Patch-mainline: v5.16-rc7

Git-commit: 7e5cced9ca84df52d874aca6b632f930b3dc5bc6

References: git-fixes

From: Willem de Bruijn <willemb@google.com>

Date: Mon, 20 Dec 2021 09:49:01 -0500

Subject: [PATCH] net: accept UFOv6 packages in virtio_net_hdr_to_skb

Skb with skb->protocol 0 at the time of virtio_net_hdr_to_skb may have

a protocol inferred from virtio_net_hdr with virtio_net_hdr_set_proto.

Unlike TCP, UDP does not have separate types for IPv4 and IPv6. Type

VIRTIO_NET_HDR_GSO_UDP is guessed to be IPv4/UDP. As of the below

commit, UFOv6 packets are dropped due to not matching the protocol as

obtained from dev_parse_header_protocol.

Invert the test to take that L2 protocol field as starting point and

pass both UFOv4 and UFOv6 for VIRTIO_NET_HDR_GSO_UDP.

Fixes: 924a9bc362a5 ("net: check if protocol extracted by virtio_net_hdr_set_proto is correct")

Link: https://lore.kernel.org/netdev/CABcq3pG9GRCYqFDBAJ48H1vpnnX=41u+MhQnayF1ztLH4WX0Fw@mail.gmail.com/

Reported-by: Andrew Melnichenko <andrew@daynix.com>

Signed-off-by: Willem de Bruijn <willemb@google.com>

Link: https://lore.kernel.org/r/20211220144901.2784030-1-willemdebruijn.kernel@gmail.com

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Juergen Gross <jgross@suse.com>

---

 include/linux/virtio_net.h | 22 ++++++++++++++++++++--

 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h

index 04e87f4b9417..22dd48c82560 100644

--- a/include/linux/virtio_net.h

+++ b/include/linux/virtio_net.h

@@ -7,6 +7,21 @@

 #include <uapi/linux/udp.h>

 #include <uapi/linux/virtio_net.h>

+static inline bool virtio_net_hdr_match_proto(__be16 protocol, __u8 gso_type)

+{

+	switch (gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {

+	case VIRTIO_NET_HDR_GSO_TCPV4:

+		return protocol == cpu_to_be16(ETH_P_IP);

+	case VIRTIO_NET_HDR_GSO_TCPV6:

+		return protocol == cpu_to_be16(ETH_P_IPV6);

+	case VIRTIO_NET_HDR_GSO_UDP:

+		return protocol == cpu_to_be16(ETH_P_IP) ||

+		       protocol == cpu_to_be16(ETH_P_IPV6);

+	default:

+		return false;

+	}

+}

+

 static inline int virtio_net_hdr_set_proto(struct sk_buff *skb,

 					   const struct virtio_net_hdr *hdr)

 {

@@ -88,9 +103,12 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,

 			if (!skb->protocol) {

 				__be16 protocol = dev_parse_header_protocol(skb);

-				virtio_net_hdr_set_proto(skb, hdr);

-				if (protocol && protocol != skb->protocol)

+				if (!protocol)

+					virtio_net_hdr_set_proto(skb, hdr);

+				else if (!virtio_net_hdr_match_proto(protocol, hdr->gso_type))

 					return -EINVAL;

+				else

+					skb->protocol = protocol;

 			}

 retry:

 			if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,

-- 

2.35.3