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a4f0e9466f
The cursor in DIX is actually split in two parts, the cursor itself and
the cursor bits, each with their own devPrivates.
The cursor itself includes the cursor bits, meaning that the cursor bits
devPrivates in within structure of the cursor.
Both Xephyr and Xwayland were using the private key for the cursor bits
to store the data for the cursor, and when using XSELINUX which comes
with its own special devPrivates, the data stored in that cursor bits'
devPrivates would interfere with the XSELINUX devPrivates data and the
SELINUX security ID would point to some other unrelated data, causing a
crash in the XSELINUX code when trying to (re)use the security ID.
CVE-2024-0409
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit
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| .. | ||
| man | ||
| .gitignore | ||
| ephyr.c | ||
| ephyr.h | ||
| ephyr_draw.c | ||
| ephyr_glamor_glx.c | ||
| ephyr_glamor_glx.h | ||
| ephyr_glamor_xv.c | ||
| ephyrcursor.c | ||
| ephyrinit.c | ||
| ephyrlog.h | ||
| ephyrvideo.c | ||
| hostx.c | ||
| hostx.h | ||
| Makefile.am | ||
| meson.build | ||
| README | ||
Xephyr README
=============
What Is It ?
============
Xephyr is a a kdrive server that outputs to a window on a pre-existing
'host' X display. Think Xnest but with support for modern extensions
like composite, damage and randr.
Unlike Xnest which is an X proxy, i.e. limited to the
capabilities of the host X server, Xephyr is a real X server which
uses the host X server window as "framebuffer" via fast SHM XImages.
It also has support for 'visually' debugging what the server is
painting.
How To Use
==========
You probably want to run like;
Xephyr :1 -ac -screen 800x600 &
Then set DISPLAY=:1 and run whatever X apps you like.
Use 'xrandr' to change to orientation/size.
There is a '-parent' switch which works just like Xnest's ( for use
with things like matchbox-nest - http://matchbox.handhelds.org ).
There is also a '-host-cursor' switch to set 'cursor acceleration' -
The host's cursor is reused. This is only really there to aid
debugging by avoiding server paints for the cursor. Performance
improvement is negligible.
Send a SIGUSR1 to the server ( eg kill -USR1 `pidof Xephyr` ) to
toggle the debugging mode. In this mode red rectangles are painted to
screen areas getting painted before painting the actual content. The
delay between this can be altered by setting a XEPHYR_PAUSE env var to
a value in microseconds.
Caveats
=======
- Depth is limited to being the same as the host.
*Update* As of 8/11/2004. Xephyr can now do 8bpp & 16bpp
on 24bpp host.
- Rotated displays are currently updated via full blits. This
is slower than a normal oprientated display. Debug mode will
therefore not be of much use rotated.
- The '-host-cursor' cursor is static in its appearance.
- The build gets a warning about 'nanosleep'. I think the various '-D'
build flags are causing this. I haven't figured as yet how to work
around it. It doesn't appear to break anything however.
- Keyboard handling is basic but works.
- Mouse button 5 probably won't work.
Matthew Allum <mallum@o-hand.com> 2004