[4.4,20/43] l2tp: purge socket queues in the .destruct() callback
diff mbox series

Message ID 20170501212600.352918204@linuxfoundation.org
State New, archived
Headers show
  • 4.4.66-stable review
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Commit Message

Greg KH May 1, 2017, 9:27 p.m. UTC
4.4-stable review patch.  If anyone has any objections, please let me know.


From: Guillaume Nault <g.nault@alphalink.fr>

[ Upstream commit e91793bb615cf6cdd59c0b6749fe173687bb0947 ]

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: 9e9cb6221aa7 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 net/l2tp/l2tp_ppp.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff mbox series

--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -467,6 +467,10 @@  static void pppol2tp_session_close(struc
 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);
@@ -505,9 +509,6 @@  static int pppol2tp_release(struct socke
-	skb_queue_purge(&sk->sk_receive_queue);
-	skb_queue_purge(&sk->sk_write_queue);
 	/* This will delete the session context via