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From: herber@ssc-vax.UUCP (David A Wilson)
Newsgroups: comp.misc
Subject: access-lists vs. unix permissions
Message-ID: <1334@ssc-vax.UUCP>
Date: Tue, 14-Jul-87 19:13:24 EDT
Article-I.D.: ssc-vax.1334
Posted: Tue Jul 14 19:13:24 1987
Date-Received: Fri, 17-Jul-87 04:13:42 EDT
Organization: Boeing Aerospace Corp., Seattle WA
Lines: 27
Keywords: security

I have been encountering articles on computer security that refer to the
US Government Specification document, I believe it is known as the 'Orange
book'. The articles refer to requirements for computer security categories
referred to by designators such as: C1, C2, B1, B2, A1. There was an article
in Unix Review a few months ago about how unix fits in to these categories.
According to the article, Unix can satisfy levels up to C2 without any
significant changes, but no higher. The problem occurs at level B1 which
requires access-lists for files.

	The issue I would like to discuss is why are access-lists considered
more secure that unix-style owner/group/other permission(as the specification
seems to apply)? Are there any studies that show this? I can see no reason
that unix permissions cannot provide equivalent level of data access
protection to access-lists. With multiple group membership, such as provided
in BSD Unix, file access can be controlled to any level desired.

	Unix should be able to meet all other criteria specified in the
document without much change, if this requirement were changed to allow
unix-style permissions.

	Does anyone have any other thoughts on this subject?

David A. Wilson
uw-beaver!ssc-vax!herber  
-- 
	David A. Wilson
	uw-beaver!ssc-vax!iscland w