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 from django.utils.translation import ugettext as _
  30
  31 from lxml import etree
  32 from cas_provider.attribute_formatters import NSMAP, CAS
  33 from cas_provider.models import ProxyGrantingTicket, ProxyTicket
  34 from cas_provider.models import ServiceTicket
  35
  36 from cas_provider.forms import LoginForm, MergeLoginForm
  37
  38 from . import signals
  39
  40 __all__ = ['login', 'validate', 'logout', 'service_validate']
  41
  42 INVALID_TICKET = 'INVALID_TICKET'
  43 INVALID_SERVICE = 'INVALID_SERVICE'
  44 INVALID_REQUEST = 'INVALID_REQUEST'
  45 INTERNAL_ERROR = 'INTERNAL_ERROR'
  46
  47 ERROR_MESSAGES = (
  48     (INVALID_TICKET, u'The provided ticket is invalid.'),
  49     (INVALID_SERVICE, u'Service is invalid'),
  50     (INVALID_REQUEST, u'Not all required parameters were sent.'),
  51     (INTERNAL_ERROR, u'An internal error occurred during ticket validation'),
  52     )
  53
  54
  55 logger = logging.getLogger(__name__)
  56
  57
  58 _never_cache = cache_control(no_cache=True, must_revalidate=True)
  59
  60
  61 def never_cache(view_func):
  62     """
  63     Decorator that adds headers to a response so that it will
  64     never be cached.
  65     """
  66     @wraps(view_func, assigned=available_attrs(view_func))
  67     def _wrapped_view_func(request, *args, **kwargs):
  68         response = view_func(request, *args, **kwargs)
  69         patch_cache_control(response, no_cache=True,
  70                             must_revalidate=True, proxy_revalidate=True)
  71         response['Pragma'] = 'no-cache'
  72         return response
  73     return _wrapped_view_func
  74
  75
  76 @sensitive_post_parameters()
  77 @csrf_protect
  78 @never_cache
  79 def login(request, template_name='cas/login.html',
  80           success_redirect=settings.LOGIN_REDIRECT_URL,
  81           warn_template_name='cas/warn.html', **kwargs):
  82     merge = kwargs.get('merge', False)
  83     logging.debug('CAS Provider Login view. Method is %s, merge is %s, template is %s.',
  84                   request.method, merge, template_name)
  85
  86     service = request.GET.get('service', None)
  87     if service is not None:
  88         # Save the service on the session, for later use if we end up
  89         # in one of the more complicated workflows.
  90         request.session['service'] = service
  91
  92     user = request.user
  93
  94     errors = []
  95
  96     if request.method == 'POST':
  97         if merge:
  98             form = MergeLoginForm(request.POST, request=request)
  99         else:
 100             form = LoginForm(request.POST, request=request)
 101
 102         if form.is_valid():
 103             service = form.cleaned_data.get('service', None)
 104             try:
 105                 auth_args = dict(username=form.cleaned_data['username'],
 106                                  password=form.cleaned_data['password'])
 107                 if merge:
 108                     # We only want to send the merge argument if it's
 109                     # True. If it it's False, we want it to propagate
 110                     # through the auth backends properly.
 111                     auth_args['merge'] = merge
 112                 user = authenticate(**auth_args)
 113             except:
 114                 # Need to merge the accounts?
 115                 if merge:
 116                     # We shouldn't get here...
 117                     raise
 118                 else:
 119                     base_url = reverse('cas_provider_merge')
 120                     args = dict(
 121                         success_redirect=success_redirect,
 122                         username=form.cleaned_data['username'],
 123                         )
 124                     if service is not None:
 125                         args['service'] = service
 126                     args = urlencode(args)
 127
 128                     url = '%s?%s' % (base_url, args)
 129                     logging.debug('Redirecting to %s', url)
 130                     return HttpResponseRedirect(url)
 131
 132             if user is None:
 133                 errors.append(_('Incorrect username and/or password.'))
 134             else:
 135                 if user.is_active:
 136                     auth_login(request, user)
 137
 138     else:  # Not a POST...
 139         if merge:
 140             form = MergeLoginForm(initial={'service': service, 'username': request.GET.get('username')})
 141         else:
 142             form = LoginForm(initial={'service': service})
 143
 144     if user is not None and user.is_authenticated():
 145         # We have an authenticated user.
 146         if not user.is_active:
 147             errors.append(_('This account is disabled. Please contact us if you feel it should be enabled again.'))
 148         else:
 149             # Send the on_cas_login signal. If we get an HttpResponse, return that.
 150             for receiver, response in signals.on_cas_login.send(sender=login, request=request, **kwargs):
 151                 if isinstance(response, HttpResponse):
 152                     return response
 153
 154             if service is None:
 155                 # Try and pull the service off the session
 156                 service = request.session.pop('service', service)
 157
 158             signals.on_cas_login_success.send(sender=login, request=request,
 159                                               service=service, **kwargs)
 160
 161             if service is None:
 162                 # Normal internal success redirection.
 163                 logging.debug('Redirecting to %s', success_redirect)
 164                 return HttpResponseRedirect(success_redirect)
 165             else:
 166                 if request.GET.get('warn', False):
 167                     return render_to_response(warn_template_name, {
 168                         'service': service,
 169                         'warn': False
 170                     }, context_instance=RequestContext(request))
 171
 172                 # Create a service ticket and redirect to the service.
 173                 ticket = ServiceTicket.objects.create(service=service, user=user)
 174                 if 'service' in request.session:
 175                     # Don't need this any more.
 176                     del request.session['service']
 177
 178                 url = ticket.get_redirect_url()
 179                 logging.debug('Redirecting to %s', url)
 180                 return HttpResponseRedirect(url)
 181
 182     logging.debug('Rendering response on %s, merge is %s', template_name, merge)
 183     return render_to_response(template_name, {'form': form, 'errors': errors}, context_instance=RequestContext(request))
 184
 185
 186 @never_cache
 187 def validate(request):
 188     """Validate ticket via CAS v.1 protocol
 189     """
 190     service = request.GET.get('service', None)
 191     ticket_string = request.GET.get('ticket', None)
 192     logger.info('Validating ticket %s for %s', ticket_string, service)
 193     if service is not None and ticket_string is not None:
 194         #renew = request.GET.get('renew', True)
 195         #if not renew:
 196         # TODO: check user SSO session
 197         try:
 198             ticket = ServiceTicket.objects.get(ticket=ticket_string)
 199             assert ticket.service == service
 200         except ServiceTicket.DoesNotExist:
 201             logger.exception("Tried to validate with an invalid ticket %s for %s", ticket_string, service)
 202         except Exception as e:
 203             logger.exception('Got an exception: %s', e)
 204         else:
 205             username = ticket.user.username
 206             ticket.delete()
 207
 208             results = signals.on_cas_collect_histories.send(sender=validate, for_user=ticket.user)
 209             histories = '\n'.join('\n'.join(rs) for rc, rs in results)
 210             logger.info('Validated %s %s', username, "(also %s)" % histories if histories else '')
 211             return HttpResponse("yes\n%s\n%s" % (username, histories))
 212
 213     logger.info('Validation failed.')
 214     return HttpResponse("no\n\n")
 215
 216
 217 @never_cache
 218 def logout(request, template_name='cas/logout.html',
 219            auto_redirect=settings.CAS_AUTO_REDIRECT_AFTER_LOGOUT):
 220     url = request.GET.get('url', None)
 221     if request.user.is_authenticated():
 222         for ticket in ServiceTicket.objects.filter(user=request.user):
 223             ticket.delete()
 224         auth_logout(request)
 225         if url and auto_redirect:
 226             return HttpResponseRedirect(url)
 227     return render_to_response(template_name, {'url': url},
 228         context_instance=RequestContext(request))
 229
 230
 231 @never_cache
 232 def proxy(request):
 233     targetService = request.GET['targetService']
 234     pgt_id = request.GET['pgt']
 235
 236     try:
 237         proxyGrantingTicket = ProxyGrantingTicket.objects.get(ticket=pgt_id)
 238     except ProxyGrantingTicket.DoesNotExist:
 239         return _cas2_error_response(INVALID_TICKET)
 240
 241     pt = ProxyTicket.objects.create(proxyGrantingTicket=proxyGrantingTicket,
 242         user=proxyGrantingTicket.user,
 243         service=targetService)
 244     return _cas2_proxy_success(pt.ticket)
 245
 246
 247 def ticket_validate(service, ticket_string, pgtUrl):
 248     if service is None or ticket_string is None:
 249         return _cas2_error_response(INVALID_REQUEST)
 250
 251     try:
 252         if ticket_string.startswith('ST'):
 253             ticket = ServiceTicket.objects.get(ticket=ticket_string)
 254         elif ticket_string.startswith('PT'):
 255             ticket = ProxyTicket.objects.get(ticket=ticket_string)
 256         else:
 257             return _cas2_error_response(INVALID_TICKET,
 258                 '%(ticket)s is neither Service (ST-...) nor Proxy Ticket (PT-...)' % {
 259                     'ticket': ticket_string})
 260     except ServiceTicket.DoesNotExist:
 261         return _cas2_error_response(INVALID_TICKET)
 262
 263     ticketUrl = urlparse(ticket.service)
 264     serviceUrl = urlparse(service)
 265
 266     if not(ticketUrl.hostname == serviceUrl.hostname and ticketUrl.path == serviceUrl.path and ticketUrl.port == serviceUrl.port):
 267         return _cas2_error_response(INVALID_SERVICE)
 268
 269     pgtIouId = None
 270     proxies = ()
 271     if pgtUrl is not None:
 272         pgt = generate_proxy_granting_ticket(pgtUrl, ticket)
 273         if pgt:
 274             pgtIouId = pgt.pgtiou
 275
 276     if hasattr(ticket, 'proxyticket'):
 277         pgt = ticket.proxyticket.proxyGrantingTicket
 278         # I am issued by this proxy granting ticket
 279         while pgt.pgt is not None:
 280             proxies += (pgt.service,)
 281             pgt = pgt.pgt
 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(urlsplit(pgt_url))
 312
 313     pgt = ProxyGrantingTicket()
 314     pgt.user = ticket.user
 315     pgt.service = ticket.service
 316     # Remember if it's a chained PGT.
 317     pgt.pgt = getattr(ticket, 'proxyGrantingTicket', None)
 318
 319     params = {'pgtId': pgt.ticket, 'pgtIou': pgt.pgtiou}
 320
 321     query = dict(parse_qsl(uri[4]))
 322     query.update(params)
 323
 324     uri[3] = urlencode(query)
 325
 326     try:
 327         urlopen(urlunsplit(uri))
 328     except 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 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), content_type='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     }, content_type='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 etree.tostring(response, encoding='unicode')
 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 etree.tostring(response, encoding='unicode')