Linux Virtualization - Dec 2014 - [PATCH net-next] virtio-net: don't do header check for dodgy gso packets

There's no need to do header check for virito-net since:

- Host set dodgy for all gso packets from guest and check the header.
- Host should prepare for all kinds of evil packets from guest, since
  malicious guest can send any kinds of packet.

So this patch sets NETIF_F_GSO_ROBUST for virtio-net to skip the check.

Cc: Rusty Russell <rusty at rustcorp.com.au>
Cc: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
 drivers/net/virtio_net.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index b0bc8ea..4cd242b 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1760,6 +1760,8 @@ static int virtnet_probe(struct virtio_device *vdev)
 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 			dev->hw_features |= NETIF_F_TSO_ECN;
 
+		dev->features |= NETIF_F_GSO_ROBUST;
+
 		if (gso)
 			dev->features |= dev->hw_features & NETIF_F_ALL_TSO;
 		/* (!csum && gso) case will be fixed by register_netdev() */
-- 
1.9.1

On Wed, Dec 03, 2014 at 02:40:44PM +0800, Jason Wang
wrote:
> There's no need to do header check for virito-net since:
s/virito/virtio/
> 
> - Host set dodgy for all gso packets from guest and check the header.
s/set/sets/
> - Host should prepare for all kinds of evil packets from guest, since
s/prepare/be prepared/
>   malicious guest can send any kinds of packet.
> 
> So this patch sets NETIF_F_GSO_ROBUST for virtio-net to skip the check.
> 
> Cc: Rusty Russell <rusty at rustcorp.com.au>
> Cc: Michael S. Tsirkin <mst at redhat.com>
> Signed-off-by: Jason Wang <jasowang at redhat.com>
with the comment fixes:

Acked-by: Michael S. Tsirkin <mst at redhat.com>
> ---
>  drivers/net/virtio_net.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index b0bc8ea..4cd242b 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1760,6 +1760,8 @@ static int virtnet_probe(struct virtio_device *vdev)
>  		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
>  			dev->hw_features |= NETIF_F_TSO_ECN;
>  
> +		dev->features |= NETIF_F_GSO_ROBUST;
> +
>  		if (gso)
>  			dev->features |= dev->hw_features & NETIF_F_ALL_TSO;
>  		/* (!csum && gso) case will be fixed by register_netdev() */
> -- 
> 1.9.1
> 
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