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| -rw-r--r-- | laas-fog/source/api/vpn.py | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/laas-fog/source/api/vpn.py b/laas-fog/source/api/vpn.py new file mode 100644 index 0000000..336a681 --- /dev/null +++ b/laas-fog/source/api/vpn.py @@ -0,0 +1,235 @@ +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) |