From: Jesper Dangaard Brouer <brouer@redhat.com>
To: sameehj@amazon.com
Cc: "Toshiaki Makita" <toshiaki.makita1@gmail.com>,
"Mao Wenan" <maowenan@huawei.com>,
"Toshiaki Makita" <toshiaki.makita1@gmail.com>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org, zorik@amazon.com,
akiyano@amazon.com, gtzalik@amazon.com,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Daniel Borkmann" <borkmann@iogearbox.net>,
"Alexei Starovoitov" <alexei.starovoitov@gmail.com>,
"John Fastabend" <john.fastabend@gmail.com>,
"Alexander Duyck" <alexander.duyck@gmail.com>,
"Jeff Kirsher" <jeffrey.t.kirsher@intel.com>,
"David Ahern" <dsahern@gmail.com>,
"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Lorenzo Bianconi" <lorenzo@kernel.org>,
"Saeed Mahameed" <saeedm@mellanox.com>,
steffen.klassert@secunet.com
Subject: [PATCH net-next 09/33] veth: adjust hard_start offset on redirect XDP frames
Date: Wed, 22 Apr 2020 18:08:06 +0200 [thread overview]
Message-ID: <158757168676.1370371.9335548837047528670.stgit@firesoul> (raw)
In-Reply-To: <158757160439.1370371.13213378122947426220.stgit@firesoul>
When native XDP redirect into a veth device, the frame arrives in the
xdp_frame structure. It is then processed in veth_xdp_rcv_one(),
which can run a new XDP bpf_prog on the packet. Doing so requires
converting xdp_frame to xdp_buff, but the tricky part is that
xdp_frame memory area is located in the top (data_hard_start) memory
area that xdp_buff will point into.
The current code tried to protect the xdp_frame area, by assigning
xdp_buff.data_hard_start past this memory. This results in 32 bytes
less headroom to expand into via BPF-helper bpf_xdp_adjust_head().
This protect step is actually not needed, because BPF-helper
bpf_xdp_adjust_head() already reserve this area, and don't allow
BPF-prog to expand into it. Thus, it is safe to point data_hard_start
directly at xdp_frame memory area.
Cc: Toshiaki Makita <toshiaki.makita1@gmail.com>
Fixes: 9fc8d518d9d5 ("veth: Handle xdp_frames in xdp napi ring")
Reported-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toshiaki Makita <toshiaki.makita1@gmail.com>
---
drivers/net/veth.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index aece0e5eec8c..d5691bb84448 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -564,13 +564,15 @@ static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
struct veth_stats *stats)
{
void *hard_start = frame->data - frame->headroom;
- void *head = hard_start - sizeof(struct xdp_frame);
int len = frame->len, delta = 0;
struct xdp_frame orig_frame;
struct bpf_prog *xdp_prog;
unsigned int headroom;
struct sk_buff *skb;
+ /* bpf_xdp_adjust_head() assures BPF cannot access xdp_frame area */
+ hard_start -= sizeof(struct xdp_frame);
+
rcu_read_lock();
xdp_prog = rcu_dereference(rq->xdp_prog);
if (likely(xdp_prog)) {
@@ -592,7 +594,6 @@ static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
break;
case XDP_TX:
orig_frame = *frame;
- xdp.data_hard_start = head;
xdp.rxq->mem = frame->mem;
if (unlikely(veth_xdp_tx(rq, &xdp, bq) < 0)) {
trace_xdp_exception(rq->dev, xdp_prog, act);
@@ -605,7 +606,6 @@ static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
goto xdp_xmit;
case XDP_REDIRECT:
orig_frame = *frame;
- xdp.data_hard_start = head;
xdp.rxq->mem = frame->mem;
if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
frame = &orig_frame;
@@ -629,7 +629,7 @@ static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
rcu_read_unlock();
headroom = sizeof(struct xdp_frame) + frame->headroom - delta;
- skb = veth_build_skb(head, headroom, len, 0);
+ skb = veth_build_skb(hard_start, headroom, len, 0);
if (!skb) {
xdp_return_frame(frame);
stats->rx_drops++;
next prev parent reply other threads:[~2020-04-22 16:08 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <158757160439.1370371.13213378122947426220.stgit@firesoul>
2020-04-22 16:07 ` [PATCH net-next 01/33] xdp: add frame size to xdp_buff Jesper Dangaard Brouer
2020-04-24 14:00 ` Toke Høiland-Jørgensen
2020-04-28 16:06 ` Jesper Dangaard Brouer
2020-04-22 16:07 ` [PATCH net-next 02/33] bnxt: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-22 16:07 ` [PATCH net-next 03/33] sfc: add XDP frame size Jesper Dangaard Brouer
2020-04-22 16:07 ` [PATCH net-next 04/33] mvneta: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-22 16:07 ` [PATCH net-next 05/33] net: netsec: Add support for XDP frame size Jesper Dangaard Brouer
2020-04-22 16:07 ` [PATCH net-next 06/33] net: XDP-generic determining " Jesper Dangaard Brouer
2020-04-24 14:03 ` Toke Høiland-Jørgensen
2020-04-22 16:07 ` [PATCH net-next 07/33] xdp: xdp_frame add member frame_sz and handle in convert_to_xdp_frame Jesper Dangaard Brouer
2020-04-24 14:04 ` Toke Høiland-Jørgensen
2020-04-25 3:24 ` Toshiaki Makita
2020-04-27 15:20 ` Jesper Dangaard Brouer
2020-04-22 16:08 ` [PATCH net-next 08/33] xdp: cpumap redirect use frame_sz and increase skb_tailroom Jesper Dangaard Brouer
2020-04-24 14:04 ` Toke Høiland-Jørgensen
2020-04-22 16:08 ` Jesper Dangaard Brouer [this message]
2020-04-24 14:05 ` [PATCH net-next 09/33] veth: adjust hard_start offset on redirect XDP frames Toke Høiland-Jørgensen
2020-04-22 16:08 ` [PATCH net-next 10/33] veth: xdp using frame_sz in veth driver Jesper Dangaard Brouer
2020-04-24 14:07 ` Toke Høiland-Jørgensen
2020-04-25 3:10 ` Toshiaki Makita
2020-04-22 16:08 ` [PATCH net-next 11/33] dpaa2-eth: add XDP frame size Jesper Dangaard Brouer
2020-04-22 16:08 ` [PATCH net-next 12/33] hv_netvsc: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-22 16:57 ` Haiyang Zhang
2020-04-22 16:08 ` [PATCH net-next 13/33] qlogic/qede: " Jesper Dangaard Brouer
2020-04-22 16:08 ` [PATCH net-next 14/33] net: ethernet: ti: add XDP frame size to driver cpsw Jesper Dangaard Brouer
2020-04-22 20:28 ` Grygorii Strashko
2020-04-22 16:08 ` [PATCH net-next 15/33] ena: add XDP frame size to amazon NIC driver Jesper Dangaard Brouer
2020-04-22 16:08 ` [PATCH net-next 16/33] mlx4: add XDP frame size and adjust max XDP MTU Jesper Dangaard Brouer
2020-04-22 16:08 ` [PATCH net-next 17/33] net: thunderx: add XDP frame size Jesper Dangaard Brouer
2020-04-22 16:08 ` [PATCH net-next 18/33] nfp: add XDP frame size to netronome driver Jesper Dangaard Brouer
2020-04-23 2:43 ` Jakub Kicinski
2020-04-22 16:08 ` [PATCH net-next 19/33] tun: add XDP frame size Jesper Dangaard Brouer
2020-04-27 5:51 ` Jason Wang
2020-05-06 20:30 ` Michael S. Tsirkin
2020-04-22 16:09 ` [PATCH net-next 20/33] vhost_net: also populate " Jesper Dangaard Brouer
2020-04-27 5:50 ` Jason Wang
2020-04-30 9:54 ` Jesper Dangaard Brouer
2020-05-06 6:43 ` Jason Wang
2020-04-22 16:09 ` [PATCH net-next 21/33] virtio_net: add XDP frame size in two code paths Jesper Dangaard Brouer
2020-04-27 7:21 ` Jason Wang
2020-04-27 14:32 ` Jesper Dangaard Brouer
2020-04-28 9:50 ` Jason Wang
2020-04-30 10:14 ` Jesper Dangaard Brouer
2020-05-06 6:38 ` Jason Wang
2020-04-22 16:09 ` [PATCH net-next 22/33] ixgbe: fix XDP redirect on archs with PAGE_SIZE above 4K Jesper Dangaard Brouer
2020-04-22 16:09 ` [PATCH net-next 23/33] ixgbe: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-27 19:51 ` Daniel Borkmann
2020-04-22 16:09 ` [PATCH net-next 24/33] ixgbevf: add XDP frame size to VF driver Jesper Dangaard Brouer
2020-04-22 16:09 ` [PATCH net-next 25/33] i40e: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-22 16:09 ` [PATCH net-next 26/33] ice: " Jesper Dangaard Brouer
2020-04-22 16:09 ` [PATCH net-next 27/33] xdp: for Intel AF_XDP drivers add XDP frame_sz Jesper Dangaard Brouer
2020-04-22 16:09 ` [PATCH net-next 28/33] mlx5: rx queue setup time determine frame_sz for XDP Jesper Dangaard Brouer
2020-04-25 0:58 ` Alexei Starovoitov
2020-04-27 20:22 ` Jesper Dangaard Brouer
2020-04-22 16:09 ` [PATCH net-next 29/33] xdp: allow bpf_xdp_adjust_tail() to grow packet size Jesper Dangaard Brouer
2020-04-24 14:09 ` Toke Høiland-Jørgensen
2020-04-27 19:01 ` Daniel Borkmann
2020-04-28 16:37 ` Jesper Dangaard Brouer
2020-04-28 19:36 ` Daniel Borkmann
2020-04-22 16:09 ` [PATCH net-next 30/33] xdp: clear grow memory in bpf_xdp_adjust_tail() Jesper Dangaard Brouer
2020-04-24 14:09 ` Toke Høiland-Jørgensen
2020-04-27 5:26 ` John Fastabend
2020-04-28 14:50 ` Jesper Dangaard Brouer
2020-04-22 16:09 ` [PATCH net-next 31/33] bpf: add xdp.frame_sz in bpf_prog_test_run_xdp() Jesper Dangaard Brouer
2020-04-22 16:10 ` [PATCH net-next 32/33] selftests/bpf: adjust BPF selftest for xdp_adjust_tail Jesper Dangaard Brouer
2020-04-22 16:10 ` [PATCH net-next 33/33] selftests/bpf: xdp_adjust_tail add grow tail tests Jesper Dangaard Brouer
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