FreeBSD -- jail(2) information leak

Problem Description:
The jail(2) system call has not limited a visiblity of allocated
TTYs (the kern.ttys sysctl). This gives rise to an information
leak about processes outside the current jail.
Impact:
Attacker can get information about TTYs allocated on the host
or in other jails. Effectively, the information printed by “pstat
-t” may be leaked.