6.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Breno Leitao <leitao@xxxxxxxxxx>
[ Upstream commit 157f29152b61ca41809dd7ead29f5733adeced19 ]
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 <leitao@xxxxxxxxxx>
Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Reviewed-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
Acked-by: Nikolay Aleksandrov <razor@xxxxxxxxxxxxx>
Acked-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
Link: https://patch.msgid.link/20240912155620.1334587-1-leitao@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/netkit.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/net/netkit.c b/drivers/net/netkit.c
index 16789cd446e9e..3f4187102e773 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 @@ static netdev_tx_t netkit_xmit(struct sk_buff *skb, struct net_device *dev)
break;
}
rcu_read_unlock();
+ bpf_net_ctx_clear(bpf_net_ctx);
return ret_dev;
}
--
2.43.0
