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Date:      Wed, 24 Apr 2002 10:21:54 +0200
From:      Jochem Kossen <j.kossen@home.nl>
To:        "Greg 'groggy' Lehey" <grog@FreeBSD.ORG>
Cc:        hackers@FreeBSD.org
Subject:   Re: Security through obscurity? (was: ssh + compiled-in SKEY support considered harmful?)
Message-ID:  <200204241021.54339.j.kossen@home.nl>
In-Reply-To: <20020424084444.N6425@wantadilla.lemis.com>
References:  <rwatson@FreeBSD.ORG> <200204231206.01451.j.kossen@home.nl> <20020424084444.N6425@wantadilla.lemis.com>

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On Wednesday 24 April 2002 01:14, you wrote:
> On Tuesday, 23 April 2002 at 12:06:01 +0200, Jochem Kossen wrote:
> > On Tuesday 23 April 2002 11:04, you wrote:
> > [...]
> >
> >>>> I've been noticing a continuing trend for more and more "safe"
> >>>> configurations the default.  I spent half a day recently trying
> >>>> to find why I could no longer open windows on my X display, only
> >>>> to discover that somebody had turned off tcp connections by
> >>>> default.
> >>>
> >>> *shrug* I was the one who sent in the patch. It was added some
> >>> time around 2001/10/26 to the XFree86-4 megaport. When the
> >>> metaport was created, the patch was incorporated too.
> >>>
> >>> A simple 'man startx' should have cleared your mind:
> >>
> >> Well, yes.  But I've been using X for 11 years.  Why should I have
> >> to read the man page to find changes?
> >
> > Because things evolve? :)
>
> Not a good reason.  If they evolve, the evolution should be more
> clearly documented.

Yep, I agree. It was a mistake to not document it further, so let's=20
solve that problem.

> >> How do I know which man page to read?
> >
> > You start X with startx, seems obvious to me. The disabling of tcp
> > connections only applies to startx
>
> I don't stay with startx.  Next I go to xinit, then to Xwrapper, then
> to X.  All of these work fine.  When I try to start an xterm, nothing
> happens.  So I read the haystack of man pages for all these programs
> looking for a possible needle?  That's 4314 lines of man pages
> (Xwrapper doesn't have a man page, so Murphy says that it's probably
> in Xwrapper).  Based on prior experience, startx would be the last
> place I would look.  In fact, I suspected a networking problem.

Hmm...yes, you're right about this!

> >> If I did that for everything that happened, I wouldn't get any
> >> work done.  And you can bet your bottom dollar that somebody
> >> coming from another UNIX variant and trying out FreeBSD won't do
> >> so.
> >
> > OK, then i suggest we mention it in the handbook, the security
> > policy document, the manpage AND the release notes :)
>
> You've heard my suggestions.

Yes, and I still like number 1 best (document it clearly)

> >> They'll just say that it's broken and wander off again.
>
> I note you don't comment on this one.

OK, hereby I do:

You're talking about users coming from a different UNIX OS. I think it's=20
reasonable for those users to expect differences in a different system.=20
Things like this are normal between different operating systems in my=20
opinion. That it should be documented far better, I agree (but i=20
already said that 1000 times now I believe)

I think the issue is mostly an annoying thing for users which already=20
have been using FreeBSD for a while. Suddenly something changes, and=20
stuff doesn't work anymore the way it used to do, just like with you.

> >>> In the case of the X patch, i'd add it to the release notes AND
> >>> the security policy document, since - i think - few people will
> >>> look in the security policy document for such a problem.
> >>
> >> I think it shouldn't happen at all unless people agree to it.
> >
> > 3 people did, 0 people did not...read below
>
> So only 3 people use X?  Get real.  You just haven't heard any
> objections up to now.  I found out about this several weeks ago, but
> I didn't complain because I was expecting replies with the
> perspective you're showing.

So what? You avoided the discussion? Apparently quite a few people agree=20
with you. IMHO if people want things to change for the better, people=20
need to speak up. Wether they are wrong or right doesn't really matter.=20
Discussions are a good way to come to a reasonable conclusion/solution.

> >>> I do have to say you're the first one I see who complains about
> >>> this...
> >>
> >> Maybe the others have given up.
> >
> > LOL
>
> THIS IS NO LAUGHING MATTER.  It's this kind of change which is going
> to stop people from using FreeBSD.

If this kind of thing happens too often(yeah yeah, "once is already too=20
often"), then yes, you're right i guess.

> >> But since we're on the subject, why?  What's so insecure about X
> >> TCP connections?  Until you explicitly allow connections, the only
> >> system that can open the server is the local system.
> >
> > For the simple reason I don't like useless open ports on my system.
> > I don't use it, _most_ other people don't use it, so i sent in a
> > patch.

> Fine, I'm not telling you how to run your system.  I don't want you
> telling me how to run my network.

I didn't, and I don't. I changed a default which seemed wrong to me.

But let's say you don't like something about FreeBSD, and you make a=20
change. You like the result. You show it to others, who also like the=20
result. What would you do when you think it really is an improvement?=20
send it in, or keep it to yourself?

>  I note that you still haven't given a good technical reason for it.

1) Other people in the thread have done so (X11 over ssh should be=20
encouraged among other things...)
2) Why would every change have to have a technical reason? I made this=20
patch for security reasons.
Security is not only a process of solving problems. It's _mostly_ a=20
process of taking precautions and solving problems BEFORE they occur.=20
IMHO I took a precaution here, which is a good enough reason to me.

When i sent in the patch, I didn't have a good _technical_ reason,=20
unless you consider security precautions itself as a technical reason.

> > Of course, it was only discussed on the ports@ mailinglist, but it
> > didn't seem like such a big deal to me or apparently the others...
>
> That doesn't help end users.  We have a user community out there.

True, thus we need to do something about it. So here are a few concrete=20
suggestions, also mentioned by others in the thread:

  - startx is just a normal shellscript. It could display a message like=20
this whenever you start it without the -listen_tcp option:

*** WARNING ***
startx has been defaulted to disable TCP connections for security=20
reasons.
If you require this, use 'startx -listen_tcp'
***************

  - Put a message like that in pkg-message
  - Add an environment variable like "X11TCP" which can be set to YES or=20
NO (I don't like the name "X11TCP" for this, anyone got a better=20
suggestion?)
  - Document it everywhere reasonable. Someone (I think Robert Watson)=20
mentioned "ports release notes" which sounds like a good thing to me=20
for things like this. Of course, this would only help for one release,=20
since at the next release it won't be in there anymore. Perhaps=20
deciding where to document it needs another -small- discussion on doc@

I'd like your response to the suggestions here...IMHO we should do these=20
all. If it's ok with you and others who read this message, I'll open a=20
PR on ports@ with a revised patch to startx with the pkg-message, the=20
warning when startx starts and startx which looks for the environment=20
variable.

If someone else wants to do it, or has better suggestions, please do and=20
let me/us know.

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