Merge changes from apertis/v2022-security into apertis/v2022

debian/patches/21_composite-Fix-use-after-free-of-the-COW.patch

+From 947bd1b3f4a23565bf10879ec41ba06ebe1e1c76 Mon Sep 17 00:00:00 2001
+From: Olivier Fourdan <ofourdan@redhat.com>
+Date: Mon, 13 Mar 2023 11:08:47 +0100
+Subject: [PATCH xserver] composite: Fix use-after-free of the COW
+
+ZDI-CAN-19866/CVE-2023-1393
+
+If a client explicitly destroys the compositor overlay window (aka COW),
+we would leave a dangling pointer to that window in the CompScreen
+structure, which will trigger a use-after-free later.
+
+Make sure to clear the CompScreen pointer to the COW when the latter gets
+destroyed explicitly by the client.
+
+This vulnerability was discovered by:
+Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
+
+Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
+Reviewed-by: Adam Jackson <ajax@redhat.com>
+---
+ composite/compwindow.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+--- a/composite/compwindow.c
++++ b/composite/compwindow.c
+@@ -613,6 +613,11 @@ compDestroyWindow(WindowPtr pWin)
+     ret = (*pScreen->DestroyWindow) (pWin);
+     cs->DestroyWindow = pScreen->DestroyWindow;
+     pScreen->DestroyWindow = compDestroyWindow;
++
++    /* Did we just destroy the overlay window? */
++    if (pWin == cs->pOverlayWin)
++        cs->pOverlayWin = NULL;
++
+ /*    compCheckTree (pWin->drawable.pScreen); can't check -- tree isn't good*/
+     return ret;
+ }