From: Willem de Bruijn <will...@google.com> When pulling the NSH header in nsh_gso_segment, set the mac length based on the encapsulated packet type.
skb_reset_mac_len computes an offset to the network header, which here still points to the outer packet: > skb_reset_network_header(skb); > [...] > __skb_pull(skb, nsh_len); > skb_reset_mac_header(skb); // now mac hdr starts nsh_len == 8B after net hdr > skb_reset_mac_len(skb); // mac len = net hdr - mac hdr == (u16) -8 == 65528 > [..] > skb_mac_gso_segment(skb, ..) Link: http://lkml.kernel.org/r/CAF=yd-keactson4axiraxl8m7qas8gbbe1w09eziywvpbbu...@mail.gmail.com Reported-by: syzbot+7b9ed9872dab8c323...@syzkaller.appspotmail.com Fixes: c411ed854584 ("nsh: add GSO support") Signed-off-by: Willem de Bruijn <will...@google.com> --- net/nsh/nsh.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/nsh/nsh.c b/net/nsh/nsh.c index 9696ef96b719..1a30e165eeb4 100644 --- a/net/nsh/nsh.c +++ b/net/nsh/nsh.c @@ -104,7 +104,7 @@ static struct sk_buff *nsh_gso_segment(struct sk_buff *skb, __skb_pull(skb, nsh_len); skb_reset_mac_header(skb); - skb_reset_mac_len(skb); + skb->mac_len = proto == htons(ETH_P_TEB) ? ETH_HLEN : 0; skb->protocol = proto; features &= NETIF_F_SG; -- 2.18.0.203.gfac676dfb9-goog
