redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

net: fix bpf_xdp_adjust_head regression for generic-XDP 

When generic-XDP was moved to a later processing step by commit
458bf2f224 ("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: 458bf2f224 ("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>
alistair/sunxi64-5.4-dsi
Jesper Dangaard Brouer 2019-08-01 20:00:31 +02:00 committed by David S. Miller
parent 13978d1e73
commit 065af35547
1 changed files with 10 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
net/core/dev.c
View File

@ -4374,12 +4374,17 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb,
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.