From c4642f26325f783ead12895897d34175e218a6a8 Mon Sep 17 00:00:00 2001
From: "Enrico Weigelt, metux IT consult" <info@metux.net>
Date: Tue, 6 May 2025 16:56:51 +0200
Subject: [PATCH] Xext: shape: fix warning on possible NULL dereference
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Try not to rely on deep black magic of calloc(), instead skip the whole
part of nrects is zero.

| ../Xext/shape.c: In function ‘ProcShapeGetRectangles’:
| ../Xext/shape.c:995:24: warning: dereference of possibly-NULL ‘rects’ [CWE-690] [-Wanalyzer-possible-null-dereference]
|   995 |             rects[i].x = box->x1;
|       |             ~~~~~~~~~~~^~~~~~~~~

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
---
 Xext/shape.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/Xext/shape.c b/Xext/shape.c
index 05e071be5..8b8615828 100644
--- a/Xext/shape.c
+++ b/Xext/shape.c
@@ -938,7 +938,7 @@ ProcShapeGetRectangles(ClientPtr client)
     REQUEST(xShapeGetRectanglesReq);
     WindowPtr pWin;
     xShapeGetRectanglesReply rep;
-    xRectangle *rects;
+    xRectangle *rects = NULL;
     int nrects, i, rc;
     RegionPtr region;
 
@@ -991,14 +991,16 @@ ProcShapeGetRectangles(ClientPtr client)
 
         nrects = RegionNumRects(region);
         box = RegionRects(region);
-        rects = xallocarray(nrects, sizeof(xRectangle));
-        if (!rects && nrects)
-            return BadAlloc;
-        for (i = 0; i < nrects; i++, box++) {
-            rects[i].x = box->x1;
-            rects[i].y = box->y1;
-            rects[i].width = box->x2 - box->x1;
-            rects[i].height = box->y2 - box->y1;
+        if (nrects) {
+            rects = calloc(nrects, sizeof(xRectangle));
+            if (!rects)
+                return BadAlloc;
+            for (i = 0; i < nrects; i++, box++) {
+                rects[i].x = box->x1;
+                rects[i].y = box->y1;
+                rects[i].width = box->x2 - box->x1;
+                rects[i].height = box->y2 - box->y1;
+            }
         }
     }
     rep = (xShapeGetRectanglesReply) {