fix: Minecraft login packet version difference

layou233 · Jul 19, 2024 · da6f5b6 · da6f5b6
1 parent 8662e4a
commit da6f5b6
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Showing 5 changed files with 71 additions and 31 deletions.
diff --git a/common/bufio/cached.go b/common/bufio/cached.go
@@ -27,6 +27,10 @@ func NewCachedConn(c net.Conn) *CachedConn {
 	}
 }
 
+func (c *CachedConn) Cache() *buf.Buffer {
+	return c.cache
+}
+
 func (c *CachedConn) Read(p []byte) (n int, err error) {
 	if c.cache != nil && !c.cache.IsEmpty() {
 		return c.cache.Read(p)

diff --git a/protocol/minecraft/outbound.go b/protocol/minecraft/outbound.go
@@ -201,9 +201,15 @@ func (o *Outbound) InjectConnection(ctx context.Context, conn *bufio.CachedConn,
 	}
 	switch metadata.Minecraft.NextState {
 	case mcprotocol.NextStateStatus:
+		// skip Status Request packet
+		_, err := conn.Peek(2)
+		if err != nil {
+			return common.Cause("skip status request: ", err)
+		}
 		if o.config.Minecraft.MotdFavicon == "" && o.config.Minecraft.MotdDescription == "" {
 			// directly proxy MOTD from server
-			remoteConn, err := o.connectServer(ctx, metadata)
+			var remoteConn net.Conn
+			remoteConn, err = o.connectServer(ctx, metadata)
 			if err != nil {
 				return common.Cause("request remote MOTD: ", err)
 			}
@@ -261,7 +267,7 @@ func (o *Outbound) InjectConnection(ctx context.Context, conn *bufio.CachedConn,
 				Writer: common.UnwrapWriter(conn), // unwrap to make writev syscall possible
 				Conn:   conn,
 			}
-			err := clientMC.WriteVectorizedPacket(buffer, motd)
+			err = clientMC.WriteVectorizedPacket(buffer, motd)
 			if err != nil {
 				return common.Cause("respond MOTD: ", err)
 			}
@@ -366,26 +372,16 @@ func (o *Outbound) InjectConnection(ctx context.Context, conn *bufio.CachedConn,
 		binary.BigEndian.PutUint16(buffer.Extend(2), port)
 		buffer.WriteByte(mcprotocol.NextStateLogin)
 		mcprotocol.AppendPacketLength(buffer, buffer.Len())
-		// construct login packet
-		loginPacketSize := 2 + len(metadata.Minecraft.PlayerName) // should not exceed 127
-		hasUUID := false
-		if metadata.Minecraft.UUID != [16]byte{} { // is not empty
-			loginPacketSize += 16
-			hasUUID = true
-		}
-		buffer.WriteByte(byte(loginPacketSize))
-		buffer.WriteByte(0) // Server bound : Login Start
-		buffer.WriteByte(byte(len(metadata.Minecraft.PlayerName)))
-		buffer.WriteString(metadata.Minecraft.PlayerName)
-		if hasUUID {
-			buffer.Write(metadata.Minecraft.UUID[:])
-		}
-		_, err = serverConn.Write(buffer.Bytes())
+		// write handshake and login packet
+		cache := conn.Cache()
+		vector := net.Buffers{buffer.Bytes(), cache.Bytes()}
+		_, err = vector.WriteTo(serverConn)
 		buffer.Release()
 		if err != nil {
 			serverConn.Close()
 			return common.Cause("server handshake: ", err)
 		}
+		cache.Advance(cache.Len()) // all written
 		o.logger.Info().Str("id", metadata.ConnectionID).Str("outbound", o.config.Name).
 			Str("player", metadata.Minecraft.PlayerName).Msg("Created Minecraft connection")
 		o.onlineCount.Add(1)

diff --git a/protocol/minecraft/sniff.go b/protocol/minecraft/sniff.go
@@ -2,6 +2,7 @@ package minecraft
 
 import (
 	"errors"
+	"io"
 	"time"
 
 	"github.com/layou233/zbproxy/v3/adapter"
@@ -85,6 +86,7 @@ func SniffClientHandshake(conn bufio.PeekConn, metadata *adapter.Metadata) error
 	}
 	metadata.Minecraft.NextState = int8(nextState)
 
+	metadata.Minecraft.SniffPosition = conn.CurrentPosition()
 	if nextState == mcprotocol.NextStateStatus {
 		// status packet
 		conn.SetReadDeadline(time.Now().Add(10 * time.Second))
@@ -99,9 +101,6 @@ func SniffClientHandshake(conn bufio.PeekConn, metadata *adapter.Metadata) error
 		if err != nil {
 			return common.Cause("read packet size: ", err)
 		}
-		if packetSize > 33 { // maximum possible size of this kind of packet
-			return ErrBadPacket
-		}
 		conn.SetReadDeadline(time.Now().Add(10 * time.Second))
 		packetContent, err = conn.Peek(int(packetSize))
 		if err != nil {
@@ -120,11 +119,52 @@ func SniffClientHandshake(conn bufio.PeekConn, metadata *adapter.Metadata) error
 		if err != nil {
 			return common.Cause("read player name: ", err)
 		}
-		if buffer.Len() == 16 { // UUID exists
-			copy(metadata.Minecraft.UUID[:], buffer.Bytes())
+		if metadata.Minecraft.ProtocolVersion >= 764 { // 1.20.2
+			if buffer.Len() == 16 { // UUID exists
+				copy(metadata.Minecraft.UUID[:], buffer.Bytes())
+			}
+		} else if metadata.Minecraft.ProtocolVersion >= 761 { // 1.19.3
+			var hasUUID byte
+			hasUUID, err = buffer.ReadByte()
+			if err != nil {
+				return common.Cause("read has UUID: ", err)
+			}
+			if hasUUID == mcprotocol.BooleanTrue {
+				copy(metadata.Minecraft.UUID[:], buffer.Bytes())
+			}
+		} else if metadata.Minecraft.ProtocolVersion >= 759 { // 1.19
+			var hasSigData byte
+			hasSigData, err = buffer.ReadByte()
+			if err != nil {
+				return common.Cause("read has sig data: ", err)
+			}
+			if hasSigData == mcprotocol.BooleanTrue {
+				// skip timestamp
+				buffer.Advance(8) // size of Long
+				var length int32
+				// skip public key
+				length, _, err = mcprotocol.ReadVarIntFrom(buffer)
+				if err != nil {
+					return common.Cause("read public key length: ", err)
+				}
+				buffer.Advance(int(length))
+				// skip signature
+				length, _, err = mcprotocol.ReadVarIntFrom(buffer)
+				if err != nil {
+					return common.Cause("read signature length: ", err)
+				}
+				buffer.Advance(int(length))
+			}
+			var hasUUID byte
+			hasUUID, err = buffer.ReadByte()
+			if err != nil && err != io.EOF {
+				return common.Cause("read has UUID: ", err)
+			}
+			if hasUUID == mcprotocol.BooleanTrue {
+				copy(metadata.Minecraft.UUID[:], buffer.Bytes())
+			}
 		}
 	}
 
-	metadata.Minecraft.SniffPosition = conn.CurrentPosition()
 	return nil
 }
diff --git a/protocol/sniff.go b/protocol/sniff.go
@@ -33,7 +33,7 @@ func Sniff(logger *log.Logger, conn bufio.PeekConn, metadata *adapter.Metadata,
 			if metadata.Minecraft == nil {
 				err = minecraft.SniffClientHandshake(conn, metadata)
 				if err != nil {
-					logger.Trace().Str("protocol", protocol).Err(err).Msg("sniff error")
+					logger.Trace().Str("protocol", protocol).Err(err).Msg("Sniff error")
 				}
 			}
 			if !sniffAll {
@@ -48,21 +48,21 @@ func Sniff(logger *log.Logger, conn bufio.PeekConn, metadata *adapter.Metadata,
 				for _, snifferFunc := range registry {
 					err = snifferFunc(logger, conn, metadata)
 					if err != nil {
-						logger.Trace().Str("protocol", protocol).Err(err).Msg("sniff error")
+						logger.Trace().Str("protocol", protocol).Err(err).Msg("Sniff error")
 					}
 				}
 				return
 			} else if len(registry) > 0 {
 				if snifferFunc := registry[protocol]; snifferFunc != nil {
 					err = snifferFunc(logger, conn, metadata)
 					if err != nil {
-						logger.Trace().Str("protocol", protocol).Err(err).Msg("sniff error")
+						logger.Trace().Str("protocol", protocol).Err(err).Msg("Sniff error")
 					}
 				} else {
-					logger.Fatal().Str("protocol", protocol).Msg("unsupported protocol")
+					logger.Fatal().Str("protocol", protocol).Msg("Unsupported protocol")
 				}
 			} else {
-				logger.Fatal().Str("protocol", protocol).Msg("unsupported protocol")
+				logger.Fatal().Str("protocol", protocol).Msg("Unsupported protocol")
 			}
 		}
 		conn.Rewind(startPosition)

diff --git a/route/router.go b/route/router.go
@@ -142,11 +142,11 @@ func (r *Router) HandleConnection(conn net.Conn, metadata *adapter.Metadata) {
 		}
 		r.access.RUnlock()
 		err = bufio.CopyConn(destinationConn, cachedConn)
-		logger := r.logger.Warn().Str("id", metadata.ConnectionID).Str("outbound", outbound.Name())
 		if err != nil {
-			logger = logger.Err(err)
+			r.logger.Warn().Str("id", metadata.ConnectionID).Str("outbound", outbound.Name()).Err(err).Msg("Handled connection")
+		} else {
+			r.logger.Info().Str("id", metadata.ConnectionID).Str("outbound", outbound.Name()).Msg("Handled connection")
 		}
-		logger.Msg("Handled connection")
 		cachedConn.Close()
 		return
 	}