Re: [Qemu-devel] [PATCH] blockdev: Refuse to open encrypted image unless paused

[Eric Blake <eblake@redhat.com>]

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On 03/12/2014 11:00 AM, Markus Armbruster wrote:
> Opening an encrypted image takes an additional step: setting the key.
> Between open and the key set, the image must not be used.
> 
> We have some protection against accidental use in place: you can't
> unpause a guest while we're missing keys.  You can, however, hot-plug
> block devices lacking keys into a running guest just fine, or insert
> media lacking keys.  In the latter case, notifying the guest of the
> insert is delayed until the key is set, which may suffice to protect
> at least some guests in common usage.
> 
> This patch makes the protection apply in more cases, in a rather
> heavy-handed way: it doesn't let you open encrypted images unless
> we're in a paused state.
> 
> It doesn't extend the protection to users other than the guest (block
> jobs?).  Use of runstate_check() from block.c is disgusting.  Best I
> can do right now.

Better than what we had before, and worth having in 2.0

> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  block.c                | 8 +++++++-
>  stubs/Makefile.objs    | 1 +
>  stubs/runstate-check.c | 6 ++++++
>  3 files changed, 14 insertions(+), 1 deletion(-)
>  create mode 100644 stubs/runstate-check.c
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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