Misc improvements to PASSWORD_SCHEME

- remove PASSWORD_SCHEME altogether
- introduce CREDENTIAL_ROUNDS
- migrate all old hashes to the current format
- auto-detect/enable all hash types that passlib supports
- upgrade passlib to 1.7.4 (see #1706: ldap_salted_sha512 support)

core/admin/mailu/configuration.py

@@ -33,6 +33,7 @@ DEFAULT_CONFIG = {
     'TLS_FLAVOR': 'cert',
     'AUTH_RATELIMIT': '10/minute;1000/hour',
     'AUTH_RATELIMIT_SUBNET': True,
+    'CREDENTIAL_ROUNDS': 12,
     'DISABLE_STATISTICS': False,
     # Mail settings
     'DMARC_RUA': None,
@@ -52,7 +53,6 @@ DEFAULT_CONFIG = {
     'RECAPTCHA_PUBLIC_KEY': '',
     'RECAPTCHA_PRIVATE_KEY': '',
     # Advanced settings
-    'PASSWORD_SCHEME': 'PBKDF2',
     'LOG_LEVEL': 'WARNING',
     'SESSION_COOKIE_SECURE': True,
     # Host settings

core/admin/mailu/manage.py

@@ -86,13 +86,10 @@ def admin(localpart, domain_name, password, mode='create'):
 @click.argument('localpart')
 @click.argument('domain_name')
 @click.argument('password')
-@click.argument('hash_scheme', required=False)
 @flask_cli.with_appcontext
-def user(localpart, domain_name, password, hash_scheme=None):
+def user(localpart, domain_name, password):
     """ Create a user
     """
-    if hash_scheme is None:
-        hash_scheme = app.config['PASSWORD_SCHEME']
     domain = models.Domain.query.get(domain_name)
     if not domain:
         domain = models.Domain(name=domain_name)
@@ -102,7 +99,7 @@ def user(localpart, domain_name, password, hash_scheme=None):
         domain=domain,
         global_admin=False
     )
-    user.set_password(password, hash_scheme=hash_scheme)
+    user.set_password(password)
     db.session.add(user)
     db.session.commit()
 
@@ -111,17 +108,14 @@ def user(localpart, domain_name, password, hash_scheme=None):
 @click.argument('localpart')
 @click.argument('domain_name')
 @click.argument('password')
-@click.argument('hash_scheme', required=False)
 @flask_cli.with_appcontext
-def password(localpart, domain_name, password, hash_scheme=None):
+def password(localpart, domain_name, password):
     """ Change the password of an user
     """
     email = '{0}@{1}'.format(localpart, domain_name)
     user   = models.User.query.get(email)
-    if hash_scheme is None:
-        hash_scheme = app.config['PASSWORD_SCHEME']
     if user:
-        user.set_password(password, hash_scheme=hash_scheme)
+        user.set_password(password)
     else:
         print("User " + email + " not found.")
     db.session.commit()
@@ -148,13 +142,10 @@ def domain(domain_name, max_users=-1, max_aliases=-1, max_quota_bytes=0):
 @click.argument('localpart')
 @click.argument('domain_name')
 @click.argument('password_hash')
-@click.argument('hash_scheme')
 @flask_cli.with_appcontext
-def user_import(localpart, domain_name, password_hash, hash_scheme = None):
+def user_import(localpart, domain_name, password_hash):
     """ Import a user along with password hash.
     """
-    if hash_scheme is None:
-        hash_scheme = app.config['PASSWORD_SCHEME']
     domain = models.Domain.query.get(domain_name)
     if not domain:
         domain = models.Domain(name=domain_name)
@@ -164,7 +155,7 @@ def user_import(localpart, domain_name, password_hash, hash_scheme = None):
         domain=domain,
         global_admin=False
     )
-    user.set_password(password_hash, hash_scheme=hash_scheme, raw=True)
+    user.set_password(password_hash, raw=True)
     db.session.add(user)
     db.session.commit()
 
@@ -217,7 +208,6 @@ def config_update(verbose=False, delete_objects=False):
         localpart = user_config['localpart']
         domain_name = user_config['domain']
         password_hash = user_config.get('password_hash', None)
-        hash_scheme = user_config.get('hash_scheme', None)
         domain = models.Domain.query.get(domain_name)
         email = '{0}@{1}'.format(localpart, domain_name)
         optional_params = {}
@@ -239,7 +229,7 @@ def config_update(verbose=False, delete_objects=False):
         else:
             for k in optional_params:
                 setattr(user, k, optional_params[k])
-        user.set_password(password_hash, hash_scheme=hash_scheme, raw=True)
+        user.set_password(password_hash, raw=True)
         db.session.add(user)
 
     aliases = new_config.get('aliases', [])

core/admin/mailu/models.py

@@ -1,7 +1,7 @@
 from mailu import dkim
 
 from sqlalchemy.ext import declarative
-from passlib import context, hash
+from passlib import context, hash, registry
 from datetime import datetime, date
 from email.mime import text
 from flask import current_app as app
@@ -370,17 +370,30 @@ class User(Base, Email):
                    'CRYPT': "des_crypt"}
 
     def get_password_context(self):
+        schemes = registry.list_crypt_handlers()
+        # scrypt throws a warning if the native wheels aren't found
+        schemes.remove('scrypt')
+        # we can't leave plaintext schemes as they will be misidentified
+        for scheme in schemes:
+            if scheme.endswith('plaintext'):
+                schemes.remove(scheme)
         return context.CryptContext(
-            schemes=self.scheme_dict.values(),
-            default=self.scheme_dict[app.config['PASSWORD_SCHEME']],
+            schemes=schemes,
+            default='bcrypt_sha256',
+            bcrypt_sha256__rounds=app.config['CREDENTIAL_ROUNDS'],
+            deprecated='auto'
         )
 
     def check_password(self, password):
         context = self.get_password_context()
-        reference = re.match('({[^}]+})?(.*)', self.password).group(2)
-        result = context.verify(password, reference)
-        if result and context.identify(reference) != context.default_scheme():
-            self.set_password(password)
+        # {scheme} will most likely be migrated on first use
+        reference = self.password
+        if self.password.startswith("{"):
+            reference = re.match('({[^}]+})?(.*)', reference).group(2)
+
+        result, new_hash = context.verify_and_update(password, reference)
+        if new_hash:
+            self.password = new_hash
             db.session.add(self)
             db.session.commit()
         return result
@@ -389,13 +402,11 @@ class User(Base, Email):
         """Set password for user with specified encryption scheme
            @password: plain text password to encrypt (if raw == True the hash itself)
         """
-        if hash_scheme is None:
-            hash_scheme = app.config['PASSWORD_SCHEME']
-        # for the list of hash schemes see https://wiki2.dovecot.org/Authentication/PasswordSchemes
         if raw:
-            self.password = '{'+hash_scheme+'}' + password
+            self.password = password
         else:
-            self.password = '{'+hash_scheme+'}' + self.get_password_context().encrypt(password, self.scheme_dict[hash_scheme])
+            self.password = self.get_password_context().hash(password)
+        app.cache.delete(self.get_id())
 
     def get_managed_domains(self):
         if self.global_admin:

core/admin/requirements-prod.txt

@@ -29,7 +29,7 @@ limits==1.3
 Mako==1.0.9
 MarkupSafe==1.1.1
 mysqlclient==1.4.2.post1
-passlib==1.7.1
+passlib==1.7.4
 psycopg2==2.8.2
 pycparser==2.19
 pyOpenSSL==19.0.0

docs/cli.rst

@@ -85,7 +85,6 @@ where mail-config.yml looks like:
     - localpart: foo
       domain: example.com
       password_hash: klkjhumnzxcjkajahsdqweqqwr
-      hash_scheme: MD5-CRYPT
 
   aliases:
     - localpart: alias1

docs/compose/.env

@@ -144,9 +144,8 @@ LOG_DRIVER=json-file
 # Docker-compose project name, this will prepended to containers names.
 COMPOSE_PROJECT_NAME=mailu
 
-# Default password scheme used for newly created accounts and changed passwords
-# (value: PBKDF2, BLF-CRYPT, SHA512-CRYPT, SHA256-CRYPT)
-PASSWORD_SCHEME=PBKDF2
+# Number of rounds used by the password hashing scheme
+CREDENTIAL_ROUNDS=12
 
 # Header to take the real ip from
 REAL_IP_HEADER=

docs/configuration.rst

@@ -138,9 +138,7 @@ Depending on your particular deployment you most probably will want to change th
 Advanced settings
 -----------------
 
-The ``PASSWORD_SCHEME`` is the password encryption scheme. You should use the
-default value, unless you are importing password from a separate system and
-want to keep using the old password encryption scheme.
+The ``CREDENTIAL_ROUNDS`` (default: 12) is the number of rounds used by the password hashing scheme. You should use the default value.
 
 The ``SESSION_COOKIE_SECURE`` (default: True) setting controls the secure flag on the cookies of the administrative interface. It should only be turned off if you intend to access it over plain HTTP.