From fe0c050276c09f43cc1ae80b4553db42398ca84c Mon Sep 17 00:00:00 2001

From: Povilas Kanapickas <povilas@radix.lt>

Date: Tue, 14 Dec 2021 15:00:02 +0200

Subject: [PATCH xserver 3/4] Xext: Fix out of bounds access in

 SProcScreenSaverSuspend()

ZDI-CAN-14951, CVE-2021-4010

This vulnerability was discovered and the fix was suggested by:

Jan-Niklas Sohn working with Trend Micro Zero Day Initiative

Signed-off-by: Povilas Kanapickas <povilas@radix.lt>

(cherry picked from commit 6c4c53010772e3cb4cb8acd54950c8eec9c00d21)

---

 Xext/saver.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Xext/saver.c b/Xext/saver.c

index 1d7e3cadf..f813ba08d 100644

--- a/Xext/saver.c

+++ b/Xext/saver.c

@@ -1351,8 +1351,8 @@ SProcScreenSaverSuspend(ClientPtr client)

     REQUEST(xScreenSaverSuspendReq);

     swaps(&stuff->length);

-    swapl(&stuff->suspend);

     REQUEST_SIZE_MATCH(xScreenSaverSuspendReq);

+    swapl(&stuff->suspend);

     return ProcScreenSaverSuspend(client);

 }

-- 

2.33.1