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Date:   Tue, 1 Sep 2020 16:42:17 +0100
From:   Mark Rutland <mark.rutland@arm.com>
To:     =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= <mic@digikod.net>
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Subject: Re: [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor
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On Wed, Aug 19, 2020 at 08:53:42PM +0200, Mickaël Salaün wrote:
> On 12/08/2020 12:06, Mark Rutland wrote:
> > Contemporary W^X means that a given virtual alias cannot be writeable
> > and executeable simultaneously, permitting (a) and (b). If you read the
> > references on the Wikipedia page for W^X you'll see the OpenBSD 3.3
> > release notes and related presentation make this clear, and further they
> > expect (b) to occur with JITS flipping W/X with mprotect().
> 
> W^X (with "permanent" mprotect restrictions [1]) goes back to 2000 with
> PaX [2] (which predates partial OpenBSD implementation from 2003).
> 
> [1] https://pax.grsecurity.net/docs/mprotect.txt
> [2] https://undeadly.org/cgi?action=article;sid=20030417082752

Thanks for the pointers!

Mark.