[PATCH 3.17 023/319] drivers/net: Disable UFO through virtio

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ben Hutchings <ben@decadent.org.uk>

[ Upstream commit 3d0ad09412ffe00c9afa201d01effdb6023d09b4 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/macvtap.c    |   13 +++++--------
 drivers/net/tun.c        |   19 +++++++++++--------
 drivers/net/virtio_net.c |   24 ++++++++++++++----------
 3 files changed, 30 insertions(+), 26 deletions(-)

--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -65,7 +65,7 @@ static struct cdev macvtap_cdev;
 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 @@ static int macvtap_skb_from_vnet_hdr(str
 			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 @@ static void macvtap_skb_to_vnet_hdr(cons
 			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 @@ static int set_offload(struct macvtap_qu
 			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 @@ static int set_offload(struct macvtap_qu
 	 * 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 @@ static long macvtap_ioctl(struct file *f
 	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();
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -174,7 +174,7 @@ struct tun_struct {
 	struct net_device	*dev;
 	netdev_features_t	set_features;
 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
-			  NETIF_F_TSO6|NETIF_F_UFO)
+			  NETIF_F_TSO6)
 
 	int			vnet_hdr_sz;
 	int			sndbuf;
@@ -1149,8 +1149,18 @@ static ssize_t tun_get_user(struct tun_s
 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 			break;
 		case VIRTIO_NET_HDR_GSO_UDP:
+		{
+			static bool warned;
+
+			if (!warned) {
+				warned = true;
+				netdev_warn(tun->dev,
+					    "%s: using disabled UFO feature; please fix this program\n",
+					    current->comm);
+			}
 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 			break;
+		}
 		default:
 			tun->dev->stats.rx_frame_errors++;
 			kfree_skb(skb);
@@ -1251,8 +1261,6 @@ static ssize_t tun_put_user(struct tun_s
 				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 			else if (sinfo->gso_type & SKB_GSO_TCPV6)
 				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
-			else if (sinfo->gso_type & SKB_GSO_UDP)
-				gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 			else {
 				pr_err("unexpected GSO type: "
 				       "0x%x, gso_size %d, hdr_len %d\n",
@@ -1762,11 +1770,6 @@ static int set_offload(struct tun_struct
 				features |= NETIF_F_TSO6;
 			arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
 		}
-
-		if (arg & TUN_F_UFO) {
-			features |= NETIF_F_UFO;
-			arg &= ~TUN_F_UFO;
-		}
 	}
 
 	/* This gives the user a way to test for new features in future by
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -497,8 +497,17 @@ static void receive_buf(struct receive_q
 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 			break;
 		case VIRTIO_NET_HDR_GSO_UDP:
+		{
+			static bool warned;
+
+			if (!warned) {
+				warned = true;
+				netdev_warn(dev,
+					    "host using disabled UFO feature; please fix it\n");
+			}
 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 			break;
+		}
 		case VIRTIO_NET_HDR_GSO_TCPV6:
 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 			break;
@@ -885,8 +894,6 @@ static int xmit_skb(struct send_queue *s
 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
-		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
-			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 		else
 			BUG();
 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
@@ -1710,7 +1717,7 @@ static int virtnet_probe(struct virtio_d
 			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 
 		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
-			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
+			dev->hw_features |= NETIF_F_TSO
 				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
 		}
 		/* Individual feature bits: what can host handle? */
@@ -1720,11 +1727,9 @@ static int virtnet_probe(struct virtio_d
 			dev->hw_features |= NETIF_F_TSO6;
 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 			dev->hw_features |= NETIF_F_TSO_ECN;
-		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
-			dev->hw_features |= NETIF_F_UFO;
 
 		if (gso)
-			dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
+			dev->features |= dev->hw_features & NETIF_F_ALL_TSO;
 		/* (!csum && gso) case will be fixed by register_netdev() */
 	}
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
@@ -1764,8 +1769,7 @@ static int virtnet_probe(struct virtio_d
 	/* If we can receive ANY GSO packets, we must allocate large ones. */
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
-	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
-	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
+	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
 		vi->big_packets = true;
 
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
@@ -1965,9 +1969,9 @@ static struct virtio_device_id id_table[
 static unsigned int features[] = {
 	VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
 	VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
-	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
+	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_TSO6,
 	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
-	VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
+	VIRTIO_NET_F_GUEST_ECN,
 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
 	VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,