--- ruby-1.8.7-p330/lib/fileutils.rb	2010-06-08 15:31:50.000000000 +0900
+++ ruby-1.8.7-p334/lib/fileutils.rb	2011-02-18 21:18:10.000000000 +0900
@@ -658,10 +658,10 @@
   # removing directories.  This requires the current process is the
   # owner of the removing whole directory tree, or is the super user (root).
   #
-  # WARNING: You must ensure that *ALL* parent directories are not
-  # world writable.  Otherwise this method does not work.
-  # Only exception is temporary directory like /tmp and /var/tmp,
-  # whose permission is 1777.
+  # WARNING: You must ensure that *ALL* parent directories cannot be
+  # moved by other untrusted users.  For example, parent directories
+  # should not be owned by untrusted users, and should not be world
+  # writable except when the sticky bit set.
   #
   # WARNING: Only the owner of the removing directory tree, or Unix super
   # user (root) should invoke this method.  Otherwise this method does not
@@ -704,6 +704,11 @@
       end
       f.chown euid, -1
       f.chmod 0700
+      unless fu_stat_identical_entry?(st, File.lstat(fullpath))
+        # TOC-to-TOU attack?
+        File.unlink fullpath
+        return
+      end
     }
     # ---- tree root is frozen ----
     root = Entry_.new(path)