virtio-net: zero unused hash fields

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.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Fixes: a2fb4bc4e2a6a ("net: implement virtio helpers to handle UDP GSO tunneling")
Cc: <stable@vger.kernel.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Link: https://patch.msgid.link/20251022034421.70244-1-jasowang@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 20e0584db1dd5bd81854bdcdbfa08873c6daedc6..4d1780848d0e04908bd627b02928c2d740693e89 100644 (file)
--- 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);