pam auth module

kvmd/plugins/auth/pam.py

@@ -0,0 +1,99 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main Pi-KVM daemon.                                          #
+#                                                                            #
+#    Copyright (C) 2018  Maxim Devaev <mdevaev@gmail.com>                    #
+#                                                                            #
+#    This program 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 program 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 this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+import asyncio
+import pwd
+
+from typing import List
+from typing import Dict
+
+import pam
+
+from ...yamlconf import Option
+
+from ...validators.basic import valid_number
+from ...validators.auth import valid_users_list
+
+from ...logging import get_logger
+
+from ... import aiotools
+
+from . import BaseAuthService
+
+
+# =====
+class Plugin(BaseAuthService):
+    def __init__(  # pylint: disable=super-init-not-called
+        self,
+        service: str,
+        allow_users: List[str],
+        deny_users: List[str],
+        allow_uids_at: int,
+    ) -> None:
+
+        self.__service = service
+        self.__allow_users = allow_users
+        self.__deny_users = deny_users
+        self.__allow_uids_at = allow_uids_at
+
+        self.__lock = asyncio.Lock()
+
+    @classmethod
+    def get_plugin_options(cls) -> Dict:
+        return {
+            "service":       Option("login"),
+            "allow_users":   Option([], type=valid_users_list),
+            "deny_users":    Option([], type=valid_users_list),
+            "allow_uids_at": Option(0, type=(lambda arg: valid_number(arg, min=0))),
+        }
+
+    async def authorize(self, user: str, passwd: str) -> bool:
+        async with self.__lock:
+            return (await aiotools.run_async(self.__inner_authorize, user, passwd))
+
+    def __inner_authorize(self, user: str, passwd: str) -> bool:
+        if self.__allow_users and user not in self.__allow_users:
+            get_logger().error("User %r not in allow-list", user)
+            return False
+
+        if self.__deny_users and user in self.__deny_users:
+            get_logger().error("User %r in deny-list", user)
+            return False
+
+        if self.__allow_uids_at > 0:
+            try:
+                uid = pwd.getpwnam(user).pw_uid
+            except Exception:
+                get_logger().exception("Can't find UID of user %r", user)
+                return False
+            else:
+                if uid < self.__allow_uids_at:
+                    get_logger().error("Unallowed UID of user %r: uid=%d < allow_uids_at=%d",
+                                       user, uid, self.__allow_uids_at)
+                    return False
+
+        pam_obj = pam.pam()
+        if not pam_obj.authenticate(user, passwd, service=self.__service):
+            get_logger().error("Can't authorize user %r using PAM: code=%d; reason=%s",
+                               user, pam_obj.code, pam_obj.reason)
+            return False
+        return True