Re: [Qemu-devel] [PATCH] seccomp: adding a second whitelist

[Eduardo Otubo <otubo@linux.vnet.ibm.com>]

On 09/03/2013 03:21 PM, Paul Moore wrote:
> On Tuesday, September 03, 2013 02:08:28 PM Corey Bryant wrote:
>> On 09/03/2013 02:02 PM, Corey Bryant wrote:
>>> On 08/30/2013 10:21 AM, Eduardo Otubo wrote:
>>>> On 08/29/2013 05:34 AM, Stefan Hajnoczi wrote:
>>>>> On Wed, Aug 28, 2013 at 10:04:32PM -0300, Eduardo Otubo wrote:
>>>>>> Now there's a second whitelist, right before the vcpu starts. The
>>>>>> second
>>>>>> whitelist is the same as the first one, except for exec() and select().
>>>>>
>>>>> -netdev tap,downscript=/path/to/script requires exec() in the QEMU
>>>>> shutdown code path.  Will this work with seccomp?
>>>>
>>>> I actually don't know, but I'll test that as well. Can you run a test
>>>> with this patch and -netdev? I mean, if you're pointing that out you
>>>> might have a scenario already setup, right?
>>>>
>>>> Thanks!
>>>
>>> This uses exec() in net/tap.c.
>>>
>>> I think if we're going to introduce a sandbox environment that restricts
>>> existing QEMU behavior, then we have to introduce a new argument to the
>>> -sandbox option.  So for example, "-sandbox on" would continue to use
>>> the whitelist that allows everything in QEMU to work (or at least it
>>> should :).  And something like "-sandbox on,strict=on" would use the
>>> whitelist + blacklist.
>>>
>>> If this is acceptable though, then I wonder how we could go about adding
>>> new syscalls to the blacklist in future QEMU releases without regressing
>>> "-sandbox on,strict=on".
>>
>> Maybe a better approach is to provide support that allows libvirt to
>> define the blacklist and pass it to QEMU?
>
> FYI: I didn't want to mention this until I had some patches ready to post, but
> I'm currently working on adding syscall filtering, via libseccomp, to libvirt.
> I hope to get an initial RFC-quality patch out "soon".
>

Paul, if you need any help with Qemu and/or testing, please let me know. 
I would be glad to help :) When you post your RFC to libvirt mailing 
list please add me as CC.

-- 
Eduardo Otubo
IBM Linux Technology Center