Merge pull request #1218 from petervarkoly/master

Initial version of ldap authentication plugin.

DOCUMENTATION.md

@@ -744,6 +744,9 @@ Available backends:
   authentication. This can be used to provide the username from a reverse
   proxy.
 
+`ldap`
+: Use a LDAP or AD server to authenticate users.
+
 Default: `none`
 
 ##### htpasswd_filename
@@ -799,6 +802,42 @@ Message displayed in the client when a password is needed.
 
 Default: `Radicale - Password Required`
 
+##### ldap_uri
+
+The URI to the ldap server
+
+Default: `ldap://localhost`
+
+##### ldap_base
+
+LDAP base DN of the ldap server. This parameter must be provided if auth type is ldap.
+
+Default:
+
+##### ldap_reader_dn
+
+The DN of a ldap user with read access to get the user accounts. This parameter must be provided if auth type is ldap.
+
+Default:
+
+##### ldap_secret
+
+The password of the ldap_reader_dn. This parameter must be provided if auth type is ldap.
+
+Default:
+
+##### ldap_filter
+
+The search filter to find the user DN to authenticate by the username. User '{0}' as placeholder for the user name.
+
+Default: `(cn={0})`
+
+##### ldap_load_groups
+
+Load the ldap groups of the authenticated user. These groups can be used later on to define rights.
+
+Default: False
+
 ##### lc_username
 
 Сonvert username to lowercase, must be true for case-insensitive auth 

config

@@ -53,6 +53,24 @@
 [auth]
 
 # Authentication method
+# Value: none | htpasswd | remote_user | http_x_remote_user | ldap
+#type = none
+
+# URI to the LDAP server
+#ldap_uri = ldap://localhost
+
+# The base DN of the LDAP server
+#ldap_base = ##BASE_DN##
+
+# The reader DN of the LDAP server
+#ldap_reader_dn = CN=ldapreader,CN=Users,##BASE_DN##
+
+# Password of the reader DN
+#ldap_secret = ldapreader-secret
+
+# If the ldap groups of the user need to be loaded
+#ldap_load_groups = True
+
 # Value: none | htpasswd | remote_user | http_x_remote_user | denyall
 #type = none
 

radicale/app/__init__.py

@@ -250,6 +250,12 @@ def response(status: int, headers: types.WSGIResponseHeaders,
                     authorization.encode("ascii"))).split(":", 1)
 
         user = self._auth.login(login, password) or "" if login else ""
+        if self.configuration.get("auth", "type") == "ldap":
+            try:
+                logger.debug("Groups %r", ",".join(self._auth._ldap_groups))
+                self._rights._user_groups = self._auth._ldap_groups
+            except AttributeError:
+                pass
         if user and login == user:
             logger.info("Successful login: %r", user)
         elif user:

radicale/auth/__init__.py

@@ -29,14 +29,15 @@
 
 """
 
-from typing import Sequence, Tuple, Union
+from typing import Sequence, Set, Tuple, Union
 
 from radicale import config, types, utils
 from radicale.log import logger
 
 INTERNAL_TYPES: Sequence[str] = ("none", "remote_user", "http_x_remote_user",
                                  "denyall",
-                                 "htpasswd")
+                                 "htpasswd",
+                                 "ldap")
 
 
 def load(configuration: "config.Configuration") -> "BaseAuth":
@@ -51,6 +52,7 @@ def load(configuration: "config.Configuration") -> "BaseAuth":
 
 class BaseAuth:
 
+    _ldap_groups: Set[str] = set([])
     _lc_username: bool
     _strip_domain: bool
 

radicale/auth/ldap.py

@@ -0,0 +1,147 @@
+# This file is part of Radicale - CalDAV and CardDAV server
+# Copyright 2022 Peter Varkoly
+#
+# 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 backend that checks credentials with a ldap server.
+Following parameters are needed in the configuration
+   ldap_uri       The ldap url to the server like ldap://localhost
+   ldap_base      The baseDN of the ldap server
+   ldap_reader_dn The DN of a ldap user with read access to get the user accounts
+   ldap_secret    The password of the ldap_reader_dn
+   ldap_filter    The search filter to find the user to authenticate by the username
+   ldap_load_groups If the groups of the authenticated users need to be loaded
+"""
+
+from radicale import auth, config
+from radicale.log import logger
+
+
+class Auth(auth.BaseAuth):
+    _ldap_uri: str
+    _ldap_base: str
+    _ldap_reader_dn: str
+    _ldap_secret: str
+    _ldap_filter: str
+    _ldap_load_groups: bool
+    _ldap_version: int = 3
+
+    def __init__(self, configuration: config.Configuration) -> None:
+        super().__init__(configuration)
+        try:
+            import ldap3
+            self.ldap3 = ldap3
+        except ImportError:
+            try:
+                import ldap
+                self._ldap_version = 2
+                self.ldap = ldap
+            except ImportError as e:
+                raise RuntimeError("LDAP authentication requires the ldap3 module") from e
+        self._ldap_uri = configuration.get("auth", "ldap_uri")
+        self._ldap_base = configuration.get("auth", "ldap_base")
+        self._ldap_reader_dn = configuration.get("auth", "ldap_reader_dn")
+        self._ldap_load_groups = configuration.get("auth", "ldap_load_groups")
+        self._ldap_secret = configuration.get("auth", "ldap_secret")
+        self._ldap_filter = configuration.get("auth", "ldap_filter")
+
+    def _login2(self, login: str, password: str) -> str:
+        try:
+            """Bind as reader dn"""
+            conn = self.ldap.initialize(self._ldap_uri)
+            conn.protocol_version = 3
+            conn.set_option(self.ldap.OPT_REFERRALS, 0)
+            conn.simple_bind_s(self._ldap_reader_dn, self._ldap_secret)
+            """Search for the dn of user to authenticate"""
+            res = conn.search_s(self._ldap_base, self.ldap.SCOPE_SUBTREE, filterstr=self._ldap_filter.format(login), attrlist=['memberOf'])
+            if len(res) == 0:
+                """User could not be find"""
+                return ""
+            user_dn = res[0][0]
+            logger.debug("LDAP Auth user: %s", user_dn)
+            """Close ldap connection"""
+            conn.unbind()
+        except Exception:
+            raise RuntimeError("Invalide ldap configuration")
+
+        try:
+            """Bind as user to authenticate"""
+            conn = self.ldap.initialize(self._ldap_uri)
+            conn.protocol_version = 3
+            conn.set_option(self.ldap.OPT_REFERRALS, 0)
+            conn.simple_bind_s(user_dn, password)
+            tmp: list[str] = []
+            if self._ldap_load_groups:
+                tmp = []
+                for t in res[0][1]['memberOf']:
+                    tmp.append(t.decode('utf-8').split(',')[0][3:])
+                self._ldap_groups = set(tmp)
+                logger.debug("LDAP Auth groups of user: %s", ",".join(self._ldap_groups))
+            conn.unbind()
+            return login
+        except self.ldap.INVALID_CREDENTIALS:
+            return ""
+
+    def _login3(self, login: str, password: str) -> str:
+        """Connect the server"""
+        try:
+            server = self.ldap3.Server(self._ldap_uri)
+            conn = self.ldap3.Connection(server, self._ldap_reader_dn, password=self._ldap_secret)
+        except self.ldap3.core.exceptions.LDAPSocketOpenError:
+            raise RuntimeError("Unable to reach ldap server")
+        except Exception:
+            pass
+
+        if not conn.bind():
+            raise RuntimeError("Unable to read from ldap server")
+
+        """Search the user dn"""
+        conn.search(
+            search_base=self._ldap_base,
+            search_filter=self._ldap_filter.format(login),
+            search_scope='SUBTREE',
+            attributes=['memberOf']
+        )
+        if len(conn.entries) == 0:
+            """User could not be find"""
+            return ""
+
+        user_entry = conn.entries[0].entry_to_json()
+        conn.unbind()
+        user_dn = user_entry['dn']
+        try:
+            """Try to bind as the user itself"""
+            conn = self.ldap3.Connection(server, user_dn, password=password)
+            if not conn.bind():
+                return ""
+            if self._ldap_load_groups:
+                tmp = []
+                for g in user_entry['attributes']['memberOf']:
+                    tmp.append(g)
+                self._ldap_groups = set(tmp)
+            conn.unbind()
+            return login
+        except Exception:
+            pass
+        return ""
+
+    def login(self, login: str, password: str) -> str:
+        """Validate credentials.
+        In first step we make a connection to the ldap server with the ldap_reader_dn credential.
+        In next step the DN of the user to authenticate will be searched.
+        In the last step the authentication of the user will be proceeded.
+        """
+        if self._ldap_version == 2:
+            return self._login2(login, password)
+        return self._login3(login, password)

radicale/config.py

@@ -191,6 +191,30 @@ def json_str(value: Any) -> dict:
             "value": "1",
             "help": "incorrect authentication delay",
             "type": positive_float}),
+        ("ldap_uri", {
+            "value": "ldap://localhost",
+            "help": "URI to the ldap server",
+            "type": str}),
+        ("ldap_base", {
+            "value": "none",
+            "help": "LDAP base DN of the ldap server",
+            "type": str}),
+        ("ldap_reader_dn", {
+            "value": "none",
+            "help": "the DN of a ldap user with read access to get the user accounts",
+            "type": str}),
+        ("ldap_secret", {
+            "value": "none",
+            "help": "the password of the ldap_reader_dn",
+            "type": str}),
+        ("ldap_filter", {
+            "value": "(cn={0})",
+            "help": "the search filter to find the user DN to authenticate by the username",
+            "type": str}),
+        ("ldap_load_groups", {
+            "value": "False",
+            "help": "load the ldap groups of the authenticated user",
+            "type": bool}),
         ("strip_domain", {
             "value": "False",
             "help": "strip domain from username",

radicale/rights/__init__.py

@@ -32,7 +32,7 @@
 
 """
 
-from typing import Sequence
+from typing import Sequence, Set
 
 from radicale import config, utils
 
@@ -57,6 +57,8 @@ def intersect(a: str, b: str) -> str:
 
 class BaseRights:
 
+    _user_groups: Set[str] = set([])
+
     def __init__(self, configuration: "config.Configuration") -> None:
         """Initialize BaseRights.
 

radicale/rights/from_file.py

@@ -65,24 +65,40 @@ def authorization(self, user: str, path: str) -> str:
         if not self._log_rights_rule_doesnt_match_on_debug:
             logger.debug("logging of rules which doesn't match suppressed by config/option [logging] rights_rule_doesnt_match_on_debug")
         for section in rights_config.sections():
+            group_match = False
             try:
                 user_pattern = rights_config.get(section, "user")
                 collection_pattern = rights_config.get(section, "collection")
+                allowed_groups = rights_config.get(section, "groups", fallback="").split(",")
+                try:
+                    group_match = len(self._user_groups.intersection(allowed_groups)) > 0
+                except Exception:
+                    pass
                 # Use empty format() for harmonized handling of curly braces
                 user_match = re.fullmatch(user_pattern.format(), user)
-                collection_match = user_match and re.fullmatch(
+                user_collection_match = user_match and re.fullmatch(
                     collection_pattern.format(
                         *(re.escape(s) for s in user_match.groups()),
                         user=escaped_user), sane_path)
+                group_collection_match = re.fullmatch(collection_pattern.format(user=escaped_user), sane_path)
             except Exception as e:
                 raise RuntimeError("Error in section %r of rights file %r: "
                                    "%s" % (section, self._filename, e)) from e
-            if user_match and collection_match:
+            if user_match and user_collection_match:
                 permission = rights_config.get(section, "permissions")
                 logger.debug("Rule %r:%r matches %r:%r from section %r permission %r",
                              user, sane_path, user_pattern,
                              collection_pattern, section, permission)
                 return permission
+            if group_match and group_collection_match:
+                permission = rights_config.get(section, "permissions")
+                logger.debug("Rule %r:%r matches %r:%r from section %r permission %r by group membership",
+                             user, sane_path, user_pattern,
+                             collection_pattern, section, permission)
+                return permission
+            logger.debug("Rule %r:%r doesn't match %r:%r from section %r",
+                         user, sane_path, user_pattern, collection_pattern,
+                         section)
             if self._log_rights_rule_doesnt_match_on_debug:
                 logger.debug("Rule %r:%r doesn't match %r:%r from section %r",
                              user, sane_path, user_pattern, collection_pattern,

rights

@@ -1,5 +1,29 @@
 # -*- mode: conf -*-
 # vim:ft=cfg
+# Allow all rights for the Administrator
+#[root]
+#user: Administrator
+#collection: .*
+#permissions: RW
+
+# Allow reading principal collection (same as username)
+#[principal]
+#user: .+
+#collection: {user}
+#permissions: R
+
+# Allow reading and writing private collection (same as username)
+#[private]
+#user: .+
+#collection: {user}/private/
+#permissions: RW
+
+# Allow reading calendars and address books that are direct
+# children of the principal collection for other users
+#[calendarsReader]
+#user: .+
+#collection: {user}/[^/]+
+#permissions: r
 
 # Rights management file for Radicale - A simple calendar server
 #