From 10cafd0bbebfbb92c4e73088ba168ef96fcb983c Mon Sep 17 00:00:00 2001
From: Alan Coopersmith <alan.coopersmith@oracle.com>
Date: Sun, 8 Sep 2024 11:03:41 -0700
Subject: [PATCH] dix: dixChangeWindowProperty: don't call memcpy if malloc
 failed
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It shouldn't matter, since it would have a length of 0, but it
clears warnings from gcc 14.1:

../dix/property.c: In function ‘dixChangeWindowProperty’:
../dix/property.c:287:9: warning: use of possibly-NULL ‘data’ where
 non-null expected [CWE-690] [-Wanalyzer-possible-null-argument]
  287 |         memcpy(data, value, totalSize);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../dix/property.c:324:13: warning: use of possibly-NULL ‘data’ where
 non-null expected [CWE-690] [-Wanalyzer-possible-null-argument]
  324 |             memcpy(data, value, totalSize);
      |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1673>
---
 dix/property.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/dix/property.c b/dix/property.c
index 435450973..b51b371f0 100644
--- a/dix/property.c
+++ b/dix/property.c
@@ -280,11 +280,13 @@ dixChangeWindowProperty(ClientPtr pClient, WindowPtr pWin, Atom property,
         if (!pProp)
             return BadAlloc;
         data = malloc(totalSize);
-        if (!data && len) {
-            dixFreeObjectWithPrivates(pProp, PRIVATE_PROPERTY);
-            return BadAlloc;
+        if (totalSize) {
+            if (!data) {
+                dixFreeObjectWithPrivates(pProp, PRIVATE_PROPERTY);
+                return BadAlloc;
+            }
+            memcpy(data, value, totalSize);
         }
-        memcpy(data, value, totalSize);
         pProp->propertyName = property;
         pProp->type = type;
         pProp->format = format;
@@ -317,9 +319,11 @@ dixChangeWindowProperty(ClientPtr pClient, WindowPtr pWin, Atom property,
 
         if (mode == PropModeReplace) {
             data = malloc(totalSize);
-            if (!data && len)
-                return BadAlloc;
-            memcpy(data, value, totalSize);
+            if (totalSize) {
+                if (!data)
+                    return BadAlloc;
+                memcpy(data, value, totalSize);
+            }
             pProp->data = data;
             pProp->size = len;
             pProp->type = type;