From 6c4c53010772e3cb4cb8acd54950c8eec9c00d21 Mon Sep 17 00:00:00 2001
From: Povilas Kanapickas <povilas@radix.lt>
Date: Tue, 14 Dec 2021 15:00:02 +0200
Subject: [PATCH] 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>
---
 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);
 }
 
-- 
GitLab
