xserver/hw
Olivier Fourdan baa2531501 xwayland: Fix a segfault with pointer locking
Xwayland would crash in some circumstances while trying to issue a
pointer locking when the cursor is hidden when there is no seat focus
window set.

The crash signature looks like:

 #0  zwp_pointer_constraints_v1_lock_pointer ()
 #1  xwl_pointer_warp_emulator_lock () at xwayland-input.c:2584
 #2  xwl_seat_maybe_lock_on_hidden_cursor () at xwayland-input.c:2756
 #3  xwl_seat_maybe_lock_on_hidden_cursor () at xwayland-input.c:2765
 #4  xwl_seat_cursor_visibility_changed () at xwayland-input.c:2768
 #5  xwl_set_cursor () at xwayland-cursor.c:245
 #6  miPointerUpdateSprite () at mipointer.c:468
 #7  miPointerDisplayCursor () at mipointer.c:206
 #8  CursorDisplayCursor () at cursor.c:150
 #9  AnimCurDisplayCursor () at animcur.c:220
 #10 ChangeToCursor () at events.c:936
 #11 ActivatePointerGrab () at events.c:1542
 #12 GrabDevice () at events.c:5120
 #13 ProcGrabPointer () at events.c:4908
 #14 Dispatch () at dispatch.c:478
 #15 dix_main () at main.c:276

xwl_pointer_warp_emulator_lock() tries to use the surface from the
xwl_seat->focus_window leading to a NULL pointer dereference when that
value is NULL.

Check that xwl_seat->focus_window is not NULL earlier in the stack in
xwl_seat_maybe_lock_on_hidden_cursor() and return early if not the case
to avoid the crash.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=102474
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit cdd0352ba0)
2017-09-25 15:34:10 -04:00
..
dmx dmx: Fix null pointer dereference 2017-09-22 18:45:59 +02:00
kdrive xephyr: Check for host XVideo support before trying to use it 2017-09-22 18:45:59 +02:00
vfb Remove fd_set from Block/Wakeup handler API 2016-07-18 15:27:51 -04:00
xfree86 dri2: Sync i965_pci_ids.h from Mesa. 2017-09-25 15:34:10 -04:00
xnest Remove fd_set from Block/Wakeup handler API 2016-07-18 15:27:51 -04:00
xquartz os: Handle SIGABRT 2017-09-25 15:34:10 -04:00
xwayland xwayland: Fix a segfault with pointer locking 2017-09-25 15:34:10 -04:00
xwin hw/xwin: Add 'dri' to DIST_SUBDIRS 2016-09-16 10:57:23 -07:00
Makefile.am Xwayland DDX 2014-04-03 15:19:22 -07:00