[client,management] Rewrite the SSH feature (#4015)

client/cmd/ssh_sftp_windows.go

@@ -0,0 +1,94 @@
+//go:build windows
+
+package cmd
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/user"
+	"strings"
+
+	"github.com/pkg/sftp"
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+
+	sshserver "github.com/netbirdio/netbird/client/ssh/server"
+)
+
+var (
+	sftpWorkingDir  string
+	windowsUsername string
+	windowsDomain   string
+)
+
+var sshSftpCmd = &cobra.Command{
+	Use:    "sftp",
+	Short:  "SFTP server with user switching for Windows (internal use)",
+	Hidden: true,
+	RunE:   sftpMain,
+}
+
+func init() {
+	sshSftpCmd.Flags().StringVar(&sftpWorkingDir, "working-dir", "", "Working directory")
+	sshSftpCmd.Flags().StringVar(&windowsUsername, "windows-username", "", "Windows username for user switching")
+	sshSftpCmd.Flags().StringVar(&windowsDomain, "windows-domain", "", "Windows domain for user switching")
+}
+
+func sftpMain(cmd *cobra.Command, _ []string) error {
+	return sftpMainDirect(cmd)
+}
+
+func sftpMainDirect(cmd *cobra.Command) error {
+	currentUser, err := user.Current()
+	if err != nil {
+		cmd.PrintErrf("failed to get current user: %v\n", err)
+		os.Exit(sshserver.ExitCodeValidationFail)
+	}
+
+	if windowsUsername != "" {
+		expectedUsername := windowsUsername
+		if windowsDomain != "" {
+			expectedUsername = fmt.Sprintf(`%s\%s`, windowsDomain, windowsUsername)
+		}
+		if !strings.EqualFold(currentUser.Username, expectedUsername) && !strings.EqualFold(currentUser.Username, windowsUsername) {
+			cmd.PrintErrf("user switching failed\n")
+			os.Exit(sshserver.ExitCodeValidationFail)
+		}
+	}
+
+	log.Debugf("SFTP process running as: %s (UID: %s, Name: %s)", currentUser.Username, currentUser.Uid, currentUser.Name)
+
+	if sftpWorkingDir != "" {
+		if err := os.Chdir(sftpWorkingDir); err != nil {
+			cmd.PrintErrf("failed to change to working directory %s: %v\n", sftpWorkingDir, err)
+		}
+	}
+
+	sftpServer, err := sftp.NewServer(struct {
+		io.Reader
+		io.WriteCloser
+	}{
+		Reader:      os.Stdin,
+		WriteCloser: os.Stdout,
+	})
+	if err != nil {
+		cmd.PrintErrf("SFTP server creation failed: %v\n", err)
+		os.Exit(sshserver.ExitCodeShellExecFail)
+	}
+
+	log.Debugf("starting SFTP server")
+	exitCode := sshserver.ExitCodeSuccess
+	if err := sftpServer.Serve(); err != nil && !errors.Is(err, io.EOF) {
+		cmd.PrintErrf("SFTP server error: %v\n", err)
+		exitCode = sshserver.ExitCodeShellExecFail
+	}
+
+	if err := sftpServer.Close(); err != nil {
+		log.Debugf("SFTP server close error: %v", err)
+	}
+
+	os.Exit(exitCode)
+	return nil
+}