Commit e91793bb authored Mar 29, 2017 by Guillaume Nault Committed by David S. Miller Mar 29, 2017

l2tp: purge socket queues in the .destruct() callback



The Rx path may grab the socket right before pppol2tp_release(), but
nothing guarantees that it will enqueue packets before
skb_queue_purge(). Therefore, the socket can be destroyed without its
queues fully purged.

Fix this by purging queues in pppol2tp_session_destruct() where we're
guaranteed nothing is still referencing the socket.

Fixes: 9e9cb622 ("l2tp: fix userspace reception on plain L2TP sockets")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 94d7ee0b

net/l2tp/l2tp_ppp.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -450,6 +450,10 @@ static void pppol2tp_session_close(struct l2tp_session *session)
		static void pppol2tp_session_destruct(struct sock *sk)
		{
		struct l2tp_session *session = sk->sk_user_data;

		skb_queue_purge(&sk->sk_receive_queue);
		skb_queue_purge(&sk->sk_write_queue);

		if (session) {
		sk->sk_user_data = NULL;
		BUG_ON(session->magic != L2TP_SESSION_MAGIC);
		@@ -488,9 +492,6 @@ static int pppol2tp_release(struct socket *sock)
		l2tp_session_queue_purge(session);
		sock_put(sk);
		}
		skb_queue_purge(&sk->sk_receive_queue);
		skb_queue_purge(&sk->sk_write_queue);

		release_sock(sk);

		/* This will delete the session context via

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