Allow CONTENT_LENGTH to be present but empty

The CONTENT_LENGTH environ can be present, but empty, which returns
None, and causes a ValueError when attempting to use .int().

This patch removes the setting of CONTENT_LENGTH to an integer, but
instead ensures that if CONTENT_LENGTH is not empty it is an integer, to
prevent a situation where a bogus "CONTENT_LENGTH" header is specified.

Additionally, as the CONTENT_TYPE environ can similarly be present but
empty, we should .get() it in a similar fashion to ensure it isn't
present but None when CONTENT_LENGTH is specified.

Change-Id: I66b6f9afbea8bf037997a59ba0b976f83c9825fb
Closes-Bug: #1681843

nova/api/openstack/placement/handler.py

@@ -177,13 +177,19 @@ class PlacementHandler(object):
                 raise webob.exc.HTTPForbidden(
                     _('admin required'),
                     json_formatter=util.json_error_formatter)
-        # Check that an incoming request with a content-length
+        # Check that an incoming request with a content-length header
-        # header also has a content-type header. If not raise a 400.
+        # that is an integer > 0 and not empty, also has a content-type
-        if int(environ.get('CONTENT_LENGTH', 0)):
+        # header that is not empty. If not raise a 400.
-            if 'CONTENT_TYPE' not in environ:
+        clen = environ.get('CONTENT_LENGTH')
+        try:
+            if clen and (int(clen) > 0) and not environ.get('CONTENT_TYPE'):
                 raise webob.exc.HTTPBadRequest(
-                    _('content-type header required'),
+                   _('content-type header required when content-length > 0'),
-                    json_formatter=util.json_error_formatter)
+                   json_formatter=util.json_error_formatter)
+        except ValueError as exc:
+            raise webob.exc.HTTPBadRequest(
+                _('content-length header must be an integer'),
+                json_formatter=util.json_error_formatter)
         try:
             return dispatch(environ, start_response, self._map)
         # Trap the NotFound exceptions raised by the objects used

nova/tests/unit/api/openstack/placement/test_handler.py

@@ -142,3 +142,42 @@ class DeclarationsTest(test.NoDBTestCase):
         environ = _environ(path='')
         result = self.mapper.match(environ=environ)
         self.assertEqual(root.home, result['action'])
+
+
+class ContentHeadersTest(test.NoDBTestCase):
+
+    def setUp(self):
+        super(ContentHeadersTest, self).setUp()
+        self.environ = _environ(path='/')
+        self.app = handler.PlacementHandler()
+
+    def test_no_content_type(self):
+        self.environ['CONTENT_LENGTH'] = '10'
+        self.assertRaisesRegex(webob.exc.HTTPBadRequest,
+                               "content-type header required when "
+                               "content-length > 0", self.app,
+                               self.environ, start_response)
+
+    def test_non_integer_content_length(self):
+        self.environ['CONTENT_LENGTH'] = 'foo'
+        self.assertRaisesRegex(webob.exc.HTTPBadRequest,
+                               "content-length header must be an integer",
+                               self.app, self.environ, start_response)
+
+    def test_empty_content_type(self):
+        self.environ['CONTENT_LENGTH'] = '10'
+        self.environ['CONTENT_TYPE'] = ''
+        self.assertRaisesRegex(webob.exc.HTTPBadRequest,
+                               "content-type header required when "
+                               "content-length > 0", self.app,
+                               self.environ, start_response)
+
+    def test_empty_content_length_and_type_works(self):
+        self.environ['CONTENT_LENGTH'] = ''
+        self.environ['CONTENT_TYPE'] = ''
+        self.app(self.environ, start_response)
+
+    def test_content_length_and_type_works(self):
+        self.environ['CONTENT_LENGTH'] = '10'
+        self.environ['CONTENT_TYPE'] = 'foo'
+        self.app(self.environ, start_response)