBuffer(b)
c, err := util.NewTLV8ContainerFromReader(buf)
if err != nil {
return nil, err
}
return c.GetBytes(0x00), nil
}
// 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
}
func (endpoint *PairVerify) ServeHTTP(response http.ResponseWriter, request *http.Request) {
log.Printf("[VERB] %v POST /pair-verify", request.RemoteAddr)
response.Header().Set("Content-Type", netio.HTTPContentTypePairingTLV8)
key := endpoint.context.GetConnectionKey(request)
session := endpoint.context.Get(key).(netio.Session)
ctlr := session.PairVerifyHandler()
if ctlr == nil {
log.Println("[VERB] Create new pair verify controller")
ctlr = pair.NewVerifyServerController(endpoint.database, endpoint.context)
session.SetPairVerifyHandler(ctlr)
}
var err error
var in util.Container
var out util.Container
var secSession crypto.Cryptographer
if in, err = util.NewTLV8ContainerFromReader(request.Body); err == nil {
out, err = ctlr.Handle(in)
}
if err != nil {
log.Println(err)
response.WriteHeader(http.StatusInternalServerError)
} else {
io.Copy(response, out.BytesBuffer())
// When key verification is done, switch to a secure session
// based on the negotiated shared session key
b := out.GetByte(pair.TagSequence)
switch pair.VerifyStepType(b) {
case pair.VerifyStepFinishResponse:
if secSession, err = crypto.NewSecureSessionFromSharedKey(ctlr.SharedKey()); err == nil {
log.Println("[VERB] Setup secure session")
session.SetCryptographer(secSession)
} else {
log.Println("[ERRO] Could not setup secure session.", err)
}
}
}
}
// HandleReaderForHandler wraps h.Handle() call and logs sequence numbers and errors to the console.
func HandleReaderForHandler(r io.Reader, h netio.ContainerHandler) (rOut io.Reader, err error) {
in, err := util.NewTLV8ContainerFromReader(r)
if err != nil {
return nil, err
}
log.Println("[VERB] -> Seq:", in.GetByte(TagSequence))
out, err := h.Handle(in)
if err != nil {
log.Println("[ERRO]", err)
} else {
if out != nil {
log.Println("[VERB] <- Seq:", out.GetByte(TagSequence))
rOut = out.BytesBuffer()
}
}
log.Println("[VERB] --------------------------")
return rOut, err
}
func (endpoint *PairSetup) ServeHTTP(response http.ResponseWriter, request *http.Request) {
log.Debug.Printf("%v POST /pair-setup", request.RemoteAddr)
response.Header().Set("Content-Type", hap.HTTPContentTypePairingTLV8)
var err error
var in util.Container
var out util.Container
key := endpoint.context.GetConnectionKey(request)
session := endpoint.context.Get(key).(hap.Session)
ctrl := session.PairSetupHandler()
if ctrl == nil {
log.Debug.Println("Create new pair setup controller")
if ctrl, err = pair.NewSetupServerController(endpoint.device, endpoint.database); err != nil {
log.Info.Panic(err)
}
session.SetPairSetupHandler(ctrl)
}
if in, err = util.NewTLV8ContainerFromReader(request.Body); err == nil {
out, err = ctrl.Handle(in)
}
if err != nil {
log.Info.Println(err)
response.WriteHeader(http.StatusInternalServerError)
} else {
io.Copy(response, out.BytesBuffer())
// Send event when key exchange is done
b := out.GetByte(pair.TagSequence)
switch pair.PairStepType(b) {
case pair.PairStepKeyExchangeResponse:
endpoint.emitter.Emit(event.DevicePaired{})
}
}
}
// Server -> Client
// - B: server public key
// - encrypted message
// - username
// - signature: from server session public key, server name, client session public key
//
// Client -> Server
// - encrypted message
// - username
// - signature: from client session public key, server name, server session public key,
func (verify *VerifyClientController) handlePairStepVerifyResponse(in util.Container) (util.Container, error) {
serverPublicKey := in.GetBytes(TagPublicKey)
if len(serverPublicKey) != 32 {
return nil, fmt.Errorf("Invalid server public key size %d", len(serverPublicKey))
}
var otherPublicKey [32]byte
copy(otherPublicKey[:], serverPublicKey)
verify.session.GenerateSharedKeyWithOtherPublicKey(otherPublicKey)
verify.session.SetupEncryptionKey([]byte("Pair-Verify-Encrypt-Salt"), []byte("Pair-Verify-Encrypt-Info"))
fmt.Println("Client")
fmt.Println("-> B:", hex.EncodeToString(serverPublicKey))
fmt.Println(" S:", hex.EncodeToString(verify.session.PrivateKey[:]))
fmt.Println("Shared:", hex.EncodeToString(verify.session.SharedKey[:]))
fmt.Println(" K:", hex.EncodeToString(verify.session.EncryptionKey[:]))
// Decrypt
data := in.GetBytes(TagEncryptedData)
message := data[:(len(data) - 16)]
var mac [16]byte
copy(mac[:], data[len(message):]) // 16 byte (MAC)
decryptedBytes, err := chacha20poly1305.DecryptAndVerify(verify.session.EncryptionKey[:], []byte("PV-Msg02"), message, mac, nil)
if err != nil {
return nil, err
}
decryptedIn, err := util.NewTLV8ContainerFromReader(bytes.NewBuffer(decryptedBytes))
if err != nil {
return nil, err
}
username := decryptedIn.GetString(TagUsername)
signature := decryptedIn.GetBytes(TagSignature)
fmt.Println(" Username:"******" Signature:", hex.EncodeToString(signature))
// Validate signature
var material []byte
material = append(material, verify.session.OtherPublicKey[:]...)
material = append(material, username...)
material = append(material, verify.session.PublicKey[:]...)
entity := verify.database.EntityWithName(username)
if entity == nil {
return nil, fmt.Errorf("Server %s is unknown", username)
}
if len(entity.PublicKey()) == 0 {
return nil, fmt.Errorf("No LTPK available for client %s", username)
}
if crypto.ValidateED25519Signature(entity.PublicKey(), material, signature) == false {
return nil, fmt.Errorf("Could not validate signature")
}
out := util.NewTLV8Container()
out.SetByte(TagSequence, VerifyStepFinishRequest.Byte())
encryptedOut := util.NewTLV8Container()
encryptedOut.SetString(TagUsername, verify.client.Name())
material = make([]byte, 0)
material = append(material, verify.session.PublicKey[:]...)
material = append(material, verify.client.Name()...)
material = append(material, verify.session.OtherPublicKey[:]...)
signature, err = crypto.ED25519Signature(verify.client.PrivateKey(), material)
if err != nil {
return nil, err
}
encryptedOut.SetBytes(TagSignature, signature)
encryptedBytes, mac, _ := chacha20poly1305.EncryptAndSeal(verify.session.EncryptionKey[:], []byte("PV-Msg03"), encryptedOut.BytesBuffer().Bytes(), nil)
out.SetBytes(TagEncryptedData, append(encryptedBytes, mac[:]...))
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
}
