level5: add source file

level5/source.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void o(void)
+{
+	system("/bin/sh");
+	exit(1);
+}
+
+void n(void)
+{
+	char buf[520];
+
+	fgets(buf, 512, stdin);
+	printf(buf);
+	exit(1);
+}
+
+int main(void)
+{
+	n();
+	return 0;
+}