add max password length, default 72, configurable via ZXCVBN_MAX_LENGTH env var

Author: musicsnobj

README.rst

@@ -103,6 +103,18 @@ Output:
         }],
     }
 
+To override the default maximum password length of 72 characters, set the
+``ZXCVBN_MAX_LENGTH`` environment variable:
+
+.. code-block:: bash
+
+   export ZXCVBN_MAX_LENGTH=128
+
+.. warning::
+   We strongly advise against setting ``ZXCVBN_MAX_LENGTH`` to a value greater than 72,
+   as it can lead to long processing times and may leave server-side applications open
+   to denial-of-service scenarios.
+
 
 Custom Ranked Dictionaries
 --------------------------
@@ -121,6 +133,7 @@ In order to support more languages or just add password dictionaries of your own
 These lists will be added to the current ones, but you can also overwrite the current ones if you wish.
 The lists you add should be in order of how common the word is used with the most common words appearing first.
 
+
 CLI
 ~~~
 

tests/l33t_exploit_test.py

@@ -0,0 +1,12 @@
+import pytest
+from zxcvbn import zxcvbn
+
+# Test ACsploit-generated password targeting zxcvbn's l33t matching algorithm
+# (see https://github.com/GoSimpleLLC/nbvcxz/issues/60)
+def test_l33t_exploit():
+
+    password = "4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/4@8({[</369&#!1/|0$5+7%2/"
+
+    # Function should raise ValueError for input exceeding default MAX_LENGTH of 72 chars
+    with pytest.raises(ValueError, match="Password length exceeds 72 characters"):
+        zxcvbn(password, user_inputs=[None])

tests/zxcvbn_test.py

@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+import pytest
 from zxcvbn import zxcvbn
 
 
@@ -23,7 +24,9 @@ def test_long_password():
     input_ = None
     password = "weopiopdsjmkldjvoisdjfioejiojweopiopdsjmkldjvoisdjfioejiojweopiopdsjmkldjvoisdjfioejiojweopiopdsjmkldjvoisdjfioejiojweopiopdsjmkldjvoisdjfioejiojweopiopdsjmkldjvoisdjfioejiojweopiopdsjmkldjvoisdjfioejiojweopiopdsjmkldjvoisdjfioejiojweopiopdsjmkldjvoisdjfioejiojweopiopdsjmkldjvoisdjfioejiojweopiopdsjmkldjvoisdjfioej"
 
-    zxcvbn(password, user_inputs=[input_])
+    # Function should raise ValueError for input exceeding default MAX_LENGTH of 72 chars
+    with pytest.raises(ValueError, match="Password length exceeds 72 characters"):
+        zxcvbn(password, user_inputs=[input_])
 
 
 def test_dictionary_password():

zxcvbn/__init__.py

@@ -1,8 +1,16 @@
+import os
 from datetime import datetime
 
 from . import matching, scoring, time_estimates, feedback
 
+DEFAULT_MAX_LENGTH = 72
+MAX_LENGTH = int(os.environ.get('ZXCVBN_MAX_LENGTH', DEFAULT_MAX_LENGTH))
+
 def zxcvbn(password, user_inputs=None):
+    # Throw error if password exceeds max length
+    if len(password) > MAX_LENGTH:
+        raise ValueError(f"Password length exceeds {MAX_LENGTH} characters.")
+
     try:
         # Python 2 string types
         basestring = (str, unicode)