Merge pull request #196 from YunoHost/cracklib

[enh] Automatically check for weak password

data/actionsmap/yunohost.yml

@@ -125,6 +125,7 @@ user:
                         pattern: &pattern_password
                             - !!str ^.{3,}$
                             - "pattern_password"
+                        comment: good_practices_about_user_password
                 -q:
                     full: --mailbox-quota
                     help: Mailbox size quota
@@ -1456,6 +1457,7 @@ tools:
                         password: ask_new_admin_password
                         pattern: *pattern_password
                         required: True
+                        comment: good_practices_about_admin_password
 
         ### tools_maindomain()
         maindomain:
@@ -1493,9 +1495,13 @@ tools:
                         password: ask_new_admin_password
                         pattern: *pattern_password
                         required: True
+                        comment: good_practices_about_admin_password
                 --ignore-dyndns:
                     help: Do not subscribe domain to a DynDNS service
                     action: store_true
+                --force-password:
+                    help: Use this if you really want to set a weak password
+                    action: store_true
 
         ### tools_update()
         update:

debian/install

@@ -4,6 +4,7 @@ data/bash-completion.d/yunohost /etc/bash_completion.d/
 data/actionsmap/* /usr/share/moulinette/actionsmap/
 data/hooks/* /usr/share/yunohost/hooks/
 data/other/yunoprompt.service /etc/systemd/system/
+data/other/password/* /usr/share/yunohost/other/password/
 data/other/* /usr/share/yunohost/yunohost-config/moulinette/
 data/templates/* /usr/share/yunohost/templates/
 data/helpers /usr/share/yunohost/

locales/en.json

@@ -196,6 +196,8 @@
     "global_settings_setting_example_string": "Example string option",
     "global_settings_unknown_setting_from_settings_file": "Unknown key in settings: '{setting_key:s}', discarding it and save it in /etc/yunohost/unkown_settings.json",
     "global_settings_unknown_type": "Unexpected situation, the setting {setting:s} appears to have the type {unknown_type:s} but it's not a type supported by the system.",
+    "good_practices_about_admin_password": "You are now about to define a new administration password. The password should be at least 8 characters - though it is good practice to use longer password (i.e. a passphrase) and/or to use various kind of characters (uppercase, lowercase, digits and special characters).",
+    "good_practices_about_user_password": "You are now about to define a new user password. The password should be at least 8 characters - though it is good practice to use longer password (i.e. a passphrase) and/or to use various kind of characters (uppercase, lowercase, digits and special characters).",
     "hook_exec_failed": "Script execution failed: {path:s}",
     "hook_exec_not_terminated": "Script execution hasn\u2019t terminated: {path:s}",
     "hook_list_by_invalid": "Invalid property to list hook by",
@@ -329,6 +331,11 @@
     "packages_no_upgrade": "There is no package to upgrade",
     "packages_upgrade_critical_later": "Critical packages ({packages:s}) will be upgraded later",
     "packages_upgrade_failed": "Unable to upgrade all of the packages",
+    "password_listed": "This password is among the most used password in the world. Please choose something a bit more unique.",
+    "password_too_simple_1": "Password needs to be at least 8 characters long",
+    "password_too_simple_2": "Password needs to be at least 8 characters long and contains digit, upper and lower characters",
+    "password_too_simple_3": "Password needs to be at least 8 characters long and contains digit, upper, lower and special characters",
+    "password_too_simple_4": "Password needs to be at least 12 characters long and contains digit, upper, lower and special characters",
     "path_removal_failed": "Unable to remove path {:s}",
     "pattern_backup_archive_name": "Must be a valid filename with max 30 characters, and alphanumeric and -_. characters only",
     "pattern_domain": "Must be a valid domain name (e.g. my-domain.org)",

src/yunohost/app.py

@@ -2207,11 +2207,15 @@ def _parse_action_args_in_yunohost_format(args, action_args, auth=None):
                     for domain in domain_list(auth)['domains']:
                         msignals.display("- {}".format(domain))
 
-                if arg_type == 'user':
+                elif arg_type == 'user':
                     msignals.display(m18n.n('users_available'))
                     for user in user_list(auth)['users'].keys():
                         msignals.display("- {}".format(user))
 
+                elif arg_type == 'password':
+                    msignals.display(m18n.n('good_practices_about_user_password'))
+
+
                 try:
                     input_string = msignals.prompt(ask_string, is_password)
                 except NotImplementedError:
@@ -2269,6 +2273,9 @@ def _parse_action_args_in_yunohost_format(args, action_args, auth=None):
                     raise MoulinetteError(errno.EINVAL,
                         m18n.n('app_argument_choice_invalid',
                             name=arg_name, choices='yes, no, y, n, 1, 0'))
+        elif arg_type == 'password':
+            from yunohost.utils.password import assert_password_is_strong_enough
+            assert_password_is_strong_enough('user', arg_value)
         args_dict[arg_name] = arg_value
 
     # END loop over action_args...

src/yunohost/settings.py

@@ -29,12 +29,16 @@ SETTINGS_PATH_OTHER_LOCATION = "/etc/yunohost/settings-%s.json"
 # * string
 # * enum (in form a python list)
 
-# we don't store the value in default options
 DEFAULTS = OrderedDict([
     ("example.bool", {"type": "bool", "default": True}),
     ("example.int", {"type": "int", "default": 42}),
     ("example.string", {"type": "string", "default": "yolo swag"}),
     ("example.enum", {"type": "enum", "default": "a", "choices": ["a", "b", "c"]}),
+
+    # Password Validation
+    # -1 disabled, 0 alert if listed, 1 8-letter, 2 normal, 3 strong, 4 strongest
+    ("security.password.admin.strength", {"type": "int", "default": 1}),
+    ("security.password.user.strength", {"type": "int", "default": 1}),
 ])
 
 
@@ -90,9 +94,12 @@ def settings_set(key, value):
                 received_type=type(value).__name__, expected_type=key_type))
     elif key_type == "int":
         if not isinstance(value, int) or isinstance(value, bool):
-            raise MoulinetteError(errno.EINVAL, m18n.n(
-                'global_settings_bad_type_for_setting', setting=key,
-                received_type=type(value).__name__, expected_type=key_type))
+            if isinstance(value, str):
+                value=int(value)
+            else:
+                raise MoulinetteError(errno.EINVAL, m18n.n(
+                    'global_settings_bad_type_for_setting', setting=key,
+                    received_type=type(value).__name__, expected_type=key_type))
     elif key_type == "string":
         if not isinstance(value, basestring):
             raise MoulinetteError(errno.EINVAL, m18n.n(

src/yunohost/tools.py

@@ -32,6 +32,7 @@ import logging
 import subprocess
 import pwd
 import socket
+import cracklib
 from xmlrpclib import Fault
 from importlib import import_module
 from collections import OrderedDict
@@ -127,6 +128,10 @@ def tools_adminpw(auth, new_password):
 
     """
     from yunohost.user import _hash_user_password
+    from yunohost.utils.password import assert_password_is_strong_enough
+
+    assert_password_is_strong_enough("admin", new_password)
+
     try:
         auth.update("cn=admin", {
             "userPassword": _hash_user_password(new_password),
@@ -250,7 +255,8 @@ def _is_inside_container():
 
 
 @is_unit_operation()
-def tools_postinstall(operation_logger, domain, password, ignore_dyndns=False):
+def tools_postinstall(operation_logger, domain, password, ignore_dyndns=False,
+                      force_password=False):
     """
     YunoHost post-install
 
@@ -261,6 +267,8 @@ def tools_postinstall(operation_logger, domain, password, ignore_dyndns=False):
         password -- YunoHost admin password
 
     """
+    from yunohost.utils.password import assert_password_is_strong_enough
+
     dyndns_provider = "dyndns.yunohost.org"
 
     # Do some checks at first
@@ -268,6 +276,10 @@ def tools_postinstall(operation_logger, domain, password, ignore_dyndns=False):
         raise MoulinetteError(errno.EPERM,
                               m18n.n('yunohost_already_installed'))
 
+    # Check password
+    if not force_password:
+        assert_password_is_strong_enough("admin", password)
+
     if not ignore_dyndns:
         # Check if yunohost dyndns can handle the given domain
         # (i.e. is it a .nohost.me ? a .noho.st ?)
@@ -299,6 +311,7 @@ def tools_postinstall(operation_logger, domain, password, ignore_dyndns=False):
     else:
         dyndns = False
 
+
     operation_logger.start()
     logger.info(m18n.n('yunohost_installing'))
 
@@ -1045,3 +1058,4 @@ class Migration(object):
     @property
     def description(self):
         return m18n.n("migration_description_%s" % self.id)
+

src/yunohost/user.py

@@ -32,6 +32,7 @@ import crypt
 import random
 import string
 import subprocess
+import cracklib
 
 from moulinette import m18n
 from moulinette.core import MoulinetteError
@@ -116,6 +117,10 @@ def user_create(operation_logger, auth, username, firstname, lastname, mail, pas
     from yunohost.domain import domain_list, _get_maindomain
     from yunohost.hook import hook_callback
     from yunohost.app import app_ssowatconf
+    from yunohost.utils.password import assert_password_is_strong_enough
+
+    # Ensure sufficiently complex password
+    assert_password_is_strong_enough("user", password)
 
     # Validate uniqueness of username and mail in LDAP
     auth.validate_uniqueness({
@@ -283,6 +288,7 @@ def user_update(operation_logger, auth, username, firstname=None, lastname=None,
     """
     from yunohost.domain import domain_list
     from yunohost.app import app_ssowatconf
+    from yunohost.utils.password import assert_password_is_strong_enough
 
     attrs_to_fetch = ['givenName', 'sn', 'mail', 'maildrop']
     new_attr_dict = {}
@@ -307,6 +313,9 @@ def user_update(operation_logger, auth, username, firstname=None, lastname=None,
         new_attr_dict['cn'] = new_attr_dict['displayName'] = firstname + ' ' + lastname
 
     if change_password:
+        # Ensure sufficiently complex password
+        assert_password_is_strong_enough("user", password)
+
         new_attr_dict['userPassword'] = _hash_user_password(change_password)
 
     if mail:

src/yunohost/utils/password.py

@@ -0,0 +1,196 @@
+# -*- coding: utf-8 -*-
+
+""" License
+
+    Copyright (C) 2018 YunoHost
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published
+    by the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program; if not, see http://www.gnu.org/licenses
+
+"""
+
+import sys
+import os
+import json
+import string
+import subprocess
+
+SMALL_PWD_LIST = ["yunohost", "olinuxino", "olinux", "raspberry", "admin",
+                  "root", "test", "rpi"]
+
+MOST_USED_PASSWORDS = '/usr/share/yunohost/other/password/100000-most-used.txt'
+
+# Length, digits, lowers, uppers, others
+STRENGTH_LEVELS = [
+    (8, 0, 0, 0, 0),
+    (8, 1, 1, 1, 0),
+    (8, 1, 1, 1, 1),
+    (12, 1, 1, 1, 1),
+]
+
+def assert_password_is_strong_enough(profile, password):
+    PasswordValidator(profile).validate(password)
+
+class PasswordValidator(object):
+
+    def __init__(self, profile):
+        """
+        Initialize a password validator.
+
+        The profile shall be either "user" or "admin"
+        and will correspond to a validation strength
+        defined via the setting "security.password.<profile>.strength"
+        """
+
+        self.profile = profile
+        try:
+            # We do this "manually" instead of using settings_get()
+            # from settings.py because this file is also meant to be
+            # use as a script by ssowat.
+            # (or at least that's my understanding -- Alex)
+            settings = json.load(open('/etc/yunohost/settings.json', "r"))
+            setting_key = "security.password." + profile + ".strength"
+            self.validation_strength = int(settings[setting_key])
+        except Exception as e:
+            # Fallback to default value if we can't fetch settings for some reason
+            self.validation_strength = 1
+
+    def validate(self, password):
+        """
+        Check the validation_summary and trigger an exception
+        if the password does not pass tests.
+
+        This method is meant to be used from inside YunoHost's code
+        (compared to validation_summary which is meant to be called
+        by ssowat)
+        """
+        if self.validation_strength == -1:
+            return
+
+        # Note that those imports are made here and can't be put
+        # on top (at least not the moulinette ones)
+        # because the moulinette needs to be correctly initialized
+        # as well as modules available in python's path.
+        import errno
+        import logging
+        from moulinette import m18n
+        from moulinette.core import MoulinetteError
+        from moulinette.utils.log import getActionLogger
+
+        logger = logging.getLogger('yunohost.utils.password')
+
+        status, msg = self.validation_summary(password)
+        if status == "error":
+            raise MoulinetteError(1, m18n.n(msg))
+
+    def validation_summary(self, password):
+        """
+        Check if a password is listed in the list of most used password
+        and if the overall strength is good enough compared to the
+        validation_strength defined in the constructor.
+
+        Produces a summary-tuple comprised of a level (succes or error)
+        and a message key describing the issues found.
+        """
+        if self.validation_strength < 0:
+            return ("success", "")
+
+        listed = password in SMALL_PWD_LIST or self.is_in_most_used_list(password)
+        strength_level = self.strength_level(password)
+        if listed:
+            return ("error", "password_listed")
+        if strength_level < self.validation_strength:
+            return ("error", "password_too_simple_%s" % self.validation_strength)
+
+        return ("success", "")
+
+    def strength(self, password):
+        """
+        Returns the strength of a password, defined as a tuple
+        containing the length of the password, the number of digits,
+        lowercase letters, uppercase letters, and other characters.
+
+        For instance, "PikachuDu67" is (11, 2, 7, 2, 0)
+        """
+
+        length = len(password)
+        digits = 0
+        uppers = 0
+        lowers = 0
+        others = 0
+
+        for character in password:
+            if character in string.digits:
+                digits = digits + 1
+            elif character in string.ascii_uppercase:
+                uppers = uppers + 1
+            elif character in string.ascii_lowercase:
+                lowers = lowers + 1
+            else:
+                others = others + 1
+
+        return (length, digits, lowers, uppers, others)
+
+    def strength_level(self, password):
+        """
+        Computes the strength of a password and compares
+        it to the STRENGTH_LEVELS.
+
+        Returns an int corresponding to the highest STRENGTH_LEVEL
+        satisfied by the password.
+        """
+
+        strength = self.strength(password)
+
+        strength_level = 0
+        # Iterate over each level and its criterias
+        for level, level_criterias in enumerate(STRENGTH_LEVELS):
+            # Iterate simulatenously over the level criterias (e.g. [8, 1, 1, 1, 0])
+            # and the strength of the password (e.g. [11, 2, 7, 2, 0])
+            # and compare the values 1-by-1.
+            # If one False is found, the password does not satisfy the level
+            if False in [s>=c for s, c in zip(strength, level_criterias)]:
+                break
+            # Otherwise, the strength of the password is at least of the current level.
+            strength_level = level + 1
+
+        return strength_level
+
+    def is_in_most_used_list(self, password):
+
+        # Decompress file if compressed
+        if os.path.exists("%s.gz" % MOST_USED_PASSWORDS):
+            os.system("gzip -fd %s.gz" % MOST_USED_PASSWORDS)
+
+        # Grep the password in the file
+        # We use '-f -' to feed the pattern (= the password) through
+        # stdin to avoid it being shown in ps -ef --forest...
+        command = "grep -q -f - %s" % MOST_USED_PASSWORDS
+        p = subprocess.Popen(command.split(), stdin=subprocess.PIPE)
+        p.communicate(input=password)
+        return not bool(p.returncode)
+
+
+# This file is also meant to be used as an executable by
+# SSOwat to validate password from the portal when an user
+# change its password.
+if __name__ == '__main__':
+    if len(sys.argv) < 2:
+        import getpass
+        pwd = getpass.getpass("")
+        #print("usage: password.py PASSWORD")
+    else:
+        pwd = sys.argv[1]
+    status, msg = PasswordValidator('user').validation_summary(pwd)
+    print(msg)
+    sys.exit(0)