Fix for CVE-2023-1393

Resolves: rhbz#2180296

0001-composite-Fix-use-after-free-of-the-COW.patch

@@ -0,0 +1,42 @@
+From 26ef545b3502f61ca722a7a3373507e88ef64110 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(+)
+
+diff --git a/composite/compwindow.c b/composite/compwindow.c
+index 4e2494b86..b30da589e 100644
+--- a/composite/compwindow.c
++++ b/composite/compwindow.c
+@@ -620,6 +620,11 @@ 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;
+ }
+-- 
+2.40.0
+

xorg-x11-server.spec

@@ -46,7 +46,7 @@
 Summary:   X.Org X11 X server
 Name:      xorg-x11-server
 Version:   1.20.11
-Release:   15%{?gitdate:.%{gitdate}}%{?dist}
+Release:   16%{?gitdate:.%{gitdate}}%{?dist}
 URL:       http://www.x.org
 License:   MIT
 Group:     User Interface/X
@@ -145,6 +145,8 @@ Patch10024: 0007-xkb-reset-the-radio_groups-pointer-to-NULL-after-fre.patch
 Patch10025: 0008-Xext-fix-invalid-event-type-mask-in-XTestSwapFakeInp.patch
 # CVE-2023-0494
 Patch10026: 0001-Xi-fix-potential-use-after-free-in-DeepCopyPointerCl.patch
+# CVE-2023-1393
+Patch10027: 0001-composite-Fix-use-after-free-of-the-COW.patch
 
 BuildRequires: make
 BuildRequires: systemtap-sdt-devel
@@ -572,6 +574,10 @@ find %{inst_srcdir}/hw/xfree86 -name \*.c -delete
 
 
 %changelog
+* Fri Mar 31 2023 Olivier Fourdan <ofourdan@redhat.com> - 1.20.11-16
+- CVE fix for: CVE-2023-1393
+  Resolves: rhbz#2180296
+
 * Wed Feb 22 2023 Olivier Fourdan <ofourdan@redhat.com> - 1.20.11-15
 - Rebuild for the missing debuginfo
   Related: rhbz#2169522