FreeBSD -- msdosfs data disclosure

Problem Description:
In certain cases using the truncate or ftruncate system call
to extend a file size populates the additional space in the file
with unallocated data from the underlying disk device, rather than
zero bytes.
Impact:
A user with write access to files on a msdosfs file system may
be able to read unintended data (for example, from a previously
deleted file).