http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?revision=30896&view=revision --- lib/fileutils.rb 2009-06-29 04:21:32.000000000 +0000 +++ lib/fileutils.rb.oden 2011-05-23 07:57:31.000000000 +0000 @@ -657,10 +657,10 @@ module FileUtils # 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 @@ -703,6 +703,11 @@ module FileUtils 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)