Introduce naming scheme for request handlers

The do_ prefix and upper case name allows easy
distinction between methods that handle requests
and other methods.
Without this distinction an attacker could
call arbitrary methods.
Currently there is no method that matches the
argument count, but that's easy to miss when new
methods are added.

radicale/__init__.py

@@ -267,7 +267,7 @@ class Application(object):
         path = environ["PATH_INFO"]
 
         # Get function corresponding to method
-        function = getattr(self, environ["REQUEST_METHOD"].lower())
+        function = getattr(self, "do_%s" % environ["REQUEST_METHOD"].upper())
 
         # Ask authentication backend to check rights
         authorization = environ.get("HTTP_AUTHORIZATION", None)
@@ -325,8 +325,8 @@ class Application(object):
 
         if is_valid_user and (
                 (read_allowed_items or write_allowed_items) or
-                (is_authenticated and function == self.propfind) or
-                function == self.options):
+                (is_authenticated and function == self.do_PROPFIND) or
+                function == self.do_OPTIONS):
             status, headers, answer = function(
                 environ, read_allowed_items, write_allowed_items, content,
                 user)
@@ -365,8 +365,8 @@ class Application(object):
     # All these functions must have the same parameters, some are useless
     # pylint: disable=W0612,W0613,R0201
 
-    def delete(self, environ, read_collections, write_collections, content,
-               user):
+    def do_DELETE(self, environ, read_collections, write_collections, content,
+                  user):
         """Manage DELETE request."""
         if not len(write_collections):
             return NOT_ALLOWED
@@ -392,7 +392,8 @@ class Application(object):
         # No item or ETag precondition not verified, do not delete item
         return client.PRECONDITION_FAILED, {}, None
 
-    def get(self, environ, read_collections, write_collections, content, user):
+    def do_GET(self, environ, read_collections, write_collections, content,
+               user):
         """Manage GET request.
 
         In Radicale, GET requests create collections when the URL is not
@@ -449,15 +450,15 @@ class Application(object):
         answer = answer_text.encode(self.encoding)
         return client.OK, headers, answer
 
-    def head(self, environ, read_collections, write_collections, content,
-             user):
+    def do_HEAD(self, environ, read_collections, write_collections, content,
+                user):
         """Manage HEAD request."""
         status, headers, answer = self.get(
             environ, read_collections, write_collections, content, user)
         return status, headers, None
 
-    def mkcalendar(self, environ, read_collections, write_collections, content,
-                   user):
+    def do_MKCALENDAR(self, environ, read_collections, write_collections,
+                      content, user):
         """Manage MKCALENDAR request."""
         if not len(write_collections):
             return NOT_ALLOWED
@@ -475,8 +476,8 @@ class Application(object):
             collection.write()
         return client.CREATED, {}, None
 
-    def mkcol(self, environ, read_collections, write_collections, content,
-              user):
+    def do_MKCOL(self, environ, read_collections, write_collections, content,
+                 user):
         """Manage MKCOL request."""
         if not len(write_collections):
             return NOT_ALLOWED
@@ -490,8 +491,8 @@ class Application(object):
         collection.write()
         return client.CREATED, {}, None
 
-    def move(self, environ, read_collections, write_collections, content,
-             user):
+    def do_MOVE(self, environ, read_collections, write_collections, content,
+                user):
         """Manage MOVE request."""
         if not len(write_collections):
             return NOT_ALLOWED
@@ -526,8 +527,8 @@ class Application(object):
             # Moving collections, not supported
             return client.FORBIDDEN, {}, None
 
-    def options(self, environ, read_collections, write_collections, content,
-                user):
+    def do_OPTIONS(self, environ, read_collections, write_collections,
+                   content, user):
         """Manage OPTIONS request."""
         headers = {
             "Allow": ("DELETE, HEAD, GET, MKCALENDAR, MKCOL, MOVE, "
@@ -535,8 +536,8 @@ class Application(object):
             "DAV": "1, 2, 3, calendar-access, addressbook, extended-mkcol"}
         return client.OK, headers, None
 
-    def propfind(self, environ, read_collections, write_collections, content,
-                 user):
+    def do_PROPFIND(self, environ, read_collections, write_collections,
+                    content, user):
         """Manage PROPFIND request."""
         # Rights is handled by collection in xmlutils.propfind
         headers = {
@@ -547,8 +548,8 @@ class Application(object):
             environ["PATH_INFO"], content, collections, user)
         return client.MULTI_STATUS, headers, answer
 
-    def proppatch(self, environ, read_collections, write_collections, content,
-                  user):
+    def do_PROPPATCH(self, environ, read_collections, write_collections,
+                     content, user):
         """Manage PROPPATCH request."""
         if not len(write_collections):
             return NOT_ALLOWED
@@ -562,7 +563,8 @@ class Application(object):
             "Content-Type": "text/xml"}
         return client.MULTI_STATUS, headers, answer
 
-    def put(self, environ, read_collections, write_collections, content, user):
+    def do_PUT(self, environ, read_collections, write_collections, content,
+               user):
         """Manage PUT request."""
         if not len(write_collections):
             return NOT_ALLOWED
@@ -597,8 +599,8 @@ class Application(object):
             status = client.PRECONDITION_FAILED
         return status, headers, None
 
-    def report(self, environ, read_collections, write_collections, content,
-               user):
+    def do_REPORT(self, environ, read_collections, write_collections, content,
+                  user):
         """Manage REPORT request."""
         if not len(read_collections):
             return NOT_ALLOWED