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From: edhall@rand.org (Ed Hall)
Newsgroups: comp.unix.sysv386
Subject: Re: SECURITY BUG IN INTERACTIVE UNIX SYSV386
Message-ID: <1991Feb23.073721.7800@rand.org>
Date: 23 Feb 91 07:37:21 GMT
References: <7667@crash.cts.com> <4507@alliant.Alliant.COM>
Sender: news@rand.org
Reply-To: edhall@rand.org
Organization: The RAND Corporation
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Originator: edhall@ives

In article <4507@alliant.Alliant.COM> werme@Alliant.COM (Ric Werme) writes:
>In article <7667@crash.cts.com> jca@pnet01.cts.com (John C. Archambeau) writes:
>I'd be inclined to put the FP regs in a completely separate page, either a
>page in the U area or a page pointed at by the U area and swapped separately.

Ah, but remember, the '386 has segmentation as well!  Just put the
u structure out of reach for the default segments, and add another
segment that only covers the FP register area.  Of course, this would
mean that the emulator would probably have to reload a segment register
or two, but that's lots faster than entering the kernel.  I suspect
there are other ways, though...

		-Ed Hall
		edhall@rand.org