From 737ba3c82c71c15de498f63527d264dc996ffa11 Mon Sep 17 00:00:00 2001
From: topimiettinen <topimiettinen@users.noreply.github.com>
Date: Mon, 16 May 2016 02:34:05 +0000
Subject: namespace: Make private /dev noexec and readonly (#3263)

Private /dev will not be managed by udev or others, so we can make it
noexec and readonly after we have made all device nodes. As /dev/shm
needs to be writable, we can't use bind_remount_recursive().
---
 man/systemd.exec.xml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'man')

diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index 2a93760428..3cf6de8256 100644
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -933,7 +933,10 @@
         (propagation in the opposite direction continues to work).
         This means that this setting may not be used for services
         which shall be able to install mount points in the main mount
-        namespace.</para></listitem>
+        namespace. The /dev namespace will be mounted read-only and 'noexec'.
+        The latter may break old programs which try to set up executable
+        memory by using <citerefentry><refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+        of <filename>/dev/zero</filename> instead of using <constant>MAP_ANON</constant>.</para></listitem>
       </varlistentry>
 
       <varlistentry>
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