Files
edx-platform/common/djangoapps/external_auth/views.py
2012-08-31 06:43:28 -04:00

549 lines
19 KiB
Python

import functools
import json
import logging
import random
import re
import string
import fnmatch
from external_auth.models import ExternalAuthMap
from django.conf import settings
from django.contrib.auth import REDIRECT_FIELD_NAME, authenticate, login
from django.contrib.auth.models import User
from student.models import UserProfile
from django.http import HttpResponse, HttpResponseRedirect
from django.utils.http import urlquote
from django.shortcuts import redirect
from mitxmako.shortcuts import render_to_response, render_to_string
try:
from django.views.decorators.csrf import csrf_exempt
except ImportError:
from django.contrib.csrf.middleware import csrf_exempt
from django_future.csrf import ensure_csrf_cookie
from util.cache import cache_if_anonymous
import django_openid_auth.views as openid_views
from django_openid_auth import auth as openid_auth
from openid.consumer.consumer import SUCCESS
from openid.server.server import Server
from openid.server.trustroot import TrustRoot
from openid.store.filestore import FileOpenIDStore
from openid.extensions import ax, sreg
import student.views as student_views
log = logging.getLogger("mitx.external_auth")
# -----------------------------------------------------------------------------
# OpenID Common
# -----------------------------------------------------------------------------
@csrf_exempt
def default_render_failure(request,
message,
status=403,
template_name='extauth_failure.html',
exception=None):
"""Render an Openid error page to the user"""
log.debug("In openid_failure " + message)
data = render_to_string(template_name,
dict(message=message, exception=exception))
return HttpResponse(data, status=status)
# -----------------------------------------------------------------------------
# OpenID Authentication
# -----------------------------------------------------------------------------
def generate_password(length=12, chars=string.letters + string.digits):
"""Generate internal password for externally authenticated user"""
choice = random.SystemRandom().choice
return ''.join([choice(chars) for i in range(length)])
@csrf_exempt
def openid_login_complete(request,
redirect_field_name=REDIRECT_FIELD_NAME,
render_failure=None):
"""Complete the openid login process"""
render_failure = (render_failure or default_render_failure)
openid_response = openid_views.parse_openid_response(request)
if not openid_response:
return render_failure(request,
'This is an OpenID relying party endpoint.')
if openid_response.status == SUCCESS:
external_id = openid_response.identity_url
oid_backend = openid_auth.OpenIDBackend()
details = oid_backend._extract_user_details(openid_response)
log.debug('openid success, details=%s' % details)
url = getattr(settings, 'OPENID_SSO_SERVER_URL', None)
external_domain = "openid:%s" % url
fullname = '%s %s' % (details.get('first_name', ''),
details.get('last_name', ''))
return external_login_or_signup(request,
external_id,
external_domain,
details,
details.get('email', ''),
fullname)
return render_failure(request, 'Openid failure')
def external_login_or_signup(request,
external_id,
external_domain,
credentials,
email,
fullname,
retfun=None):
"""Generic external auth login or signup"""
# see if we have a map from this external_id to an edX username
try:
eamap = ExternalAuthMap.objects.get(external_id=external_id,
external_domain=external_domain)
log.debug('Found eamap=%s' % eamap)
except ExternalAuthMap.DoesNotExist:
# go render form for creating edX user
eamap = ExternalAuthMap(external_id=external_id,
external_domain=external_domain,
external_credentials=json.dumps(credentials))
eamap.external_email = email
eamap.external_name = fullname
eamap.internal_password = generate_password()
log.debug('Created eamap=%s' % eamap)
eamap.save()
internal_user = eamap.user
if internal_user is None:
log.debug('No user for %s yet, doing signup' % eamap.external_email)
return signup(request, eamap)
uname = internal_user.username
user = authenticate(username=uname, password=eamap.internal_password)
if user is None:
log.warning("External Auth Login failed for %s / %s" %
(uname, eamap.internal_password))
return signup(request, eamap)
if not user.is_active:
log.warning("User %s is not active" % (uname))
# TODO: improve error page
msg = 'Account not yet activated: please look for link in your email'
return default_render_failure(request, msg)
login(request, user)
request.session.set_expiry(0)
student_views.try_change_enrollment(request)
log.info("Login success - {0} ({1})".format(user.username, user.email))
if retfun is None:
return redirect('/')
return retfun()
@ensure_csrf_cookie
@cache_if_anonymous
def signup(request, eamap=None):
"""
Present form to complete for signup via external authentication.
Even though the user has external credentials, he/she still needs
to create an account on the edX system, and fill in the user
registration form.
eamap is an ExteralAuthMap object, specifying the external user
for which to complete the signup.
"""
if eamap is None:
pass
# save this for use by student.views.create_account
request.session['ExternalAuthMap'] = eamap
# default conjoin name, no spaces
username = eamap.external_name.replace(' ', '')
context = {'has_extauth_info': True,
'show_signup_immediately': True,
'extauth_email': eamap.external_email,
'extauth_username': username,
'extauth_name': eamap.external_name,
}
log.debug('Doing signup for %s' % eamap.external_email)
return student_views.index(request, extra_context=context)
# -----------------------------------------------------------------------------
# MIT SSL
# -----------------------------------------------------------------------------
def ssl_dn_extract_info(dn):
"""
Extract username, email address (may be anyuser@anydomain.com) and
full name from the SSL DN string. Return (user,email,fullname) if
successful, and None otherwise.
"""
ss = re.search('/emailAddress=(.*)@([^/]+)', dn)
if ss:
user = ss.group(1)
email = "%s@%s" % (user, ss.group(2))
else:
return None
ss = re.search('/CN=([^/]+)/', dn)
if ss:
fullname = ss.group(1)
else:
return None
return (user, email, fullname)
@csrf_exempt
def ssl_login(request):
"""
This is called by student.views.index when
MITX_FEATURES['AUTH_USE_MIT_CERTIFICATES'] = True
Used for MIT user authentication. This presumes the web server
(nginx) has been configured to require specific client
certificates.
If the incoming protocol is HTTPS (SSL) then authenticate via
client certificate. The certificate provides user email and
fullname; this populates the ExternalAuthMap. The user is
nevertheless still asked to complete the edX signup.
Else continues on with student.views.index, and no authentication.
"""
certkey = "SSL_CLIENT_S_DN" # specify the request.META field to use
cert = request.META.get(certkey, '')
if not cert:
cert = request.META.get('HTTP_' + certkey, '')
if not cert:
try:
# try the direct apache2 SSL key
cert = request._req.subprocess_env.get(certkey, '')
except Exception:
cert = None
if not cert:
# no certificate information - go onward to main index
return student_views.index(request)
(user, email, fullname) = ssl_dn_extract_info(cert)
retfun = functools.partial(student_views.index, request)
return external_login_or_signup(request,
external_id=email,
external_domain="ssl:MIT",
credentials=cert,
email=email,
fullname=fullname,
retfun=retfun)
# -----------------------------------------------------------------------------
# OpenID Provider
# -----------------------------------------------------------------------------
def get_xrds_url(resource, request):
"""
Return the XRDS url for a resource
"""
host = request.META['HTTP_HOST']
if not host.endswith('edx.org'):
return None
location = host + '/openid/provider/' + resource + '/'
if request.is_secure():
return 'https://' + location
else:
return 'http://' + location
def add_openid_simple_registration(request, response, data):
sreg_data = {}
sreg_request = sreg.SRegRequest.fromOpenIDRequest(request)
sreg_fields = sreg_request.allRequestedFields()
# if consumer requested simple registration fields, add them
if sreg_fields:
for field in sreg_fields:
if field == 'email' and 'email' in data:
sreg_data['email'] = data['email']
elif field == 'fullname' and 'fullname' in data:
sreg_data['fullname'] = data['fullname']
# construct sreg response
sreg_response = sreg.SRegResponse.extractResponse(sreg_request,
sreg_data)
sreg_response.toMessage(response.fields)
def add_openid_attribute_exchange(request, response, data):
try:
ax_request = ax.FetchRequest.fromOpenIDRequest(request)
except ax.AXError:
# not using OpenID attribute exchange extension
pass
else:
ax_response = ax.FetchResponse()
# if consumer requested attribute exchange fields, add them
if ax_request and ax_request.requested_attributes:
for type_uri in ax_request.requested_attributes.iterkeys():
email_schema = 'http://axschema.org/contact/email'
name_schema = 'http://axschema.org/namePerson'
if type_uri == email_schema and 'email' in data:
ax_response.addValue(email_schema, data['email'])
elif type_uri == name_schema and 'fullname' in data:
ax_response.addValue(name_schema, data['fullname'])
# construct ax response
ax_response.toMessage(response.fields)
def provider_respond(server, request, response, data):
"""
Respond to an OpenID request
"""
# get and add extensions
add_openid_simple_registration(request, response, data)
add_openid_attribute_exchange(request, response, data)
# create http response from OpenID response
webresponse = server.encodeResponse(response)
http_response = HttpResponse(webresponse.body)
http_response.status_code = webresponse.code
# add OpenID headers to response
for k, v in webresponse.headers.iteritems():
http_response[k] = v
return http_response
def validate_trust_root(openid_request):
"""
Only allow OpenID requests from valid trust roots
"""
trusted_roots = getattr(settings, 'OPENID_PROVIDER_TRUSTED_ROOT', None)
if not trusted_roots:
# not using trusted roots
return True
# don't allow empty trust roots
if (not hasattr(openid_request, 'trust_root') or
not openid_request.trust_root):
log.error('no trust_root')
return False
# ensure trust root parses cleanly (one wildcard, of form *.foo.com, etc.)
trust_root = TrustRoot.parse(openid_request.trust_root)
if not trust_root:
log.error('invalid trust_root')
return False
# don't allow empty return tos
if (not hasattr(openid_request, 'return_to') or
not openid_request.return_to):
log.error('empty return_to')
return False
# ensure return to is within trust root
if not trust_root.validateURL(openid_request.return_to):
log.error('invalid return_to')
return False
# check that the root matches the ones we trust
if not any(r for r in trusted_roots if fnmatch.fnmatch(trust_root, r)):
log.error('non-trusted root')
return False
return True
@csrf_exempt
def provider_login(request):
"""
OpenID login endpoint
"""
# make and validate endpoint
endpoint = get_xrds_url('login', request)
if not endpoint:
return default_render_failure(request, "Invalid OpenID request")
# initialize store and server
store = FileOpenIDStore('/tmp/openid_provider')
server = Server(store, endpoint)
# handle OpenID request
querydict = dict(request.REQUEST.items())
error = False
if 'openid.mode' in request.GET or 'openid.mode' in request.POST:
# decode request
openid_request = server.decodeRequest(querydict)
if not openid_request:
return default_render_failure(request, "Invalid OpenID request")
# don't allow invalid and non-trusted trust roots
if not validate_trust_root(openid_request):
return default_render_failure(request, "Invalid OpenID trust root")
# checkid_immediate not supported, require user interaction
if openid_request.mode == 'checkid_immediate':
return provider_respond(server, openid_request,
openid_request.answer(False), {})
# checkid_setup, so display login page
elif openid_request.mode == 'checkid_setup':
if openid_request.idSelect():
# remember request and original path
request.session['openid_setup'] = {
'request': openid_request,
'url': request.get_full_path()
}
# user failed login on previous attempt
if 'openid_error' in request.session:
error = True
del request.session['openid_error']
# OpenID response
else:
return provider_respond(server, openid_request,
server.handleRequest(openid_request), {})
# handle login
if request.method == 'POST' and 'openid_setup' in request.session:
# get OpenID request from session
openid_setup = request.session['openid_setup']
openid_request = openid_setup['request']
openid_request_url = openid_setup['url']
del request.session['openid_setup']
# don't allow invalid trust roots
if not validate_trust_root(openid_request):
return default_render_failure(request, "Invalid OpenID trust root")
# check if user with given email exists
email = request.POST.get('email', None)
try:
user = User.objects.get(email=email)
except User.DoesNotExist:
request.session['openid_error'] = True
msg = "OpenID login failed - Unknown user email: {0}".format(email)
log.warning(msg)
return HttpResponseRedirect(openid_request_url)
# attempt to authenticate user
username = user.username
password = request.POST.get('password', None)
user = authenticate(username=username, password=password)
if user is None:
request.session['openid_error'] = True
msg = "OpenID login failed - password for {0} is invalid"
msg = msg.format(email)
log.warning(msg)
return HttpResponseRedirect(openid_request_url)
# authentication succeeded, so log user in
if user is not None and user.is_active:
# remove error from session since login succeeded
if 'openid_error' in request.session:
del request.session['openid_error']
# fullname field comes from user profile
profile = UserProfile.objects.get(user=user)
log.info("OpenID login success - {0} ({1})".format(user.username,
user.email))
# redirect user to return_to location
url = endpoint + urlquote(user.username)
response = openid_request.answer(True, None, url)
return provider_respond(server,
openid_request,
response,
{
'fullname': profile.name,
'email': user.email
})
request.session['openid_error'] = True
msg = "Login failed - Account not active for user {0}".format(username)
log.warning(msg)
return HttpResponseRedirect(openid_request_url)
# determine consumer domain if applicable
return_to = ''
if 'openid.return_to' in request.REQUEST:
return_to = request.REQUEST['openid.return_to']
matches = re.match(r'\w+:\/\/([\w\.-]+)', return_to)
return_to = matches.group(1)
# display login page
response = render_to_response('provider_login.html', {
'error': error,
'return_to': return_to
})
# custom XRDS header necessary for discovery process
response['X-XRDS-Location'] = get_xrds_url('xrds', request)
return response
def provider_identity(request):
"""
XRDS for identity discovery
"""
response = render_to_response('identity.xml',
{'url': get_xrds_url('login', request)},
mimetype='text/xml')
# custom XRDS header necessary for discovery process
response['X-XRDS-Location'] = get_xrds_url('identity', request)
return response
def provider_xrds(request):
"""
XRDS for endpoint discovery
"""
response = render_to_response('xrds.xml',
{'url': get_xrds_url('login', request)},
mimetype='text/xml')
# custom XRDS header necessary for discovery process
response['X-XRDS-Location'] = get_xrds_url('xrds', request)
return response