Re: [Xen-users] Where does PyGrub run?

[Simon Hobson <linux@xxxxxxxxxxxxxxxx>]

eva wrote:

> 1- if pygrub needs to mount the domU, why does it says this?
> http://wiki.xen.org/wiki/PyGrub
>
> "This means that reading the guest filesystem does not require
> mounting the filesystem"
Read the sentence before that : "PyGrub accesses the guest filesystem 
using a userspace filesystem library ..."
Ie, instead of mounting the image to copy the files, it uses a 
userspace library to access the filesystem. The difference is that if 
you just do a regular mount, then the filesystem is mounted by kernel 
level code in Dom0 - and there is a theoretic risk that if someone 
finds a vulnerability in that, they can use it to compromise Dom0 
with a carefully crafted DomU filesystem. Using a userspace library 
means that while there's still a risk of compromising the system, 
they cannot "crash" it as they could be compromising kernel level 
code.

--
Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users