From 1836cee5fbc415dd7c71633827e89f8825c752a1 Mon Sep 17 00:00:00 2001
From: Anthony Bourguignon <contact@toniob.net>
Date: Sun, 14 Oct 2018 10:33:58 +0200
Subject: [PATCH] Improve code quality

move doveadm call to sysutils
password hashers name and label are now class properties
---
 modoboa/core/password_hashers/__init__.py | 34 +++++++------------
 modoboa/core/password_hashers/advanced.py | 12 +------
 modoboa/core/password_hashers/base.py     | 28 ++++++++--------
 modoboa/lib/sysutils.py                   | 40 +++++++++++++++++++++++
 4 files changed, 68 insertions(+), 46 deletions(-)

diff --git a/modoboa/core/password_hashers/__init__.py b/modoboa/core/password_hashers/__init__.py
index 11e076cf1..80a5a8529 100644
--- a/modoboa/core/password_hashers/__init__.py
+++ b/modoboa/core/password_hashers/__init__.py
@@ -6,17 +6,13 @@ Password hashers for Modoboa.
 
 from __future__ import unicode_literals
 
-import os
-
-from django.utils.encoding import force_text
-
 from modoboa.core.password_hashers.advanced import (  # NOQA:F401
     BLFCRYPTHasher, MD5CRYPTHasher, SHA256CRYPTHasher, SHA512CRYPTHasher
 )
 from modoboa.core.password_hashers.base import (  # NOQA:F401
     CRYPTHasher, MD5Hasher, PLAINHasher, SHA256Hasher
 )
-from modoboa.lib.sysutils import exec_cmd
+from modoboa.lib.sysutils import doveadm_cmd
 
 
 def get_password_hasher(scheme):
@@ -35,25 +31,19 @@ def get_password_hasher(scheme):
         hasher = PLAINHasher
     return hasher
 
+
 def get_dovecot_schemes():
     """Return schemes supported by dovecot"""
-    supported_schemes = ["{PLAIN}"]
-    dpath = None
-    code, output = exec_cmd("which doveadm")
-    if not code:
-        dpath = force_text(output).strip()
+    supported_schemes = None
+    try:
+        code, schemes = doveadm_cmd("pw -l")
+    except OSError:
+        pass
     else:
-        known_paths = ("/usr/bin/doveadm", "/usr/local/bin/doveadm")
-        for fpath in known_paths:
-            if os.path.isfile(fpath) and os.access(fpath, os.X_OK):
-                dpath = fpath
-    if dpath:
-        try:
-            code, schemes = exec_cmd("%s pw -l" % dpath)
-        except OSError:
-            pass
-        else:
-            supported_schemes = ["{{{}}}".format(scheme)
-                                 for scheme in force_text(schemes).split()]
+        supported_schemes = ["{{{}}}".format(scheme)
+                             for scheme in schemes.split()]
+
+    if not supported_schemes:
+        supported_schemes = ['{PLAIN}']
 
     return supported_schemes
diff --git a/modoboa/core/password_hashers/advanced.py b/modoboa/core/password_hashers/advanced.py
index 40fa9d499..8aaaf506c 100644
--- a/modoboa/core/password_hashers/advanced.py
+++ b/modoboa/core/password_hashers/advanced.py
@@ -21,8 +21,6 @@ class BLFCRYPTHasher(PasswordHasher):
     Supports rounds and provides compatibility with dovecot on
     *BSD systems.
     """
-    name = "blfcrypt"
-    label = "blfcrypt"
 
     @property
     def scheme(self):
@@ -46,14 +44,12 @@ class BLFCRYPTHasher(PasswordHasher):
 
 
 class MD5CRYPTHasher(PasswordHasher):
-
     """
     MD5-CRYPT password hasher.
 
     This scheme can't be considered as secure anymore.
     """
-    name = "md5crypt"
-    label = "md5crypt"
+    _weak = True
 
     @property
     def scheme(self):
@@ -70,15 +66,12 @@ class MD5CRYPTHasher(PasswordHasher):
 
 
 class SHA256CRYPTHasher(PasswordHasher):
-
     """
     SHA256-CRYPT password hasher.
 
     Supports rounds and is a good compromise between security and
     performance.
     """
-    name = "sha256crypt"
-    label = "sha256crypt"
 
     @property
     def scheme(self):
@@ -97,15 +90,12 @@ class SHA256CRYPTHasher(PasswordHasher):
 
 
 class SHA512CRYPTHasher(PasswordHasher):
-
     """
     SHA512-CRYPT password hasher.
 
     Supports rounds and is the strongest scheme provided by
     Modoboa. Requires more resource than SHA256-CRYPT.
     """
-    name = "sha512crypt"
-    label = "sha512crypt"
 
     @property
     def scheme(self):
diff --git a/modoboa/core/password_hashers/base.py b/modoboa/core/password_hashers/base.py
index 3d8d2b354..88652de13 100644
--- a/modoboa/core/password_hashers/base.py
+++ b/modoboa/core/password_hashers/base.py
@@ -19,14 +19,24 @@ from django.utils.encoding import force_bytes, force_text
 
 
 class PasswordHasher(object):
-
     """
     Base class of all hashers.
     """
+    _weak = False
 
     def __init__(self, target="local"):
         self._target = target
 
+    class __metaclass__(type):
+        """class properties"""
+        @property
+        def name(cls):
+            return cls.__name__.rstrip('Hasher').lower()
+
+        @property
+        def label(cls):
+            return cls.name if not cls._weak else "{} (weak)".format(cls.name)
+
     def _encrypt(self, clearvalue, salt=None):
         raise NotImplementedError
 
@@ -75,12 +85,10 @@ class PasswordHasher(object):
 
 
 class PLAINHasher(PasswordHasher):
-
     """
     Plain (ie. clear) password hasher.
     """
-    name = "plain"
-    label = "plain (weak)"
+    _weak = True
 
     @property
     def scheme(self):
@@ -91,14 +99,12 @@ class PLAINHasher(PasswordHasher):
 
 
 class CRYPTHasher(PasswordHasher):
-
     """
     crypt password hasher.
 
     Uses python `crypt` standard module.
     """
-    name = "crypt"
-    label = "crypt (weak)"
+    _weak = True
 
     @property
     def scheme(self):
@@ -117,14 +123,12 @@ class CRYPTHasher(PasswordHasher):
 
 
 class MD5Hasher(PasswordHasher):
-
     """
     MD5 password hasher.
 
     Uses python `hashlib` standard module.
     """
-    name = "md5"
-    label = "md5 (weak)"
+    _weak = True
 
     @property
     def scheme(self):
@@ -136,14 +140,12 @@ class MD5Hasher(PasswordHasher):
 
 
 class SHA256Hasher(PasswordHasher):
-
     """
     SHA256 password hasher.
 
     Uses python `hashlib` and `base64` standard modules.
     """
-    name = "sha256"
-    label = "sha256 (weak)"
+    _weak = True
 
     @property
     def scheme(self):
diff --git a/modoboa/lib/sysutils.py b/modoboa/lib/sysutils.py
index 3d21445bf..a363643fc 100644
--- a/modoboa/lib/sysutils.py
+++ b/modoboa/lib/sysutils.py
@@ -8,9 +8,13 @@ This module extra functions/shortcuts to communicate with the system
 from __future__ import unicode_literals
 
 import inspect
+import os
 import re
 import subprocess
 
+from django.conf import settings
+from django.utils.encoding import force_text
+
 
 def exec_cmd(cmd, sudo_user=None, pinput=None, capture_output=True, **kwargs):
     """Execute a shell command.
@@ -42,6 +46,42 @@ def exec_cmd(cmd, sudo_user=None, pinput=None, capture_output=True, **kwargs):
     return process.returncode, output
 
 
+def doveadm_cmd(params, sudo_user=None, pinput=None, capture_output=True, **kwargs):
+    """Execute doveadm command.
+
+    Run doveadm command using the current user. Set :keyword:`sudo_user` if
+    you need different privileges.
+
+    :param str params: the parameters to give to doveadm
+    :param str sudo_user: a valid system username
+    :param str pinput: data to send to process's stdin
+    :param bool capture_output: capture process output or not
+    :rtype: tuple
+    :return: return code, command output
+    """
+    dpath = None
+    code, output = exec_cmd("which doveadm")
+    if not code:
+        dpath = force_text(output).strip()
+    else:
+        known_paths = getattr(
+            settings, "DOVEADM_LOOKUP_PATH",
+            ("/usr/bin/doveadm", "/usr/local/bin/doveadm")
+        )
+        for fpath in known_paths:
+            if os.path.isfile(fpath) and os.access(fpath, os.X_OK):
+                dpath = fpath
+                break
+    if dpath:
+        return exec_cmd("{} {}".format(dpath, params),
+                        sudo_user=sudo_user,
+                        pinput=pinput,
+                        capture_output=capture_output,
+                        **kwargs)
+    else:
+        raise OSError("doveadm command not found")
+
+
 def guess_extension_name():
     """Tries to guess the application's name by inspecting the stack.