diff --git a/ChangeLog b/ChangeLog
index 715009141..6d0941e5c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2015-09-27  suzuki toshiya  <mpsuzuki@hiroshima-u.ac.jp>
+
+	[mac] Fix buffer size calculation for LWFN font.
+
+	* src/base/ftmac.c (read_lwfn): Cast post_size to FT_ULong
+	to prevent confused copy by too large chunk size.
+
 2015-09-26  Alexei Podtelezhnikov  <apodtele@gmail.com>
 
 	* src/smooth/ftgrays.c (PIXEL_MASK): Remove unused macro.
diff --git a/src/base/ftmac.c b/src/base/ftmac.c
index 846319045..114bbb639 100644
--- a/src/base/ftmac.c
+++ b/src/base/ftmac.c
@@ -618,7 +618,7 @@
           total_size += 6; /* code + 4 bytes chunk length */
       }
 
-      total_size += GetHandleSize( post_data ) - 2;
+      total_size += (FT_ULong)GetHandleSize( post_data ) - 2;
       last_code = code;
 
       /* detect resource fork overflow */