From 027ab3b8ee5a1dcb7d0f61175b3fb0d0a8afe0f0 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Sun, 23 Oct 2016 21:32:47 -0700 Subject: [PATCH] netvsc: fix incorrect receive checksum offloading [ Upstream commit e52fed7177f74382f742c27de2cc5314790aebb6 ] The Hyper-V netvsc driver was looking at the incorrect status bits in the checksum info. It was setting the receive checksum unnecessary flag based on the IP header checksum being correct. The checksum flag is skb is about TCP and UDP checksum status. Because of this bug, any packet received with bad TCP checksum would be passed up the stack and to the application causing data corruption. The problem is reproducible via netcat and netem. This had a side effect of not doing receive checksum offload on IPv6. The driver was also also always doing checksum offload independent of the checksum setting done via ethtool. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/hyperv/netvsc_drv.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 3ba29fc80d05..c4d9653cae66 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -624,15 +624,18 @@ static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net, packet->total_data_buflen); skb->protocol = eth_type_trans(skb, net); - if (csum_info) { - /* We only look at the IP checksum here. - * Should we be dropping the packet if checksum - * failed? How do we deal with other checksums - TCP/UDP? - */ - if (csum_info->receive.ip_checksum_succeeded) + + /* skb is already created with CHECKSUM_NONE */ + skb_checksum_none_assert(skb); + + /* + * In Linux, the IP checksum is always checked. + * Do L4 checksum offload if enabled and present. + */ + if (csum_info && (net->features & NETIF_F_RXCSUM)) { + if (csum_info->receive.tcp_checksum_succeeded || + csum_info->receive.udp_checksum_succeeded) skb->ip_summed = CHECKSUM_UNNECESSARY; - else - skb->ip_summed = CHECKSUM_NONE; } if (vlan_tci & VLAN_TAG_PRESENT) -- 2.11.4.GIT