Fix race in file upload handling that may cause panic

[rbdr/mobius] / hotline / server.go

diff --git a/hotline/server.go b/hotline/server.go
index 1da2859ba479773c65d3176ab3c87f41e34459b3..3a58893fdcc1858e5338bcc7f2273955448c187e 100644 (file)
--- a/hotline/server.go
+++ b/hotline/server.go
@@ -609,13 +609,14 @@ const dlFldrActionNextFile = 3
 func (s *Server) TransferFile(conn net.Conn) error {
        defer func() { _ = conn.Close() }()
 
-       buf := make([]byte, 1024)
-       if _, err := conn.Read(buf); err != nil {
+       txBuf := make([]byte, 16)
+       _, err := conn.Read(txBuf)
+       if err != nil {
                return err
        }
 
        var t transfer
-       _, err := t.Write(buf[:16])
+       _, err = t.Write(txBuf)
        if err != nil {
                return err
        }
@@ -667,11 +668,16 @@ func (s *Server) TransferFile(conn net.Conn) error {
                        }
                }
        case FileUpload:
-               if _, err := conn.Read(buf); err != nil {
+               const buffSize = 1460
+
+               uploadBuf := make([]byte, buffSize)
+
+               _, err := conn.Read(uploadBuf)
+               if err != nil {
                        return err
                }
 
-               ffo := ReadFlattenedFileObject(buf)
+               ffo := ReadFlattenedFileObject(uploadBuf)
                payloadLen := len(ffo.BinaryMarshal())
                fileSize := int(binary.BigEndian.Uint32(ffo.FlatFileDataForkHeader.DataSize))
 
@@ -691,9 +697,7 @@ func (s *Server) TransferFile(conn net.Conn) error {
 
                defer func() { _ = newFile.Close() }()
 
-               const buffSize = 1024
-
-               if _, err := newFile.Write(buf[payloadLen:]); err != nil {
+               if _, err := newFile.Write(uploadBuf[payloadLen:]); err != nil {
                        return err
                }
                receivedBytes := buffSize - payloadLen