[Bf-blender-cvs] [7afd84df409] master: Fix possible use-after-free on error handling during VR view drawing

[Julian Eisel]

Commit: 7afd84df409ac40bc92faaa74181fa13015fe781
Author: Julian Eisel
Date:   Tue Dec 14 20:10:05 2021 +0100
Branches: master
https://developer.blender.org/rB7afd84df409ac40bc92faaa74181fa13015fe781

Fix possible use-after-free on error handling during VR view drawing

Whenever an exception happens in VR session code, we cancel the entire
session. Alongside that, we removed the "surface" item used to draw into
an offscreen context. But this may still be stored as active surface,
leading to a use-after-free when deactivating this active surface, for
example.

===================================================================

M	source/blender/windowmanager/intern/wm_surface.c

===================================================================

diff --git a/source/blender/windowmanager/intern/wm_surface.c b/source/blender/windowmanager/intern/wm_surface.c
index 72b68788e79..39bff205cbd 100644
--- a/source/blender/windowmanager/intern/wm_surface.c
+++ b/source/blender/windowmanager/intern/wm_surface.c
@@ -119,6 +119,9 @@ void wm_surface_add(wmSurface *surface)
 
 void wm_surface_remove(wmSurface *surface)
 {
+  if (surface == g_drawable) {
+    wm_surface_clear_drawable();
+  }
   BLI_remlink(&global_surface_list, surface);
   surface->free_data(surface);
   MEM_freeN(surface);