4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Willem de Bruijn willemb@google.com
[ 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 willemb@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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(-)
--- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -777,13 +777,16 @@ static ssize_t tap_put_user(struct tap_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) != --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1648,7 +1648,8 @@ static ssize_t tun_put_user(struct tun_s 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", --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1237,7 +1237,8 @@ static int xmit_skb(struct send_queue *s 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) --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -58,7 +58,8 @@ static inline int virtio_net_hdr_to_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_sk
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 && --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2046,7 +2046,7 @@ static int packet_rcv_vnet(struct msghdr 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 *s 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; }