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from abc import ABCMeta, abstractmethod
import ldap
import os
import random
from base64 import b64encode
from database import BookingDataBase
class VPN_BaseClass:
"""
the vpn handler abstract class / interface
"""
__metaclass__ = ABCMeta
@abstractmethod
def __init__(self, config):
"""
config is the parsed vpn.yaml file
"""
pass
@abstractmethod
def makeNewUser(self, user=None):
"""
This method is called when a vpn user is needed.
This method should create a vpn user in whatever
runs the vpn in our infrastructure. returns the
credentials for the vpn user and some uid
that will be associated with the booking in the
database. This uid is used to track the vpn user and
to delete the user when there are no bookings associated
with that uid.
"""
user = "username"
passwd = "password"
uid = "some way for you to identify this user in the database"
return user, passwd, uid
@abstractmethod
def removeOldUsers(self):
"""
checks the list of all vpn users against a list of
vpn users associated with active bookings and removes
users who dont have an active booking
If you want your vpn accounts to be persistent,
you can just ignore this
"""
pass
names = [
'frodo baggins', 'samwise gamgee', 'peregrin took', 'meriadoc brandybuck',
'bilbo baggins', 'gandalf grey', 'aragorn dunadan', 'arwen evenstar',
'saruman white', 'pippin took', 'merry brandybuck', 'legolas greenleaf',
'gimli gloin', 'anakin skywalker', 'padme amidala', 'han solo',
'jabba hut', 'mace windu', 'sount dooku', 'qui-gon jinn',
'admiral ackbar', 'emperor palpatine'
]
class VPN:
"""
This class communicates with the ldap server to manage vpn users.
This class extends the above ABC, and implements the makeNewUser,
removeOldUser, and __init__ abstract functions you must override to
extend the VPN_BaseClass
"""
def __init__(self, config):
"""
init takes the parsed vpn config file as an arguement.
automatically connects and authenticates on the ldap server
based on the configuration file
"""
self.config = config
server = config['server']
self.uri = "ldap://"+server
self.conn = None
user = config['authentication']['user']
pswd = config['authentication']['pass']
if os.path.isfile(pswd):
pswd = open(pswd).read()
self.connect(user, pswd)
def connect(self, root_dn, root_pass):
"""
Opens a connection to the server in the config file
and authenticates as the given user
"""
self.conn = ldap.initialize(self.uri)
self.conn.simple_bind_s(root_dn, root_pass)
def addUser(self, full_name, passwd):
"""
Adds a user to the ldap server. Creates the new user with the classes
and in the directory given in the config file.
full_name should be two tokens seperated by a space. The first token
will become the username
private helper function for the makeNewUser()
"""
first = full_name.split(' ')[0]
last = full_name.split(' ')[1]
user_dir = self.config['directory']['user']
user_dir += ','+self.config['directory']['root']
dn = "uid=" + first + ',' + user_dir
record = [
('objectclass', ['top', 'inetOrgPerson']),
('uid', first),
('cn', full_name),
('sn', last),
('userpassword', passwd),
('ou', self.config['directory']['user'].split('=')[1])
]
self.conn.add_s(dn, record)
return dn
def makeNewUser(self, name=None):
"""
creates a new user in the ldap database, with the given name
if supplied. If no name is given, we will try to select from the
pre-written list above, and will resort to generating a random string
as a username if the preconfigured names are all taken.
Returns the username and password the user needs to authenticate, and
the dn that we can use to manage the user.
"""
if name is None:
i = 0
while not self.checkName(name):
i += 1
if i == 20:
name = self.randoString(8)
name += ' '+self.randoString(8)
break # generates a random name to prevent infinite loop
name = self.genUserName()
passwd = self.randoString(15)
dn = self.addUser(name, passwd)
return name, passwd, dn
def checkName(self, name):
"""
returns true if the name is available
"""
if name is None:
return False
uid = name.split(' ')[0]
base = self.config['directory']['user'] + ','
base += self.config['directory']['root']
filtr = '(uid=' + uid + ')'
timeout = 5
ans = self.conn.search_st(
base,
ldap.SCOPE_SUBTREE,
filtr,
timeout=timeout
)
return len(ans) < 1
@staticmethod
def randoString(n):
"""
uses /dev/urandom to generate a random string of length n
"""
n = int(n)
# defines valid characters
alpha = 'abcdefghijklmnopqrstuvwxyz'
alpha_num = alpha
alpha_num += alpha.upper()
alpha_num += "0123456789"
# generates random string from /dev/urandom
rnd = b64encode(os.urandom(3*n)).decode('utf-8')
random_string = ''
for char in rnd:
if char in alpha_num:
random_string += char
return str(random_string[:n])
def genUserName(self):
"""
grabs a random name from the list above
"""
i = random.randint(0, len(names) - 1)
return names[i]
def deleteUser(self, dn):
self.conn.delete(dn)
def getAllUsers(self):
"""
returns all the user dn's in the ldap database in a list
"""
base = self.config['directory']['user'] + ','
base += self.config['directory']['root']
filtr = '(objectclass='+self.config['user']['objects'][-1]+')'
timeout = 10
ans = self.conn.search_st(
base,
ldap.SCOPE_SUBTREE,
filtr,
timeout=timeout
)
users = []
for user in ans:
users.append(user[0]) # adds the dn of each user
return users
def removeOldUsers(self):
"""
removes users from the ldap server who dont have any active bookings.
will not delete a user if their uid's are named in the config
file as permanent users.
"""
db = self.config['database']
# the dn of all users who have an active booking
active_users = BookingDataBase(db).getVPN()
all_users = self.getAllUsers()
for user in all_users:
# checks if they are a permanent user
if self.is_permanent_user(user):
continue
# deletes the user if they dont have an active booking
if user not in active_users:
self.deleteUser(user)
def is_permanent_user(self, dn):
for user in self.config['permanent_users']:
if (user in dn) or (dn in user):
return True
return False
VPN_BaseClass.register(VPN)
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