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skmsg: Clear skb redirect pointer before dropping it 

When we drop skb inside sk_psock_skb_redirect(), we have to clear
its skb->_sk_redir pointer too, otherwise kfree_skb() would
misinterpret it as a valid skb->_skb_refdst and dst_release()
would eventually complain.

Fixes: e3526bb92a ("skmsg: Move sk_redir from TCP_SKB_CB to skb")
Reported-by: Jiang Wang <jiang.wang@bytedance.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210615021342.7416-5-xiyou.wangcong@gmail.com
This commit is contained in:
Cong Wang 2021-06-14 19:13:38 -07:00 committed by Daniel Borkmann
parent e00a5c331b
commit 30b9c54a70
1 changed files with 2 additions and 0 deletions
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2
net/core/skmsg.c
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@ -843,12 +843,14 @@ static void sk_psock_skb_redirect(struct sk_buff *skb)
* a socket that is in this state so we drop the skb.
*/
if (!psock_other || sock_flag(sk_other, SOCK_DEAD)) {
skb_bpf_redirect_clear(skb);
kfree_skb(skb);
return;
}
spin_lock_bh(&psock_other->ingress_lock);
if (!sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) {
spin_unlock_bh(&psock_other->ingress_lock);
skb_bpf_redirect_clear(skb);
kfree_skb(skb);
return;
}