rb_str_new_frozen: new object if tainted/untrusted unmatch

* string.c (rb_str_new_frozen): since the result object should have
  same tainted/untrusted bits with the original object, return new
  object if the shared object unmatch.  [ruby-core:39745][Bug #5374]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36373 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Thu Jul 12 11:44:23 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* string.c (rb_str_new_frozen): since the result object should have
+	  same tainted/untrusted bits with the original object, return new
+	  object if the shared object unmatch.  [ruby-core:39745][Bug #5374]
+
 Thu Jul 12 10:46:39 2012  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* test/net/http/test_http.rb (TestNetHTTPLocalBind#test_bind_to_local*):

string.c

@@ -681,7 +681,7 @@ rb_str_new_frozen(VALUE orig)
 	assert(OBJ_FROZEN(str));
 	ofs = RSTRING_LEN(str) - RSTRING_LEN(orig);
 	if ((ofs > 0) || (klass != RBASIC(str)->klass) ||
-	    (!OBJ_TAINTED(str) && OBJ_TAINTED(orig)) ||
+	    ((RBASIC(str)->flags ^ RBASIC(orig)->flags) & (FL_TAINT|FL_UNTRUSTED)) ||
 	    ENCODING_GET(str) != ENCODING_GET(orig)) {
 	    str = str_new3(klass, str);
 	    RSTRING(str)->as.heap.ptr += ofs;

test/ruby/test_file.rb

@@ -316,6 +316,16 @@ class TestFile < Test::Unit::TestCase
     end
   end
 
+  def test_untainted_path
+    bug5374 = '[ruby-core:39745]'
+    cwd = ("./"*40+".".taint).dup.untaint
+    in_safe = proc {|safe| $SAFE = safe; File.stat(cwd)}
+    assert_not_send([cwd, :tainted?])
+    (0..1).each do |level|
+      assert_nothing_raised(SecurityError, bug5374) {in_safe[level]}
+    end
+  end
+
   if /(bcc|ms|cyg)win|mingw|emx/ =~ RUBY_PLATFORM
     def test_long_unc
       feature3399 = '[ruby-core:30623]'