On Tue, Oct 21, 2025 at 12:01:55PM +0800, Jason Wang wrote:

When GSO tunnel is negotiated virtio_net_hdr_tnl_from_skb() tries to initialize the tunnel metadata but forget to zero unused rxhash fields. This may leak information to another side. Fixing this by zeroing the unused hash fields.

Fixes: a2fb4bc4e2a6a ("net: implement virtio helpers to handle UDP GSO tunneling")x Cc: stable@vger.kernel.org Signed-off-by: Jason Wang jasowang@redhat.com

Acked-by: Michael S. Tsirkin mst@redhat.com

---

include/linux/virtio_net.h | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 20e0584db1dd..4d1780848d0e 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -401,6 +401,10 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, if (!tnl_hdr_negotiated) return -EINVAL;

•    vhdr->hash_hdr.hash_value = 0;
  

•    vhdr->hash_hdr.hash_report = 0;
  

•    vhdr->hash_hdr.padding = 0;
  

• /* Let the basic parsing deal with plain GSO features. */ skb_shinfo(skb)->gso_type &= ~tnl_gso_type; ret = virtio_net_hdr_from_skb(skb, hdr, true, false, vlan_hlen);

-- 2.42.0

On Tue, Oct 21, 2025 at 12:01:55PM +0800, Jason Wang wrote:

When GSO tunnel is negotiated virtio_net_hdr_tnl_from_skb() tries to initialize the tunnel metadata but forget to zero unused rxhash fields. This may leak information to another side. Fixing this by zeroing the unused hash fields.

Fixes: a2fb4bc4e2a6a ("net: implement virtio helpers to handle UDP GSO tunneling")x

nit: there is a stray 'x' at the end of the line above

Cc: stable@vger.kernel.org Signed-off-by: Jason Wang jasowang@redhat.com

---

include/linux/virtio_net.h | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 20e0584db1dd..4d1780848d0e 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -401,6 +401,10 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, if (!tnl_hdr_negotiated) return -EINVAL;

•    vhdr->hash_hdr.hash_value = 0;
  

•    vhdr->hash_hdr.hash_report = 0;
  

•    vhdr->hash_hdr.padding = 0;
  

nit: The indentation seems off, probably a spaces vs tabs issue

/* Let the basic parsing deal with plain GSO features. */ skb_shinfo(skb)->gso_type &= ~tnl_gso_type; ret = virtio_net_hdr_from_skb(skb, hdr, true, false, vlan_hlen); -- 2.42.0