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From: dshr@eng.sun.COM (David Rosenthal)
Newsgroups: comp.windows.x
Subject: Re: Unix security additions
Message-ID: <9103262132.AA22287@devnull.Eng.Sun.COM>
Date: 26 Mar 91 21:27:34 GMT
Sender: tytso@athena.mit.edu (Theodore Y. Ts'o)
Organization: The Internet
Lines: 25

> In X any events created by a client program (the one that asks for things to be
> drawn in windows, not the thing that does all the drawing) have a bit set. Well
> it is a 16 or 32 bit field that gets set to a "non-zero" value, when makeing a
> MAC (is that the right term?).  I guess that you could make the non-zero value the
> clasifaction level of the progam that sends.  The only program that I know of that

This is not correct.  To quote from the protocol spec Section 1 [page 370
of the Digital Press 2nd edition]:

	Every event contains an 8-bit type code.  The most-significant
	bit in this code is set if the event was generated from a
	SendEvent request.

In other words,  there is only one bit of information transferred from the
server to the client,  not a 16 or 32-bit field whose value could be used.

General comment.  When making claims about what X does or does not do,
please do not depend on the arguments to the Xlib functions.  Read
the protocol specification to make sure what the real information
transferred between the server and the client is.

	David.