File U_xwayland-Avoid-a-crash-on-pointer-enter-with-... of Package xorg-x11-server

Overview Repositories Revisions Requests Users Attributes Meta

File U_xwayland-Avoid-a-crash-on-pointer-enter-with-a-grab.patch of Package xorg-x11-server (Revision 6976f53306cd562ef3573a1aa94cfc77)

Currently displaying revision 6976f53306cd562ef3573a1aa94cfc77 , Show latest

From 6711b5c6fdf0581c77150306fff909d7bc63b8a4 Mon Sep 17 00:00:00 2001
From: Olivier Fourdan <ofourdan@redhat.com>
Date: Thu, 9 May 2019 10:36:19 +0200
Subject: [PATCH] xwayland: Avoid a crash on pointer enter with a grab

On pointer enter notification, Xwayland checks for an existing pointer
warp with a `NULL` sprite.

In turn, `xwl_pointer_warp_emulator_maybe_lock()` checks for an existing
grab and the destination window using `XYToWindow()` which does not
check for the actual sprite not being `NULL`.

So, in some cases, when the pointer enters the surface and there is an
existing X11 grab which is not an ownerEvents grab, Xwayland would crash
trying to dereference the `NULL` sprite pointer:

#0  __GI_raise ()
  #1  __GI_abort () at abort.c:79
  #2  OsAbort () at utils.c:1351
  #3  AbortServer () at log.c:879
  #4  FatalError () at log.c:1017
  #5  OsSigHandler () at osinit.c:156
  #6  OsSigHandler () at osinit.c:110
  #7  <signal handler called>
  #8  XYToWindow (pSprite=0x0, x=0, y=0) at events.c:2880
  #9  xwl_pointer_warp_emulator_maybe_lock () at xwayland-input.c:2673
  #10 pointer_handle_enter () at xwayland-input.c:434

Avoid the crash by simply checking for the sprite being not `NULL` in
`xwl_pointer_warp_emulator_maybe_lock()`

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/1708119
(cherry picked from commit 0a07446318f248b65fcbc8ab8a73ead51153f09e)
---
 hw/xwayland/xwayland-input.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/xwayland/xwayland-input.c b/hw/xwayland/xwayland-input.c
index fbbcb39cc..fa46ac3e7 100644
--- a/hw/xwayland/xwayland-input.c
+++ b/hw/xwayland/xwayland-input.c
@@ -2667,6 +2667,7 @@ xwl_pointer_warp_emulator_maybe_lock(struct xwl_pointer_warp_emulator *warp_emul
      */
     if (pointer_grab &&
         !pointer_grab->ownerEvents &&
+        sprite &&
         XYToWindow(sprite, x, y) != xwl_seat->focus_window->window)
         return;
 
-- 
2.16.4

Places

File U_xwayland-Avoid-a-crash-on-pointer-enter-with-a-grab.patch of Package xorg-x11-server (Revision 6976f53306cd562ef3573a1aa94cfc77)

Places