diff --git a/ChangeLog b/ChangeLog
index afcd6ac09d..101fb3bcd9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Mar  3 14:25:19 2011  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* strftime.c (STRFTIME): return 0 and ERANGE when precision is too
+	  large. [ruby-dev:43284] fixes #4456
+
 Thu Mar  3 00:46:51 2011  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* addr2line.c (uleb128): cast the value to unsigned long.
diff --git a/strftime.c b/strftime.c
index dc6df615d7..9d9f48d0de 100644
--- a/strftime.c
+++ b/strftime.c
@@ -237,6 +237,10 @@ rb_strftime_with_timespec(char *s, size_t maxsize, const char *format, const str
 			i = rb_strftime_with_timespec(s, endp - s, (fmt), vtm, timev, ts, gmt); \
 			if (!i) return 0; \
 			if (precision > i) {\
+				if (start + maxsize < s + precision) { \
+					errno = ERANGE; \
+					return 0; \
+				} \
 				memmove(s + precision - i, s, i);\
 				memset(s, padding ? padding : ' ', precision - i); \
 				s += precision;	\