cas_provider/views.py

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