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Date:      Sun, 13 Sep 1998 22:15:26 +0200
From:      Mark Murray <mark@grondar.za>
To:        Chuck Robey <chuckr@mat.net>
Cc:        Brian Feldman <green@unixhelp.org>, William Woods <wwoods@cybcon.com>, FreebSD Current <freebsd-current@FreeBSD.ORG>
Subject:   Re: ssh port problem..... 
Message-ID:  <199809132015.WAA17429@gratis.grondar.za>
In-Reply-To: Your message of " Sun, 13 Sep 1998 12:52:42 -0400." <Pine.BSF.4.02A.9809131243570.343-200000@picnic.mat.net> 
References:  <Pine.BSF.4.02A.9809131243570.343-200000@picnic.mat.net> 

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Chuck Robey wrote:
> The problem is, for the gmp and z libs, those are system libs, but the
> lib callouts for them assume that they aren't system libs.  The
> difference is that you use a -L switch for non-system libs, to tell the
> compiler where to look for them.  You *don't* do that for sytem libs,
> the system does that.  This is most especially critically important for
> FreeBSD-current, where the lib situation is (shall we say) a little
> muddy right now.  Those -L/usr/lib switches have to go away.  They're
> encapsulated in the patch-ac.  I included a new patch-ac with a couple
> of small edits to take the -L's out of libz and libgmp.

Chuck is speaking a large measure of truth. When a port has a certain
library, and the os has the _same_ library, the port must not use its
own copy of that library unless it has diverged far enough to be
considered a different package.

> Doing this, tho, I think might have some impact on security.  I don't
> know what it is.  I hope maybe someone who knows security might comment.
> Don't have to know ports, just tell me if the concept is good or bad, or
> what other solution _would_ be PC for a security-type application.

Correct. Many software authors package useful (but not very common)
libraries with their sources. (SSH includes libz and libgmp, exim
includes libident). This is a nasty practice, as it prevents the
OS authors' patches from providing that OS's enhancements _and_security_
fixes_ from taking effect.

<RAVE>
Taking this practice to its (extreme) logical conclusion, one might
see software _ignoring_ the system libraries, and attempting to be
reliant only on syscalls or (2) calls. Highly bogus! The security-
minded programmer/sysadmin wants to see as much of the system-provided
services as possible (particularly if that system is responsive to
security-related bugs) looked after by the system, and not by
third party add-ons.

SSH is an interesting case; by itself, it is a "third-party-addon";
but it is also very dependant on the host OS for certain bits. It
relies on the host for file-system security, port security, memory
protection and so on. It and its ilk should be given as much OS-
provided protection as possible, and its own provided sources
should be as limited as possible to that which is specific to
what it needs do do; the rest is the OS's (hopefully audited)
"stuff". When the author notices a security hole, his job is
not to silently patch it deep in his own enhancement of some
system library, but to report it to the OS authors, for inclusion
in future fixes, and provide that info to users who wish to fix
their own environments.

FreeBSD has libraries; they work; use them. If they are broken,
fix them, don't work around them.
</RAVE>

M
--
Mark Murray
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