https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=6846

diff --git a/MagickCore/draw.c b/MagickCore/draw.c
index 0ec1ec1898cedcc9731fd091534ea22a774758df..3ce289e8bd252e34cdc2455fc77aa2236e57c925 100644 (file)
--- a/MagickCore/draw.c
+++ b/MagickCore/draw.c
@@ -1520,7 +1520,7 @@ static MagickBooleanType DrawDashPolygon(const DrawInfo *draw_info,
   for (i=0; primitive_info[i].primitive != UndefinedPrimitive; i++) ;
   number_vertices=(size_t) i;
   dash_polygon=(PrimitiveInfo *) AcquireQuantumMemory((size_t)
-    (2UL*number_vertices+1UL),sizeof(*dash_polygon));
+    (2UL*(number_vertices+1UL)+1UL),sizeof(*dash_polygon));
   if (dash_polygon == (PrimitiveInfo *) NULL)
     return(MagickFalse);
   clone_info=CloneDrawInfo((ImageInfo *) NULL,draw_info);