Patch "l2tp: hold tunnel in pppol2tp_connect()" has been added to the 4.13-stable tree

Patch "l2tp: hold tunnel in pppol2tp_connect()" has been added to the 4.13-stable tree

[gregkh]

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

    l2tp: hold tunnel in pppol2tp_connect()

to the 4.13-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-tunnel-in-pppol2tp_connect.patch
and it can be found in the queue-4.13 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 foo@baz Wed Nov 15 17:25:34 CET 2017
From: Guillaume Nault <g.nault@alphalink.fr>
Date: Mon, 30 Oct 2017 17:58:58 +0100
Subject: l2tp: hold tunnel in pppol2tp_connect()

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


[ Upstream commit f9e56baf03f9d36043a78f16e3e8b2cfd211e09e ]

Use l2tp_tunnel_get() in pppol2tp_connect() to ensure the tunnel isn't
going to disappear while processing the rest of the function.

Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
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, 6 insertions(+), 1 deletion(-)

--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -584,6 +584,7 @@ static int pppol2tp_connect(struct socke
 	u32 tunnel_id, peer_tunnel_id;
 	u32 session_id, peer_session_id;
 	bool drop_refcnt = false;
+	bool drop_tunnel = false;
 	int ver = 2;
 	int fd;
 
@@ -652,7 +653,9 @@ static int pppol2tp_connect(struct socke
 	if (tunnel_id == 0)
 		goto end;
 
-	tunnel = l2tp_tunnel_find(sock_net(sk), tunnel_id);
+	tunnel = l2tp_tunnel_get(sock_net(sk), tunnel_id);
+	if (tunnel)
+		drop_tunnel = true;
 
 	/* Special case: create tunnel context if session_id and
 	 * peer_session_id is 0. Otherwise look up tunnel using supplied
@@ -781,6 +784,8 @@ out_no_ppp:
 end:
 	if (drop_refcnt)
 		l2tp_session_dec_refcount(session);
+	if (drop_tunnel)
+		l2tp_tunnel_dec_refcount(tunnel);
 	release_sock(sk);
 
 	return error;


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

queue-4.13/ppp-fix-race-in-ppp-device-destruction.patch
queue-4.13/l2tp-hold-tunnel-in-pppol2tp_connect.patch
queue-4.13/l2tp-check-ps-sock-before-running-pppol2tp_session_ioctl.patch