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Date: Fri, 11 Nov 2016 19:40:12 +0100
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Subject: PaX MPROTECT / W^X protection
From: cmbecker69@gmx.de ("Christoph M. Becker")

Hi!

There are currently at least two unresolved tickets[1][2] in our bug
tracker regarding PaX MPROTECT / W^X protection issues with regard to
PCRE JIT.  The problem is that PCRE JIT mmaps W|X pages[3], what is no
longer allowed on several platforms, such as OpenBSD, FreeBSD and
SELinux.  It seems that there are workarounds (e.g. using paxctl to
allow W|X mapping[1], or mounting with wxallowed[4]), but these appear
to be very system specific.

My best idea to resolve the reports is to document this issue.  Maybe
somebody has a better idea?

[1] <https://bugs.php.net/bug.php?id=72281>
[2] <https://bugs.php.net/bug.php?id=73114>
[3] <https://bugs.exim.org/show_bug.cgi?id=1749>
[4] <http://undeadly.org/cgi?action=article&sid=20160527203200>

-- 
Christoph M. Becker