password: ask for it, but don't tell that S/key password required.
It looks like non-s/key system from outside.
Additionally tell that s/key required when it is so for normal case
It happens if 1) regular passwords not allowed, 2) skey database
not activated for given user.
Under some rare circumstanes skey_challenge can return empty
diagnostic or even previous buffer, fix it.
or addresses other than the requestor's address. This violates the FTP
protocol (hmm...as I write this, I'm going to change this to a run-time var.)
Require login before PASV and RNTO commands.
Close unused PASV ports so they don't hang around forever.
Do not allow file overwrites via rename or STOR when anonymous
(suspenders).
Clean up buffer utilization.
My code, but heavily inspired by Hobbit's changes to wu-ftpd as pointed out
by Mike Prettejohn and Kit Knox.
