cas_provider/views.py

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