Re: [Xen-devel] [PATCH] [Xend] Move some backend configuration

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 2/10/08 10:34, "Ian Jackson" <Ian.Jackson@xxxxxxxxxxxxx> wrote:

> Once again we have this tradeoff: in an old installation which has not
> been properly patched or updated, should we
>   (a) continue to let the system `work' but be vulnerable
>   (b) make the system report an error so that the administrator
>       knows that it needs to be fixed.
> 
> At least in this case I suppose we can expect old installations to be
> patched _eventually_ ...

An update on this: I solved this issue by fiddling permissions in xenstore
after all! /local/domain/<domid> is now read-only to the guest, and specific
subdirs only are writable (currently device, error and control).

This fixes the console vulnerability with no annoying movement of entries,
and also gets rid of the new /vm_path entries in xenstore since
/l/d/<domid>/vm can be trusted now.

I've compacted the changesets together and backported to 3.3 for 3.3.1.
It'll also be an obvious candidate for 3.2 branch if that branch gets an
ongoing maintainer.

Of course the one downside is that this slightly changes the guest-visible
interface since it can't scribble at will in /l/d/<domid> any more. I hope
noone was relying on that! If we need to open up some more specific subdirs
for write access, I will consider that.

 -- Keir



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