Security oops: limited path traversal possible with FileStore.join()

[Jason Gerard DeRose]

Just noticed that FileStore.join() allows path traversals to directories that are siblings of FileStore.base and whose names start with basename(base). For example:

>>> from dmedia.filestore import FileStore
>>> store = FileStore('/foo/bar')
>>> store.join('..', 'barNone', 'other', 'place')
'/foo/barNone/other/place'

This would probably be pretty hard to exploit usefully, but it is none the less a security issue. FileStore.create_parent() has the same problem.

[Jason Gerard DeRose (jderose)]

Now this is looks better:

>>> from dmedia.filestore import FileStore
>>> store = FileStore('/foo/bar')
>>> store.join('..', 'barNone', 'other', 'place')
Traceback (most recent call last):
  ...
FileStoreTraversal: '/foo/barNone/other/place' outside base '/foo/bar'

Will be merging to trunk shortly.