Remove extra auth, rights and storage modules

radicale/auth.py

@@ -0,0 +1,181 @@
+# This file is part of Radicale Server - Calendar Server
+# Copyright © 2008 Nicolas Kandel
+# Copyright © 2008 Pascal Halter
+# Copyright © 2008-2016 Guillaume Ayoub
+#
+# This library is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This library 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Radicale.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+Authentication management.
+
+Default is htpasswd authentication.
+
+Apache's htpasswd command (httpd.apache.org/docs/programs/htpasswd.html) manages
+a file for storing user credentials. It can encrypt passwords using different
+methods, e.g. BCRYPT, MD5-APR1 (a version of MD5 modified for Apache), SHA1, or
+by using the system's CRYPT routine. The CRYPT and SHA1 encryption methods
+implemented by htpasswd are considered as insecure. MD5-APR1 provides medium
+security as of 2015. Only BCRYPT can be considered secure by current standards.
+
+MD5-APR1-encrypted credentials can be written by all versions of htpasswd (its
+the default, in fact), whereas BCRYPT requires htpasswd 2.4.x or newer.
+
+The `is_authenticated(user, password)` function provided by this module
+verifies the user-given credentials by parsing the htpasswd credential file
+pointed to by the ``htpasswd_filename`` configuration value while assuming
+the password encryption method specified via the ``htpasswd_encryption``
+configuration value.
+
+The following htpasswd password encrpytion methods are supported by Radicale
+out-of-the-box:
+
+    - plain-text (created by htpasswd -p...) -- INSECURE
+    - CRYPT      (created by htpasswd -d...) -- INSECURE
+    - SHA1       (created by htpasswd -s...) -- INSECURE
+
+When passlib (https://pypi.python.org/pypi/passlib) is importable, the
+following significantly more secure schemes are parsable by Radicale:
+
+    - MD5-APR1   (htpasswd -m...) -- htpasswd's default method
+    - BCRYPT     (htpasswd -B...) -- Requires htpasswd 2.4.x
+
+"""
+
+import base64
+import hashlib
+import os
+import sys
+
+from . import config, log
+
+
+def _load():
+    """Load the authentication manager chosen in configuration."""
+    auth_type = config.get("auth", "type")
+    log.LOGGER.debug("Authentication type is %s" % auth_type)
+    if auth_type == "None":
+        sys.modules[__name__].is_authenticated = lambda user, password: True
+    elif auth_type == "htpasswd":
+        pass  # is_authenticated is already defined
+    else:
+        __import__(auth_type)
+        sys.modules[__name__].is_authenticated = (
+            sys.modules[auth_type].is_authenticated)
+
+
+FILENAME = os.path.expanduser(config.get("auth", "htpasswd_filename"))
+ENCRYPTION = config.get("auth", "htpasswd_encryption")
+
+
+def _plain(hash_value, password):
+    """Check if ``hash_value`` and ``password`` match, using plain method."""
+    return hash_value == password
+
+
+def _crypt(hash_value, password):
+    """Check if ``hash_value`` and ``password`` match, using crypt method."""
+    return crypt.crypt(password, hash_value) == hash_value
+
+
+def _sha1(hash_value, password):
+    """Check if ``hash_value`` and ``password`` match, using sha1 method."""
+    hash_value = hash_value.replace("{SHA}", "").encode("ascii")
+    password = password.encode(config.get("encoding", "stock"))
+    sha1 = hashlib.sha1()  # pylint: disable=E1101
+    sha1.update(password)
+    return sha1.digest() == base64.b64decode(hash_value)
+
+
+def _ssha(hash_salt_value, password):
+    """Check if ``hash_salt_value`` and ``password`` match, using salted sha1
+    method. This method is not directly supported by htpasswd, but it can be
+    written with e.g. openssl, and nginx can parse it."""
+    hash_salt_value = hash_salt_value.replace(
+        "{SSHA}", "").encode("ascii").decode('base64')
+    password = password.encode(config.get("encoding", "stock"))
+    hash_value = hash_salt_value[:20]
+    salt_value = hash_salt_value[20:]
+    sha1 = hashlib.sha1()  # pylint: disable=E1101
+    sha1.update(password)
+    sha1.update(salt_value)
+    return sha1.digest() == hash_value
+
+
+def _bcrypt(hash_value, password):
+    return _passlib_bcrypt.verify(password, hash_value)
+
+
+def _md5apr1(hash_value, password):
+    return _passlib_md5apr1.verify(password, hash_value)
+
+
+# Prepare mapping between encryption names and verification functions.
+# Pre-fill with methods that do not have external dependencies.
+_verifuncs = {
+    "ssha": _ssha,
+    "sha1": _sha1,
+    "plain": _plain}
+
+
+# Conditionally attempt to import external dependencies.
+if ENCRYPTION == "md5":
+    try:
+        from passlib.hash import apr_md5_crypt as _passlib_md5apr1
+    except ImportError:
+        raise RuntimeError(("The htpasswd_encryption method 'md5' requires "
+            "availability of the passlib module."))
+    _verifuncs["md5"] = _md5apr1
+elif ENCRYPTION == "bcrypt":
+    try:
+        from passlib.hash import bcrypt as _passlib_bcrypt
+    except ImportError:
+        raise RuntimeError(("The htpasswd_encryption method 'bcrypt' requires "
+            "availability of the passlib module with bcrypt support."))
+    # A call to `encrypt` raises passlib.exc.MissingBackendError with a good
+    # error message if bcrypt backend is not available. Trigger this here.
+    _passlib_bcrypt.encrypt("test-bcrypt-backend")
+    _verifuncs["bcrypt"] = _bcrypt
+elif ENCRYPTION == "crypt":
+    try:
+        import crypt
+    except ImportError:
+        raise RuntimeError(("The htpasswd_encryption method 'crypt' requires "
+            "crypt() system support."))
+    _verifuncs["crypt"] = _crypt
+
+
+# Validate initial configuration.
+if ENCRYPTION not in _verifuncs:
+    raise RuntimeError(("The htpasswd encryption method '%s' is not "
+        "supported." % ENCRYPTION))
+
+
+def is_authenticated(user, password):
+    """Validate credentials.
+
+    Iterate through htpasswd credential file until user matches, extract hash
+    (encrypted password) and check hash against user-given password, using the
+    method specified in the Radicale config.
+
+    """
+    with open(FILENAME) as f:
+        for line in f:
+            strippedline = line.strip()
+            if strippedline:
+                login, hash_value = strippedline.split(":")
+                if login == user:
+                    # Allow encryption method to be overridden at runtime.
+                    return _verifuncs[ENCRYPTION](hash_value, password)
+    return False
+