The X server swapping code is a huge attack surface, much of this code
is untested and prone to security issues. The use-case of byte-swapped
clients is very niche, so allow users to disable this if they don't
need it, using either a config option or commandline flag.
For Xorg, this adds the ServerFlag "AllowByteSwappedClients" "off".
For all DDX, this adds the commandline options +byteswappedclients and
-byteswappedclients to enable or disable, respectively.
Fixes#1201
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
---
(cherry picked from commit 412777664a)
(cherry picked from commit af5cd5acc9012e527ee869f8e98bf6c2e9a02ca4)
Backport to server-21.1-branch modified to keep byte-swapping enabled
by default but easy to disable by users or admins (or even by distros
shipping an xorg.conf.d fragment in their packages).
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1440>
5d7272f05d