gso: fix payload length when gso_size is zero

When gso_size reset to zero for the tail segment in skb_segment(), later
in ipv6_gso_segment(), __skb_udp_tunnel_segment() and gre_gso_segment()
we will get incorrect results (payload length, pcsum) for that segment.
inet_gso_segment() already has a check for gso_size before calculating
payload.

The issue was found with LTP vxlan & gre tests over ixgbe NIC.

Fixes: 07b26c9454a2 ("gso: Support partial splitting at the frag_list pointer")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index 416bb304a281..1859c473b21a 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -86,7 +86,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
                 greh = (struct gre_base_hdr *)skb_transport_header(skb);
                 pcsum = (__sum16 *)(greh + 1);
 
-                if (gso_partial) {
+                if (gso_partial && skb_is_gso(skb)) {
                         unsigned int partial_adj;
 
                         /* Adjust checksum to account for the fact that
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 97658bfc1b58..e360d55be555 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -120,7 +120,7 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
                  * will be using a length value equal to only one MSS sized
                  * segment instead of the entire frame.
                  */
-                if (gso_partial) {
+                if (gso_partial && skb_is_gso(skb)) {
                         uh->len = htons(skb_shinfo(skb)->gso_size +
                                         SKB_GSO_CB(skb)->data_offset +
                                         skb->head - (unsigned char *)uh);
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index cdb3728faca7..4a87f9428ca5 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -105,7 +105,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
 
         for (skb = segs; skb; skb = skb->next) {
                 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
-                if (gso_partial)
+                if (gso_partial && skb_is_gso(skb))
                         payload_len = skb_shinfo(skb)->gso_size +
                                       SKB_GSO_CB(skb)->data_offset +
                                       skb->head - (unsigned char *)(ipv6h + 1);