Commit f7613120 authored Apr 25, 2018 by Nikita V. Shirokov Committed by Daniel Borkmann Apr 26, 2018

bpf: fix xdp_generic for bpf_adjust_tail usecase



When bpf_adjust_tail was introduced for generic xdp, it changed skb's tail
pointer, so it was pointing to the new "end of the packet". However skb's
len field wasn't properly modified, so on the wire ethernet frame had
original (or even bigger, if adjust_head was used) size. This diff is
fixing this.

Fixes: 198d83bb (" bpf: make generic xdp compatible w/ bpf_xdp_adjust_tail")
Signed-off-by: Nikita V. Shirokov <tehnerd@tehnerd.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent 9b984a20

net/core/dev.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -4057,8 +4057,10 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb,
		* pckt.
		*/
		off = orig_data_end - xdp.data_end;
		if (off != 0)
		if (off != 0) {
		skb_set_tail_pointer(skb, xdp.data_end - xdp.data);
		skb->len -= off;
		}

		switch (act) {
		case XDP_REDIRECT:

Admin message