Files
go2rtc/pkg/homekit/client.go
2022-09-01 16:11:34 +03:00

733 lines
15 KiB
Go

package homekit
import (
"bufio"
"crypto/sha512"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"github.com/AlexxIT/go2rtc/pkg/homekit/mdns"
"github.com/AlexxIT/go2rtc/pkg/streamer"
"github.com/brutella/hap"
"github.com/brutella/hap/chacha20poly1305"
"github.com/brutella/hap/curve25519"
"github.com/brutella/hap/ed25519"
"github.com/brutella/hap/hkdf"
"github.com/brutella/hap/tlv8"
"github.com/tadglines/go-pkgs/crypto/srp"
"io"
"net"
"net/http"
"net/url"
"strings"
)
// Client for HomeKit. DevicePublic can be null.
type Client struct {
streamer.Element
DeviceAddress string // including port
DeviceID string
DevicePublic []byte
ClientID string
ClientPrivate []byte
OnEvent func(res *http.Response)
Output func(msg interface{})
conn net.Conn
secure *Secure
httpResponse chan *bufio.Reader
}
func NewClient(rawURL string) (*Client, error) {
u, err := url.Parse(rawURL)
if err != nil {
return nil, err
}
query := u.Query()
c := &Client{
DeviceAddress: u.Host,
DeviceID: query.Get("device_id"),
DevicePublic: DecodeKey(query.Get("device_public")),
ClientID: query.Get("client_id"),
ClientPrivate: DecodeKey(query.Get("client_private")),
}
return c, nil
}
func Pair(deviceID, pin string) (*Client, error) {
entry := mdns.GetEntry(deviceID)
if entry == nil {
return nil, errors.New("can't find device via mDNS")
}
c := &Client{
DeviceAddress: fmt.Sprintf("%s:%d", entry.AddrV4.String(), entry.Port),
DeviceID: deviceID,
ClientID: GenerateUUID(),
ClientPrivate: GenerateKey(),
}
var mfi bool
for _, field := range entry.InfoFields {
if field[:2] == "ff" {
if field[3] == '1' {
mfi = true
}
break
}
}
return c, c.Pair(mfi, pin)
}
func (c *Client) ClientPublic() []byte {
return c.ClientPrivate[32:]
}
func (c *Client) URL() string {
return fmt.Sprintf(
"homekit://%s?device_id=%s&device_public=%16x&client_id=%s&client_private=%32x",
c.DeviceAddress, c.DeviceID, c.DevicePublic, c.ClientID, c.ClientPrivate,
)
}
func (c *Client) DialAndServe() error {
if err := c.Dial(); err != nil {
return err
}
return c.Handle()
}
func (c *Client) Dial() error {
// update device host before dial
if host := mdns.GetAddress(c.DeviceID); host != "" {
c.DeviceAddress = host
}
var err error
c.conn, err = net.Dial("tcp", c.DeviceAddress)
if err != nil {
return err
}
// STEP M1: send our session public to device
sessionPublic, sessionPrivate := curve25519.GenerateKeyPair()
// 1. generate payload
// important not include other fields
requestM1 := struct {
State byte `tlv8:"6"`
PublicKey []byte `tlv8:"3"`
}{
State: hap.M1,
PublicKey: sessionPublic[:],
}
// 2. pack payload to TLV8
buf, err := tlv8.Marshal(requestM1)
if err != nil {
return err
}
// 3. send request
resp, err := c.Post(UriPairVerify, buf)
if err != nil {
return err
}
// STEP M2: unpack deviceID from response
responseM2 := PairVerifyPayload{}
if err = tlv8.UnmarshalReader(resp.Body, &responseM2); err != nil {
return err
}
// 1. generate session shared key
var deviceSessionPublic [32]byte
copy(deviceSessionPublic[:], responseM2.PublicKey)
sessionShared := curve25519.SharedSecret(sessionPrivate, deviceSessionPublic)
sessionKey, err := hkdf.Sha512(
sessionShared[:], []byte("Pair-Verify-Encrypt-Salt"),
[]byte("Pair-Verify-Encrypt-Info"),
)
// 2. decrypt M2 response with session key
msg := responseM2.EncryptedData[:len(responseM2.EncryptedData)-16]
var mac [16]byte
copy(mac[:], responseM2.EncryptedData[len(msg):]) // 16 byte (MAC)
buf, err = chacha20poly1305.DecryptAndVerify(
sessionKey[:], []byte("PV-Msg02"), msg, mac, nil,
)
// 3. unpack payload from TLV8
payloadM2 := PairVerifyPayload{}
if err = tlv8.Unmarshal(buf, &payloadM2); err != nil {
return err
}
// 4. verify signature for M2 response with device public
// device session + device id + our session
if c.DevicePublic != nil {
buf = nil
buf = append(buf, responseM2.PublicKey[:]...)
buf = append(buf, []byte(payloadM2.Identifier)...)
buf = append(buf, sessionPublic[:]...)
if !ed25519.ValidateSignature(
c.DevicePublic[:], buf, payloadM2.Signature,
) {
return errors.New("device public signature invalid")
}
}
// STEP M3: send our clientID to device
// 1. generate signature with our private key
// (our session + our ID + device session)
buf = nil
buf = append(buf, sessionPublic[:]...)
buf = append(buf, []byte(c.ClientID)...)
buf = append(buf, responseM2.PublicKey[:]...)
signature, err := ed25519.Signature(c.ClientPrivate[:], buf)
if err != nil {
return err
}
// 2. generate payload
payloadM3 := struct {
Identifier string `tlv8:"1"`
Signature []byte `tlv8:"10"`
}{
Identifier: c.ClientID,
Signature: signature,
}
// 3. pack payload to TLV8
buf, err = tlv8.Marshal(payloadM3)
if err != nil {
return err
}
// 4. encrypt payload with session key
msg, mac, _ = chacha20poly1305.EncryptAndSeal(
sessionKey[:], []byte("PV-Msg03"), buf, nil,
)
// 4. generate request
requestM3 := struct {
EncryptedData []byte `tlv8:"5"`
State byte `tlv8:"6"`
}{
State: hap.M3,
EncryptedData: append(msg, mac[:]...),
}
// 5. pack payload to TLV8
buf, err = tlv8.Marshal(requestM3)
if err != nil {
return err
}
resp, err = c.Post(UriPairVerify, buf)
if err != nil {
return err
}
// STEP M4. Read response
responseM4 := PairVerifyPayload{}
if err = tlv8.UnmarshalReader(resp.Body, &responseM4); err != nil {
return err
}
// 1. check response state
if responseM4.State != 4 || responseM4.Status != 0 {
return fmt.Errorf("wrong M4 response: %+v", responseM4)
}
c.secure, err = NewSecure(sessionShared, false)
//c.secure.Buffer = bytes.NewBuffer(nil)
c.secure.Conn = c.conn
c.httpResponse = make(chan *bufio.Reader, 10)
return err
}
// https://github.com/apple/HomeKitADK/blob/master/HAP/HAPPairingPairSetup.c
func (c *Client) Pair(mfi bool, pin string) (err error) {
pin = strings.ReplaceAll(pin, "-", "")
if len(pin) != 8 {
return fmt.Errorf("wrong PIN format: %s", pin)
}
pin = pin[:3] + "-" + pin[3:5] + "-" + pin[5:]
c.conn, err = net.Dial("tcp", c.DeviceAddress)
if err != nil {
return
}
// STEP M1. Generate request
reqM1 := struct {
Method byte `tlv8:"0"`
State byte `tlv8:"6"`
}{
State: hap.M1,
}
if mfi {
reqM1.Method = 1 // ff=1 => method=1, ff=2 => method=0
}
buf, err := tlv8.Marshal(reqM1)
if err != nil {
return
}
// STEP M1. Send request
res, err := c.Post(UriPairSetup, buf)
if err != nil {
return
}
// STEP M2. Read response
resM2 := struct {
Salt []byte `tlv8:"2"`
PublicKey []byte `tlv8:"3"` // server public key, aka session.B
State byte `tlv8:"6"`
Error byte `tlv8:"7"`
}{}
if err = tlv8.UnmarshalReader(res.Body, &resM2); err != nil {
return
}
if resM2.State != 2 || resM2.Error > 0 {
return fmt.Errorf("wrong M2: %+v", resM2)
}
// STEP M3. Generate session using pin
username := []byte("Pair-Setup")
SRP, err := srp.NewSRP(
"rfc5054.3072", sha512.New, keyDerivativeFuncRFC2945(username),
)
if err != nil {
return
}
SRP.SaltLength = 16
// username: "Pair-Setup"
// password: PIN (with dashes)
session := SRP.NewClientSession(username, []byte(pin))
sessionShared, err := session.ComputeKey(resM2.Salt, resM2.PublicKey)
if err != nil {
return
}
// STEP M3. Generate request
reqM3 := struct {
PublicKey []byte `tlv8:"3"`
Proof []byte `tlv8:"4"`
State byte `tlv8:"6"`
}{
PublicKey: session.GetA(), // client public key, aka session.A
Proof: session.ComputeAuthenticator(),
State: hap.M3,
}
buf, err = tlv8.Marshal(reqM3)
if err != nil {
return err
}
// STEP M3. Send request
res, err = c.Post(UriPairSetup, buf)
if err != nil {
return
}
// STEP M4. Read response
resM4 := struct {
Proof []byte `tlv8:"4"` // server proof
State byte `tlv8:"6"`
Error byte `tlv8:"7"`
}{}
if err = tlv8.UnmarshalReader(res.Body, &resM4); err != nil {
return
}
if resM4.Error == 2 {
return fmt.Errorf("wrong PIN: %s", pin)
}
if resM4.State != 4 || resM4.Error > 0 {
return fmt.Errorf("wrong M4: %+v", resM4)
}
// STEP M4. Verify response
if !session.VerifyServerAuthenticator(resM4.Proof) {
return errors.New("verify server auth fail")
}
// STEP M5. Generate signature
saltKey, err := hkdf.Sha512(
sessionShared, []byte("Pair-Setup-Controller-Sign-Salt"),
[]byte("Pair-Setup-Controller-Sign-Info"),
)
if err != nil {
return
}
buf = nil
buf = append(buf, saltKey[:]...)
buf = append(buf, []byte(c.ClientID)...)
buf = append(buf, c.ClientPublic()...)
signature, err := ed25519.Signature(c.ClientPrivate, buf)
if err != nil {
return
}
// STEP M5. Generate payload
msgM5 := struct {
Identifier string `tlv8:"1"`
PublicKey []byte `tlv8:"3"`
Signature []byte `tlv8:"10"`
}{
Identifier: c.ClientID,
PublicKey: c.ClientPublic(),
Signature: signature,
}
buf, err = tlv8.Marshal(msgM5)
if err != nil {
return
}
// STEP M5. Encrypt payload
sessionKey, err := hkdf.Sha512(
sessionShared, []byte("Pair-Setup-Encrypt-Salt"),
[]byte("Pair-Setup-Encrypt-Info"),
)
if err != nil {
return
}
buf, mac, _ := chacha20poly1305.EncryptAndSeal(
sessionKey[:], []byte("PS-Msg05"), buf, nil,
)
// STEP M5. Generate request
reqM5 := struct {
EncryptedData []byte `tlv8:"5"`
State byte `tlv8:"6"`
}{
EncryptedData: append(buf, mac[:]...),
State: hap.M5,
}
buf, err = tlv8.Marshal(reqM5)
if err != nil {
return err
}
// STEP M5. Send request
res, err = c.Post(UriPairSetup, buf)
if err != nil {
return
}
// STEP M6. Read response
resM6 := struct {
EncryptedData []byte `tlv8:"5"`
State byte `tlv8:"6"`
Error byte `tlv8:"7"`
}{}
if err = tlv8.UnmarshalReader(res.Body, &resM6); err != nil {
return
}
if resM6.State != 6 || resM6.Error > 0 {
return fmt.Errorf("wrong M6: %+v", resM2)
}
// STEP M6. Decrypt payload
msg := resM6.EncryptedData[:len(resM6.EncryptedData)-16]
copy(mac[:], resM6.EncryptedData[len(msg):]) // 16 byte (MAC)
buf, err = chacha20poly1305.DecryptAndVerify(
sessionKey[:], []byte("PS-Msg06"), msg, mac, nil,
)
if err != nil {
return
}
msgM6 := struct {
Identifier []byte `tlv8:"1"`
PublicKey []byte `tlv8:"3"`
Signature []byte `tlv8:"10"`
}{}
if err = tlv8.Unmarshal(buf, &msgM6); err != nil {
return
}
// STEP M6. Verify payload
if saltKey, err = hkdf.Sha512(
sessionShared, []byte("Pair-Setup-Accessory-Sign-Salt"),
[]byte("Pair-Setup-Accessory-Sign-Info"),
); err != nil {
return
}
buf = nil
buf = append(buf, saltKey[:]...)
buf = append(buf, msgM6.Identifier...)
buf = append(buf, msgM6.PublicKey...)
if !ed25519.ValidateSignature(
msgM6.PublicKey[:], buf, msgM6.Signature,
) {
return errors.New("wrong server signature")
}
if c.DeviceID != string(msgM6.Identifier) {
return fmt.Errorf("wrong Device ID: %s", msgM6.Identifier)
}
c.DevicePublic = msgM6.PublicKey
return nil
}
func (c *Client) Close() error {
if c.conn == nil {
return nil
}
conn := c.conn
c.conn = nil
return conn.Close()
}
func (c *Client) GetAccessories() ([]*Accessory, error) {
res, err := c.Get("/accessories")
if err != nil {
return nil, err
}
data, err := io.ReadAll(res.Body)
if err != nil {
return nil, err
}
p := Accessories{}
if err = json.Unmarshal(data, &p); err != nil {
return nil, err
}
for _, accs := range p.Accessories {
for _, serv := range accs.Services {
for _, char := range serv.Characters {
char.AID = accs.AID
}
}
}
return p.Accessories, nil
}
func (c *Client) GetCharacters(query string) ([]*Character, error) {
res, err := c.Get("/characteristics?id=" + query)
if err != nil {
return nil, err
}
data, err := io.ReadAll(res.Body)
if err != nil {
return nil, err
}
ch := Characters{}
if err = json.Unmarshal(data, &ch); err != nil {
return nil, err
}
return ch.Characters, nil
}
func (c *Client) GetCharacter(char *Character) error {
query := fmt.Sprintf("%d.%d", char.AID, char.IID)
chars, err := c.GetCharacters(query)
if err != nil {
return err
}
char.Value = chars[0].Value
return nil
}
func (c *Client) PutCharacters(characters ...*Character) (err error) {
for i, char := range characters {
if char.Event != nil {
char = &Character{AID: char.AID, IID: char.IID, Event: char.Event}
} else {
char = &Character{AID: char.AID, IID: char.IID, Value: char.Value}
}
characters[i] = char
}
var data []byte
if data, err = json.Marshal(Characters{characters}); err != nil {
return
}
var res *http.Response
if res, err = c.Put("/characteristics", data); err != nil {
return
}
if res.StatusCode >= 400 {
return errors.New("wrong response status")
}
return
}
func (c *Client) GetImage(width, height int) ([]byte, error) {
res, err := c.Post(
"/resource", []byte(fmt.Sprintf(
`{"image-width":%d,"image-height":%d,"resource-type":"image","reason":0}`,
width, height,
)),
)
if err != nil {
return nil, err
}
return io.ReadAll(res.Body)
}
//func (c *Client) onEventData(r io.Reader) error {
// if c.OnEvent == nil {
// return nil
// }
//
// data, err := io.ReadAll(r)
//
// ch := Characters{}
// if err = json.Unmarshal(data, &ch); err != nil {
// return err
// }
//
// c.OnEvent(ch.Characters)
//
// return nil
//}
func (c *Client) ListPairings() error {
pReq := struct {
Method byte `tlv8:"0"`
State byte `tlv8:"6"`
}{
Method: hap.MethodListPairings,
State: hap.M1,
}
data, err := tlv8.Marshal(pReq)
if err != nil {
return err
}
res, err := c.Post("/pairings", data)
if err != nil {
return err
}
data, err = io.ReadAll(res.Body)
// TODO: don't know how to fix array of items
var pRes struct {
State byte `tlv8:"6"`
Identifier string `tlv8:"1"`
PublicKey []byte `tlv8:"3"`
Permission byte `tlv8:"11"`
}
if err = tlv8.Unmarshal(data, &pRes); err != nil {
return err
}
return nil
}
func (c *Client) PairingsAdd(clientID string, clientPublic []byte, admin bool) error {
pReq := struct {
Method byte `tlv8:"0"`
Identifier string `tlv8:"1"`
PublicKey []byte `tlv8:"3"`
State byte `tlv8:"6"`
Permission byte `tlv8:"11"`
}{
Method: hap.MethodAddPairing,
Identifier: clientID,
PublicKey: clientPublic,
State: hap.M1,
Permission: hap.PermissionUser,
}
if admin {
pReq.Permission = hap.PermissionAdmin
}
data, err := tlv8.Marshal(pReq)
if err != nil {
return err
}
res, err := c.Post("/pairings", data)
if err != nil {
return err
}
data, err = io.ReadAll(res.Body)
var pRes struct {
State byte `tlv8:"6"`
Unknown byte `tlv8:"7"`
}
if err = tlv8.Unmarshal(data, &pRes); err != nil {
return err
}
return nil
}
func (c *Client) DeletePairing(id string) error {
reqM1 := struct {
State byte `tlv8:"6"`
Method byte `tlv8:"0"`
Identifier string `tlv8:"1"`
}{
State: hap.M1,
Method: hap.MethodDeletePairing,
Identifier: id,
}
data, err := tlv8.Marshal(reqM1)
if err != nil {
return err
}
res, err := c.Post("/pairings", data)
if err != nil {
return err
}
data, err = io.ReadAll(res.Body)
var resM2 struct {
State byte `tlv8:"6"`
}
if err = tlv8.Unmarshal(data, &resM2); err != nil {
return err
}
if resM2.State != hap.M2 {
return errors.New("wrong state")
}
return nil
}
func (c *Client) LocalAddr() string {
return c.conn.LocalAddr().String()
}
func DecodeKey(s string) []byte {
if s == "" {
return nil
}
data, err := hex.DecodeString(s)
if err != nil {
return nil
}
return data
}