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

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* overlay window use-after-free (CVE-2023-1393, ZDI-CAN-19866,
    bsc#1209543)

OBS-URL: https://build.opensuse.org/package/show/X11:XOrg/xorg-x11-server?expand=0&rev=854
This commit is contained in:
Stefan Dirsch 2023-03-29 13:38:58 +00:00 committed by Git OBS Bridge
parent 8832186295
commit d2f12e3cf3
3 changed files with 53 additions and 0 deletions
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42
U_xserver-composite-Fix-use-after-free-of-the-COW.patch Normal file
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@ -0,0 +1,42 @@
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(+)
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

7
xorg-x11-server.changes
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@ -1,3 +1,10 @@
-------------------------------------------------------------------
Wed Mar 22 13:48:21 UTC 2023 - Stefan Dirsch <sndirsch@suse.com>
- U_xserver-composite-Fix-use-after-free-of-the-COW.patch
* overlay window use-after-free (CVE-2023-1393, ZDI-CAN-19866,
bsc#1209543)
-------------------------------------------------------------------
Tue Feb 7 14:35:33 UTC 2023 - Stefan Dirsch <sndirsch@suse.com>

4
xorg-x11-server.spec
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@ -242,6 +242,8 @@ Patch1940: U_xephyr-Don-t-check-for-SeatId-anymore.patch
Patch1960: u_sync-pci-ids-with-Mesa.patch
Patch1209543: U_xserver-composite-Fix-use-after-free-of-the-COW.patch
%description
This package contains the X.Org Server.
@ -400,6 +402,8 @@ sh %{SOURCE92} --verify . %{SOURCE91}
%patch1940 -p1
%patch1960 -p1
%patch1209543 -p1
%build
# We have some -z now related errors during X default startup (boo#1197994):
# - when loading modesetting: gbm_bo_get_plane_count