Fixed #26033 -- Added Argon2 password hasher.

tests/auth_tests/test_hashers.py

@@ -25,6 +25,11 @@ try:
 except ImportError:
     bcrypt = None
 
+try:
+    import argon2
+except ImportError:
+    argon2 = None
+
 
 class PBKDF2SingleIterationHasher(PBKDF2PasswordHasher):
     iterations = 1
@@ -434,3 +439,58 @@ class TestUtilsHashPass(SimpleTestCase):
         with six.assertRaisesRegex(self, ValueError,
                 "Couldn't load 'PlainHasher' algorithm library: No module named '?plain'?"):
             PlainHasher()._load_library()
+
+
+@skipUnless(argon2, "argon2-cffi not installed")
+@override_settings(PASSWORD_HASHERS=PASSWORD_HASHERS)
+class TestUtilsHashPassArgon2(SimpleTestCase):
+
+    def test_argon2(self):
+        encoded = make_password('lètmein', hasher='argon2')
+        self.assertTrue(is_password_usable(encoded))
+        self.assertTrue(encoded.startswith('argon2$'))
+        self.assertTrue(check_password('lètmein', encoded))
+        self.assertFalse(check_password('lètmeinz', encoded))
+        self.assertEqual(identify_hasher(encoded).algorithm, 'argon2')
+        # Blank passwords
+        blank_encoded = make_password('', hasher='argon2')
+        self.assertTrue(blank_encoded.startswith('argon2$'))
+        self.assertTrue(is_password_usable(blank_encoded))
+        self.assertTrue(check_password('', blank_encoded))
+        self.assertFalse(check_password(' ', blank_encoded))
+
+    def test_argon2_upgrade(self):
+        self._test_argon2_upgrade('time_cost', 'time cost', 1)
+        self._test_argon2_upgrade('memory_cost', 'memory cost', 16)
+        self._test_argon2_upgrade('parallelism', 'parallelism', 1)
+
+    def _test_argon2_upgrade(self, attr, summary_key, new_value):
+        hasher = get_hasher('argon2')
+        self.assertEqual('argon2', hasher.algorithm)
+        self.assertNotEqual(getattr(hasher, attr), new_value)
+
+        old_value = getattr(hasher, attr)
+        try:
+            # Generate hash with attr set to 1
+            setattr(hasher, attr, new_value)
+            encoded = make_password('letmein', hasher='argon2')
+            attr_value = hasher.safe_summary(encoded)[summary_key]
+            self.assertEqual(attr_value, new_value)
+
+            state = {'upgraded': False}
+
+            def setter(password):
+                state['upgraded'] = True
+
+            # Check that no upgrade is triggered.
+            self.assertTrue(check_password('letmein', encoded, setter, 'argon2'))
+            self.assertFalse(state['upgraded'])
+
+            # Revert to the old rounds count and ...
+            setattr(hasher, attr, old_value)
+
+            # ... check if the password would get updated to the new count.
+            self.assertTrue(check_password('letmein', encoded, setter, 'argon2'))
+            self.assertTrue(state['upgraded'])
+        finally:
+            setattr(hasher, attr, old_value)