ungleich-user/dal/views.py

# Imports from django
from django.shortcuts import render
from django.views.generic import View, FormView
from django.contrib.auth import authenticate, login, logout
from django.contrib.auth.models import User
from django.http import HttpResponse, HttpResponseRedirect
from django.core.validators import validate_email, ValidationError
from django.urls import reverse_lazy
from django.contrib.auth.tokens import PasswordResetTokenGenerator
from django.core.mail import EmailMessage
from .models import ResetToken
from .forms import LoginForm

# Imports for the extra stuff not in django

from base64 import b64encode, b64decode
from datetime import datetime

from random import choice, randint
import string

import os

# Use ldap, like django_auth_backend
import ldap
import ldap.modlist as modlist

from django.conf import settings



class LDAP(object):
    def __init__(self):
        self.uri = settings.AUTH_LDAP_SERVER_URI
        self.user = settings.AUTH_LDAP_BIND_DN
        self.password = settings.AUTH_LDAP_BIND_PASSWORD

        # FIXME: take from settings
        self.search_base = os.environ['LDAPSEARCH']
        self.search_scope = ldap.SCOPE_SUBTREE
        self.search_filter = "objectClass=inetOrgPerson"

        # FIXME: hard coded
        self.dn = "uid={{}},{}".format(os.environ['LDAPCREATE'])
        self.gid = "10004"

        self.conn = ldap.initialize(self.uri)
        if settings.AUTH_LDAP_START_TLS:
            self.conn.start_tls_s()

        self.conn.bind_s(self.user, self.password)


    def check_user_exists(self, username):
        exists = False

        result = self.conn.search_s(self.search_base,
                                    self.search_scope,
                                    self.dn.format(username))
        if len(result) > 0:
            exists = True

        return exists

    def create_user(self, user, password, firstname, lastname, email):
        dn = self.dn.format(user)
        attr = {
            "objectClass": ["inetOrgPerson".encode("utf-8"),
                            "posixAccount".encode("utf-8"),
                            "ldapPublickey".encode("utf-8")],
            "uid": [user.encode("utf-8")],
            "sn": [lastname.encode("utf-8")],
            "givenName": [firstname.encode("utf-8")],
            "cn": ["{} {}".format(firstname, lastname).encode("utf-8")],
            "displayName": ["{} {}".format(firstname, lastname).encode("utf-8")],
            "uidNumber": ["{}".format(self.get_new_uid_number()).encode("utf-8")],
            "gidNumber": [self.gid.encode("utf-8")],
            "loginShell": ["/bin/bash".encode("utf-8")],
            "homeDirectory": ["/home/{}".format(user).encode("utf-8")],
            "mail": email.encode("utf-8"),
            "userPassword": password.encode("utf-8")
        }

        ldif = modlist.addModlist(attr)

        print("just before: {} {}".format(dn, ldif))
        return self.conn.add_s(dn, ldif)

    def get_new_uid_number(self):
        uidlist = [0]

        for result in self.conn.search_s(self.search_base,
                                         self.search_scope,
                                         self.search_filter):
            if 'uidNumber' in result[1]:
                uidlist.append(int(result[1]['uidNumber'][0]))

        return sorted(uidlist)[-1] + 1

class Index(FormView):
    template_name = "landing.html"
    form_class = LoginForm

class Register(View):
    def get(self, request):
        return render(request, 'registeruser.html')

    # Someone filled out the register page, do some basic checks and throw it at nameko
    def post(self, request):
        l = LDAP()

        service = 'register an user'
        urlname = 'register'
        username = request.POST.get('username')

        if username == "" or not username:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'Please supply a username.' } )

        if l.check_user_exists(username):
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'User already exists.' } )

        password1 = request.POST.get('password1')
        password2 = request.POST.get('password2')
        if password1 != password2:
            return render(request, 'error.html', { 'urlname': urlname,
                                                   'service': service,
                                                   'error': "Passwords don't match." } )

        email = request.POST.get('email')
        try:
            validate_email(email)
        except ValidationError:
            return render(request, 'error.html', { 'urlname': urlname,
                                                   'service': service,
                                                   'error': 'The supplied email address is invalid.' } )

        firstname = request.POST.get('firstname')
        lastname = request.POST.get('lastname')
        if not firstname or not lastname:
            return render(request, 'error.html', { 'urlname': urlname,
                                                   'service': service,
                                                   'error': 'Please enter your firstname and lastname.' } )

        # so nothing strange happens if there are escapable chars
        pwd = r'%s' % password1

        try:
            l.create_user(username, pwd, firstname, lastname, email)
        except Exception as e:
            return render(request, 'error.html', { 'urlname': urlname,
                                                   'service': service,
                                                   'error': e } )

        return render(request, 'usercreated.html', { 'user': username } )

class ChangeData(View):
    # provide the form for the change request
    def get(self, request):
        urlname = 'change_data'
        service = 'get default data for logged in user'
        if not request.user.is_authenticated:
            return render(request, 'mustbeloggedin.html')
        user = request.user
        login(request, user)
        # get basic data (firstname, lastname, email)
        with get_pool().next() as rpc:
            (state, firstname, lastname, email) = rpc.getuserdata.get_data(str(request.user))
        # If it throws an error, the errormessage gets put into firstname.. not great naming, but works best this way
        if state == "error":
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': firstname } )
        # The template puts the old data as standard in the fields
        else:
            return render(request, 'changeuserdata.html', { 'user': str(request.user), 'firstname': firstname, 'lastname': lastname, 'email': email } )

    # get the change request
    def post(self, request):
        # variables for the error page
        service = 'change user data'
        urlname = 'change_data'

        # Only logged in users may change data
        if not request.user.is_authenticated:
            return render(request, 'mustbeloggedin.html')

        user = str(request.user)
        firstname = request.POST.get('firstname')
        lastname = request.POST.get('lastname')
        email = request.POST.get('email')

        # Some sanity checks for the supplied data
        if firstname == "":
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'Please enter a firstname.' } )
        elif lastname == "":
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'Please enter a lastname.' } )
        elif email == "":
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'Please enter an email.' } )
        try:
            validate_email(email)
        except ValidationError:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'The supplied email address is invalid.' } )
        # Trying to change the data
        with get_pool().next() as rpc:
            result = rpc.changeuserdata.change_data(user, firstname, lastname, email)
        # Data change worked
        if result == True:
            return render(request, 'changeddata.html', { 'user': user, 'firstname': firstname, 'lastname': lastname, 'email': email } )
        # Data change did not work, display error
        else:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': result } )


class ResetPassword(View):
    def get(self, request):
        return render(request, 'resetpassword.html')

    def post(self, request):
        urlname = 'reset_password'
        service = 'send a password reset request'
        user = request.POST.get('user')
        # First, check if the user exists
        if not check_user_exists(user):
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'The user does not exist.' } )
        # user exists, so try to get email
        with get_pool().next() as rpc:
            (state, tmp1, tmp2, email) = rpc.getuserdata.get_data(user)
        # Either error with the datalookup or no email provided
        if state == "error" or email == 'No email given' or not email:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'Unable to retrieve email address for user.' } )
        # Try to send the email out
        emailsend = self.email(user, email)
        # Email got sent out
        if emailsend == True:
            return render(request, 'send_resetrequest.html', { 'user': user } )
        # Error while trying to send email
        else:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': emailsend } )

    # Sends an email to the user with the 24h active link for a password reset
    def email(self, user, email):
        # getting epoch for the time now in UTC to spare us headache with timezones
        creationtime = int(datetime.utcnow().timestamp())
        # Construct the data for the email
        email_from = 'Userservice at ungleich <%s>' % config['EMAIL']['EMAILFROM']
        to = ['%s <%s>' % (user, email)]
        subject = 'Password reset request for %s' % user
        link = self.build_reset_link(user, creationtime)
        body = 'This is an automated email which was triggered by a reset request for the user %s. Please do not reply to this email.\n' % user
        body += 'If you received this email in error, please disregard it. If you get multiple emails like this, please contact us to look into potential abuse.\n'
        body += 'To reset your password, please follow the link below:\n'
        body += '%s\n\n' % link
        body += 'The link will remain active for 24 hours.\n'
        # Build the email
        mail = EmailMessage(
                subject=subject,
                body=body,
                from_email=email_from,
                to=to
                )
        try:
            mail.send()
            result = True
        except:
            result = "An error occurred while trying to send the mail."
        return result

    # Builds the reset link for the email and puts the token into the database
    def build_reset_link(self, user, epochutc):
        # set up the data
        host = 'account-staging.ungleich.ch'
        tokengen = PasswordResetTokenGenerator()
        # create some noise for use in the tokengenerator
        pseudouser = PseudoUser()
        token = tokengen.make_token(pseudouser)
        buser = bytes(user, 'utf-8')
        userpart = b64encode(buser)
        # create entry into the database
        newdbentry = ResetToken(user=user, token=token, creation=epochutc)
        newdbentry.save()
        # set up the link
        link = 'https://%s/reset/%s/%s/' % (host, userpart.decode('utf-8'), token)
        return link


# Catch the resetrequest URL and check it
class ResetRequest(View):

    # Gets the URL with user in b64 and the token, and checks it
    # Also cleans the database
    def get(self, request, user=None, token=None):
        # Cleans up outdated tokens
        # If we expect quite a bit of old tokens, maybe somewhere else is better,
        # but for now we don't really expect many unused tokens
        self.clean_db()
        # If user and token are not supplied by django, it was called from somewhere else, so it's
        # invalid
        if user == None or token == None:
            return HttpResponse('Invalid URL.', status=404)
        # extract user from b64 format
        tmp_user = bytes(user, 'utf-8')
        user = b64decode(tmp_user)
        user_clean = user.decode('utf-8')
        # set checks_out = True if token is found in database
        dbentries = ResetToken.objects.all().filter(user=user_clean)
        for entry in dbentries:
            if entry.token == token:
                # found the token, now delete it since it's used
                checks_out = True
                entry.delete()
        # No token was found
        if not checks_out:
            return HttpResponse('Invalid URL.', status=404)
        # Token was found, supply the form
        else:
            return render(request, 'resetpasswordnew.html', { 'user': user_clean } )


    # Gets the post form with the new password and sets it
    def post(self, request):
        service = 'reset the password'
        # get the supplied passwords
        password1 = request.POST.get("password1")
        password2 = request.POST.get("password2")
        # get the hidden value of user
        user = request.POST.get("user")
        # some checks over the supplied data
        if user == "" or not user:
            return render(request, 'error.html', { 'service': service, 'error': 'Something went wrong. Did you use the supplied form?' } )
        if password1 == "" or not password1 or password2 == "" or not password2:
            return render(request, 'error.html', { 'service': service, 'error': 'Please supply a password and confirm it.' } )
        if password1 != password2:
            return render(request, 'error.html', { 'service': service, 'error': 'The supplied passwords do not match.' } )
        if len(password1) < 8:
            return render(request, 'error.html', { 'service': service, 'error': 'The password is too short, please use a longer one. At least 8 characters.' } )
        # everything checks out, now change the password
        with get_pool().next() as rpc:
            pwd = r'%s' % password1
            result = rpc.changepassword.change_password(user, pwd)
        # password change successfull
        if result == True:
            return render(request, 'changedpassword.html', { 'user': user } )
        # Something went wrong while changing the password
        else:
            return render(request, 'error.html', { 'service': service, 'error': result } )

    # Cleans up outdated tokens
    def clean_db(self):
        # cutoff time is set to 24h hours
        # using utcnow() to have no headache with timezones
        cutoff = int(datetime.utcnow().timestamp()) - (24*60*60)
        # Get all tokens older than 24 hours
        oldtokens = ResetToken.objects.all().filter(creation__lt=cutoff)
        for token in oldtokens:
            # delete all tokens older than 24 hours
            token.delete()
        return True

# The logged in user can change the password here

class ChangePassword(View):

    # Presents the page for a logged in user
    def get(self, request):
        if not request.user.is_authenticated:
            return render(request, 'mustbeloggedin.html')
        return render(request, 'changepassword.html', { 'user': request.user } )

    # Does some checks on the supplied data and changes the password
    def post(self, request):
        # Variables for the error page
        urlname = 'change_password'
        service = 'change the password'

        if not request.user.is_authenticated:
            return render(request, 'mustbeloggedin.html')
        login(request, request.user)

        user = str(request.user)
        oldpassword = request.POST.get('oldpassword')
        check = authenticate(request, username=user, password=oldpassword)
        # Is the right password for the user supplied?
        if check is None:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'Wrong password for the user.' } )

        password1 = request.POST.get('password1')
        password2 = request.POST.get('password2')
        # Are both passwords from the form the same?
        if password1 != password2:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service,
                'error': 'Please check if you typed the same password both times for the new password' } )
        # Check for password length
        if len(password1) < 8:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service,
                'error': 'The password is too short, please use a longer one. At least 8 characters.' } )
        with get_pool().next() as rpc:
            # Trying to change the password
            pwd = r'%s' % password1
            result = rpc.changepassword.change_password(user, pwd)
        # Password was changed
        if result == True:
            return render(request, 'changedpassword.html', { 'user': user } )
        # Password not changed, instead got some kind of error
        else:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': result } )


# Deletes an account
class DeleteAccount(View):
    # Show the basic form for deleting an account
    def get(self, request):
        return render(request, 'deleteaccount.html')

    # Reads the filled out form
    def post(self, request):
        # Variables for error page
        urlname = 'account_delete'
        service = 'delete an account'

        # Does the user exist?
        username = request.POST.get('username')
        if not check_user_exists(username):
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'Unknown user.' } )

        # Do user and password match?
        password = request.POST.get('password')
        pwd = r'%s' % password
        check = authenticate(request, username=username, password=pwd)
        if check is None:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': 'Wrong password for user.' } )

        # Try to delete the user
        with get_pool().next() as rpc:
            result = rpc.deleteuser.delete_user(username)
        # User deleted
        if result == True:
            logout(request)
            return render(request, 'deleteduser.html', { 'user': username } )
        # User not deleted, got some kind of error
        else:
            return render(request, 'error.html', { 'urlname': urlname, 'service': service, 'error': result } )

# Log out the session
class LogOut(View):
    def get(self, request):
        logout(request)
        return HttpResponse("You have been logged out.", status=200)



# TO be clarified

# To trick the tokengenerator to work with us, because we don't really
# have the expected user Class since we are reading the user from a form
# We store the tokens and don't have to use the check function,
# some one time data works fine.

class LastLogin():
    def replace(self, microsecond=0, tzinfo=None):
        return randint(1,100000)

class PseudoUser():
    # easiest way to handle the check for lastlogin
    last_login = LastLogin()
    # random alphanumeric strings for primary key and password, just used for token generation
    pk = ''.join(choice(string.ascii_letters + string.digits) for _ in range(20))
    password = ''.join(choice(string.ascii_letters + string.digits) for _ in range(30))