4.20-stable review patch. If anyone has any objections, please let me know.
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From: Willem de Bruijn willemb@google.com
[ Upstream commit 8c76e77f9069f10505c08e02646c3ee11ad79038 ]
The BPF flow dissector expects either skb->sk or skb->dev set on all skbs. Delay flow dissection until after skb->dev is set.
This requires calling from within an rcu read-side critical section. That is fine, see also the call from tun_xdp_one.
Fixes: d0e13a1488ad ("flow_dissector: lookup netns by skb->sk if skb->dev is NULL") Reported-by: Christian Borntraeger borntraeger@de.ibm.com 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 | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -1177,8 +1177,6 @@ static int tap_get_user_xdp(struct tap_q goto err_kfree; }
- skb_probe_transport_header(skb, ETH_HLEN); - /* Move network header to the right position for VLAN tagged packets */ if ((skb->protocol == htons(ETH_P_8021Q) || skb->protocol == htons(ETH_P_8021AD)) && @@ -1189,6 +1187,7 @@ static int tap_get_user_xdp(struct tap_q tap = rcu_dereference(q->tap); if (tap) { skb->dev = tap->dev; + skb_probe_transport_header(skb, ETH_HLEN); dev_queue_xmit(skb); } else { kfree_skb(skb);