Nov 13, 2022 · Nov 13, 2022
diff --git a/agent/agent.go b/agent/agent.go
 },
 SubsystemHandlers: map[string]ssh.SubsystemHandler{
 "sftp": func(session ssh.Session) {
 ctx := session.Context()

 // Typically sftp sessions don't request a TTY, but if they do,
 // we must ensure the gliderlabs/ssh CRLF emulation is disabled.
 // Otherwise sftp will be broken. This can happen if a user sets
 // `RequestTTY force` in their SSH config.
 session.DisablePTYEmulation()

 var opts []sftp.ServerOption
 // https://github.com/coder/coder/issues/3620
 u, err := user.Current()
 if err != nil {
 a.logger.Warn(ctx, "get sftp working directory failed, unable to get current user", slog.Error(err))
 sshLogger.Warn(ctx, "get sftp working directory failed, unable to get current user", slog.Error(err))
 } else {
 opts = append(opts, sftp.WithServerWorkingDirectory(u.HomeDir))
 }

 server, err := sftp.NewServer(session, opts...)
 if err != nil {
 a.logger.Debug(session.Context(), "initialize sftp server", slog.Error(err))
 sshLogger.Debug(ctx, "initialize sftp server", slog.Error(err))
 return
 }
 defer server.Close()

 err = server.Serve()
 if errors.Is(err, io.EOF) {
 // Unless we call `session.Exit(0)` here, the client won't
 // receive `exit-status` because `(*sftp.Server).Close()`
 // calls `Close()` on the underlying connection (session),
 // which actually calls `channel.Close()` because it isn't
 // wrapped. This causes sftp clients to receive a non-zero
 // exit code. Typically sftp clients don't echo this exit
 // code but `scp` on macOS does (when using the default
 // SFTP backend).
 _ = session.Exit(0)
 return
 }
 a.logger.Debug(session.Context(), "sftp server exited with error", slog.Error(err))
 sshLogger.Warn(ctx, "sftp server closed with error", slog.Error(err))
 _ = session.Exit(1)
 },
 },
 }
Original file line number	Diff line number	Diff line change
Expand Up		@@ -476,6 +476,12 @@ func (a *agent) init(ctx context.Context) {
		},
		SubsystemHandlers: map[string]ssh.SubsystemHandler{
		"sftp": func(session ssh.Session) {
		ctx := session.Context()

		// Typically sftp sessions don't request a TTY, but if they do,
		// we must ensure the gliderlabs/ssh CRLF emulation is disabled.
		// Otherwise sftp will be broken. This can happen if a user sets
		// `RequestTTY force` in their SSH config.
		session.DisablePTYEmulation()

		var opts []sftp.ServerOption
Expand All		@@ -484,22 +490,33 @@ func (a *agent) init(ctx context.Context) {
		// https://github.com/coder/coder/issues/3620
		u, err := user.Current()
		if err != nil {
		a.logger.Warn(ctx, "get sftp working directory failed, unable to get current user", slog.Error(err))
		sshLogger.Warn(ctx, "get sftp working directory failed, unable to get current user", slog.Error(err))
		} else {
		opts = append(opts, sftp.WithServerWorkingDirectory(u.HomeDir))
		}

		server, err := sftp.NewServer(session, opts...)
		if err != nil {
		a.logger.Debug(session.Context(), "initialize sftp server", slog.Error(err))
		sshLogger.Debug(ctx, "initialize sftp server", slog.Error(err))
		return
		}
		defer server.Close()

		err = server.Serve()
		if errors.Is(err, io.EOF) {
		// Unless we call `session.Exit(0)` here, the client won't
		// receive `exit-status` because `(*sftp.Server).Close()`
		// calls `Close()` on the underlying connection (session),
		// which actually calls `channel.Close()` because it isn't
		// wrapped. This causes sftp clients to receive a non-zero
		// exit code. Typically sftp clients don't echo this exit
		// code but `scp` on macOS does (when using the default
		// SFTP backend).
		_ = session.Exit(0)
		return
		}
		a.logger.Debug(session.Context(), "sftp server exited with error", slog.Error(err))
		sshLogger.Warn(ctx, "sftp server closed with error", slog.Error(err))
		_ = session.Exit(1)
		},
		},
		}
Expand Down