Fix for wrong fnmatch patttern

* dir.c (file_s_fnmatch): ensure that pattern does not contain a
  NUL character.  https://hackerone.com/reports/449617

2 files changed, 7 insertions, 1 deletions

diff --git a/dir.c b/dir.c
index 6d1f501927..d20cf60a7f 100644
--- a/dir.c
+++ b/dir.c
@@ -3211,7 +3211,7 @@ file_s_fnmatch(int argc, VALUE *argv, VALUE obj)
     else
 	flags = 0;
 
-    StringValue(pattern);
+    StringValueCStr(pattern);
     FilePathStringValue(path);
 
     if (flags & FNM_EXTGLOB) {
diff --git a/test/ruby/test_fnmatch.rb b/test/ruby/test_fnmatch.rb
index f594a00ad3..16f1076e48 100644
--- a/test/ruby/test_fnmatch.rb
+++ b/test/ruby/test_fnmatch.rb
@@ -160,4 +160,10 @@ class TestFnmatch < Test::Unit::TestCase
     assert_file.fnmatch("[a-\u3042]*", "\u3042")
     assert_file.not_fnmatch("[a-\u3042]*", "\u3043")
   end
+
+  def test_nullchar
+    assert_raise(ArgumentError) {
+      File.fnmatch("a\0z", "a")
+    }
+  end
 end