Avoid sequences of malloc(0) / free() by checking the length.

b2d96b5cd459963a9587ee9c86afc9266ba3d02b in xserver git

originally from deraadt@

1 files changed, 5 insertions, 2 deletions

diff --git a/xserver/mi/miexpose.c b/xserver/mi/miexpose.c
index c34530c34..610829f98 100644
--- a/xserver/mi/miexpose.c
+++ b/xserver/mi/miexpose.c
@@ -411,7 +411,7 @@ miPaintWindow(WindowPtr pWin, RegionPtr prgn, int what)
     int i;
     BoxPtr pbox;
     xRectangle *prect;
-    int numRects;
+    int numRects, regionnumrects;
 
     /*
      * Distance from screen to destination drawable, use this
@@ -515,7 +515,10 @@ miPaintWindow(WindowPtr pWin, RegionPtr prgn, int what)
         gcmask |= GCFillStyle | GCTile | GCTileStipXOrigin | GCTileStipYOrigin;
     }
 
-    prect = xallocarray(RegionNumRects(prgn), sizeof(xRectangle));
+    regionnumrects = RegionNumRects(prgn);
+    if (regionnumrects == 0)
+        return;
+    prect = xallocarray(regionnumrects, sizeof(xRectangle));
     if (!prect)
         return;