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