From: Jesper Dangaard Brouer brouer@redhat.com
[ Upstream commit 065af355470519bd184019a93ac579f22b036045 ]
When generic-XDP was moved to a later processing step by commit 458bf2f224f0 ("net: core: support XDP generic on stacked devices.") a regression was introduced when using bpf_xdp_adjust_head.
The issue is that after this commit the skb->network_header is now changed prior to calling generic XDP and not after. Thus, if the header is changed by XDP (via bpf_xdp_adjust_head), then skb->network_header also need to be updated again. Fix by calling skb_reset_network_header().
Fixes: 458bf2f224f0 ("net: core: support XDP generic on stacked devices.") Reported-by: Brandon Cazander brandon.cazander@multapplied.net Signed-off-by: Jesper Dangaard Brouer brouer@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/dev.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)
--- a/net/core/dev.c +++ b/net/core/dev.c @@ -4382,12 +4382,17 @@ static u32 netif_receive_generic_xdp(str
act = bpf_prog_run_xdp(xdp_prog, xdp);
+ /* check if bpf_xdp_adjust_head was used */ off = xdp->data - orig_data; - if (off > 0) - __skb_pull(skb, off); - else if (off < 0) - __skb_push(skb, -off); - skb->mac_header += off; + if (off) { + if (off > 0) + __skb_pull(skb, off); + else if (off < 0) + __skb_push(skb, -off); + + skb->mac_header += off; + skb_reset_network_header(skb); + }
/* check if bpf_xdp_adjust_tail was used. it can only "shrink" * pckt.