fatal
2018-Dec-25 16:27 UTC
[libvirt-users] Network filters with clean-traffic not working on Debian Stretch
Hello,
I'm recently stumbled over the libvirt network filter capabilities and
got pretty excited. Unfortunately I'm not able to get the the
"clean-traffic" filterset working. I'm using a freshly installed
Debian
Stretch with libvirt, qemu and KVM.
My config snippet looks as follows:
sudo virsh edit <VM>
[...]
<interface type='bridge'>
<mac address='52:54:00:0c:14:07'/>
<source bridge='br0'/>
<model type='virtio'/>
<filterref filter='clean-traffic'>
<parameter name='IP' value='10.10.1.2'/>
</filterref>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x03'
function='0x0'/>
</interface>
<interface type='bridge'>
<mac address='52:54:00:0c:24:17'/>
<source bridge='br1'/>
<model type='virtio'/>
<filterref filter='clean-traffic'>
<parameter name='IP' value='172.16.1.2'/>
</filterref>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x03'
function='0x0'/>
</interface>
[...]
I restarted the VM from within the VM, did a "virsh reboot
<VM>",
restarted libvirtd and even did a reboot of the host - just to be sure.
Unfortunately neither "iptables -L" nor "ebtables --list"
show any
entries added by libvirt. Also omitting the "parameter
name='IP'" part
didn't change anything.
There are no error messages in /var/log/syslog nor in
/var/log/libvirt/qemu/<VM>
My main references were:
https://libvirt.org/firewall.html
https://libvirt.org/formatnwfilter.html
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_deployment_and_administration_guide/sect-virtual_networking-applying_network_filtering
https://www.berrange.com/posts/2011/10/03/guest-mac-spoofing-denial-of-service-and-preventing-it-with-libvirt-and-kvm/
Any help really would be much appreciated!
Thanks a lot!
Sam
Yalan Zhang
2018-Dec-29 05:51 UTC
Re: [libvirt-users] Network filters with clean-traffic not working on Debian Stretch
Hi Sam,
You can find the rules by below command, and it looks as below:
# ebtables -t nat --list
Bridge table: nat
Bridge chain: PREROUTING, entries: 2, policy: ACCEPT
-j PREROUTING_direct
-i vnet0 -j libvirt-I-vnet0
Bridge chain: OUTPUT, entries: 1, policy: ACCEPT
-j OUTPUT_direct
Bridge chain: POSTROUTING, entries: 2, policy: ACCEPT
-j POSTROUTING_direct
-o vnet0 -j libvirt-O-vnet0
Bridge chain: PREROUTING_direct, entries: 0, policy: RETURN
Bridge chain: POSTROUTING_direct, entries: 0, policy: RETURN
Bridge chain: OUTPUT_direct, entries: 0, policy: RETURN
Bridge chain: libvirt-I-vnet0, entries: 9, policy: ACCEPT
-j I-vnet0-mac
-p IPv4 -j I-vnet0-ipv4-ip
-p IPv4 -j ACCEPT
-p ARP -j I-vnet0-arp-mac
-p ARP -j I-vnet0-arp-ip
-p ARP -j ACCEPT
-p 0x8035 -j I-vnet0-rarp
-p 0x835 -j ACCEPT
-j DROP
Bridge chain: libvirt-O-vnet0, entries: 4, policy: ACCEPT
-p IPv4 -j O-vnet0-ipv4
-p ARP -j ACCEPT
-p 0x8035 -j O-vnet0-rarp
-j DROP
Bridge chain: I-vnet0-mac, entries: 2, policy: ACCEPT
-s 52:54:0:3a:40:b7 -j RETURN
-j DROP
Bridge chain: I-vnet0-ipv4-ip, entries: 3, policy: ACCEPT
-p IPv4 --ip-src 0.0.0.0 --ip-proto udp -j RETURN
-p IPv4 --ip-src 172.16.1.2 -j RETURN
-j DROP
Bridge chain: O-vnet0-ipv4, entries: 1, policy: ACCEPT
-j ACCEPT
Bridge chain: I-vnet0-arp-mac, entries: 2, policy: ACCEPT
-p ARP --arp-mac-src 52:54:0:3a:40:b7 -j RETURN
-j DROP
Bridge chain: I-vnet0-arp-ip, entries: 2, policy: ACCEPT
-p ARP --arp-ip-src 172.16.1.2 -j RETURN
-j DROP
Bridge chain: I-vnet0-rarp, entries: 2, policy: ACCEPT
-p 0x8035 -s 52:54:0:3a:40:b7 -d Broadcast --arp-op Request_Reverse
--arp-ip-src 0.0.0.0 --arp-ip-dst 0.0.0.0 --arp-mac-src 52:54:0:3a:40:b7
--arp-mac-dst 52:54:0:3a:40:b7 -j ACCEPT
-j DROP
Bridge chain: O-vnet0-rarp, entries: 2, policy: ACCEPT
-p 0x8035 -d Broadcast --arp-op Request_Reverse --arp-ip-src 0.0.0.0
--arp-ip-dst 0.0.0.0 --arp-mac-src 52:54:0:3a:40:b7 --arp-mac-dst
52:54:0:3a:40:b7 -j ACCEPT
-j DROP
For interface set as:
<interface type='bridge'>
<mac address='52:54:00:3a:40:b7'/>
<source bridge='br0'/>
<target dev='vnet0'/>
<model type='rtl8139'/>
<filterref filter='clean-traffic'>
<parameter name='IP' value='172.16.1.2'/>
</filterref>
<alias name='net0'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x03'
function='0x0'/>
</interface>
-------
Best Regards,
Yalan Zhang
IRC: yalzhang
On Wed, Dec 26, 2018 at 12:28 AM fatal <fatal@mailbox.org> wrote:
> Hello,
>
> I'm recently stumbled over the libvirt network filter capabilities and
> got pretty excited. Unfortunately I'm not able to get the the
> "clean-traffic" filterset working. I'm using a freshly
installed Debian
> Stretch with libvirt, qemu and KVM.
>
> My config snippet looks as follows:
>
> sudo virsh edit <VM>
>
> [...]
> <interface type='bridge'>
> <mac address='52:54:00:0c:14:07'/>
> <source bridge='br0'/>
> <model type='virtio'/>
> <filterref filter='clean-traffic'>
> <parameter name='IP' value='10.10.1.2'/>
> </filterref>
> <address type='pci' domain='0x0000' bus='0x00'
slot='0x03'
> function='0x0'/>
> </interface>
> <interface type='bridge'>
> <mac address='52:54:00:0c:24:17'/>
> <source bridge='br1'/>
> <model type='virtio'/>
> <filterref filter='clean-traffic'>
> <parameter name='IP' value='172.16.1.2'/>
> </filterref>
> <address type='pci' domain='0x0000' bus='0x00'
slot='0x03'
> function='0x0'/>
> </interface>
> [...]
>
> I restarted the VM from within the VM, did a "virsh reboot
<VM>",
> restarted libvirtd and even did a reboot of the host - just to be sure.
> Unfortunately neither "iptables -L" nor "ebtables
--list" show any
> entries added by libvirt. Also omitting the "parameter
name='IP'" part
> didn't change anything.
>
> There are no error messages in /var/log/syslog nor in
> /var/log/libvirt/qemu/<VM>
>
> My main references were:
>
> https://libvirt.org/firewall.html
> https://libvirt.org/formatnwfilter.html
>
>
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_deployment_and_administration_guide/sect-virtual_networking-applying_network_filtering
>
>
https://www.berrange.com/posts/2011/10/03/guest-mac-spoofing-denial-of-service-and-preventing-it-with-libvirt-and-kvm/
>
> Any help really would be much appreciated!
>
> Thanks a lot!
>
> Sam
>
> _______________________________________________
> libvirt-users mailing list
> libvirt-users@redhat.com
> https://www.redhat.com/mailman/listinfo/libvirt-users
>
fatal
2018-Dec-29 10:51 UTC
Re: [libvirt-users] Network filters with clean-traffic not working on Debian Stretch
Dear Yalang, that did the trick. If I look in the NAT table of the bridge I can see the generated rules. Probably wouldn't have though about that ever. Thanks a lot! Best Sam On 29.12.18 06:51, Yalan Zhang wrote:> Hi Sam, > > You can find the rules by below command, and it looks as below: > # ebtables -t nat --list > Bridge table: nat > > Bridge chain: PREROUTING, entries: 2, policy: ACCEPT > -j PREROUTING_direct > -i vnet0 -j libvirt-I-vnet0 > > Bridge chain: OUTPUT, entries: 1, policy: ACCEPT > -j OUTPUT_direct > > Bridge chain: POSTROUTING, entries: 2, policy: ACCEPT > -j POSTROUTING_direct > -o vnet0 -j libvirt-O-vnet0 > > Bridge chain: PREROUTING_direct, entries: 0, policy: RETURN > > Bridge chain: POSTROUTING_direct, entries: 0, policy: RETURN > > Bridge chain: OUTPUT_direct, entries: 0, policy: RETURN > > Bridge chain: libvirt-I-vnet0, entries: 9, policy: ACCEPT > -j I-vnet0-mac > -p IPv4 -j I-vnet0-ipv4-ip > -p IPv4 -j ACCEPT > -p ARP -j I-vnet0-arp-mac > -p ARP -j I-vnet0-arp-ip > -p ARP -j ACCEPT > -p 0x8035 -j I-vnet0-rarp > -p 0x835 -j ACCEPT > -j DROP > > Bridge chain: libvirt-O-vnet0, entries: 4, policy: ACCEPT > -p IPv4 -j O-vnet0-ipv4 > -p ARP -j ACCEPT > -p 0x8035 -j O-vnet0-rarp > -j DROP > > Bridge chain: I-vnet0-mac, entries: 2, policy: ACCEPT > -s 52:54:0:3a:40:b7 -j RETURN > -j DROP > > Bridge chain: I-vnet0-ipv4-ip, entries: 3, policy: ACCEPT > -p IPv4 --ip-src 0.0.0.0 --ip-proto udp -j RETURN > -p IPv4 --ip-src 172.16.1.2 -j RETURN > -j DROP > > Bridge chain: O-vnet0-ipv4, entries: 1, policy: ACCEPT > -j ACCEPT > > Bridge chain: I-vnet0-arp-mac, entries: 2, policy: ACCEPT > -p ARP --arp-mac-src 52:54:0:3a:40:b7 -j RETURN > -j DROP > > Bridge chain: I-vnet0-arp-ip, entries: 2, policy: ACCEPT > -p ARP --arp-ip-src 172.16.1.2 -j RETURN > -j DROP > > Bridge chain: I-vnet0-rarp, entries: 2, policy: ACCEPT > -p 0x8035 -s 52:54:0:3a:40:b7 -d Broadcast --arp-op Request_Reverse > --arp-ip-src 0.0.0.0 --arp-ip-dst 0.0.0.0 --arp-mac-src 52:54:0:3a:40:b7 > --arp-mac-dst 52:54:0:3a:40:b7 -j ACCEPT > -j DROP > > Bridge chain: O-vnet0-rarp, entries: 2, policy: ACCEPT > -p 0x8035 -d Broadcast --arp-op Request_Reverse --arp-ip-src 0.0.0.0 > --arp-ip-dst 0.0.0.0 --arp-mac-src 52:54:0:3a:40:b7 --arp-mac-dst > 52:54:0:3a:40:b7 -j ACCEPT > -j DROP > > For interface set as: > <interface type='bridge'> > <mac address='52:54:00:3a:40:b7'/> > <source bridge='br0'/> > <target dev='vnet0'/> > <model type='rtl8139'/> > <filterref filter='clean-traffic'> > <parameter name='IP' value='172.16.1.2'/> > </filterref> > <alias name='net0'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x03' > function='0x0'/> > </interface> > > > > ------- > Best Regards, > Yalan Zhang > IRC: yalzhang
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