Fix Issue6631 - Disallow relative files paths in urllib*.open()

Lib/test/test_urllib.py

@@ -134,6 +134,9 @@ class urlopen_FileTests(unittest.TestCase):
         for line in self.returned_obj.__iter__():
             self.assertEqual(line, self.text)
 
+    def test_relativelocalfile(self):
+        self.assertRaises(ValueError,urllib.urlopen,'./' + self.pathname)
+
 class ProxyTests(unittest.TestCase):
 
     def setUp(self):

Lib/test/test_urllib2net.py

@@ -126,6 +126,8 @@ class OtherNetworkTests(unittest.TestCase):
         finally:
             os.remove(TESTFN)
 
+        self.assertRaises(ValueError, urllib2.urlopen,'./relative_path/to/file')
+
     # XXX Following test depends on machine configurations that are internal
     # to CNRI.  Need to set up a public server with the right authentication
     # configuration for test purposes.

Lib/urllib.py

@@ -484,6 +484,8 @@ class URLopener:
             urlfile = file
             if file[:1] == '/':
                 urlfile = 'file://' + file
+            elif file[:2] == './':
+                raise ValueError("local file url may start with / or file:. Unknown url of type: %s" % url)
             return addinfourl(open(localname, 'rb'),
                               headers, urlfile)
         host, port = splitport(host)