New middleware to handle ssl termination proxies

Murano doesn't handle request properly if it is behind an SSL
termination proxy. In this case HTTP redirection and returned URLs
use http instead of https.

New middleware helps to handle the situation below properly. The purpose of the
SSLMiddleware is to update the wsgi.url_scheme environment variable of
the request with the value contained in an HTTP header that can be
configured in the configuration file (by default: 'X-Forwarded-Proto')

Closes-Bug: #1504610
Change-Id: Id7cfa1bce00c965b618a4f3e4ca2c915a57bbe52

etc/murano/murano-paste.ini

@@ -2,7 +2,7 @@
 pipeline = cloudfoundryapi
 
 [pipeline:murano]
-pipeline = request_id versionnegotiation faultwrap authtoken context rootapp
+pipeline = request_id ssl versionnegotiation faultwrap authtoken context rootapp
 
 [filter:context]
 paste.filter_factory = murano.api.middleware.context:ContextMiddleware.factory
@@ -35,3 +35,6 @@ paste.filter_factory = murano.api.middleware.fault:FaultWrapper.factory
 # Middleware to set x-openstack-request-id in http response header
 [filter:request_id]
 paste.filter_factory = oslo_middleware.request_id:RequestId.factory
+
+[filter:ssl]
+paste.filter_factory = murano.api.middleware.ssl:SSLMiddleware.factory

murano/api/middleware/ssl.py

@@ -0,0 +1,52 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from oslo_config import cfg
+from oslo_log import log as logging
+
+from murano.common import wsgi
+
+ssl_middleware_opts = [
+    cfg.StrOpt('secure_proxy_ssl_header',
+               default='X-Forwarded-Proto',
+               help="The HTTP Header that will be used to determine which "
+                    "the original request protocol scheme was, even if it was "
+                    "removed by an SSL terminator proxy.")
+]
+cfg.CONF.register_opts(ssl_middleware_opts)
+LOG = logging.getLogger(__name__)
+
+
+class SSLMiddleware(wsgi.Middleware):
+    """A middleware that replaces the request wsgi.url_scheme environment
+    variable with the value of HTTP header configured in
+    secure_proxy_ssl_header if exists in the incoming request.
+    This is useful if the server is behind a SSL termination proxy.
+    """
+
+    @classmethod
+    def factory(cls, global_conf, **local_conf):
+        def filter(app):
+            return cls(app)
+        return filter
+
+    def __init__(self, application):
+        super(SSLMiddleware, self).__init__(application)
+        self.secure_proxy_ssl_header = 'HTTP_{0}'.format(
+            cfg.CONF.secure_proxy_ssl_header.upper().replace('-', '_'))
+
+    def process_request(self, req):
+        LOG.debug('Default url_scheme: {0}. {1}: {2}'.format(
+            req.environ['wsgi.url_scheme'], self.secure_proxy_ssl_header,
+            req.environ.get(self.secure_proxy_ssl_header)))
+        req.environ['wsgi.url_scheme'] = req.environ.get(
+            self.secure_proxy_ssl_header, req.environ['wsgi.url_scheme'])

murano/opts.py

@@ -18,6 +18,7 @@ import itertools
 
 import oslo_service.sslutils
 
+import murano.api.middleware.ssl
 import murano.common.config
 import murano.common.wsgi
 
@@ -43,6 +44,7 @@ _opt_lists = [
         murano.common.config.bind_opts,
         murano.common.config.file_server,
         murano.common.wsgi.wsgi_opts,
+        murano.api.middleware.ssl.ssl_middleware_opts
     ])),
 ]
 

murano/tests/unit/api/middleware/test_ssl.py

@@ -0,0 +1,46 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import webob
+
+from murano.api.middleware import ssl
+
+from murano.tests.unit import base
+
+
+class SSLMiddlewareTest(base.MuranoTestCase):
+
+    def test_ssl_middleware_default_forwarded_proto(self):
+        middleware = ssl.SSLMiddleware(None)
+        request = webob.Request.blank('/environments',
+                                      headers={'X-Forwarded-Proto': 'https'})
+        middleware.process_request(request)
+        self.assertEqual('https',
+                         request.environ['wsgi.url_scheme'])
+
+    def test_ssl_middleware_custon_forwarded_proto(self):
+        self.override_config('secure_proxy_ssl_header',
+                             'X-My-Forwarded-Proto')
+        middleware = ssl.SSLMiddleware(None)
+        request = webob.Request.blank('/environments',
+                                      headers={
+                                          'X-My-Forwarded-Proto': 'https'})
+        middleware.process_request(request)
+        self.assertEqual('https',
+                         request.environ['wsgi.url_scheme'])
+
+    def test_ssl_middleware_plain_request(self):
+        middleware = ssl.SSLMiddleware(None)
+        request = webob.Request.blank('/environments', headers={})
+        middleware.process_request(request)
+        self.assertEqual('http',
+                         request.environ['wsgi.url_scheme'])