Re: [Intel-wired-lan] [PATCH net-next 1/2] igc: AF_XDP zero-copy metadata adjust breaks SKBs on XDP_PASS
From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Date: 2021-11-26 15:27:08
Also in:
intel-wired-lan, netdev
On Mon, Nov 15, 2021 at 09:36:25PM +0100, Jesper Dangaard Brouer wrote:
Driver already implicitly supports XDP metadata access in AF_XDP
zero-copy mode, as xsk_buff_pool's xp_alloc() naturally set xdp_buff
data_meta equal data.
This works fine for XDP and AF_XDP, but if a BPF-prog adjust via
bpf_xdp_adjust_meta() and choose to call XDP_PASS, then igc function
igc_construct_skb_zc() will construct an invalid SKB packet. The
function correctly include the xdp->data_meta area in the memcpy, but
forgot to pull header to take metasize into account.
Fixes: fc9df2a0b520 ("igc: Enable RX via AF_XDP zero-copy")
Signed-off-by: Jesper Dangaard Brouer <redacted>Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Great catch. Will take a look at other ZC enabled Intel drivers if they are affected as well. Thanks!
quoted hunk ↗ jump to hunk
--- drivers/net/ethernet/intel/igc/igc_main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index 8e448288ee26..76b0a7311369 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c@@ -2448,8 +2448,10 @@ static struct sk_buff *igc_construct_skb_zc(struct igc_ring *ring, skb_reserve(skb, xdp->data_meta - xdp->data_hard_start); memcpy(__skb_put(skb, totalsize), xdp->data_meta, totalsize); - if (metasize) + if (metasize) { skb_metadata_set(skb, metasize); + __skb_pull(skb, metasize); + } return skb; }_______________________________________________ Intel-wired-lan mailing list Intel-wired-lan@osuosl.org https://lists.osuosl.org/mailman/listinfo/intel-wired-lan