Gate FUSE behind a runsc flag

This change gates all FUSE commands (by gating /dev/fuse) behind a runsc
flag. In order to use FUSE commands, use the --fuse flag with the --vfs2
flag. Check if FUSE is enabled by running dmesg in the sandbox.

1 files changed, 10 insertions, 4 deletions

diff --git a/runsc/boot/vfs.go b/runsc/boot/vfs.go
index 6ee6fae04..56f4ba15d 100644
--- a/runsc/boot/vfs.go
+++ b/runsc/boot/vfs.go
@@ -86,9 +86,12 @@ func registerFilesystems(k *kernel.Kernel) error {
 		return fmt.Errorf("registering ttydev: %w", err)
 	}
 
-	if err := fuse.Register(vfsObj); err != nil {
-		return fmt.Errorf("registering fusedev: %w", err)
+	if kernel.FUSEEnabled {
+		if err := fuse.Register(vfsObj); err != nil {
+			return fmt.Errorf("registering fusedev: %w", err)
+		}
 	}
+
 	if err := tundev.Register(vfsObj); err != nil {
 		return fmt.Errorf("registering tundev: %v", err)
 	}
@@ -110,8 +113,11 @@ func registerFilesystems(k *kernel.Kernel) error {
 	if err := tundev.CreateDevtmpfsFiles(ctx, a); err != nil {
 		return fmt.Errorf("creating tundev devtmpfs files: %v", err)
 	}
-	if err := fuse.CreateDevtmpfsFile(ctx, a); err != nil {
-		return fmt.Errorf("creating fusedev devtmpfs files: %w", err)
+
+	if kernel.FUSEEnabled {
+		if err := fuse.CreateDevtmpfsFile(ctx, a); err != nil {
+			return fmt.Errorf("creating fusedev devtmpfs files: %w", err)
+		}
 	}
 	return nil
 }