The XTS cipher mode needs to be used with a cipher which has
a block size of 16 bytes. If a mis-matching block size is used,
the code will either corrupt memory beyond the IV array, or
not fully encrypt/decrypt the IV.
This fixes a memory corruption crash when attempting to use
cast5-128 with xts, since the former has an 8 byte block size.
A test case is added to ensure the cipher creation fails with
such an invalid combination.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
a5d2f44d0d