Incorrect argument handling in sendmsg(2)

To all the FreeBSD users out there, don’t forget to update your systems.

The sendmsg(2) system call allows to send data to a socket.  The data
may be accompanied by optional ancillary data.

For details please visit: https://www.freebsd.org/security/advisories/FreeBSD-SA-16:19.sendmsg.asc