cas_provider/views.py

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