drivers/net: Disable UFO through virtio
IPv6 does not allow fragmentation by routers, so there is no
fragmentation ID in the fixed header. UFO for IPv6 requires the ID to
be passed separately, but there is no provision for this in the virtio
net protocol.
Until recently our software implementation of UFO/IPv6 generated a new
ID, but this was a bug. Now we will use ID=0 for any UFO/IPv6 packet
passed through a tap, which is even worse.
Unfortunately there is no distinction between UFO/IPv4 and v6
features, so disable UFO on taps and virtio_net completely until we
have a proper solution.
We cannot depend on VM managers respecting the tap feature flags, so
keep accepting UFO packets but log a warning the first time we do
this.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Fixes: 916e4cf46d02 ("ipv6: reuse ip6_frag_id from ip6_ufo_append_data")
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 65e2892..2aeaa61 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -65,7 +65,7 @@
static const struct proto_ops macvtap_socket_ops;
#define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
- NETIF_F_TSO6 | NETIF_F_UFO)
+ NETIF_F_TSO6)
#define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
#define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG)
@@ -569,6 +569,8 @@
gso_type = SKB_GSO_TCPV6;
break;
case VIRTIO_NET_HDR_GSO_UDP:
+ pr_warn_once("macvtap: %s: using disabled UFO feature; please fix this program\n",
+ current->comm);
gso_type = SKB_GSO_UDP;
break;
default:
@@ -614,8 +616,6 @@
vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
else if (sinfo->gso_type & SKB_GSO_TCPV6)
vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
- else if (sinfo->gso_type & SKB_GSO_UDP)
- vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
else
BUG();
if (sinfo->gso_type & SKB_GSO_TCP_ECN)
@@ -950,9 +950,6 @@
if (arg & TUN_F_TSO6)
feature_mask |= NETIF_F_TSO6;
}
-
- if (arg & TUN_F_UFO)
- feature_mask |= NETIF_F_UFO;
}
/* tun/tap driver inverts the usage for TSO offloads, where
@@ -963,7 +960,7 @@
* When user space turns off TSO, we turn off GSO/LRO so that
* user-space will not receive TSO frames.
*/
- if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO))
+ if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6))
features |= RX_OFFLOADS;
else
features &= ~RX_OFFLOADS;
@@ -1064,7 +1061,7 @@
case TUNSETOFFLOAD:
/* let the user check for future flags */
if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
- TUN_F_TSO_ECN | TUN_F_UFO))
+ TUN_F_TSO_ECN))
return -EINVAL;
rtnl_lock();