generic: test for weaknesses in filesystem encryption

Add an xfstest which can detect some basic crypto mistakes that would
reduce the confidentiality guarantee provided by filesystem encryption.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>
4 files changed