tmpdir.rb: permission of user given directory

* lib/tmpdir.rb (Dir.mktmpdir): check if the permission of the
  parent directory only when using the default temporary
  directory, and no check against user given directory.  the
  security is the user's responsibility in that case.
  [ruby-core:91216] [Bug #15555]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66909 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/tmpdir.rb

@@ -83,14 +83,20 @@ def self.tmpdir
   #  end
   #
   def self.mktmpdir(prefix_suffix=nil, *rest)
-    path = Tmpname.create(prefix_suffix || "d", *rest) {|n| mkdir(n, 0700)}
+    base = nil
+    path = Tmpname.create(prefix_suffix || "d", *rest) {|path, _, _, d|
+      base = d
+      mkdir(path, 0700)
+    }
     if block_given?
       begin
         yield path
       ensure
-        stat = File.stat(File.dirname(path))
-        if stat.world_writable? and !stat.sticky?
-          raise ArgumentError, "parent directory is world writable but not sticky"
+        unless base
+          stat = File.stat(File.dirname(path))
+          if stat.world_writable? and !stat.sticky?
+            raise ArgumentError, "parent directory is world writable but not sticky"
+          end
         end
         FileUtils.remove_entry path
       end
@@ -110,6 +116,7 @@ def create(basename, tmpdir=nil, max_try: nil, **opts)
       if $SAFE > 0 and tmpdir.tainted?
         tmpdir = '/tmp'
       else
+        origdir = tmpdir
         tmpdir ||= tmpdir()
       end
       n = nil
@@ -125,7 +132,7 @@ def create(basename, tmpdir=nil, max_try: nil, **opts)
         path = "#{prefix}#{t}-#{$$}-#{rand(0x100000000).to_s(36)}"\
                "#{n ? %[-#{n}] : ''}#{suffix||''}"
         path = File.join(tmpdir, path)
-        yield(path, n, opts)
+        yield(path, n, opts, origdir)
       rescue Errno::EEXIST
         n ||= 0
         n += 1

test/test_tmpdir.rb

@@ -33,6 +33,12 @@ def test_world_writable
         assert_equal(tmpdir, Dir.tmpdir)
         File.chmod(0777, tmpdir)
         assert_not_equal(tmpdir, Dir.tmpdir)
+        newdir = Dir.mktmpdir("d", tmpdir) do |dir|
+          assert_file.directory? dir
+          assert_equal(tmpdir, File.dirname(dir))
+          dir
+        end
+        assert_file.not_exist?(newdir)
         File.chmod(01777, tmpdir)
         assert_equal(tmpdir, Dir.tmpdir)
       ensure