Merge pull request #1666 from marschap/LDAPauth-patches

LDAP auth patches - thank you!

DOCUMENTATION.md

@@ -901,6 +901,12 @@ The search filter to find the user DN to authenticate by the username. User '{0}
 
 Default: `(cn={0})`
 
+#### ldap_user_attribute
+
+The LDAP attribute whose value shall be used as the user name after successful authentication
+
+Default: not set, i.e. the login name given is used directly.
+
 ##### ldap_load_groups
 
 Load the ldap groups of the authenticated user. These groups can be used later on to define rights. This also gives you access to the group calendars, if they exist.

config

@@ -83,6 +83,9 @@
 # The filter to find the DN of the user. This filter must contain a python-style placeholder for the login
 #ldap_filter = (&(objectClass=person)(uid={0}))
 
+# the attribute holding the value to be used as username after authentication
+#ldap_user_attribute = cn
+
 # Use ssl on the ldap connection
 #ldap_use_ssl = False
 

radicale/auth/ldap.py

@@ -15,15 +15,16 @@
 # 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.
+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_secret_file The path of the file containing 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
+   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_secret_file    The path of the file containing the password of the ldap_reader_dn
+   ldap_filter         The search filter to find the user to authenticate by the username
+   ldap_user_attribute The attribute to be used as username after authentication
+   ldap_load_groups    If the groups of the authenticated users need to be loaded
 Following parameters controls SSL connections:
    ldap_use_ssl   If the connection
    ldap_ssl_verify_mode The certificate verification mode. NONE, OPTIONAL, default is REQUIRED
@@ -42,8 +43,9 @@ class Auth(auth.BaseAuth):
     _ldap_reader_dn: str
     _ldap_secret: str
     _ldap_filter: str
+    _ldap_user_attr: str
     _ldap_load_groups: bool
-    _ldap_version: int = 3
+    _ldap_module_version: int = 3
     _ldap_use_ssl: bool = False
     _ldap_ssl_verify_mode: int = ssl.CERT_REQUIRED
     _ldap_ssl_ca_file: str = ""
@@ -56,7 +58,7 @@ class Auth(auth.BaseAuth):
         except ImportError:
             try:
                 import ldap
-                self._ldap_version = 2
+                self._ldap_module_version = 2
                 self.ldap = ldap
             except ImportError as e:
                 raise RuntimeError("LDAP authentication requires the ldap3 module") from e
@@ -66,11 +68,12 @@ class Auth(auth.BaseAuth):
         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")
+        self._ldap_user_attr = configuration.get("auth", "ldap_user_attribute")
         ldap_secret_file_path = configuration.get("auth", "ldap_secret_file")
         if ldap_secret_file_path:
             with open(ldap_secret_file_path, 'r') as file:
                 self._ldap_secret = file.read().rstrip('\n')
-        if self._ldap_version == 3:
+        if self._ldap_module_version == 3:
             self._ldap_use_ssl = configuration.get("auth", "ldap_use_ssl")
             if self._ldap_use_ssl:
                 self._ldap_ssl_ca_file = configuration.get("auth", "ldap_ssl_ca_file")
@@ -84,6 +87,10 @@ class Auth(auth.BaseAuth):
         logger.info("auth.ldap_reader_dn       : %r" % self._ldap_reader_dn)
         logger.info("auth.ldap_load_groups     : %s" % self._ldap_load_groups)
         logger.info("auth.ldap_filter          : %r" % self._ldap_filter)
+        if self._ldap_user_attr:
+            logger.info("auth.ldap_user_attribute  : %r" % self._ldap_user_attr)
+        else:
+            logger.info("auth.ldap_user_attribute  : (not provided)")
         if ldap_secret_file_path:
             logger.info("auth.ldap_secret_file_path: %r" % ldap_secret_file_path)
             if self._ldap_secret:
@@ -94,7 +101,7 @@ class Auth(auth.BaseAuth):
                 logger.info("auth.ldap_secret          : (from config)")
         if self._ldap_reader_dn and not self._ldap_secret:
             logger.error("auth.ldap_secret         : (not provided)")
-            raise RuntimeError("LDAP authentication requires ldap_secret for reader_dn")
+            raise RuntimeError("LDAP authentication requires ldap_secret for ldap_reader_dn")
         logger.info("auth.ldap_use_ssl         : %s" % self._ldap_use_ssl)
         if self._ldap_use_ssl is True:
             logger.info("auth.ldap_ssl_verify_mode : %s" % self._ldap_ssl_verify_mode)
@@ -112,16 +119,29 @@ class Auth(auth.BaseAuth):
             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"""
+            escaped_login = self.ldap.filter.escape_filter_chars(login)
+            logger.debug(f"_login2 login escaped for LDAP filters: {escaped_login}")
+            attrs = ['memberof']
+            if self._ldap_user_attr:
+                attrs = ['memberOf', self._ldap_user_attr]
+            logger.debug(f"_login2 attrs: {attrs}")
+            res = conn.search_s(
+                self._ldap_base,
+                self.ldap.SCOPE_SUBTREE,
+                filterstr=self._ldap_filter.format(escaped_login),
+                attrlist=attrs
+            )
+            if len(res) != 1:
+                """User could not be found unambiguously"""
+                logger.debug(f"_login2 no unique DN found for '{login}'")
                 return ""
-            user_dn = res[0][0]
-            logger.debug("LDAP Auth user: %s", user_dn)
-            """Close ldap connection"""
+            user_entry = res[0]
+            user_dn = user_entry[0]
+            logger.debug(f"_login2 found LDAP user DN {user_dn}")
+            """Close LDAP connection"""
             conn.unbind()
         except Exception as e:
-            raise RuntimeError(f"Invalid ldap configuration:{e}")
+            raise RuntimeError(f"Invalid LDAP configuration:{e}")
 
         try:
             """Bind as user to authenticate"""
@@ -132,11 +152,19 @@ class Auth(auth.BaseAuth):
             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:])
+                for g in user_entry[1]['memberOf']:
+                    """Get group g's RDN's attribute value"""
+                    g = g.decode('utf-8').split(',')[0]
+                    tmp.append(g.partition('=')[2])
                 self._ldap_groups = set(tmp)
-                logger.debug("LDAP Auth groups of user: %s", ",".join(self._ldap_groups))
+                logger.debug("_login2 LDAP groups of user: %s", ",".join(self._ldap_groups))
+            if self._ldap_user_attr:
+                if user_entry[1][self._ldap_user_attr]:
+                    tmplogin = user_entry[1][self._ldap_user_attr][0]
+                    login = tmplogin.decode('utf-8')
+                    logger.debug(f"_login2 user set to: '{login}'")
             conn.unbind()
+            logger.debug(f"_login2 {login} successfully authenticated")
             return login
         except self.ldap.INVALID_CREDENTIALS:
             return ""
@@ -157,45 +185,59 @@ class Auth(auth.BaseAuth):
                 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")
+            raise RuntimeError("Unable to reach LDAP server")
         except Exception as e:
             logger.debug(f"_login3 error 1 {e}")
             pass
 
         if not conn.bind():
-            logger.debug("_login3 can not bind")
-            raise RuntimeError("Unable to read from ldap server")
+            logger.debug("_login3 cannot bind")
+            raise RuntimeError("Unable to read from LDAP server")
 
         logger.debug(f"_login3 bind as {self._ldap_reader_dn}")
         """Search the user dn"""
+        escaped_login = self.ldap3.utils.conv.escape_filter_chars(login)
+        logger.debug(f"_login3 login escaped for LDAP filters: {escaped_login}")
+        attrs = ['memberof']
+        if self._ldap_user_attr:
+            attrs = ['memberOf', self._ldap_user_attr]
+        logger.debug(f"_login3 attrs: {attrs}")
         conn.search(
             search_base=self._ldap_base,
-            search_filter=self._ldap_filter.format(login),
+            search_filter=self._ldap_filter.format(escaped_login),
             search_scope=self.ldap3.SUBTREE,
-            attributes=['memberOf']
+            attributes=attrs
         )
-        if len(conn.entries) == 0:
-            logger.debug(f"_login3 user '{login}' can not be find")
-            """User could not be find"""
+        if len(conn.entries) != 1:
+            """User could not be found unambiguously"""
+            logger.debug(f"_login3 no unique DN found for '{login}'")
             return ""
 
         user_entry = conn.response[0]
         conn.unbind()
         user_dn = user_entry['dn']
-        logger.debug(f"_login3 found user_dn {user_dn}")
+        logger.debug(f"_login3 found LDAP user DN {user_dn}")
         try:
             """Try to bind as the user itself"""
             conn = self.ldap3.Connection(server, user_dn, password=password)
             if not conn.bind():
-                logger.debug(f"_login3 user '{login}' can not be find")
+                logger.debug(f"_login3 user '{login}' cannot be found")
                 return ""
+            tmp: list[str] = []
             if self._ldap_load_groups:
                 tmp = []
                 for g in user_entry['attributes']['memberOf']:
-                    tmp.append(g.split(',')[0][3:])
+                    """Get group g's RDN's attribute value"""
+                    g = g.split(',')[0]
+                    tmp.append(g.partition('=')[2])
                 self._ldap_groups = set(tmp)
+                logger.debug("_login3 LDAP groups of user: %s", ",".join(self._ldap_groups))
+            if self._ldap_user_attr:
+                if user_entry['attributes'][self._ldap_user_attr]:
+                    login = user_entry['attributes'][self._ldap_user_attr][0]
+                    logger.debug(f"_login3 user set to: '{login}'")
             conn.unbind()
-            logger.debug(f"_login3 {login} successfully authorized")
+            logger.debug(f"_login3 {login} successfully authenticated")
             return login
         except Exception as e:
             logger.debug(f"_login3 error 2 {e}")
@@ -204,10 +246,10 @@ class Auth(auth.BaseAuth):
 
     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 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:
+        if self._ldap_module_version == 2:
             return self._login2(login, password)
         return self._login3(login, password)

radicale/config.py

@@ -227,6 +227,10 @@ DEFAULT_CONFIG_SCHEMA: types.CONFIG_SCHEMA = OrderedDict([
             "value": "(cn={0})",
             "help": "the search filter to find the user DN to authenticate by the username",
             "type": str}),
+        ("ldap_user_attribute", {
+            "value": "",
+            "help": "the attribute to be used as username after authentication",
+            "type": str}),
         ("ldap_load_groups", {
             "value": "False",
             "help": "load the ldap groups of the authenticated user",