[Zope] Prevent image-reloading...

[Ross J. Reedstrom]

Michael Bernstein wrote:
<snipped> 

> /
>  /images
>  /a
>  /b
>  /c
> 
> it is entirely possible to go to the folowing URL:
> 
> www.yourdomain.com/a/b/c/b/c/a/b/a/c/b/images/someimage.gif
> 
> and actually retrieve the image. Directories are subject to acquisition
> just like Methods are, so beware of referring to sibling directories as
> sub-directories when creating relative URL's. The browser (correctly)
> sees most of these images as having distinct URL's, and so does not
> retrieve them from the cache.

This behavior of aquiring subdirectories leads to some very interesting
issues, especially given the prevelance of buffer-overflow problems
showing up in all sorts of software these days. I noticed that a
directory even inherits _itself_ as a subdir, so
www.your.domain.com/a/b/c/c/c/c/c/c/c/c/c/c/c/c... is a possibility.
Reminds me of an old DOS exploit, involving subdir nesting > 256(?).
Anyone want to come up with a take on the security impact of this? At
minimum, I'd think you can kill browsers with this, perhaps take them
over.  It's not really a problem with Zope, just an interesting side
issue.

Ross 
-- 
Ross J. Reedstrom, Ph.D., <reedstrm@rice.edu> 
NSBRI Research Scientist/Programmer
Computer and Information Technology Institute
Rice University, 6100 S. Main St.,  Houston, TX 77005