suid bit files + securing FreeBSD (new program: LockDown)

[D J Hawkey Jr]

On Jul 27, at 03:52 PM, Socketd wrote:
> 
> On Sun, 27 Jul 2003 07:51:36 -0500
> D J Hawkey Jr <hawkeyd at visi.com> wrote:
> 
> > It could certainly be installed from the ports collection, but it
> > would be most useful to me (and p'raps others?) as a boot-time thang.
> > Think of dedicated firewalls and routers, especially those that boot
> > from custom CDs [and p'raps read floppies for "volatile"
> > configuration].
> > 
> > In my mind, the conf could be installed as /etc/rc.whatever, and the
> > program could be installed as /usr/local/etc/rc.d/whatever. In this
> > way, it'd be run on boot, and could be run anytime as
> > "/usr/local/etc/rc.d/whatever start", and p'raps as a cronjob, too.
> 
> Ah, good idea!
> 
> LockDown could search for ALL suid and gid files and set the
> permissions accordingly to the conf file, the files not listed there
> would be disabled (or set to a user specified default)...

Now you're thinking along the lines I'm thinking. Something of a system
hyper- or super-visor.

> ...But then again,
> if an admin installs a port with suid files and forget to add them to
> the LockDown conf file, they would be disabled the next time LockDown is
> executed.

We-ell, the admin ought not forget that, eh?  ;-,

The program could notify the admin in some manner or another when it
disables something - I've written a few scripts that mail a cell 'phone
or pager when they do something that should be known of when it happens.
A log entry via syslogd(8) is mandatory, of course.

> I have also thought about adding these options:
> 1. More kernel help, so you quickly can setup a kernel:
> 	kern_using_RAID=""		YES if you are using raid hardware
> 	kern_using_SCSI=""		YES if you are using SCSI hardware
> 	kern_using_IPv6=""		YES if you want to use IPv6
> 	kern_using_proc=""		YES if you want to use /proc
> 	kern_NIC=""			The nic's you use.
> 
> 2. Support for most of the files in /etc (and other?)
> 
> 3. Give security adwise:
> 	1. Setting up different daemons
> 	2. What ports to install
> 	3. How to setup scripts to be used with cron and what to
> 	   include in them

I wouldn't go too far "out of scope" too fast; you might end up re-writing
Tripwire!

I do like the idea of checking /etc... maybe... using cksum(1), or
something like that. I currently use local periodic(8) scripts, similar
to /etc/periodic/daily/2*, that backs up /etc, /etc/mail, and /etc/namedb.

Regarding the above comment about forgetful admins, they also have to
remember to update Tripwire's config file(s), don'tcha know.

> > Were you to go this way, I could see where Core might consider adding
> > your work into the base? I'd lobby for it.  :-)
> 
> My code in the base system...oh I don't even dare think the beautiful
> thought ;-)

NOTE: I'm not a committer! I only mention the possibility; I can't make
it so.

> > > I use C++
> > 
> > Oh. I was hoping you'd answer "shell script" (my preference, for quick
> > 'n easy modification), or "C".
> 
> Well, it could be written as a shell script, but I only know C++. If
> someone want to join this project and write the shell script, I would be
> happy to help with the overall design and documentation.

I've gotten pretty fluent with sh(1), awk(1), and sed(1). I could pro'lly
write what you envision in a shell script. I wouldn't want to re-write a
C++ program though; I'm not well versed in C++'s "nuances".

Dave

-- 
  ______________________                         ______________________
  \__________________   \    D. J. HAWKEY JR.   /   __________________/
     \________________/\     hawkeyd at visi.com    /\________________/
                      http://www.visi.com/~hawkeyd/