[34753] in bugtraq
Re: http://www.smashguard.org
daemon@ATHENA.MIT.EDU (Nicholas Weaver)
Sat May 1 11:38:32 2004
Date: Fri, 30 Apr 2004 19:12:56 -0700
From: Nicholas Weaver <nweaver@CS.berkeley.edu>
To: Pavel Machek <pavel@ucw.cz>
Cc: Crispin Cowan <crispin@immunix.com>,
Hilmi Ozdoganoglu <cyprian@purdue.edu>,
Dave Paris <dparis@w3works.com>, bugtraq@securityfocus.com
Message-ID: <20040430191256.A32458@ring.CS.Berkeley.EDU>
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In-Reply-To: <20040429232921.GD8232@elf.ucw.cz>; from pavel@ucw.cz on Fri, Apr 30, 2004 at 01:29:21AM +0200
On Fri, Apr 30, 2004 at 01:29:21AM +0200, Pavel Machek composed:
> Well.. they are not really separate bits.
>
> If they was, you'd have ---, --x, r--, r-x. You can't have --x
> combination (which is sad for the emulators).
>
> I believe that on most sane architectures (m68k at least), you can
> have all 4 combinations.
Silly confusion time:
The key is good separation of WRITE and EXECUTE. Far too many CPUs
don't have separate TLB bits for writeable and executable.
--
Nicholas C. Weaver nweaver@cs.berkeley.edu
