Commit 621d5536 authored Dec 20, 2021 by Willem de Bruijn Committed by Greg Kroah-Hartman Dec 29, 2021

net: accept UFOv6 packages in virtio_net_hdr_to_skb

[ Upstream commit 7e5cced9ca84df52d874aca6b632f930b3dc5bc6 ]

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: Sasha Levin <sashal@kernel.org>

parent 0b01c51c

include/linux/virtio_net.h

+20 −2

Original line number	Diff line number	Diff line
		@@ -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);

		if (!protocol)
		virtio_net_hdr_set_proto(skb, hdr);
		if (protocol && protocol != skb->protocol)
		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,