cras.sh: Tighten minijail mount options.

Minijail mountpoints with tmpfs need these additional options to
prevent an attacker from use setuid binaries or executables.

BUG=None
TEST=cras still works

Change-Id: I3867ffc7dec3e7272fb5daf0cf007d4e8d4b1a74
Signed-off-by: Allen Webb <allenwebb@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1170182
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed