Ensure return_ok_domain does proper validation

Author: tirkarthi

Lib/http/cookiejar.py

@@ -1147,6 +1147,11 @@ def return_ok_domain(self, cookie, request):
         req_host, erhn = eff_request_host(request)
         domain = cookie.domain
 
+        if domain and not domain.startswith("."):
+            dotdomain = "." + domain
+        else:
+            dotdomain = domain
+
         # strict check of non-domain cookies: Mozilla does this, MSIE5 doesn't
         if (cookie.version == 0 and
             (self.strict_ns_domain & self.DomainStrictNonDomain) and
@@ -1159,7 +1164,7 @@ def return_ok_domain(self, cookie, request):
             _debug("   effective request-host name %s does not domain-match "
                    "RFC 2965 cookie domain %s", erhn, domain)
             return False
-        if cookie.version == 0 and not ("."+erhn).endswith(domain):
+        if cookie.version == 0 and not ("."+erhn).endswith(dotdomain):
             _debug("   request-host %s does not match Netscape cookie domain "
                    "%s", req_host, domain)
             return False

Lib/test/test_http_cookiejar.py

@@ -967,6 +967,7 @@ def test_domain_block(self):
         pol.set_blocked_domains([])
         req = urllib.request.Request("http://acme.com/")
         res = FakeResponse(headers, "http://acme.com/")
+        cookies = c.make_cookies(res, req)
         c.extract_cookies(res, req)
         self.assertEqual(len(c), 1)
 
@@ -976,6 +977,7 @@ def test_domain_block(self):
 
         req = urllib.request.Request("http://badacme.com/")
         c.add_cookie_header(req)
+        self.assertFalse(pol.return_ok(cookies[0], req))
         self.assertFalse(req.has_header("Cookie"))
 
         p = pol.set_blocked_domains(["acme.com"])