/
auth.go
200 lines (169 loc) · 4.47 KB
/
auth.go
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package auth
import (
"bytes"
"crypto/aes"
"crypto/rand"
"crypto/rsa"
"crypto/sha1"
"crypto/x509"
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"strings"
"github.com/google/uuid"
"github.com/Tnze/go-mc/data/packetid"
"github.com/Tnze/go-mc/net"
"github.com/Tnze/go-mc/net/CFB8"
pk "github.com/Tnze/go-mc/net/packet"
"github.com/Tnze/go-mc/yggdrasil/user"
)
// Deprecated: Moved to go-mc/yggdrasil/user, because go-mc/bot also needs them
type (
Texture = user.Texture
Property = user.Property
PublicKey = user.PublicKey
)
const verifyTokenLen = 16
// Encrypt a connection, with authentication
func Encrypt(conn *net.Conn, name string, serverKey *rsa.PrivateKey) (*Resp, error) {
publicKey, err := x509.MarshalPKIXPublicKey(&serverKey.PublicKey)
if err != nil {
return nil, err
}
verifyToken := make([]byte, verifyTokenLen)
_, err = rand.Read(verifyToken)
if err != nil {
return nil, err
}
// encryption request
err = encryptionRequest(conn, publicKey, verifyToken)
if err != nil {
return nil, err
}
// encryption response
SharedSecret, err := encryptionResponse(conn, serverKey, verifyToken)
if err != nil {
return nil, err
}
// encryption the connection
block, err := aes.NewCipher(SharedSecret)
if err != nil {
return nil, errors.New("load aes encryption key fail")
}
conn.SetCipher( // 启用加密
CFB8.NewCFB8Encrypt(block, SharedSecret),
CFB8.NewCFB8Decrypt(block, SharedSecret),
)
hash := authDigest("", SharedSecret, publicKey)
resp, err := authentication(name, hash) // auth
if err != nil {
return nil, errors.New("auth servers down")
}
return resp, nil
}
func encryptionRequest(conn *net.Conn, publicKey, verifyToken []byte) error {
return conn.WritePacket(pk.Marshal(
packetid.ClientboundLoginEncryptionRequest,
pk.String(""),
pk.ByteArray(publicKey),
pk.ByteArray(verifyToken),
))
}
func encryptionResponse(conn *net.Conn, serverKey *rsa.PrivateKey, verifyToken []byte) ([]byte, error) {
var p pk.Packet
err := conn.ReadPacket(&p)
if err != nil {
return nil, err
}
if packetid.ServerboundPacketID(p.ID) != packetid.ServerboundLoginEncryptionResponse {
return nil, fmt.Errorf("0x%02X is not Encryption Response", p.ID)
}
var keyBytes pk.ByteArray
var encryptedVerifyToken pk.ByteArray
err = p.Scan(&keyBytes, &encryptedVerifyToken)
if err != nil {
return nil, err
}
// confirm to verify token
decryptedVerifyToken, err := rsa.DecryptPKCS1v15(rand.Reader, serverKey, encryptedVerifyToken)
if err != nil {
return nil, err
} else if !bytes.Equal(verifyToken, decryptedVerifyToken) {
return nil, errors.New("verifyToken not match")
}
// get sharedSecret
sharedSecret, err := rsa.DecryptPKCS1v15(rand.Reader, serverKey, keyBytes)
if err != nil {
return nil, err
}
return sharedSecret, nil
}
func authentication(name, hash string) (*Resp, error) {
resp, err := http.Get("https://sessionserver.mojang.com/session/minecraft/hasJoined?username=" + name + "&serverId=" + hash)
if err != nil {
return nil, err
}
defer resp.Body.Close()
body, err := io.ReadAll(resp.Body)
if err != nil {
return nil, err
}
var Resp Resp
err = json.Unmarshal(body, &Resp)
return &Resp, err
}
// authDigest computes a special SHA-1 digest required for Minecraft web
// authentication on Premium servers (online-mode=true).
// Source: http://wiki.vg/Protocol_Encryption#Server
//
// Also many, many thanks to SirCmpwn and his wonderful gist (C#):
// https://gist.github.com/SirCmpwn/404223052379e82f91e6
func authDigest(serverID string, sharedSecret, publicKey []byte) string {
h := sha1.New()
h.Write([]byte(serverID))
h.Write(sharedSecret)
h.Write(publicKey)
hash := h.Sum(nil)
// Check for negative hashes
negative := (hash[0] & 0x80) == 0x80
if negative {
hash = twosComplement(hash)
}
// Trim away zeroes
res := strings.TrimLeft(fmt.Sprintf("%x", hash), "0")
if negative {
res = "-" + res
}
return res
}
// little endian
func twosComplement(p []byte) []byte {
carry := true
for i := len(p) - 1; i >= 0; i-- {
p[i] = byte(^p[i])
if carry {
carry = p[i] == 0xff
p[i]++
}
}
return p
}
// Resp is the response of authentication
type Resp struct {
Name string
ID uuid.UUID
Properties []user.Property
}
// Texture unmarshal the base64 encoded texture of Resp
func (r *Resp) Texture() (t user.Texture, err error) {
var texture []byte
texture, err = base64.StdEncoding.DecodeString(r.Properties[0].Value)
if err != nil {
return
}
err = json.Unmarshal(texture, &t)
return
}