django-cas-server/cas_server/views.py

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# ⁻*- coding: utf-8 -*-
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# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License version 3 for
# more details.
#
# You should have received a copy of the GNU General Public License version 3
# along with this program; if not, write to the Free Software Foundation, Inc., 51
# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# (c) 2015 Valentin Samir
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"""views for the app"""
from .default_settings import settings
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from django.shortcuts import render, redirect
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from django.http import HttpResponse, HttpResponseRedirect
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from django.contrib import messages
from django.utils.decorators import method_decorator
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from django.utils.translation import ugettext as _
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from django.utils import timezone
from django.views.decorators.csrf import csrf_exempt
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from django.views.generic import View
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import requests
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from lxml import etree
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from datetime import timedelta
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import utils
import forms
import models
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class AttributesMixin(object):
"""mixin for the attributs methode"""
# pylint: disable=too-few-public-methods
def attributes(self):
"""regerate attributes list for template rendering"""
attributes = []
for key, value in self.ticket.attributs.items():
if isinstance(value, list):
for elt in value:
attributes.append((key, elt))
else:
attributes.append((key, value))
return attributes
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class LogoutMixin(object):
"""destroy CAS session utils"""
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def clean_session_variables(self):
"""Clean sessions variables"""
try:
del self.request.session["authenticated"]
except KeyError:
pass
try:
del self.request.session["username"]
except KeyError:
pass
try:
del self.request.session["warn"]
except KeyError:
pass
def logout(self):
"""effectively destroy CAS session"""
try:
user = models.User.objects.get(username=self.request.session.get("username"))
user.logout(self.request)
user.delete()
except models.User.DoesNotExist:
pass
finally:
self.clean_session_variables()
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class LogoutView(View, LogoutMixin):
"""destroy CAS session (logout) view"""
request = None
service = None
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def get(self, request, *args, **kwargs):
"""methode called on GET request on this view"""
self.request = request
self.service = request.GET.get('service')
self.logout()
# if service is set, redirect to service after logout
if self.service:
list(messages.get_messages(request)) # clean messages before leaving the django app
return HttpResponseRedirect(self.service)
# else redirect to login page
else:
if settings.CAS_REDIRECT_TO_LOGIN_AFTER_LOGOUT:
messages.add_message(request, messages.SUCCESS, _(u'Successfully logout'))
return redirect("cas_server:login")
else:
return render(request, settings.CAS_LOGOUT_TEMPLATE)
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class LoginView(View, LogoutMixin):
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"""credential requestor / acceptor"""
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# pylint: disable=too-many-instance-attributes
# Nine is reasonable in this case.
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user = None
form = None
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request = None
service = None
renew = None
gateway = None
method = None
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renewed = False
warned = False
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def post(self, request, *args, **kwargs):
"""methode called on POST request on this view"""
self.request = request
self.service = request.POST.get('service')
self.renew = True if request.POST.get('renew') else False
self.gateway = request.POST.get('gateway')
self.method = request.POST.get('method')
if not request.session.get("authenticated") or self.renew:
self.form = forms.UserCredential(
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request.POST,
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initial={
'service':self.service,
'method':self.method,
'warn':request.session.get("warn")
}
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)
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if self.form.is_valid():
self.user = models.User.objects.get(username=self.form.cleaned_data['username'])
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request.session.set_expiry(0)
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request.session["username"] = self.form.cleaned_data['username']
request.session["warn"] = True if self.form.cleaned_data.get("warn") else False
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request.session["authenticated"] = True
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self.renewed = True
self.warned = True
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else:
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self.logout()
return self.common()
def get(self, request, *args, **kwargs):
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"""methode called on GET request on this view"""
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self.request = request
self.service = request.GET.get('service')
self.renew = True if request.GET.get('renew') else False
self.gateway = request.GET.get('gateway')
self.method = request.GET.get('method')
if not request.session.get("authenticated") or self.renew:
self.form = forms.UserCredential(
initial={
'service':self.service,
'method':self.method,
'warn':request.session.get("warn")
}
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)
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return self.common()
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def service_login(self):
"""Perform login agains a service"""
try:
# is the service allowed
service_pattern = models.ServicePattern.validate(self.service)
# is the current user allowed on this service
service_pattern.check_user(self.user)
# if the user has asked to be warned before any login to a service
if self.request.session.get("warn", True) and not self.warned:
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messages.add_message(
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self.request,
messages.WARNING,
_(u"Authentication has been required by service %(name)s (%(url)s)") % \
{'name':service_pattern.name, 'url':self.service}
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)
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return render(
self.request,
settings.CAS_WARN_TEMPLATE,
{'service_ticket_url':self.user.get_service_url(
self.service,
service_pattern,
renew=self.renew
)}
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)
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else:
# redirect, using method ?
return HttpResponseRedirect(
self.user.get_service_url(self.service, service_pattern, renew=self.renew)
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)
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except models.ServicePattern.DoesNotExist:
messages.add_message(
self.request,
messages.ERROR,
_(u'Service %(url)s non allowed.') % {'url' : self.service}
)
except models.BadUsername:
messages.add_message(
self.request,
messages.ERROR,
_(u"Username non allowed")
)
except models.BadFilter:
messages.add_message(
self.request,
messages.ERROR,
_(u"User charateristics non allowed")
)
except models.UserFieldNotDefined:
messages.add_message(
self.request,
messages.ERROR,
_(u"The attribut %(field)s is needed to use" \
" that service") % {'field':service_pattern.user_field}
)
# if gateway is set and auth failed redirect to the service without authentication
if self.gateway:
list(messages.get_messages(self.request)) # clean messages before leaving django
return HttpResponseRedirect(self.service)
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return render(self.request, settings.CAS_LOGGED_TEMPLATE, {'session':self.request.session})
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def authenticated(self):
"""Processing authenticated users"""
try:
self.user = models.User.objects.get(username=self.request.session.get("username"))
except models.User.DoesNotExist:
self.logout()
return utils.redirect_params("cas_server:login", params=dict(self.request.GET))
# if login agains a service is self.requestest
if self.service:
return self.service_login()
else:
return render(
self.request,
settings.CAS_LOGGED_TEMPLATE,
{'session':self.request.session}
)
def not_authenticated(self):
"""Processing non authenticated users"""
if self.service:
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try:
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service_pattern = models.ServicePattern.validate(self.service)
if self.gateway:
list(messages.get_messages(self.request))# clean messages before leaving django
return HttpResponseRedirect(self.service)
if self.request.session.get("authenticated") and self.renew:
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messages.add_message(
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self.request,
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messages.WARNING,
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_(u"Authentication renewal required by service %(name)s (%(url)s).") %
{'name':service_pattern.name, 'url':self.service}
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)
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else:
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messages.add_message(
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self.request,
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messages.WARNING,
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_(u"Authentication required by service %(name)s (%(url)s).") %
{'name':service_pattern.name, 'url':self.service}
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)
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except models.ServicePattern.DoesNotExist:
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messages.add_message(
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self.request,
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messages.ERROR,
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_(u'Service %s non allowed') % self.service
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)
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return render(self.request, settings.CAS_LOGIN_TEMPLATE, {'form':self.form})
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def common(self):
"""Part execute uppon GET and POST request"""
# if authenticated and successfully renewed authentication if needed
if self.request.session.get("authenticated") and (not self.renew or self.renewed):
return self.authenticated()
else:
return self.not_authenticated()
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class Validate(View):
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"""service ticket validation"""
@staticmethod
def get(request):
"""methode called on GET request on this view"""
service = request.GET.get('service')
ticket = request.GET.get('ticket')
renew = True if request.GET.get('renew') else False
if service and ticket:
try:
ticket = models.ServiceTicket.objects.get(
value=ticket,
service=service,
validate=False,
renew=renew,
creation__gt=(timezone.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY))
)
ticket.validate = True
ticket.save()
return HttpResponse("yes\n", content_type="text/plain")
except models.ServiceTicket.DoesNotExist:
return HttpResponse("no\n", content_type="text/plain")
else:
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return HttpResponse("no\n", content_type="text/plain")
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class ValidateError(Exception):
"""handle service validation error"""
def __init__(self, code, msg=""):
self.code = code
self.msg = msg
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super(ValidateError, self).__init__(code)
def __unicode__(self):
return u"%s" % self.msg
def render(self, request):
"""render the error template for the exception"""
return render(
request,
"cas_server/serviceValidateError.xml",
{'code':self.code, 'msg':self.msg},
content_type="text/xml; charset=utf-8"
)
class ValidateService(View, AttributesMixin):
"""service ticket validation [CAS 2.0] and [CAS 3.0]"""
request = None
service = None
ticket = None
pgt_url = None
renew = None
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allow_proxy_ticket = False
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def get(self, request):
"""methode called on GET request on this view"""
self.request = request
self.service = request.GET.get('service')
self.ticket = request.GET.get('ticket')
self.pgt_url = request.GET.get('pgtUrl')
self.renew = True if request.GET.get('renew') else False
if not self.service or not self.ticket:
return ValidateError(
'INVALID_REQUEST',
"you must specify a service and a ticket"
).render(request)
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else:
try:
self.ticket, proxies = self.process_ticket()
params = {
'username':self.ticket.user.username,
'attributes':self.attributes(),
'proxies':proxies
}
if self.ticket.service_pattern.user_field and \
self.ticket.user.attributs.get(self.ticket.service_pattern.user_field):
params['username'] = self.ticket.user.attributs.get(
self.ticket.service_pattern.user_field
)
if self.pgt_url and self.pgt_url.startswith("https://"):
return self.process_pgturl(params)
else:
return render(
request,
"cas_server/serviceValidate.xml",
params,
content_type="text/xml; charset=utf-8"
)
except ValidateError as error:
return error.render(request)
def process_ticket(self):
"""fetch the ticket angains the database and check its validity"""
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try:
proxies = []
if self.ticket.startswith(models.ServiceTicket.PREFIX):
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ticket = models.ServiceTicket.objects.get(
value=self.ticket,
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validate=False,
renew=self.renew,
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creation__gt=(timezone.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY))
)
elif self.allow_proxy_ticket and self.ticket.startswith(models.ProxyTicket.PREFIX):
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ticket = models.ProxyTicket.objects.get(
value=self.ticket,
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validate=False,
renew=self.renew,
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creation__gt=(timezone.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY))
)
for prox in ticket.proxies.all():
proxies.append(prox.url)
else:
raise ValidateError('INVALID_TICKET')
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ticket.validate = True
ticket.save()
if ticket.service != self.service:
raise ValidateError('INVALID_SERVICE')
return ticket, proxies
except (models.ServiceTicket.DoesNotExist, models.ProxyTicket.DoesNotExist):
raise ValidateError('INVALID_TICKET', 'ticket not found')
def process_pgturl(self, params):
"""Handle PGT request"""
try:
pattern = models.ServicePattern.validate(self.pgt_url)
if pattern.proxy_callback:
proxyid = utils.gen_pgtiou()
pticket = models.ProxyGrantingTicket.objects.create(
user=self.ticket.user,
service=self.pgt_url,
service_pattern=pattern,
single_log_out=pattern.single_log_out
)
url = utils.update_url(self.pgt_url, {'pgtIou':proxyid, 'pgtId':pticket.value})
try:
ret = requests.get(url, verify=settings.CAS_PROXY_CA_CERTIFICATE_PATH)
if ret.status_code == 200:
params['proxyGrantingTicket'] = proxyid
else:
pticket.delete()
return render(
self.request,
"cas_server/serviceValidate.xml",
params,
content_type="text/xml; charset=utf-8"
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)
except requests.exceptions.SSLError as error:
error = utils.unpack_nested_exception(error)
raise ValidateError('INVALID_PROXY_CALLBACK', str(error))
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else:
raise ValidateError(
'INVALID_PROXY_CALLBACK',
"callback url not allowed by configuration"
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)
except models.ServicePattern.DoesNotExist:
raise ValidateError(
'INVALID_PROXY_CALLBACK',
'callback url not allowed by configuration'
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)
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class Proxy(View):
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"""proxy ticket service"""
request = None
pgt = None
target_service = None
def get(self, request):
"""methode called on GET request on this view"""
self.request = request
self.pgt = request.GET.get('pgt')
self.target_service = request.GET.get('targetService')
try:
if self.pgt and self.target_service:
return self.process_proxy()
else:
raise ValidateError(
'INVALID_REQUEST',
"you must specify and pgt and targetService"
)
except ValidateError as error:
return error.render(request)
def process_proxy(self):
"""handle PT request"""
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try:
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# is the target service allowed
pattern = models.ServicePattern.validate(self.target_service)
if not pattern.proxy:
raise ValidateError(
'UNAUTHORIZED_SERVICE',
'the service do not allow proxy ticket'
)
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# is the proxy granting ticket valid
ticket = models.ProxyGrantingTicket.objects.get(
value=self.pgt,
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creation__gt=(timezone.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY))
)
# is the pgt user allowed on the target service
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pattern.check_user(ticket.user)
pticket = ticket.user.get_ticket(
models.ProxyTicket,
self.target_service,
pattern,
renew=False)
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pticket.proxies.create(url=ticket.service)
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return render(
self.request,
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"cas_server/proxy.xml",
{'ticket':pticket.value},
content_type="text/xml; charset=utf-8"
)
except models.ProxyGrantingTicket.DoesNotExist:
raise ValidateError('INVALID_TICKET', 'PGT not found')
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except models.ServicePattern.DoesNotExist:
raise ValidateError('UNAUTHORIZED_SERVICE')
except (models.BadUsername, models.BadFilter, models.UserFieldNotDefined):
raise ValidateError(
'UNAUTHORIZED_USER',
'%s not allowed on %s' % (ticket.user, self.target_service)
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)
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class SamlValidateError(Exception):
"""handle saml validation error"""
def __init__(self, code, msg=""):
self.code = code
self.msg = msg
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super(SamlValidateError, self).__init__(code)
def __unicode__(self):
return u"%s" % self.msg
def render(self, request):
"""render the error template for the exception"""
return render(
request,
"cas_server/samlValidateError.xml",
{
'code':self.code,
'msg':self.msg,
'IssueInstant':timezone.now().isoformat(),
'ResponseID':utils.gen_saml_id()
},
content_type="text/xml; charset=utf-8"
)
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def _saml_validate_error(request, code, msg=""):
"""render the samlValidateError.xml templace using `code` and `msg`"""
return render(
request,
"cas_server/samlValidateError.xml",
{
'code':code,
'msg':msg,
'IssueInstant':timezone.now().isoformat(),
'ResponseID':utils.gen_saml_id()
},
content_type="text/xml; charset=utf-8"
)
class SamlValidate(View, AttributesMixin):
"""SAML ticket validation"""
request = None
target = None
ticket = None
root = None
@method_decorator(csrf_exempt)
def dispatch(self, request, *args, **kwargs):
"""dispatch requests based on method GET, POST, ..."""
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return super(SamlValidate, self).dispatch(request, *args, **kwargs)
def post(self, request):
"""methode called on POST request on this view"""
self.request = request
self.target = request.GET.get('TARGET')
self.root = etree.fromstring(request.body)
try:
self.ticket = self.process_ticket()
expire_instant = (self.ticket.creation + \
timedelta(seconds=settings.CAS_TICKET_VALIDITY)).isoformat()
attributes = self.attributes()
params = {
'IssueInstant':timezone.now().isoformat(),
'expireInstant':expire_instant,
'Recipient':self.target,
'ResponseID':utils.gen_saml_id(),
'username':self.ticket.user.username,
'attributes':attributes
}
if self.ticket.service_pattern.user_field and \
self.ticket.user.attributs.get(self.ticket.service_pattern.user_field):
params['username'] = self.ticket.user.attributs.get(
self.ticket.service_pattern.user_field
)
return render(
request,
"cas_server/samlValidate.xml",
params,
content_type="text/xml; charset=utf-8"
)
except SamlValidateError as error:
return error.render(request)
def process_ticket(self):
"""validate ticket from SAML XML body"""
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try:
auth_req = self.root.getchildren()[1].getchildren()[0]
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ticket = auth_req.getchildren()[0].text
if ticket.startswith(models.ServiceTicket.PREFIX):
ticket = models.ServiceTicket.objects.get(
value=ticket,
validate=False,
creation__gt=(timezone.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY))
)
elif ticket.startswith(models.ProxyTicket.PREFIX):
ticket = models.ProxyTicket.objects.get(
value=ticket,
validate=False,
creation__gt=(timezone.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY))
)
else:
raise SamlValidateError(
'AuthnFailed',
'ticket should begin with PT- or ST-'
)
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ticket.validate = True
ticket.save()
if ticket.service != self.target:
raise SamlValidateError(
'AuthnFailed',
'TARGET do not match ticket service'
)
return ticket
except (IndexError, KeyError):
raise SamlValidateError('VersionMismatch')
except (models.ServiceTicket.DoesNotExist, models.ProxyTicket.DoesNotExist):
raise SamlValidateError('AuthnFailed', 'ticket not found')