Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 11/54] l2tp: purge socket queues in the .destruct() callback | Date | Mon, 1 May 2017 14:31:18 -0700 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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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(-)
--- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -450,6 +450,10 @@ 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); @@ -488,9 +492,6 @@ static int pppol2tp_release(struct socke 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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