Patch "l2tp: hold session while sending creation notifications" has been added to the 4.9-stable tree

Patch "l2tp: hold session while sending creation notifications" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    l2tp: hold session while sending creation notifications

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     l2tp-hold-session-while-sending-creation-notifications.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 5e6a9e5a3554a5b3db09cdc22253af1849c65dff Mon Sep 17 00:00:00 2001
From: Guillaume Nault <g.nault@alphalink.fr>
Date: Fri, 31 Mar 2017 13:02:29 +0200
Subject: l2tp: hold session while sending creation notifications

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

commit 5e6a9e5a3554a5b3db09cdc22253af1849c65dff upstream.

l2tp_session_find() doesn't take any reference on the returned session.
Therefore, the session may disappear while sending the notification.

Use l2tp_session_get() instead and decrement session's refcount once
the notification is sent.

Fixes: 33f72e6f0c67 ("l2tp : multicast notification to the registered listeners")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/l2tp/l2tp_netlink.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -634,10 +634,12 @@ static int l2tp_nl_cmd_session_create(st
 			session_id, peer_session_id, &cfg);
 
 	if (ret >= 0) {
-		session = l2tp_session_find(net, tunnel, session_id);
-		if (session)
+		session = l2tp_session_get(net, tunnel, session_id, false);
+		if (session) {
 			ret = l2tp_session_notify(&l2tp_nl_family, info, session,
 						  L2TP_CMD_SESSION_CREATE);
+			l2tp_session_dec_refcount(session);
+		}
 	}
 
 out:


Patches currently in stable-queue which might be from g.nault@alphalink.fr are

queue-4.9/l2tp-take-a-reference-on-sessions-used-in-genetlink-handlers.patch
queue-4.9/l2tp-ensure-session-can-t-get-removed-during-pppol2tp_session_ioctl.patch
queue-4.9/l2tp-fix-race-in-l2tp_recv_common.patch
queue-4.9/l2tp-hold-session-while-sending-creation-notifications.patch
queue-4.9/l2tp-fix-duplicate-session-creation.patch