ruby.c: taint ARGV on Windows

* ruby.c (external_str_new_cstr): strings come from the external
  should be tainted.  [ruby-dev:50596] [Bug #14941]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64071 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ruby.c

@@ -2186,7 +2186,9 @@ external_str_new_cstr(const char *p)
 {
 #if UTF8_PATH
     VALUE str = rb_utf8_str_new_cstr(p);
-    return str_conv_enc(str, NULL, rb_default_external_encoding());
+    str = str_conv_enc(str, NULL, rb_default_external_encoding());
+    OBJ_TAINT_RAW(str);
+    return str;
 #else
     return rb_external_str_new_cstr(p);
 #endif

test/ruby/test_rubyoptions.rb

@@ -1068,6 +1068,13 @@ class TestRubyOptions < Test::Unit::TestCase
     assert_in_out_err([IO::NULL], success: true)
   end
 
+  def test_argv_tainted
+    assert_separately(%w[- arg], "#{<<~"begin;"}\n#{<<~'end;'}")
+    begin;
+      assert_predicate(ARGV[0], :tainted?, '[ruby-dev:50596] [Bug #14941]')
+    end;
+  end
+
   private
 
   def mjit_force_enabled?