[PATCH 4.14 08/29] net: accept UFOv6 packages in virtio_net_hdr_to_skb

Greg Kroah-Hartman
2021-12-27T15:30:42Z

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

[ 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>
---
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 162761f72c142..f5876f7a2ab24 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(skb, &keys, 0)) {
--
2.34.1