Fix overwrite of user info due to buffer re-use

[rbdr/mobius] / hotline / server.go

diff --git a/hotline/server.go b/hotline/server.go
index ec835228607d8f3052d858b24a2c9b8b1320a914..bd15a2ecea697b8ed88a2e34c29e870b6866e034 100644 (file)
--- a/hotline/server.go
+++ b/hotline/server.go
@@ -34,6 +34,7 @@ type requestCtx struct {
 }
 
 var nostalgiaVersion = []byte{0, 0, 2, 0x2c} // version ID used by the Nostalgia client
+var frogblastVersion = []byte{0, 0, 0, 0xb9} // version ID used by the Frogblast 1.2.4 client
 
 type Server struct {
        Port          int
@@ -564,8 +565,13 @@ func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser
 
        scanner.Scan()
 
+       // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
+       // scanner re-uses the buffer for subsequent scans.
+       buf := make([]byte, len(scanner.Bytes()))
+       copy(buf, scanner.Bytes())
+
        var clientLogin Transaction
-       if _, err := clientLogin.Write(scanner.Bytes()); err != nil {
+       if _, err := clientLogin.Write(buf); err != nil {
                return err
        }
 
@@ -667,7 +673,7 @@ func (s *Server) handleNewConnection(ctx context.Context, rwc io.ReadWriteCloser
        }
 
        // Used simplified hotline v1.2.3 login flow for clients that do not send login info in tranAgreed
-       if c.Version == nil || bytes.Equal(c.Version, nostalgiaVersion) {
+       if c.Version == nil || bytes.Equal(c.Version, nostalgiaVersion) || bytes.Equal(c.Version, frogblastVersion) {
                c.Agreed = true
                c.logger = c.logger.With("name", string(c.UserName))
                c.logger.Infow("Login successful", "clientVersion", fmt.Sprintf("%v", func() int { i, _ := byteToInt(c.Version); return i }()))
@@ -748,6 +754,10 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro
                delete(s.fileTransfers, t.ReferenceNumber)
                s.mux.Unlock()
 
+               // Wait a few seconds before closing the connection: this is a workaround for problems
+               // observed with Windows clients where the client must initiate close of the TCP connection before
+               // the server does.  This is gross and seems unnecessary.  TODO: Revisit?
+               time.Sleep(3 * time.Second)
        }()
 
        s.mux.Lock()
@@ -782,7 +792,9 @@ func (s *Server) handleFileTransfer(ctx context.Context, rwc io.ReadWriter) erro
        case FileDownload:
                s.Stats.DownloadCounter += 1
                s.Stats.DownloadsInProgress += 1
-               defer func() { s.Stats.DownloadsInProgress -= 1 }()
+               defer func() {
+                       s.Stats.DownloadsInProgress -= 1
+               }()
 
                var dataOffset int64
                if fileTransfer.fileResumeData != nil {