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Commit fa4c7fb2 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'sock_hold-misuses' 



Eric Dumazet says:

====================
net: fix possible sock_hold() misuses

skb_complete_wifi_ack() and skb_complete_tx_timestamp() currently
call sock_hold() on sockets that might have transitioned their sk_refcnt
to zero already.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 146d8fef 9ac25fc0

net/core/skbuff.c

+16 −14
Original line number Diff line number Diff line
@@ -3828,14 +3828,15 @@ void skb_complete_tx_timestamp(struct sk_buff *skb, 
	if (!skb_may_tx_timestamp(sk, false))

		return;



	/* take a reference to prevent skb_orphan() from freeing the socket */

	sock_hold(sk);



	/* Take a reference to prevent skb_orphan() from freeing the socket,

	 * but only if the socket refcount is not zero.

	 */

	if (likely(atomic_inc_not_zero(&sk->sk_refcnt))) {

		*skb_hwtstamps(skb) = *hwtstamps;

		__skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND);



		sock_put(sk);

	}

}

EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);



void __skb_tstamp_tx(struct sk_buff *orig_skb,
@@ -3893,7 +3894,7 @@ void skb_complete_wifi_ack(struct sk_buff *skb, bool acked) 
{

	struct sock *sk = skb->sk;

	struct sock_exterr_skb *serr;

	int err;

	int err = 1;



	skb->wifi_acked_valid = 1;

	skb->wifi_acked = acked;
@@ -3903,14 +3904,15 @@ void skb_complete_wifi_ack(struct sk_buff *skb, bool acked) 
	serr->ee.ee_errno = ENOMSG;

	serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;



	/* take a reference to prevent skb_orphan() from freeing the socket */

	sock_hold(sk);



	/* Take a reference to prevent skb_orphan() from freeing the socket,

	 * but only if the socket refcount is not zero.

	 */

	if (likely(atomic_inc_not_zero(&sk->sk_refcnt))) {

		err = sock_queue_err_skb(sk, skb);

		sock_put(sk);

	}

	if (err)

		kfree_skb(skb);



	sock_put(sk);

}

EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);