From 5320e035d7bbdade3755f90dc9b55ee542edc4d3 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Wed, 6 Jun 2018 11:23:01 -0400 Subject: [PATCH] net: in virtio_net_hdr only add VLAN_HLEN to csum_start if payload holds vlan [ Upstream commit fd3a88625844907151737fc3b4201676effa6d27 ] Tun, tap, virtio, packet and uml vector all use struct virtio_net_hdr to communicate packet metadata to userspace. For skbuffs with vlan, the first two return the packet as it may have existed on the wire, inserting the VLAN tag in the user buffer. Then virtio_net_hdr.csum_start needs to be adjusted by VLAN_HLEN bytes. Commit f09e2249c4f5 ("macvtap: restore vlan header on user read") added this feature to macvtap. Commit 3ce9b20f1971 ("macvtap: Fix csum_start when VLAN tags are present") then fixed up csum_start. Virtio, packet and uml do not insert the vlan header in the user buffer. When introducing virtio_net_hdr_from_skb to deduplicate filling in the virtio_net_hdr, the variant from macvtap which adds VLAN_HLEN was applied uniformly, breaking csum offset for packets with vlan on virtio and packet. Make insertion of VLAN_HLEN optional. Convert the callers to pass it when needed. Fixes: e858fae2b0b8f4 ("virtio_net: use common code for virtio_net_hdr and skb GSO conversion") Fixes: 1276f24eeef2 ("packet: use common code for virtio_net_hdr and skb GSO conversion") Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/tap.c | 5 ++++- drivers/net/tun.c | 3 ++- drivers/net/virtio_net.c | 3 ++- include/linux/virtio_net.h | 11 ++++------- net/packet/af_packet.c | 4 ++-- 5 files changed, 14 insertions(+), 12 deletions(-) diff --git a/drivers/net/tap.c b/drivers/net/tap.c index bfd4ded0a53f..773a3fea8f0e 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -777,13 +777,16 @@ static ssize_t tap_put_user(struct tap_queue *q, int total; if (q->flags & IFF_VNET_HDR) { + int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0; struct virtio_net_hdr vnet_hdr; + vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); if (iov_iter_count(iter) < vnet_hdr_len) return -EINVAL; if (virtio_net_hdr_from_skb(skb, &vnet_hdr, - tap_is_little_endian(q), true)) + tap_is_little_endian(q), true, + vlan_hlen)) BUG(); if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) != diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 3d9ad11e4f28..cb17ffadfc30 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1648,7 +1648,8 @@ static ssize_t tun_put_user(struct tun_struct *tun, return -EINVAL; if (virtio_net_hdr_from_skb(skb, &gso, - tun_is_little_endian(tun), true)) { + tun_is_little_endian(tun), true, + vlan_hlen)) { struct skb_shared_info *sinfo = skb_shinfo(skb); pr_err("unexpected GSO type: " "0x%x, gso_size %d, hdr_len %d\n", diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 9e93e7a5df7e..910c46b47769 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1237,7 +1237,8 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) hdr = skb_vnet_hdr(skb); if (virtio_net_hdr_from_skb(skb, &hdr->hdr, - virtio_is_little_endian(vi->vdev), false)) + virtio_is_little_endian(vi->vdev), false, + 0)) BUG(); if (vi->mergeable_rx_bufs) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index f144216febc6..9397628a1967 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -58,7 +58,8 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, struct virtio_net_hdr *hdr, bool little_endian, - bool has_data_valid) + bool has_data_valid, + int vlan_hlen) { memset(hdr, 0, sizeof(*hdr)); /* no info leak */ @@ -83,12 +84,8 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, if (skb->ip_summed == CHECKSUM_PARTIAL) { hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; - if (skb_vlan_tag_present(skb)) - hdr->csum_start = __cpu_to_virtio16(little_endian, - skb_checksum_start_offset(skb) + VLAN_HLEN); - else - hdr->csum_start = __cpu_to_virtio16(little_endian, - skb_checksum_start_offset(skb)); + hdr->csum_start = __cpu_to_virtio16(little_endian, + skb_checksum_start_offset(skb) + vlan_hlen); hdr->csum_offset = __cpu_to_virtio16(little_endian, skb->csum_offset); } else if (has_data_valid && diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 7806e166669a..4fe2e34522d6 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2046,7 +2046,7 @@ static int packet_rcv_vnet(struct msghdr *msg, const struct sk_buff *skb, return -EINVAL; *len -= sizeof(vnet_hdr); - if (virtio_net_hdr_from_skb(skb, &vnet_hdr, vio_le(), true)) + if (virtio_net_hdr_from_skb(skb, &vnet_hdr, vio_le(), true, 0)) return -EINVAL; return memcpy_to_msg(msg, (void *)&vnet_hdr, sizeof(vnet_hdr)); @@ -2313,7 +2313,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, if (do_vnet) { if (virtio_net_hdr_from_skb(skb, h.raw + macoff - sizeof(struct virtio_net_hdr), - vio_le(), true)) { + vio_le(), true, 0)) { spin_lock(&sk->sk_receive_queue.lock); goto drop_n_account; }