Commit 1581a6c1 authored by Cong Wang's avatar Cong Wang Committed by Daniel Borkmann
Browse files

skmsg: Teach sk_psock_verdict_apply() to return errors 



Currently sk_psock_verdict_apply() is void, but it handles some
error conditions too. Its caller is impossible to learn whether
it succeeds or fails, especially sk_psock_verdict_recv().

Make it return int to indicate error cases and propagate errors
to callers properly.

Fixes: ef565928 ("bpf, sockmap: Allow skipping sk_skb parser program")
Signed-off-by: default avatarCong Wang <cong.wang@bytedance.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Acked-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210615021342.7416-7-xiyou.wangcong@gmail.com
parent 0cf6672b

net/core/skmsg.c

+14 −9
Original line number Diff line number Diff line
@@ -824,7 +824,7 @@ int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock, 
}

EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);



static void sk_psock_skb_redirect(struct sk_buff *skb)

static int sk_psock_skb_redirect(struct sk_buff *skb)

{

	struct sk_psock *psock_other;

	struct sock *sk_other;
@@ -835,7 +835,7 @@ static void sk_psock_skb_redirect(struct sk_buff *skb) 
	 */

	if (unlikely(!sk_other)) {

		kfree_skb(skb);

		return;

		return -EIO;

	}

	psock_other = sk_psock(sk_other);

	/* This error indicates the socket is being torn down or had another
@@ -845,19 +845,20 @@ static void sk_psock_skb_redirect(struct sk_buff *skb) 
	if (!psock_other || sock_flag(sk_other, SOCK_DEAD)) {

		skb_bpf_redirect_clear(skb);

		kfree_skb(skb);

		return;

		return -EIO;

	}

	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;

		return -EIO;

	}



	skb_queue_tail(&psock_other->ingress_skb, skb);

	schedule_work(&psock_other->work);

	spin_unlock_bh(&psock_other->ingress_lock);

	return 0;

}



static void sk_psock_tls_verdict_apply(struct sk_buff *skb, struct sock *sk, int verdict)
@@ -894,14 +895,15 @@ int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb) 
}

EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);



static void sk_psock_verdict_apply(struct sk_psock *psock,

				   struct sk_buff *skb, int verdict)

static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,

				  int verdict)

{

	struct sock *sk_other;

	int err = -EIO;

	int err = 0;



	switch (verdict) {

	case __SK_PASS:

		err = -EIO;

		sk_other = psock->sk;

		if (sock_flag(sk_other, SOCK_DEAD) ||

		    !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
@@ -934,13 +936,15 @@ static void sk_psock_verdict_apply(struct sk_psock *psock, 
		}

		break;

	case __SK_REDIRECT:

		sk_psock_skb_redirect(skb);

		err = sk_psock_skb_redirect(skb);

		break;

	case __SK_DROP:

	default:

out_free:

		kfree_skb(skb);

	}



	return err;

}



static void sk_psock_write_space(struct sock *sk)
@@ -1107,7 +1111,8 @@ static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb, 
		ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));

		skb->sk = NULL;

	}

	sk_psock_verdict_apply(psock, skb, ret);

	if (sk_psock_verdict_apply(psock, skb, ret) < 0)

		len = 0;

out:

	rcu_read_unlock();

	return len;