utmp and friends

[Bill Nottingham]

Miroslav Lichvar (mlichvar at redhat.com) said: 
> > The entire idea of utempter is so that the terminal *doesn't* need to be
> > setgid - if it's setgid, what's the point of a helper?
> 
> Well, the terminal doesn't need to be setgid utmp, but only utempter.
> Setgid utempter allows only adding/removing entries in utmp while
> setgid utmp allows unrestricted access.

Only if it's coded wrong (doesn't drop privs, etc.). By adding a
setgid to the binary, you're making the point of separating it
merely a code-sharing issue, as opposed to any huge security gains.

I'd remove the block on the directory - basically, you're intentionally
breaking user's environments for illusory security.

Bill