diff --git a/configure.ac b/configure.ac
index 530c073764caa2..76ac9bd6a2ce0a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2013,6 +2013,7 @@ AC_REPLACE_FUNCS(strchr)
 AC_REPLACE_FUNCS(strerror)
 AC_REPLACE_FUNCS(strlcat)
 AC_REPLACE_FUNCS(strlcpy)
+AC_REPLACE_FUNCS(strndup)
 AC_REPLACE_FUNCS(strstr)
 AC_REPLACE_FUNCS(tgamma)
 
diff --git a/include/ruby/missing.h b/include/ruby/missing.h
index aea6c9088d9d22..be22b328c77cac 100644
--- a/include/ruby/missing.h
+++ b/include/ruby/missing.h
@@ -210,6 +210,10 @@ RUBY_EXTERN size_t strlcpy(char *, const char*, size_t);
 RUBY_EXTERN size_t strlcat(char *, const char*, size_t);
 #endif
 
+#ifndef HAVE_STRNDUP
+RUBY_EXTERN char *strndup(const char *, size_t);
+#endif
+
 #ifndef HAVE_FFS
 RUBY_EXTERN int ffs(int);
 #endif
diff --git a/missing/strndup.c b/missing/strndup.c
new file mode 100644
index 00000000000000..0f15e42289517f
--- /dev/null
+++ b/missing/strndup.c
@@ -0,0 +1,39 @@
+/*	$OpenBSD: strndup.c,v 1.3 2019/01/25 00:19:25 millert Exp $	*/
+
+/*
+ * Copyright (c) 2010 Todd C. Miller <millert@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+char *
+strndup(const char *str, size_t maxlen)
+{
+	char *copy;
+	size_t len;
+
+	len = strnlen(str, maxlen);
+	copy = malloc(len + 1);
+	if (copy != NULL) {
+		(void)memcpy(copy, str, len);
+		copy[len] = '\0';
+	}
+
+	return copy;
+}
diff --git a/parse.y b/parse.y
index 585130c3465ed6..83e2df9055365d 100644
--- a/parse.y
+++ b/parse.y
@@ -9315,16 +9315,16 @@ set_number_literal(struct parser_params *p, enum yytokentype type, int suffix, i
 
     switch (type) {
       case tINTEGER:
-        set_yylval_node(NEW_INTEGER(strdup(tok(p)), base, &_cur_loc));
+        set_yylval_node(NEW_INTEGER(strndup(tok(p), toklen(p)), base, &_cur_loc));
         break;
       case tFLOAT:
-        set_yylval_node(NEW_FLOAT(strdup(tok(p)), &_cur_loc));
+        set_yylval_node(NEW_FLOAT(strndup(tok(p), toklen(p)), &_cur_loc));
         break;
       case tRATIONAL:
-        set_yylval_node(NEW_RATIONAL(strdup(tok(p)), base, seen_point, &_cur_loc));
+        set_yylval_node(NEW_RATIONAL(strndup(tok(p), toklen(p)), base, seen_point, &_cur_loc));
         break;
       case tIMAGINARY:
-        set_yylval_node(NEW_IMAGINARY(strdup(tok(p)), base, seen_point, numeric_type, &_cur_loc));
+        set_yylval_node(NEW_IMAGINARY(strndup(tok(p), toklen(p)), base, seen_point, numeric_type, &_cur_loc));
         (void)numeric_type;     /* for ripper */
         break;
       default:
diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index 80a43d00dae209..147782ca732b90 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -315,7 +315,7 @@ LIBS = $(LIBS) gmp.lib
 LIBS = $(LIBS) imagehlp.lib shlwapi.lib bcrypt.lib $(EXTLIBS)
 !endif
 !if !defined(MISSING)
-MISSING = crypt.obj ffs.obj langinfo.obj lgamma_r.obj strlcat.obj strlcpy.obj win32/win32.obj win32/file.obj setproctitle.obj
+MISSING = crypt.obj ffs.obj langinfo.obj lgamma_r.obj strlcat.obj strlcpy.obj strndup.obj win32/win32.obj win32/file.obj setproctitle.obj
 !if $(RT_VER) < 120
 MISSING = $(MISSING) acosh.obj cbrt.obj erf.obj nan.obj tgamma.obj
 !endif