How to better update a jail host system

[Alexander Leidinger]

Quoting "Andrew Hotlab" <andrew.hotlab at hotmail.com> (Wed, 2 Jan 2008 13:12:24 +0100):

> --------------------------------------------------
> From: "Alexander Leidinger" <Alexander at Leidinger.net>
> Sent: Sunday, December 30, 2007 12:41 AM
> To: "Andrew Hotlab" <andrew.hotlab at hotmail.com>
> Cc: "FreeBSD-Jail" <freebsd-jail at freebsd.org>
> Subject: Re: How to better update a jail host system
> 
> >> I've spent some time on the past days to find how to build a world
> >> which contains only the "Binary base" and "man" distributions (as I
> >> always select from the sysinstall menu options during the first server
> >> setup), but I didn't found any article or man page which helped me.
> >
> > I don't know exactly what is in the binary and man dists, but what you 
> > need to do is either to just grab the new dists from an FTP server and 
> > extract them over the old ones, or to have a look what is installed by  a 
> > make world what is not in those dists and have a look for WITHOUT_  knobs 
> > which exclude those parts from the build/install. There may be  not enough 
> > WITHOU_ knobs to produce those dists, as they are generated  in a 
> > different way (make release).
> 
> Ok, thank you Alexander! But what do you think about upgrading the server on 
> the "installed binary distribution" basis? Perhaps it sounds good to me 
> because I'm coming from Windows Server experience (where it's important to 
> maintain only the Windows components you need, in order to reduce the attack 
> surface). Maintaining as few as possible binary distributions is so 
> important in FreeBSD too, or it helps only to grow unnecessary system 
> complexity?

If an attacker has access to a machine, he can probably transfer all
what he wants to the system. So often it doesn't matter if you have all
or files or not. If there's a problem with a SUID program in the
additional stuff, you may be more at risk at some point in time than
when you only install a limited set of stuff. Personally I would
install everything and maybe remove the SUID bit from stuff I don't use
(use a list of programs which are allowed to be SUID/SGID and remove all
SUID/SGID bits from files in this list after a search with "find /
-perm +06000 -print"). This can be scripted, and I think it is less
work to do it this way than to try to install only what is in a
distribution (but I may be biased, as I do all updates from source).

Bye,
Alexander.

-- 
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 "Ahhh!" -Fry 
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