tweak stat walk in forbid_hidden

IPython/html/base/handlers.py

@@ -1,529 +1,529 b''
 """Base Tornado handlers for the notebook.
 
 Authors:
 
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 
 import datetime
 import email.utils
 import functools
 import hashlib
 import json
 import logging
 import mimetypes
 import os
 import stat
 import sys
 import threading
 import traceback
 
 from tornado import web
 from tornado import websocket
 
 try:
     from tornado.log import app_log
 except ImportError:
     app_log = logging.getLogger()
 
 from IPython.config import Application
 from IPython.external.decorator import decorator
 from IPython.utils.path import filefind
 from IPython.utils.jsonutil import date_default
 
 # UF_HIDDEN is a stat flag not defined in the stat module.
 # It is used by BSD to indicate hidden files.
 UF_HIDDEN = getattr(stat, 'UF_HIDDEN', 32768)
 
 #-----------------------------------------------------------------------------
 # Monkeypatch for Tornado <= 2.1.1 - Remove when no longer necessary!
 #-----------------------------------------------------------------------------
 
 # Google Chrome, as of release 16, changed its websocket protocol number.  The
 # parts tornado cares about haven't really changed, so it's OK to continue
 # accepting Chrome connections, but as of Tornado 2.1.1 (the currently released
 # version as of Oct 30/2011) the version check fails, see the issue report:
 
 # https://github.com/facebook/tornado/issues/385
 
 # This issue has been fixed in Tornado post 2.1.1:
 
 # https://github.com/facebook/tornado/commit/84d7b458f956727c3b0d6710
 
 # Here we manually apply the same patch as above so that users of IPython can
 # continue to work with an officially released Tornado.  We make the
 # monkeypatch version check as narrow as possible to limit its effects; once
 # Tornado 2.1.1 is no longer found in the wild we'll delete this code.
 
 import tornado
 
 if tornado.version_info <= (2,1,1):
 
     def _execute(self, transforms, *args, **kwargs):
         from tornado.websocket import WebSocketProtocol8, WebSocketProtocol76
         
         self.open_args = args
         self.open_kwargs = kwargs
 
         # The difference between version 8 and 13 is that in 8 the
         # client sends a "Sec-Websocket-Origin" header and in 13 it's
         # simply "Origin".
         if self.request.headers.get("Sec-WebSocket-Version") in ("7", "8", "13"):
             self.ws_connection = WebSocketProtocol8(self)
             self.ws_connection.accept_connection()
             
         elif self.request.headers.get("Sec-WebSocket-Version"):
             self.stream.write(tornado.escape.utf8(
                 "HTTP/1.1 426 Upgrade Required\r\n"
                 "Sec-WebSocket-Version: 8\r\n\r\n"))
             self.stream.close()
             
         else:
             self.ws_connection = WebSocketProtocol76(self)
             self.ws_connection.accept_connection()
 
     websocket.WebSocketHandler._execute = _execute
     del _execute
 
 
 #-----------------------------------------------------------------------------
 # Top-level handlers
 #-----------------------------------------------------------------------------
 
 class RequestHandler(web.RequestHandler):
     """RequestHandler with default variable setting."""
 
     def render(*args, **kwargs):
         kwargs.setdefault('message', '')
         return web.RequestHandler.render(*args, **kwargs)
 
 class AuthenticatedHandler(RequestHandler):
     """A RequestHandler with an authenticated user."""
 
     def clear_login_cookie(self):
         self.clear_cookie(self.cookie_name)
     
     def get_current_user(self):
         user_id = self.get_secure_cookie(self.cookie_name)
         # For now the user_id should not return empty, but it could eventually
         if user_id == '':
             user_id = 'anonymous'
         if user_id is None:
             # prevent extra Invalid cookie sig warnings:
             self.clear_login_cookie()
             if not self.login_available:
                 user_id = 'anonymous'
         return user_id
 
     @property
     def cookie_name(self):
         default_cookie_name = 'username-{host}'.format(
             host=self.request.host,
         ).replace(':', '-')
         return self.settings.get('cookie_name', default_cookie_name)
     
     @property
     def password(self):
         """our password"""
         return self.settings.get('password', '')
     
     @property
     def logged_in(self):
         """Is a user currently logged in?
 
         """
         user = self.get_current_user()
         return (user and not user == 'anonymous')
 
     @property
     def login_available(self):
         """May a user proceed to log in?
 
         This returns True if login capability is available, irrespective of
         whether the user is already logged in or not.
 
         """
         return bool(self.settings.get('password', ''))
 
 
 class IPythonHandler(AuthenticatedHandler):
     """IPython-specific extensions to authenticated handling
     
     Mostly property shortcuts to IPython-specific settings.
     """
     
     @property
     def config(self):
         return self.settings.get('config', None)
     
     @property
     def log(self):
         """use the IPython log by default, falling back on tornado's logger"""
         if Application.initialized():
             return Application.instance().log
         else:
             return app_log
     
     @property
     def use_less(self):
         """Use less instead of css in templates"""
         return self.settings.get('use_less', False)
     
     #---------------------------------------------------------------
     # URLs
     #---------------------------------------------------------------
     
     @property
     def ws_url(self):
         """websocket url matching the current request
 
         By default, this is just `''`, indicating that it should match
         the same host, protocol, port, etc.
         """
         return self.settings.get('websocket_url', '')
     
     @property
     def mathjax_url(self):
         return self.settings.get('mathjax_url', '')
     
     @property
     def base_project_url(self):
         return self.settings.get('base_project_url', '/')
     
     @property
     def base_kernel_url(self):
         return self.settings.get('base_kernel_url', '/')
     
     #---------------------------------------------------------------
     # Manager objects
     #---------------------------------------------------------------
     
     @property
     def kernel_manager(self):
         return self.settings['kernel_manager']
 
     @property
     def notebook_manager(self):
         return self.settings['notebook_manager']
     
     @property
     def cluster_manager(self):
         return self.settings['cluster_manager']
     
     @property
     def session_manager(self):
         return self.settings['session_manager']
     
     @property
     def project_dir(self):
         return self.notebook_manager.notebook_dir
     
     #---------------------------------------------------------------
     # template rendering
     #---------------------------------------------------------------
     
     def get_template(self, name):
         """Return the jinja template object for a given name"""
         return self.settings['jinja2_env'].get_template(name)
     
     def render_template(self, name, **ns):
         ns.update(self.template_namespace)
         template = self.get_template(name)
         return template.render(**ns)
     
     @property
     def template_namespace(self):
         return dict(
             base_project_url=self.base_project_url,
             base_kernel_url=self.base_kernel_url,
             logged_in=self.logged_in,
             login_available=self.login_available,
             use_less=self.use_less,
         )
 
     def get_json_body(self):
         """Return the body of the request as JSON data."""
         if not self.request.body:
             return None
         # Do we need to call body.decode('utf-8') here?
         body = self.request.body.strip().decode(u'utf-8')
         try:
             model = json.loads(body)
         except Exception:
             self.log.debug("Bad JSON: %r", body)
             self.log.error("Couldn't parse JSON", exc_info=True)
             raise web.HTTPError(400, u'Invalid JSON in body of request')
         return model
 
 
 class AuthenticatedFileHandler(IPythonHandler, web.StaticFileHandler):
     """static files should only be accessible when logged in"""
 
     @web.authenticated
     def get(self, path):
         if os.path.splitext(path)[1] == '.ipynb':
             name = os.path.basename(path)
             self.set_header('Content-Type', 'application/json')
             self.set_header('Content-Disposition','attachment; filename="%s"' % name)
         
         return web.StaticFileHandler.get(self, path)
     
     def validate_absolute_path(self, root, absolute_path):
         """Validate and return the absolute path.
         
         Requires tornado 3.1
         
         Adding to tornado's own handling, forbids the serving of hidden files.
         """
         abs_path = super(AuthenticatedFileHandler, self).validate_absolute_path(root, absolute_path)
         abs_root = os.path.abspath(root)
         self.forbid_hidden(abs_root, abs_path)
         return abs_path
     
     def forbid_hidden(self, absolute_root, absolute_path):
         """Raise 403 if a file is hidden or contained in a hidden directory.
         
         Hidden is determined by either name starting with '.'
         or the UF_HIDDEN flag as reported by stat
         """
         inside_root = absolute_path[len(absolute_root):]
         if any(part.startswith('.') for part in inside_root.split(os.sep)):
             raise web.HTTPError(403)
         
         # check UF_HIDDEN on any location up to root
         path = absolute_path
-        while path and path.startswith(absolute_root):
+        while path and path.startswith(absolute_root) and path != absolute_root:
             st = os.stat(path)
             if getattr(st, 'st_flags', 0) & UF_HIDDEN:
                 raise web.HTTPError(403)
-            path, _ = os.path.split(path)
+            path = os.path.dirname(path)
         
         return absolute_path
 
 
 def json_errors(method):
     """Decorate methods with this to return GitHub style JSON errors.
     
     This should be used on any JSON API on any handler method that can raise HTTPErrors.
     
     This will grab the latest HTTPError exception using sys.exc_info
     and then:
     
     1. Set the HTTP status code based on the HTTPError
     2. Create and return a JSON body with a message field describing
        the error in a human readable form.
     """
     @functools.wraps(method)
     def wrapper(self, *args, **kwargs):
         try:
             result = method(self, *args, **kwargs)
         except web.HTTPError as e:
             status = e.status_code
             message = e.log_message
             self.set_status(e.status_code)
             self.finish(json.dumps(dict(message=message)))
         except Exception:
             self.log.error("Unhandled error in API request", exc_info=True)
             status = 500
             message = "Unknown server error"
             t, value, tb = sys.exc_info()
             self.set_status(status)
             tb_text = ''.join(traceback.format_exception(t, value, tb))
             reply = dict(message=message, traceback=tb_text)
             self.finish(json.dumps(reply))
         else:
             return result
     return wrapper
 
 
 
 #-----------------------------------------------------------------------------
 # File handler
 #-----------------------------------------------------------------------------
 
 # to minimize subclass changes:
 HTTPError = web.HTTPError
 
 class FileFindHandler(web.StaticFileHandler):
     """subclass of StaticFileHandler for serving files from a search path"""
     
     _static_paths = {}
     # _lock is needed for tornado < 2.2.0 compat
     _lock = threading.Lock()  # protects _static_hashes
     
     def initialize(self, path, default_filename=None):
         if isinstance(path, basestring):
             path = [path]
         self.roots = tuple(
             os.path.abspath(os.path.expanduser(p)) + os.sep for p in path
         )
         self.default_filename = default_filename
     
     @classmethod
     def locate_file(cls, path, roots):
         """locate a file to serve on our static file search path"""
         with cls._lock:
             if path in cls._static_paths:
                 return cls._static_paths[path]
             try:
                 abspath = os.path.abspath(filefind(path, roots))
             except IOError:
                 # empty string should always give exists=False
                 return ''
         
             # os.path.abspath strips a trailing /
             # it needs to be temporarily added back for requests to root/
             if not (abspath + os.sep).startswith(roots):
                 raise HTTPError(403, "%s is not in root static directory", path)
         
             cls._static_paths[path] = abspath
             return abspath
     
     def get(self, path, include_body=True):
         path = self.parse_url_path(path)
         
         # begin subclass override
         abspath = self.locate_file(path, self.roots)
         # end subclass override
         
         if os.path.isdir(abspath) and self.default_filename is not None:
             # need to look at the request.path here for when path is empty
             # but there is some prefix to the path that was already
             # trimmed by the routing
             if not self.request.path.endswith("/"):
                 self.redirect(self.request.path + "/")
                 return
             abspath = os.path.join(abspath, self.default_filename)
         if not os.path.exists(abspath):
             raise HTTPError(404)
         if not os.path.isfile(abspath):
             raise HTTPError(403, "%s is not a file", path)
 
         stat_result = os.stat(abspath)
         modified = datetime.datetime.utcfromtimestamp(stat_result[stat.ST_MTIME])
 
         self.set_header("Last-Modified", modified)
 
         mime_type, encoding = mimetypes.guess_type(abspath)
         if mime_type:
             self.set_header("Content-Type", mime_type)
 
         cache_time = self.get_cache_time(path, modified, mime_type)
 
         if cache_time > 0:
             self.set_header("Expires", datetime.datetime.utcnow() + \
                                        datetime.timedelta(seconds=cache_time))
             self.set_header("Cache-Control", "max-age=" + str(cache_time))
         else:
             self.set_header("Cache-Control", "public")
 
         self.set_extra_headers(path)
 
         # Check the If-Modified-Since, and don't send the result if the
         # content has not been modified
         ims_value = self.request.headers.get("If-Modified-Since")
         if ims_value is not None:
             date_tuple = email.utils.parsedate(ims_value)
             if_since = datetime.datetime(*date_tuple[:6])
             if if_since >= modified:
                 self.set_status(304)
                 return
         
         with open(abspath, "rb") as file:
             data = file.read()
             hasher = hashlib.sha1()
             hasher.update(data)
             self.set_header("Etag", '"%s"' % hasher.hexdigest())
             if include_body:
                 self.write(data)
             else:
                 assert self.request.method == "HEAD"
                 self.set_header("Content-Length", len(data))
 
     @classmethod
     def get_version(cls, settings, path):
         """Generate the version string to be used in static URLs.
 
         This method may be overridden in subclasses (but note that it
         is a class method rather than a static method).  The default
         implementation uses a hash of the file's contents.
 
         ``settings`` is the `Application.settings` dictionary and ``path``
         is the relative location of the requested asset on the filesystem.
         The returned value should be a string, or ``None`` if no version
         could be determined.
         """
         # begin subclass override:
         static_paths = settings['static_path']
         if isinstance(static_paths, basestring):
             static_paths = [static_paths]
         roots = tuple(
             os.path.abspath(os.path.expanduser(p)) + os.sep for p in static_paths
         )
 
         try:
             abs_path = filefind(path, roots)
         except IOError:
             app_log.error("Could not find static file %r", path)
             return None
         
         # end subclass override
         
         with cls._lock:
             hashes = cls._static_hashes
             if abs_path not in hashes:
                 try:
                     f = open(abs_path, "rb")
                     hashes[abs_path] = hashlib.md5(f.read()).hexdigest()
                     f.close()
                 except Exception:
                     app_log.error("Could not open static file %r", path)
                     hashes[abs_path] = None
             hsh = hashes.get(abs_path)
             if hsh:
                 return hsh[:5]
         return None
 
 
     def parse_url_path(self, url_path):
         """Converts a static URL path into a filesystem path.
 
         ``url_path`` is the path component of the URL with
         ``static_url_prefix`` removed.  The return value should be
         filesystem path relative to ``static_path``.
         """
         if os.sep != "/":
             url_path = url_path.replace("/", os.sep)
         return url_path
 
 class TrailingSlashHandler(web.RequestHandler):
     """Simple redirect handler that strips trailing slashes
     
     This should be the first, highest priority handler.
     """
     
     SUPPORTED_METHODS = ['GET']
     
     def get(self):
         self.redirect(self.request.uri.rstrip('/'))
 
 #-----------------------------------------------------------------------------
 # URL to handler mappings
 #-----------------------------------------------------------------------------
 
 
 default_handlers = [
     (r".*/", TrailingSlashHandler)
 ]