gro: Fix bogus gso_size on the first fraglist entry

commit 622e0ca1cd4d459f5af4f2c65f4dc0dd823cb4c3 upstream.

When GRO produces fraglist entries, and the resulting skb hits
an interface that is incapable of TSO but capable of FRAGLIST,
we end up producing a bogus packet with gso_size non-zero.

This was reported in the field with older versions of KVM that
did not set the TSO bits on tuntap.

This patch fixes that.

Reported-by: Igor Zhang <yugzhang@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 2b5eb01f9e5d74fc33c590577e28f8a3e7d00761..283f4412847996317dc24f0c1f0e7aa7b617bcd4 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2730,6 +2730,7 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
        *NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p);
        skb_shinfo(nskb)->frag_list = p;
        skb_shinfo(nskb)->gso_size = pinfo->gso_size;
+       pinfo->gso_size = 0;
        skb_header_release(p);
        nskb->prev = p;