8:24 a.m.
How is libseccomp used/enabled/configured with KVM/QEMU Hypervisor?
Does it need a system call profiling per VMs?
Regards,
10:32 a.m.
On 09.12.2014 15:24, Raymond Durand wrote:
How is libseccomp used/enabled/configured with KVM/QEMU Hypervisor?
You need to set seccomp_sandbox=1 in /etc/libvirt/qemu.conf and restart
libvirtd. From now on, any qemu/kvm guest that libvirt starts will use
seccomp or fail if qemu binary doesn't support it.
Michal
9:24 a.m.
Thanks.
How are the rules managed so as to fit the VM system calls?
Is tuning possible? recommended?
Regards,
2014-12-09 17:32 GMT+01:00 Michal Privoznik <mprivozn(a)redhat.com>:
On 09.12.2014 15:24, Raymond Durand wrote:
> How is libseccomp used/enabled/configured with KVM/QEMU Hypervisor?
>
You need to set seccomp_sandbox=1 in /etc/libvirt/qemu.conf and restart
libvirtd. From now on, any qemu/kvm guest that libvirt starts will use
seccomp or fail if qemu binary doesn't support it.
Michal
9:32 a.m.
On Fri, Dec 12, 2014 at 04:24:55PM +0100, Raymond Durand wrote:
Thanks.
How are the rules managed so as to fit the VM system calls?
Is tuning possible? recommended?
QEMU has a built-in policy that adds rules for every conceivable
function that QEMU might need to execute. Given that is quite
broad, the security benefit from seccomp enablement is quit low
IMHO
Regards,
Daniel
--
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10:06 a.m.
On 12/12/2014 10:32 AM, Daniel P. Berrange wrote:
On Fri, Dec 12, 2014 at 04:24:55PM +0100, Raymond Durand wrote:
> Thanks.
>
> How are the rules managed so as to fit the VM system calls?
> Is tuning possible? recommended?
QEMU has a built-in policy that adds rules for every conceivable
function that QEMU might need to execute. Given that is quite
broad, the security benefit from seccomp enablement is quit low
IMHO
Base code and (active) devices would each have to report what syscalls
they need so this list could be reduced to the minimum ...
Stefan
Regards,
Daniel
11:13 a.m.
Thanks.
2014-12-12 17:06 GMT+01:00 Stefan Berger <stefanb(a)linux.vnet.ibm.com>:
On 12/12/2014 10:32 AM, Daniel P. Berrange wrote:
> On Fri, Dec 12, 2014 at 04:24:55PM +0100, Raymond Durand wrote:
>
>> Thanks.
>>
>> How are the rules managed so as to fit the VM system calls?
>> Is tuning possible? recommended?
>>
> QEMU has a built-in policy that adds rules for every conceivable
> function that QEMU might need to execute. Given that is quite
> broad, the security benefit from seccomp enablement is quit low
> IMHO
>
Base code and (active) devices would each have to report what syscalls
they need so this list could be reduced to the minimum ...
"Could be reduced": how? do you have in mind by selecting the appropriate
active devices at the initialization time?
Stefan
Regards,
> Daniel
>
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Regards,
8:01 a.m.
On 12/12/2014 12:13 PM, Raymond Durand wrote:
Thanks.
2014-12-12 17:06 GMT+01:00 Stefan Berger <stefanb(a)linux.vnet.ibm.com
<mailto:stefanb@linux.vnet.ibm.com>>:
On 12/12/2014 10:32 AM, Daniel P. Berrange wrote:
On Fri, Dec 12, 2014 at 04:24:55PM +0100, Raymond Durand wrote:
Thanks.
How are the rules managed so as to fit the VM system calls?
Is tuning possible? recommended?
QEMU has a built-in policy that adds rules for every conceivable
function that QEMU might need to execute. Given that is quite
broad, the security benefit from seccomp enablement is quit low
IMHO
Base code and (active) devices would each have to report what
syscalls they need so this list could be reduced to the minimum ...
"Could be reduced": how? do you have in mind by selecting the
appropriate active devices at the initialization time?
The difficulty would be to determine which devices require which
syscalls beyond what 'base' QEMU needs (= QEMU without devices). So one
would have to use QEMU with one device after another and see which new
syscalls are required due to a specific device (syscall auditing), then
add the array of syscalls to a device's TypeInfo structure and collect
them this way. If a device's code was to change, you'd have to do it
again. So I think it would be a lot of work all the time.
Stefan
Stefan
Regards,
Daniel
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Regards,
11:12 a.m.
Thanks.
2014-12-12 16:32 GMT+01:00 Daniel P. Berrange <berrange(a)redhat.com>:
On Fri, Dec 12, 2014 at 04:24:55PM +0100, Raymond Durand wrote:
> Thanks.
>
> How are the rules managed so as to fit the VM system calls?
> Is tuning possible? recommended?
QEMU has a built-in policy that adds rules for every conceivable
function that QEMU might need to execute. Given that is quite
broad, the security benefit from seccomp enablement is quit low
IMHO
I see.
Is it something like each QEMU device enabled comes along with a
system-calls list ie. rules allowed?
Is this list of rules loaded at each time the QEMU/KVM starts?
Regards,
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/
:|
|: http://libvirt.org -o- http://virt-manager.org
:|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/
:|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc
:|
Regards,
11:24 a.m.
On Fri, Dec 12, 2014 at 06:12:40PM +0100, Raymond Durand wrote:
Thanks.
2014-12-12 16:32 GMT+01:00 Daniel P. Berrange <berrange(a)redhat.com>:
>
> On Fri, Dec 12, 2014 at 04:24:55PM +0100, Raymond Durand wrote:
> > Thanks.
> >
> > How are the rules managed so as to fit the VM system calls?
> > Is tuning possible? recommended?
>
> QEMU has a built-in policy that adds rules for every conceivable
> function that QEMU might need to execute. Given that is quite
> broad, the security benefit from seccomp enablement is quit low
> IMHO
>
>
I see.
Is it something like each QEMU device enabled comes along with a
system-calls list ie. rules allowed?
Is this list of rules loaded at each time the QEMU/KVM starts?
No, the list of rules was jsut figured out by trial & error, launching
QEMU with more rules until it stopped crashing with all tested configs.
No one has tried to figure out fine grained rules as it is an enourmous
task
Regards,
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
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8 comments
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participants (4)
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Daniel P. Berrange -
Michal Privoznik -
Raymond Durand -
Stefan Berger