Merge pull request opencontainers#1756 from rhatdan/selinux1

Label the masked tmpfs with the mount label

Author: Mrunal Patel

libcontainer/rootfs_linux.go

@@ -778,10 +778,10 @@ func remountReadonly(m *configs.Mount) error {
 // mounts ( proc/kcore ).
 // For files, maskPath bind mounts /dev/null over the top of the specified path.
 // For directories, maskPath mounts read-only tmpfs over the top of the specified path.
-func maskPath(path string) error {
+func maskPath(path string, mountLabel string) error {
 	if err := unix.Mount("/dev/null", path, "", unix.MS_BIND, ""); err != nil && !os.IsNotExist(err) {
 		if err == unix.ENOTDIR {
-			return unix.Mount("tmpfs", path, "tmpfs", unix.MS_RDONLY, "")
+			return unix.Mount("tmpfs", path, "tmpfs", unix.MS_RDONLY, label.FormatMountLabel("", mountLabel))
 		}
 		return err
 	}

libcontainer/standard_init_linux.go

@@ -110,7 +110,7 @@ func (l *linuxStandardInit) Init() error {
 		}
 	}
 	for _, path := range l.config.Config.MaskPaths {
-		if err := maskPath(path); err != nil {
+		if err := maskPath(path, l.config.Config.MountLabel); err != nil {
 			return err
 		}
 	}