init commit

utils/ldap_manager.py

@@ -0,0 +1,279 @@
+import base64
+import hashlib
+import random
+import ldap3
+import logging
+
+from django.conf import settings
+
+logger = logging.getLogger(__name__)
+
+
+class LdapManager:
+    __instance = None
+
+    def __new__(cls):
+        if LdapManager.__instance is None:
+            LdapManager.__instance = object.__new__(cls)
+        return LdapManager.__instance
+
+    def __init__(self):
+        """
+        Initialize the LDAP subsystem.
+        """
+        self.rng = random.SystemRandom()
+        self.server = ldap3.Server(settings.AUTH_LDAP_SERVER)
+
+    def get_admin_conn(self):
+        """
+        Return a bound :class:`ldap3.Connection` instance which has write
+        permissions on the dn in which the user accounts reside.
+        """
+        conn = self.get_conn(user=settings.LDAP_ADMIN_DN,
+                             password=settings.LDAP_ADMIN_PASSWORD,
+                             raise_exceptions=True)
+        conn.bind()
+        return conn
+
+    def get_conn(self, **kwargs):
+        """
+        Return an unbound :class:`ldap3.Connection` which talks to the configured
+        LDAP server.
+
+        The *kwargs* are passed to the constructor of :class:`ldap3.Connection` and
+        can be used to set *user*, *password* and other useful arguments.
+        """
+        return ldap3.Connection(self.server, **kwargs)
+
+    def _ssha_password(self, password):
+        """
+        Apply the SSHA password hashing scheme to the given *password*.
+        *password* must be a :class:`bytes` object, containing the utf-8
+        encoded password.
+
+        Return a :class:`bytes` object containing ``ascii``-compatible data
+        which can be used as LDAP value, e.g. after armoring it once more using
+        base64 or decoding it to unicode from ``ascii``.
+        """
+        SALT_BYTES = 15
+
+        sha1 = hashlib.sha1()
+        salt = self.rng.getrandbits(SALT_BYTES * 8).to_bytes(SALT_BYTES,
+                                                               "little")
+        sha1.update(password)
+        sha1.update(salt)
+
+        digest = sha1.digest()
+        passwd = b"{SSHA}" + base64.b64encode(digest + salt)
+        return passwd
+
+    def create_user(self, user, password, firstname, lastname, email):
+        conn = self.get_admin_conn()
+        uidNumber = self._get_max_uid() + 1
+        logger.debug("uidNumber={uidNumber}".format(uidNumber=uidNumber))
+        user_exists = True
+        while user_exists:
+            user_exists, _ = self.check_user_exists(
+                "",
+                '(&(objectClass=inetOrgPerson)(objectClass=posixAccount)'
+                '(objectClass=top)(uidNumber={uidNumber}))'.format(
+                    uidNumber=uidNumber
+                )
+            )
+            if user_exists:
+                logger.debug(
+                    "{uid} exists. Trying next.".format(uid=uidNumber)
+                )
+                uidNumber += 1
+        logger.debug("{uid} does not exist. Using it".format(uid=uidNumber))
+        self._set_max_uid(uidNumber)
+        try:
+            uid = user
+            conn.add("uid={uid},{customer_dn}".format(
+                    uid=uid, customer_dn=settings.LDAP_CUSTOMER_DN
+                ),
+                ["inetOrgPerson", "posixAccount", "ldapPublickey"],
+                {
+                    "uid": [uid],
+                    "sn": [lastname],
+                    "givenName": [firstname],
+                    "cn": [uid],
+                    "displayName": ["{} {}".format(firstname, lastname)],
+                    "uidNumber": [str(uidNumber)],
+                    "gidNumber": [str(settings.LDAP_CUSTOMER_GROUP_ID)],
+                    "loginShell": ["/bin/bash"],
+                    "homeDirectory": ["/home/{}".format(user)],
+                    "mail": email,
+                    "userPassword": [password]
+                }
+            )
+            logger.debug('Created user %s %s' % (user.encode('utf-8'),
+                                                 uidNumber))
+        except Exception as ex:
+            logger.debug('Could not create user %s' % user.encode('utf-8'))
+            logger.error("Exception: " + str(ex))
+            raise Exception(ex)
+        finally:
+            conn.unbind()
+
+    def change_password(self, uid, new_password):
+        """
+        Changes the password of the user identified by user_dn
+
+        :param uid: str The uid that identifies the user
+        :param new_password: str The new password string
+        :return: True if password was changed successfully False otherwise
+        """
+        conn = self.get_admin_conn()
+
+        # Make sure the user exists first to change his/her details
+        user_exists, entries = self.check_user_exists(
+            uid=uid,
+            search_base=settings.ENTIRE_SEARCH_BASE
+        )
+        return_val = False
+        if user_exists:
+            try:
+                return_val = conn.modify(
+                    entries[0].entry_dn,
+                    {
+                        "userpassword": (
+                            ldap3.MODIFY_REPLACE,
+                            [new_password]
+                        )
+                    }
+                )
+            except Exception as ex:
+                logger.error("Exception: " + str(ex))
+        else:
+            logger.error("User {} not found".format(uid))
+
+        conn.unbind()
+        return return_val
+
+    def change_user_details(self, uid, details):
+        """
+        Updates the user details as per given values in kwargs of the user
+        identified by user_dn.
+
+        Assumes that all attributes passed in kwargs are valid.
+
+        :param uid: str The uid that identifies the user
+        :param details: dict A dictionary containing the new values
+        :return: True if user details were updated successfully False otherwise
+        """
+        conn = self.get_admin_conn()
+
+        # Make sure the user exists first to change his/her details
+        user_exists, entries = self.check_user_exists(
+            uid=uid,
+            search_base=settings.ENTIRE_SEARCH_BASE
+        )
+
+        return_val = False
+        if user_exists:
+            details_dict = {k: (ldap3.MODIFY_REPLACE, [v.encode("utf-8")]) for
+                            k, v in details.items()}
+            try:
+                return_val = conn.modify(entries[0].entry_dn, details_dict)
+                msg = "success"
+            except Exception as ex:
+                msg = str(ex)
+                logger.error("Exception: " + msg)
+            finally:
+                conn.unbind()
+        else:
+            msg = "User {} not found".format(uid)
+            logger.error(msg)
+            conn.unbind()
+        return return_val, msg
+
+    def check_user_exists(self, uid, search_filter="", attributes=None,
+                          search_base=settings.LDAP_CUSTOMER_DN, search_attr="uid"):
+        """
+        Check if the user with the given uid exists in the customer group.
+
+        :param uid: str representing the user
+        :param search_filter: str representing the filter condition to find
+                            users. If its empty, the search finds the user with
+                            the given uid.
+        :param attributes: list A list of str representing all the attributes
+                           to be obtained in the result entries
+        :param search_base: str
+        :return: tuple (bool, [ldap3.abstract.entry.Entry ..])
+                       A bool indicating if the user exists
+                       A list of all entries obtained in the search
+        """
+        conn = self.get_admin_conn()
+        entries = []
+        try:
+            result = conn.search(
+                search_base=search_base,
+                search_filter=search_filter if len(search_filter) > 0 else
+                '(uid={uid})'.format(uid=uid),
+                attributes=attributes
+            )
+            entries = conn.entries
+        finally:
+            conn.unbind()
+        return result, entries
+
+    def delete_user(self, uid):
+        """
+        Deletes the user with the given uid from ldap
+
+        :param uid: str representing the user
+        :return: True if the delete was successful False otherwise
+        """
+        conn = self.get_admin_conn()
+        try:
+            return_val = conn.delete(
+                ("uid={uid}," + settings.LDAP_CUSTOMER_DN).format(uid=uid),
+            )
+            msg = "success"
+        except Exception as ex:
+            msg = str(ex)
+            logger.error("Exception: " + msg)
+            return_val = False
+        finally:
+            conn.unbind()
+        return return_val, msg
+
+    def _set_max_uid(self, max_uid):
+        """
+        a utility function to save max_uid value to a file
+
+        :param max_uid: an integer representing the max uid
+        :return:
+        """
+        with open(settings.LDAP_MAX_UID_FILE_PATH, 'w+') as handler:
+            handler.write(str(max_uid))
+
+    def _get_max_uid(self):
+        """
+        A utility function to read the max uid value that was previously set
+
+        :return: An integer representing the max uid value that was previously
+         set
+        """
+        try:
+            with open(settings.LDAP_MAX_UID_FILE_PATH, 'r+') as handler:
+                try:
+                    return_value = int(handler.read())
+                except ValueError as ve:
+                    logger.error(
+                        "Error reading int value from {}. {}"
+                        "Returning default value {} instead".format(
+                            settings.LDAP_MAX_UID_PATH,
+                            str(ve),
+                            settings.LDAP_DEFAULT_START_UID
+                        )
+                    )
+                    return_value = settings.LDAP_DEFAULT_START_UID
+                return return_value
+        except FileNotFoundError as fnfe:
+            logger.error("File not found : " + str(fnfe))
+            return_value = settings.LDAP_DEFAULT_START_UID
+            logger.error("So, returning UID={}".format(return_value))
+            return return_value
+