2 files changed, 73 insertions, 0 deletions
diff --git a/src/mailman/utilities/passwords.py b/src/mailman/utilities/passwords.py
index c14584748..0de4255da 100644
--- a/src/mailman/utilities/passwords.py
+++ b/src/mailman/utilities/passwords.py
@@ -27,23 +27,29 @@ __all__ = [
     'Schemes',
     'check_response',
     'make_secret',
+    'make_user_friendly_password',
     ]
 
 
 import os
 import re
 import hmac
+import random
 import hashlib
 
 from array import array
 from base64 import urlsafe_b64decode as decode
 from base64 import urlsafe_b64encode as encode
 from flufl.enum import Enum
+from itertools import chain, product
+from string import ascii_lowercase
 
+from mailman.config import config
 from mailman.core import errors
 
 SALT_LENGTH = 20 # bytes
 ITERATIONS  = 2000
+EMPTYSTRING = ''
 
 
 
@@ -315,3 +321,35 @@ def lookup_scheme(scheme_name):
     :rtype: `PasswordScheme`
     """
     return _SCHEMES_BY_TAG.get(scheme_name.lower())
+
+
+
+# Password generation.
+
+_vowels = tuple('aeiou')
+_consonants = tuple(c for c in ascii_lowercase if c not in _vowels)
+_syllables = tuple(x + y for (x, y) in
+                   chain(product(_vowels, _consonants),
+                         product(_consonants, _vowels)))
+
+
+def make_user_friendly_password(length=None):
+    """Make a random *user friendly* password.
+
+    Such passwords are nominally easier to pronounce and thus remember.  Their
+    security in relationship to purely random passwords has not been
+    determined.
+
+    :param length: Minimum length in characters for the resulting password.
+        The password will always be an even number of characters.  When
+        omitted, the system default length will be used.
+    :type length: int
+    :return: The user friendly password.
+    :rtype: unicode
+    """
+    if length is None:
+        length = int(config.passwords.password_length)
+    syllables = []
+    while len(syllables) * 2 < length:
+        syllables.append(random.choice(_syllables))
+    return EMPTYSTRING.join(syllables)[:length]
diff --git a/src/mailman/utilities/tests/test_passwords.py b/src/mailman/utilities/tests/test_passwords.py
index 60c201a5a..7b6989779 100644
--- a/src/mailman/utilities/tests/test_passwords.py
+++ b/src/mailman/utilities/tests/test_passwords.py
@@ -27,7 +27,11 @@ __all__ = [
 
 import unittest
 
+from itertools import izip_longest
+
+from mailman.config import config
 from mailman.core import errors
+from mailman.testing.layers import ConfigLayer
 from mailman.utilities import passwords
 
 
@@ -138,6 +142,36 @@ class TestSchemeLookup(unittest.TestCase):
 
 
 
+# See itertools doc page examples.
+def _grouper(seq):
+    args = [iter(seq)] * 2
+    return list(izip_longest(*args))
+
+
+class TestPasswordGeneration(unittest.TestCase):
+    layer = ConfigLayer
+
+    def test_default_user_friendly_password_length(self):
+        self.assertEqual(len(passwords.make_user_friendly_password()),
+                         int(config.passwords.password_length))
+
+    def test_provided_user_friendly_password_length(self):
+        self.assertEqual(len(passwords.make_user_friendly_password(12)), 12)
+
+    def test_provided_odd_user_friendly_password_length(self):
+        self.assertEqual(len(passwords.make_user_friendly_password(15)), 15)
+
+    def test_user_friendly_password(self):
+        password = passwords.make_user_friendly_password()
+        for pair in _grouper(password):
+            # There will always be one vowel and one non-vowel.
+            vowel = (pair[0] if pair[0] in 'aeiou' else pair[1])
+            consonant = (pair[0] if pair[0] not in 'aeiou' else pair[1])
+            self.assertTrue(vowel in 'aeiou', vowel)
+            self.assertTrue(consonant not in 'aeiou', consonant)
+
+
+
 def test_suite():
     suite = unittest.TestSuite()
     suite.addTest(unittest.makeSuite(TestBogusPasswords))
@@ -147,4 +181,5 @@ def test_suite():
     suite.addTest(unittest.makeSuite(TestSSHAPasswords))
     suite.addTest(unittest.makeSuite(TestPBKDF2Passwords))
     suite.addTest(unittest.makeSuite(TestSchemeLookup))
+    suite.addTest(unittest.makeSuite(TestPasswordGeneration))
     return suite