From 157f29152b61ca41809dd7ead29f5733adeced19 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 12 Sep 2024 08:56:19 -0700 Subject: netkit: Assign missing bpf_net_context MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit During the introduction of struct bpf_net_context handling for XDP-redirect, the netkit driver has been missed, which also requires it because NETKIT_REDIRECT invokes skb_do_redirect() which is accessing the per-CPU variables. Otherwise we see the following crash: BUG: kernel NULL pointer dereference, address: 0000000000000038 bpf_redirect() netkit_xmit() dev_hard_start_xmit() Set the bpf_net_context before invoking netkit_xmit() program within the netkit driver. Fixes: 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") Signed-off-by: Breno Leitao Acked-by: Daniel Borkmann Reviewed-by: Sebastian Andrzej Siewior Reviewed-by: Toke Høiland-Jørgensen Acked-by: Nikolay Aleksandrov Acked-by: Martin KaFai Lau Link: https://patch.msgid.link/20240912155620.1334587-1-leitao@debian.org Signed-off-by: Jakub Kicinski --- drivers/net/netkit.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/net/netkit.c') diff --git a/drivers/net/netkit.c b/drivers/net/netkit.c index 16789cd446e9..3f4187102e77 100644 --- a/drivers/net/netkit.c +++ b/drivers/net/netkit.c @@ -65,6 +65,7 @@ static struct netkit *netkit_priv(const struct net_device *dev) static netdev_tx_t netkit_xmit(struct sk_buff *skb, struct net_device *dev) { + struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx; struct netkit *nk = netkit_priv(dev); enum netkit_action ret = READ_ONCE(nk->policy); netdev_tx_t ret_dev = NET_XMIT_SUCCESS; @@ -72,6 +73,7 @@ static netdev_tx_t netkit_xmit(struct sk_buff *skb, struct net_device *dev) struct net_device *peer; int len = skb->len; + bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx); rcu_read_lock(); peer = rcu_dereference(nk->peer); if (unlikely(!peer || !(peer->flags & IFF_UP) || @@ -110,6 +112,7 @@ drop_stats: break; } rcu_read_unlock(); + bpf_net_ctx_clear(bpf_net_ctx); return ret_dev; } -- cgit v1.2.3