cas_provider/views.py

   1 from __future__ import unicode_literals
   2
   3 import logging
   4 logger = logging.getLogger('cas_provider.views')
   5
   6 try:
   7     from urllib.error import HTTPError, URLError
   8     from urllib.parse import parse_qsl, urlencode, urlparse, urlsplit, urlunsplit
   9     from urllib.request import urlopen
  10 except ImportError:
  11     from urllib import urlencode
  12     from urllib2 import HTTPError, URLError, urlopen
  13     from urlparse import parse_qsl, urlparse, urlsplit, urlunsplit
  14 from functools import wraps
  15
  16 from django import VERSION
  17 from django.utils.decorators import available_attrs
  18 from django.views.decorators.debug import sensitive_post_parameters
  19 from django.views.decorators.cache import cache_control
  20 from django.utils.cache import patch_cache_control
  21 from django.views.decorators.csrf import csrf_protect
  22
  23 from django.http import HttpResponse, HttpResponseRedirect
  24 from django.conf import settings
  25 from django.contrib.auth import login as auth_login, logout as auth_logout
  26
  27 from django.shortcuts import render
  28 from django.utils.translation import ugettext as _
  29 from django.template import RequestContext
  30 from django.contrib.auth import authenticate
  31 from django.utils.translation import ugettext as _
  32
  33 from lxml import etree
  34 from cas_provider.attribute_formatters import NSMAP, CAS
  35 from cas_provider.models import ProxyGrantingTicket, ProxyTicket
  36 from cas_provider.models import ServiceTicket
  37
  38 from cas_provider.forms import LoginForm, MergeLoginForm
  39
  40 from . import signals
  41
  42 if VERSION >= (1, 10):
  43     from django.urls import get_callable, reverse
  44     user_is_authenticated = lambda user: user.is_authenticated
  45 else:
  46     from django.core.urlresolvers import get_callable, reverse
  47     user_is_authenticated = lambda user: user.is_authenticated()
  48
  49 __all__ = ['login', 'validate', 'logout', 'service_validate']
  50
  51 INVALID_TICKET = 'INVALID_TICKET'
  52 INVALID_SERVICE = 'INVALID_SERVICE'
  53 INVALID_REQUEST = 'INVALID_REQUEST'
  54 INTERNAL_ERROR = 'INTERNAL_ERROR'
  55
  56 ERROR_MESSAGES = (
  57     (INVALID_TICKET, 'The provided ticket is invalid.'),
  58     (INVALID_SERVICE, 'Service is invalid'),
  59     (INVALID_REQUEST, 'Not all required parameters were sent.'),
  60     (INTERNAL_ERROR, 'An internal error occurred during ticket validation'),
  61     )
  62
  63
  64 logger = logging.getLogger(__name__)
  65
  66
  67 _never_cache = cache_control(no_cache=True, must_revalidate=True)
  68
  69
  70 def never_cache(view_func):
  71     """
  72     Decorator that adds headers to a response so that it will
  73     never be cached.
  74     """
  75     @wraps(view_func, assigned=available_attrs(view_func))
  76     def _wrapped_view_func(request, *args, **kwargs):
  77         response = view_func(request, *args, **kwargs)
  78         patch_cache_control(response, no_cache=True,
  79                             must_revalidate=True, proxy_revalidate=True)
  80         response['Pragma'] = 'no-cache'
  81         return response
  82     return _wrapped_view_func
  83
  84
  85 @sensitive_post_parameters()
  86 @csrf_protect
  87 @never_cache
  88 def login(request, template_name='cas/login.html',
  89           success_redirect=settings.LOGIN_REDIRECT_URL,
  90           warn_template_name='cas/warn.html', **kwargs):
  91     merge = kwargs.get('merge', False)
  92     logging.debug('CAS Provider Login view. Method is %s, merge is %s, template is %s.',
  93                   request.method, merge, template_name)
  94
  95     service = request.GET.get('service', None)
  96     if service is not None:
  97         # Save the service on the session, for later use if we end up
  98         # in one of the more complicated workflows.
  99         request.session['service'] = service
 100
 101     user = request.user
 102
 103     errors = []
 104
 105     if request.method == 'POST':
 106         if merge:
 107             form = MergeLoginForm(request.POST, request=request)
 108         else:
 109             form = LoginForm(request.POST, request=request)
 110
 111         if form.is_valid():
 112             service = form.cleaned_data.get('service', None)
 113             try:
 114                 auth_args = dict(username=form.cleaned_data['username'],
 115                                  password=form.cleaned_data['password'])
 116                 if merge:
 117                     # We only want to send the merge argument if it's
 118                     # True. If it it's False, we want it to propagate
 119                     # through the auth backends properly.
 120                     auth_args['merge'] = merge
 121                 user = authenticate(**auth_args)
 122             except:
 123                 # Need to merge the accounts?
 124                 if merge:
 125                     # We shouldn't get here...
 126                     raise
 127                 else:
 128                     base_url = reverse('cas_provider_merge')
 129                     args = dict(
 130                         success_redirect=success_redirect,
 131                         username=form.cleaned_data['username'],
 132                         )
 133                     if service is not None:
 134                         args['service'] = service
 135                     args = urlencode(args)
 136
 137                     url = '%s?%s' % (base_url, args)
 138                     logging.debug('Redirecting to %s', url)
 139                     return HttpResponseRedirect(url)
 140
 141             if user is None:
 142                 errors.append(_('Incorrect username and/or password.'))
 143             else:
 144                 if user.is_active:
 145                     auth_login(request, user)
 146
 147     else:  # Not a POST...
 148         if merge:
 149             form = MergeLoginForm(initial={'service': service, 'username': request.GET.get('username')})
 150         else:
 151             form = LoginForm(initial={'service': service})
 152
 153     if user is not None and user_is_authenticated(user):
 154         # We have an authenticated user.
 155         if not user.is_active:
 156             errors.append(_('This account is disabled. Please contact us if you feel it should be enabled again.'))
 157         else:
 158             # Send the on_cas_login signal. If we get an HttpResponse, return that.
 159             for receiver, response in signals.on_cas_login.send(sender=login, request=request, **kwargs):
 160                 if isinstance(response, HttpResponse):
 161                     return response
 162
 163             if service is None:
 164                 # Try and pull the service off the session
 165                 service = request.session.pop('service', service)
 166
 167             signals.on_cas_login_success.send(sender=login, request=request,
 168                                               service=service, **kwargs)
 169
 170             if service is None:
 171                 # Normal internal success redirection.
 172                 logging.debug('Redirecting to %s', success_redirect)
 173                 return HttpResponseRedirect(success_redirect)
 174             else:
 175                 if request.GET.get('warn', False):
 176                     return render(request, warn_template_name, {
 177                         'service': service,
 178                         'warn': False
 179                     })
 180
 181                 # Create a service ticket and redirect to the service.
 182                 ticket = ServiceTicket.objects.create(service=service, user=user)
 183                 if 'service' in request.session:
 184                     # Don't need this any more.
 185                     del request.session['service']
 186
 187                 url = ticket.get_redirect_url()
 188                 logging.debug('Redirecting to %s', url)
 189                 return HttpResponseRedirect(url)
 190
 191     logging.debug('Rendering response on %s, merge is %s', template_name, merge)
 192     return render(request, template_name, {'form': form, 'errors': errors})
 193
 194
 195 @never_cache
 196 def validate(request):
 197     """Validate ticket via CAS v.1 protocol
 198     """
 199     service = request.GET.get('service', None)
 200     ticket_string = request.GET.get('ticket', None)
 201     logger.info('Validating ticket %s for %s', ticket_string, service)
 202     if service is not None and ticket_string is not None:
 203         #renew = request.GET.get('renew', True)
 204         #if not renew:
 205         # TODO: check user SSO session
 206         try:
 207             ticket = ServiceTicket.objects.get(ticket=ticket_string)
 208             assert ticket.service == service
 209         except ServiceTicket.DoesNotExist:
 210             logger.exception("Tried to validate with an invalid ticket %s for %s", ticket_string, service)
 211         except Exception as e:
 212             logger.exception('Got an exception: %s', e)
 213         else:
 214             username = ticket.user.username
 215             ticket.delete()
 216
 217             results = signals.on_cas_collect_histories.send(sender=validate, for_user=ticket.user)
 218             histories = '\n'.join('\n'.join(rs) for rc, rs in results)
 219             logger.info('Validated %s %s', username, "(also %s)" % histories if histories else '')
 220             return HttpResponse("yes\n%s\n%s" % (username, histories))
 221
 222     logger.info('Validation failed.')
 223     return HttpResponse("no\n\n")
 224
 225
 226 @never_cache
 227 def logout(request, template_name='cas/logout.html',
 228            auto_redirect=settings.CAS_AUTO_REDIRECT_AFTER_LOGOUT):
 229     url = request.GET.get('url', None)
 230     if user_is_authenticated(request.user):
 231         for ticket in ServiceTicket.objects.filter(user=request.user):
 232             ticket.delete()
 233         auth_logout(request)
 234         if url and auto_redirect:
 235             return HttpResponseRedirect(url)
 236     return render(request, template_name, {'url': url})
 237
 238
 239 @never_cache
 240 def proxy(request):
 241     targetService = request.GET['targetService']
 242     pgt_id = request.GET['pgt']
 243
 244     try:
 245         proxyGrantingTicket = ProxyGrantingTicket.objects.get(ticket=pgt_id)
 246     except ProxyGrantingTicket.DoesNotExist:
 247         return _cas2_error_response(INVALID_TICKET)
 248
 249     pt = ProxyTicket.objects.create(proxyGrantingTicket=proxyGrantingTicket,
 250         user=proxyGrantingTicket.user,
 251         service=targetService)
 252     return _cas2_proxy_success(pt.ticket)
 253
 254
 255 def ticket_validate(service, ticket_string, pgtUrl):
 256     if service is None or ticket_string is None:
 257         return _cas2_error_response(INVALID_REQUEST)
 258
 259     try:
 260         if ticket_string.startswith('ST'):
 261             ticket = ServiceTicket.objects.get(ticket=ticket_string)
 262         elif ticket_string.startswith('PT'):
 263             ticket = ProxyTicket.objects.get(ticket=ticket_string)
 264         else:
 265             return _cas2_error_response(INVALID_TICKET,
 266                 '%(ticket)s is neither Service (ST-...) nor Proxy Ticket (PT-...)' % {
 267                     'ticket': ticket_string})
 268     except ServiceTicket.DoesNotExist:
 269         return _cas2_error_response(INVALID_TICKET)
 270
 271     ticketUrl = urlparse(ticket.service)
 272     serviceUrl = urlparse(service)
 273
 274     if not(ticketUrl.hostname == serviceUrl.hostname and ticketUrl.path == serviceUrl.path and ticketUrl.port == serviceUrl.port):
 275         return _cas2_error_response(INVALID_SERVICE)
 276
 277     pgtIouId = None
 278     proxies = ()
 279     if pgtUrl is not None:
 280         pgt = generate_proxy_granting_ticket(pgtUrl, ticket)
 281         if pgt:
 282             pgtIouId = pgt.pgtiou
 283
 284     try:
 285         proxyTicket = ticket.proxyticket
 286     except ProxyTicket.DoesNotExist:
 287         pass
 288     else:
 289         pgt = proxyTicket.proxyGrantingTicket
 290         # I am issued by this proxy granting ticket
 291         while pgt.pgt is not None:
 292             proxies += (pgt.service,)
 293             pgt = pgt.pgt
 294
 295     user = ticket.user
 296     ticket.delete()
 297     return _cas2_sucess_response(user, pgtIouId, proxies)
 298
 299
 300 @never_cache
 301 def service_validate(request):
 302     """Validate ticket via CAS v.2 protocol"""
 303     service = request.GET.get('service', None)
 304     ticket_string = request.GET.get('ticket', None)
 305     pgtUrl = request.GET.get('pgtUrl', None)
 306     if ticket_string.startswith('PT-'):
 307         return _cas2_error_response(INVALID_TICKET, "serviceValidate cannot verify proxy tickets")
 308     else:
 309         return ticket_validate(service, ticket_string, pgtUrl)
 310
 311
 312 @never_cache
 313 def proxy_validate(request):
 314     """Validate ticket via CAS v.2 protocol"""
 315     service = request.GET.get('service', None)
 316     ticket_string = request.GET.get('ticket', None)
 317     pgtUrl = request.GET.get('pgtUrl', None)
 318     return ticket_validate(service, ticket_string, pgtUrl)
 319
 320
 321 def generate_proxy_granting_ticket(pgt_url, ticket):
 322     proxy_callback_good_status = (200, 202, 301, 302, 304)
 323     uri = list(urlsplit(pgt_url))
 324
 325     pgt = ProxyGrantingTicket()
 326     pgt.user = ticket.user
 327     pgt.service = ticket.service
 328     # Remember if it's a chained PGT.
 329     pgt.pgt = getattr(ticket, 'proxyGrantingTicket', None)
 330
 331     params = {'pgtId': pgt.ticket, 'pgtIou': pgt.pgtiou}
 332
 333     query = dict(parse_qsl(uri[4]))
 334     query.update(params)
 335
 336     uri[3] = urlencode(query)
 337
 338     try:
 339         urlopen(urlunsplit(uri))
 340     except HTTPError as e:
 341         if not e.code in proxy_callback_good_status:
 342             logger.debug('Checking Proxy Callback URL {0} returned {1}. Not issuing PGT.'.format(uri, e.code))
 343             return
 344     except URLError as e:
 345         logger.debug('Checking Proxy Callback URL {0} raised URLError. Not issuing PGT.'.format(uri))
 346         return
 347
 348     pgt.save()
 349     return pgt
 350
 351
 352 def _cas2_proxy_success(pt):
 353     return HttpResponse(proxy_success(pt))
 354
 355
 356 def _cas2_sucess_response(user, pgt=None, proxies=None):
 357     return HttpResponse(auth_success_response(user, pgt, proxies), content_type='text/xml')
 358
 359
 360 def _cas2_error_response(code, message=None):
 361     return HttpResponse('''<cas:serviceResponse xmlns:cas="http://www.yale.edu/tp/cas">
 362             <cas:authenticationFailure code="%(code)s">
 363                 %(message)s
 364             </cas:authenticationFailure>
 365         </cas:serviceResponse>''' % {
 366         'code': code,
 367         'message': message if message else dict(ERROR_MESSAGES).get(code)
 368     }, content_type='text/xml')
 369
 370
 371 def proxy_success(pt):
 372     response = etree.Element(CAS + 'serviceResponse', nsmap=NSMAP)
 373     proxySuccess = etree.SubElement(response, CAS + 'proxySuccess')
 374     proxyTicket = etree.SubElement(proxySuccess, CAS + 'proxyTicket')
 375     proxyTicket.text = pt
 376     return etree.tostring(response, encoding='unicode')
 377
 378
 379 def auth_success_response(user, pgt, proxies):
 380     response = etree.Element(CAS + 'serviceResponse', nsmap=NSMAP)
 381     auth_success = etree.SubElement(response, CAS + 'authenticationSuccess')
 382     username = etree.SubElement(auth_success, CAS + 'user')
 383     username.text = user.username
 384
 385     attrs = {}
 386     for receiver, custom in signals.cas_collect_custom_attributes.send(sender=auth_success_response, user=user):
 387         if custom:
 388             attrs.update(custom)
 389
 390     identifiers = [i for sr, rr in signals.on_cas_collect_histories.send(sender=validate, for_user=user)
 391                    for i in rr]
 392
 393     if identifiers:
 394         # Singular `identifier`, as that is the name of the element tag(s).
 395         attrs['identifier'] = identifiers
 396
 397     if attrs:
 398         formatter = get_callable(settings.CAS_CUSTOM_ATTRIBUTES_FORMATER)
 399         formatter(auth_success, attrs)
 400
 401     if pgt:
 402         pgtElement = etree.SubElement(auth_success, CAS + 'proxyGrantingTicket')
 403         pgtElement.text = pgt
 404
 405     if proxies:
 406         proxiesElement = etree.SubElement(auth_success, CAS + "proxies")
 407         for proxy in proxies:
 408             proxyElement = etree.SubElement(proxiesElement, CAS + "proxy")
 409             proxyElement.text = proxy
 410
 411     return etree.tostring(response, encoding='unicode')