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authentik/passbook/app_gw/proxy/handler.py

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"""passbook app_gw request handler"""
import mimetypes
from logging import getLogger
from random import SystemRandom
from urllib.parse import urlparse
import certifi
import urllib3
from django.core.cache import cache
from django.utils.http import urlencode
from passbook.app_gw.models import ApplicationGatewayProvider
from passbook.app_gw.proxy.exceptions import InvalidUpstream
from passbook.app_gw.proxy.response import get_django_response
from passbook.app_gw.proxy.rewrite import Rewriter
from passbook.app_gw.proxy.utils import encode_items, normalize_request_headers
from passbook.core.models import Application
from passbook.core.policies import PolicyEngine
SESSION_UPSTREAM_KEY = 'passbook_app_gw_upstream'
IGNORED_HOSTNAMES_KEY = 'passbook_app_gw_ignored'
LOGGER = getLogger(__name__)
QUOTE_SAFE = r'<.;>\(}*+|~=-$/_:^@)[{]&\'!,"`'
ERRORS_MESSAGES = {
'upstream-no-scheme': ("Upstream URL scheme must be either "
"'http' or 'https' (%s).")
}
HTTP_NO_VERIFY = urllib3.PoolManager()
HTTP = urllib3.PoolManager(
cert_reqs='CERT_REQUIRED',
ca_certs=certifi.where())
IGNORED_HOSTS = cache.get(IGNORED_HOSTNAMES_KEY, [])
POLICY_CACHE = {}
class RequestHandler:
"""Forward requests"""
_parsed_url = None
_request_headers = None
def __init__(self, app_gw, request):
self.app_gw = app_gw
self.request = request
if self.app_gw.pk not in POLICY_CACHE:
POLICY_CACHE[self.app_gw.pk] = self.app_gw.application.policies.all()
@staticmethod
def find_app_gw_for_request(request):
"""Check if a request should be proxied or forwarded to passbook"""
# Check if hostname is in cached list of ignored hostnames
# This saves us having to query the database on each request
host_header = request.META.get('HTTP_HOST')
if host_header in IGNORED_HOSTS:
# LOGGER.debug("%s is ignored", host_header)
return False
# Look through all ApplicationGatewayProviders and check hostnames
matches = ApplicationGatewayProvider.objects.filter(
server_name__contains=[host_header],
enabled=True)
if not matches.exists():
# Mo matching Providers found, add host header to ignored list
IGNORED_HOSTS.append(host_header)
cache.set(IGNORED_HOSTNAMES_KEY, IGNORED_HOSTS)
# LOGGER.debug("Ignoring %s", host_header)
return False
# At this point we're certain there's a matching ApplicationGateway
if len(matches) > 1:
# This should never happen
raise ValueError
app_gw = matches.first()
try:
# Check if ApplicationGateway is associated with application
getattr(app_gw, 'application')
if app_gw:
return app_gw
except Application.DoesNotExist:
pass
# LOGGER.debug("ApplicationGateway not associated with Application")
return True
def _get_upstream(self):
"""Choose random upstream and save in session"""
if SESSION_UPSTREAM_KEY not in self.request.session:
self.request.session[SESSION_UPSTREAM_KEY] = {}
if self.app_gw.pk not in self.request.session[SESSION_UPSTREAM_KEY]:
upstream_index = int(SystemRandom().random() * len(self.app_gw.upstream))
self.request.session[SESSION_UPSTREAM_KEY][self.app_gw.pk] = upstream_index
return self.app_gw.upstream[self.request.session[SESSION_UPSTREAM_KEY][self.app_gw.pk]]
def get_upstream(self):
"""Get upstream as parsed url"""
upstream = self._get_upstream()
self._parsed_url = urlparse(upstream)
if self._parsed_url.scheme not in ('http', 'https'):
raise InvalidUpstream(ERRORS_MESSAGES['upstream-no-scheme'] %
upstream)
return upstream
def _format_path_to_redirect(self):
# LOGGER.debug("Path before: %s", self.request.get_full_path())
rewriter = Rewriter(self.app_gw, self.request)
after = rewriter.build()
# LOGGER.debug("Path after: %s", after)
return after
def get_proxy_request_headers(self):
"""Get normalized headers for the upstream
Gets all headers from the original request and normalizes them.
Normalization occurs by removing the prefix ``HTTP_`` and
replacing and ``_`` by ``-``. Example: ``HTTP_ACCEPT_ENCODING``
becames ``Accept-Encoding``.
.. versionadded:: 0.9.1
:param request: The original HTTPRequest instance
:returns: Normalized headers for the upstream
"""
return normalize_request_headers(self.request)
def get_request_headers(self):
"""Return request headers that will be sent to upstream.
The header REMOTE_USER is set to the current user
if AuthenticationMiddleware is enabled and
the view's add_remote_user property is True.
.. versionadded:: 0.9.8
"""
request_headers = self.get_proxy_request_headers()
if not self.app_gw.authentication_header:
return request_headers
request_headers[self.app_gw.authentication_header] = self.request.user.get_username()
# LOGGER.debug("%s set", self.app_gw.authentication_header)
return request_headers
def check_permission(self):
"""Check if user is authenticated and has permission to access app"""
if not hasattr(self.request, 'user'):
return False
if not self.request.user.is_authenticated:
return False
policy_engine = PolicyEngine(POLICY_CACHE[self.app_gw.pk])
policy_engine.for_user(self.request.user).with_request(self.request).build()
passing, _messages = policy_engine.result
return passing
def get_encoded_query_params(self):
"""Return encoded query params to be used in proxied request"""
get_data = encode_items(self.request.GET.lists())
return urlencode(get_data)
def _created_proxy_response(self, path):
request_payload = self.request.body
# LOGGER.debug("Request headers: %s", self._request_headers)
request_url = self.get_upstream() + path
# LOGGER.debug("Request URL: %s", request_url)
if self.request.GET:
request_url += '?' + self.get_encoded_query_params()
# LOGGER.debug("Request URL: %s", request_url)
http = HTTP
if not self.app_gw.upstream_ssl_verification:
http = HTTP_NO_VERIFY
try:
proxy_response = http.urlopen(self.request.method,
request_url,
redirect=False,
retries=None,
headers=self._request_headers,
body=request_payload,
decode_content=False,
preload_content=False)
# LOGGER.debug("Proxy response header: %s",
# proxy_response.getheaders())
except urllib3.exceptions.HTTPError as error:
LOGGER.exception(error)
raise
return proxy_response
def _replace_host_on_redirect_location(self, proxy_response):
location = proxy_response.headers.get('Location')
if location:
if self.request.is_secure():
scheme = 'https://'
else:
scheme = 'http://'
request_host = scheme + self.request.META.get('HTTP_HOST')
upstream_host_http = 'http://' + self._parsed_url.netloc
upstream_host_https = 'https://' + self._parsed_url.netloc
location = location.replace(upstream_host_http, request_host)
location = location.replace(upstream_host_https, request_host)
proxy_response.headers['Location'] = location
# LOGGER.debug("Proxy response LOCATION: %s",
# proxy_response.headers['Location'])
def _set_content_type(self, proxy_response):
content_type = proxy_response.headers.get('Content-Type')
if not content_type:
content_type = (mimetypes.guess_type(self.request.path)[0] or
self.app_gw.default_content_type)
proxy_response.headers['Content-Type'] = content_type
# LOGGER.debug("Proxy response CONTENT-TYPE: %s",
# proxy_response.headers['Content-Type'])
def get_response(self):
"""Pass request to upstream and return response"""
self._request_headers = self.get_request_headers()
path = self._format_path_to_redirect()
proxy_response = self._created_proxy_response(path)
self._replace_host_on_redirect_location(proxy_response)
self._set_content_type(proxy_response)
response = get_django_response(proxy_response, strict_cookies=False)
# LOGGER.debug("RESPONSE RETURNED: %s", response)
return response